Orthopaedic Surgery - Brachial Plexus Birth Palsy

Basics

Brachial plexus birth palsy is caused by stretching or disruption of the brachial plexus during delivery, usually from excessive upward or downward traction on the infant’s arm, shoulder, or neck.

The resulting weakness produces muscle imbalance around the upper extremity. Over time, this imbalance can lead to secondary muscle contractures, joint deformity, and altered growth of the affected bones.

Although the nerve injury occurs at birth, mild cases may not become obvious until the infant begins actively using the affected arm.

Classification

Brachial plexus birth palsy can be classified according to the nerve roots involved.

Type I, or Erb palsy, primarily involves the upper plexus, classically the C5–C6 roots, although adjacent root involvement may occur.

Type II, or total brachial plexus palsy, involves essentially the entire plexus from approximately C5 through T1 and may be referred to as an Erb-Duchenne-Klumpke palsy.

Type III, or Klumpke palsy, predominantly affects the lower plexus, especially C8–T1.

Synonyms

Other names include birth palsy, obstetric palsy, Erb palsy, and Klumpke palsy.

General Prevention

Some cases may be reduced by identifying pregnancies at high risk for difficult delivery.

Cesarean delivery may occasionally be considered when there is marked fetal macrosomia or significant cephalopelvic disproportion.

However, not every brachial plexus birth injury can be predicted or prevented.

Epidemiology

The reported incidence is approximately 1.5 cases per 1,000 live births.

The incidence has declined over time, likely because of improvements in obstetric management.

Erb palsy is considerably more common than Klumpke palsy, occurring approximately four times as often.

No major difference in incidence has been recognized between male and female infants.

Shoulder Dislocation

Approximately 8% of affected infants may develop posterior shoulder dislocation before the age of 1 year.

This usually develops as a secondary consequence of persistent muscle imbalance and internal rotation contracture.

Risk Factors

Important risk factors include fetal malposition, shoulder dystocia, cephalopelvic disproportion, high birth weight, maternal diabetes, and forceps-assisted delivery.

Among these, shoulder dystocia represents one of the most important obstetric risk factors.

Pathophysiology

The degree of nerve injury can range from temporary stretching to complete disruption or avulsion.

The lesion may occur close to the cervical spinal cord, where the nerve roots exit the spinal canal, or farther distally within the neck and shoulder.

More proximal injuries, particularly root avulsions, generally carry a worse prognosis.

Secondary Muscle Imbalance

Persistent denervation leads to muscle weakness and atrophy.

Because some muscle groups recover better than others, an imbalance develops across the shoulder, elbow, wrist, or hand.

Over time, this can cause joint contracture, abnormal joint development, deformity, and altered growth of the affected extremity.

Etiology of Erb Palsy

Erb palsy most commonly results from downward traction on the shoulder or arm, or lateral traction on the neck during a difficult delivery.

This mechanism preferentially stretches the upper roots of the brachial plexus.

Etiology of Klumpke Palsy

Klumpke palsy is associated with upward traction on the arm, producing injury to the lower brachial plexus.

Both patterns can occur during difficult extraction at delivery.

Associated Conditions

Brachial plexus birth palsy is associated with high birth weight and gestational diabetes, both of which increase the likelihood of difficult delivery and shoulder dystocia.

Diagnosis

Signs and Symptoms

The most common finding is reduced spontaneous use of the affected upper extremity.

The arm may rest in a characteristic internally rotated position.

Loss of active shoulder abduction and external rotation is common in upper plexus injuries.

Shoulder Position

In Erb palsy, the shoulder is often held in internal rotation and adduction.

The infant may be unable to fully abduct or externally rotate the arm.

Persistent internal rotation may eventually become fixed because of muscle contracture.

Elbow Findings

Elbow flexion may be weak or absent when the biceps is affected.

As the child grows, an elbow flexion contracture may develop because of muscle imbalance and altered use.

Muscle Atrophy

Chronic denervation may result in visible atrophy of affected muscles.

The involved extremity may also become smaller in both length and girth compared with the opposite side.

Sensory Findings

Sensory loss may occur in more extensive plexus injuries.

Complete plexus palsy is more likely to produce significant sensory impairment than an isolated upper plexus lesion.

The condition itself is generally not painful.

Horner Syndrome

A Horner syndrome may occur in lower plexus injuries, particularly Klumpke palsy.

Its presence suggests injury involving the lower cervical or upper thoracic sympathetic pathways and may indicate a more severe lesion.

History

Reduced movement of the affected arm may be apparent immediately after birth.

In milder cases, the problem may not be recognized until the infant begins using the arm and caregivers notice reduced shoulder movement, weakness, or developing contracture.

Physical Examination

Clinical examination is the primary method of diagnosis.

The infant should be assessed systematically for shoulder, elbow, wrist, and hand function.

The examiner should observe spontaneous movement and stimulate individual muscle groups when possible.

Palpation

The clavicle, proximal humerus, and ribs should be palpated for tenderness.

This helps identify fractures that may mimic a brachial plexus palsy by causing painful pseudoparalysis.

Sensory Examination

Sensation can be assessed by observing the infant’s response to light touch or gentle pinch.

The findings should be compared with those of the opposite arm.

Motor Examination

Function of the major muscle groups of the shoulder, elbow, forearm, wrist, and hand should be evaluated through stimulation and observation.

Particular attention should be paid to recovery of the deltoid and biceps, because their return is useful in determining prognosis and the possible need for surgery.

Erb Palsy Examination

In Erb palsy, the shoulder is typically internally rotated and demonstrates limited or absent abduction and external rotation.

Elbow flexion may also be weak.

A developing internal rotation contracture may be the earliest clinical sign of secondary glenohumeral dysplasia.

Klumpke Palsy Examination

Klumpke palsy predominantly affects the lower plexus.

The major deficits involve finger flexion, intrinsic hand muscle function, and fine motor control.

The hand may appear weak or clawed in severe cases.

Imaging

Plain Radiographs

Radiographs are often obtained shortly after birth to exclude other injuries causing decreased arm movement.

These include clavicle fracture and proximal humeral fracture, which can coexist with brachial plexus birth palsy.

Imaging in Older Children

In children with persistent shoulder imbalance who are being considered for late reconstruction, radiographs and CT can help evaluate the shape, congruity, and deformity of the glenohumeral joint.

These studies are particularly useful in children older than approximately 4 years.

Ultrasound

Ultrasound is useful during the first year of life.

It can be used both as a screening study and as a dynamic examination of glenohumeral alignment, humeral head position, and joint congruity.

It is particularly helpful because much of the infant shoulder is not yet ossified.

MRI

MRI provides detailed evaluation of the glenohumeral joint and surrounding soft tissues.

It can demonstrate posterior subluxation, dysplasia, joint deformity, muscle imbalance, and other structural abnormalities.

Electromyography

Electromyography may be considered when there is no meaningful clinical return of deltoid or biceps function by approximately 3–6 months of age.

Evidence of absent or poor reinnervation may support consideration of nerve reconstruction.

However, EMG can sometimes overestimate recovery in proximal muscles and must be interpreted together with the clinical examination.

Cervical Myelography

Cervical myelography may help determine the level and severity of nerve injury.

The presence of meningoceles or pseudomeningoceles at the cervical root level may indicate root avulsion from the spinal cord.

Root avulsion carries a poor prognosis and may require a different surgical strategy.

Motor Nerve Conduction Studies

Comparative motor nerve conduction studies may help select infants who are candidates for brachial plexus surgery.

These studies may be performed during the first several weeks of life, approximately 10–60 days after birth.

An axonal viability index can be calculated by comparing compound muscle action potential amplitudes between the affected and unaffected limbs.

Differential Diagnosis

Clavicle Fracture

A clavicle fracture can cause an infant to stop moving the arm because movement is painful.

Unlike brachial plexus palsy, the clavicle is usually tender to palpation, and some shoulder movement may still be present.

Radiographs usually confirm the diagnosis.

Proximal Humeral Physeal Fracture

A proximal humeral physeal injury can produce similar pseudoparalysis.

Tenderness is localized over the proximal humerus.

Because the proximal humerus is poorly ossified at birth, the injury may not initially be visible on plain radiographs.

Ultrasound or MRI can be diagnostic, and repeat radiographs after 7–10 days may demonstrate healing changes.

Septic Arthritis of the Shoulder

Septic arthritis may also present with reduced arm movement.

The infant may exhibit pseudoparalysis because movement is painful.

Fever can be minimal or absent in newborns, so infection should remain in the differential when there is pain, irritability, swelling, or systemic concern.

Treatment

General Measures

Initial treatment consists primarily of observation and maintenance of passive range of motion.

Parents should be instructed to stretch the infant’s arm several times each day according to guidance from an occupational or physical therapist.

Specialist Referral

Infants with suspected brachial plexus birth palsy should be referred to a pediatric orthopaedic or peripheral nerve specialist experienced in this condition.

Management decisions can be complex and depend heavily on serial assessment of neurologic recovery.

Spontaneous Recovery

Approximately 80% of affected infants recover spontaneously by 1 year of age.

Because of this high rate of natural recovery, immediate surgery is not required in most newborns.

Continued follow-up is essential to identify infants who fail to recover sufficiently.

Splinting

Routine splinting is generally unnecessary during the initial period.

The emphasis is instead placed on maintaining joint flexibility through gentle passive movement and stretching.

Activity

No general activity restrictions are necessary.

Normal spontaneous use of the extremity should be encouraged as function returns.

Parents should continue passive range-of-motion exercises to prevent contracture.

Occupational and Physical Therapy

Therapists play an important role in teaching parents how to perform stretching safely.

They also help identify early contractures, monitor functional progress, and encourage developmentally appropriate use of the affected arm.

Shoulder Stretching

Particular attention should be given to maintaining shoulder external rotation and abduction.

Loss of passive external rotation may signal developing internal rotation contracture and glenohumeral dysplasia.

Botulinum Toxin

Botulinum toxin A may be injected into overactive internal rotator muscles in selected patients.

It can temporarily reduce muscle imbalance and may assist in maintaining shoulder reduction or delaying more invasive surgery.

Nerve Repair and Reconstruction

When meaningful function does not return during the first several months of life, microsurgical nerve reconstruction may be considered.

Procedures may include direct nerve repair, nerve grafting, or nerve transfer, depending on the lesion.

The exact timing remains controversial but is often considered when recovery is inadequate by approximately 3–6 months.

Timing of Nerve Surgery

Nerve reconstruction is generally most useful when performed relatively early.

Very delayed reconstruction becomes less effective because denervated muscles progressively lose their capacity for meaningful reinnervation.

Root Avulsion

When nerve roots have been avulsed from the spinal cord, direct grafting from the injured root may not be possible.

Alternative nerve transfers or reconstructive strategies may therefore be required.

Tendon Transfers

Tendon transfers may be performed later in childhood when neurologic recovery has plateaued but useful muscles remain available for transfer.

These procedures aim to restore muscle balance and improve specific movements.

Shoulder Tendon Transfers

In young children without advanced fixed glenohumeral dysplasia, tendon transfers may be used to improve external rotation and abduction of the shoulder.

The goal is to restore a more balanced shoulder and improve function.

Release of Internal Rotators

Tight internal rotator muscles may require surgical release when contracture limits external rotation.

This may be combined with tendon transfer or other reconstructive procedures.

Humeral Osteotomy

In older children with established glenohumeral dysplasia or fixed dislocation, a humeral rotational osteotomy may be used.

This procedure repositions the arm into a more functional externally rotated orientation.

It does not restore the normal joint but can significantly improve hand positioning and function.

Restoration of Elbow Flexion

Several muscle transfer procedures may be used to restore elbow flexion.

One option is transfer of the latissimus dorsi, although the choice depends on available muscle function and the specific pattern of weakness.

Wrist and Finger Reconstruction

Tendon transfers for wrist and finger function are less frequently required.

They may be considered in selected children with persistent lower plexus weakness and functional hand deficits.

Follow-Up

Serial clinical assessment is essential throughout infancy and early childhood.

The child should be evaluated for return of motor function, maintenance of passive range of motion, development of contracture, shoulder alignment, and progression of secondary deformity.

Indications for Referral

Any infant with suspected brachial plexus birth palsy should be evaluated by a specialist familiar with obstetric plexus injuries.

This condition requires expertise in pediatric nerve recovery, shoulder development, therapy, and reconstructive surgery.

Prognosis

Approximately 80% of infants recover spontaneously to a substantial degree.

Many of the remaining patients can gain useful function through nerve reconstruction, tendon transfer, osteotomy, or other reconstructive procedures.

Long-Term Function

Even when children adapt well and participate in most activities, residual functional limitations may persist into adolescence.

These may include weakness, restricted shoulder motion, altered limb position, or difficulty with certain sports and overhead activities.

Complications

Important complications include contracture of the shoulder, elbow, or wrist; persistent muscle weakness; sensory loss; reduced growth of the affected extremity; and shoulder subluxation or dislocation.

Growth Disturbance

The affected arm may become smaller in length and circumference because of chronic denervation, reduced muscle activity, and altered loading.

The degree of discrepancy depends on injury severity and recovery.

Glenohumeral Dysplasia

Persistent internal rotation imbalance can progressively alter development of the glenoid and humeral head.

This may result in posterior subluxation, joint dysplasia, or fixed dislocation if not recognized and treated.

Patient Monitoring

The infant should generally be reassessed approximately every 2–3 months during the early period of recovery.

Follow-up should document return of shoulder and elbow function, passive joint motion, hand function, and signs of secondary deformity.

Serial examination guides the timing of electrodiagnostic testing, imaging, and possible surgical intervention.

Orthopaedic Surgery - Boxer’s Fracture

Basics

A boxer’s fracture refers to a fracture through the neck of the ring or small-finger metacarpal, typically with volar angulation or displacement of the metacarpal head.

It is one of the most frequently encountered hand injuries in the emergency department and usually occurs after striking a hard object, such as a wall or another person, with a closed fist.

When the injury occurs during a physical altercation, the patient should also be evaluated for other traumatic injuries.

Metacarpal Angulation

Some degree of metacarpal neck angulation is normal.

For example, normal metacarpal neck angulation may be approximately 15°, whereas a boxer’s fracture may demonstrate substantially greater volar angulation.

Marked angulation may result in loss of the normal prominence of the knuckle.

Jewelry Removal

All rings and other jewelry should ideally be removed from the injured hand before significant swelling develops and before radiographs are obtained.

If a ring is present on the injured digit and removal is too painful, a digital block or hematoma block may be considered before attempting removal.

Epidemiology

Boxer’s fractures are among the most common hand injuries evaluated in emergency departments.

They occur considerably more often in males than females, with an incidence approximately five times higher in males.

The highest incidence is seen in males aged 10–19 years, followed by males aged 20–29 years.

Incidence

Metacarpal neck fractures of this type account for approximately 10% of all hand fractures.

Risk Factors

Important risk factors include physical altercations, punching a hard surface with a closed fist, recurrent fighting behavior, boxing, and mixed martial arts.

Activities that repeatedly expose the MCP region to direct impact increase the likelihood of injury.

Etiology

The typical mechanism is a direct axial or dorsal force transmitted through the knuckle of a clenched fist.

The fracture usually develops through the metacarpal neck.

The pull of the interosseous muscles contributes to the characteristic apex-dorsal fracture angulation, which corresponds clinically to volar displacement of the metacarpal head.

Effect of Soft-Tissue Forces

The interosseous muscles and surrounding soft tissues influence the position of the fracture fragments.

Shortening of the collateral ligaments may also contribute to an MCP joint flexion posture.

These deforming forces explain why metacarpal neck fractures commonly angulate after injury.

Associated Neurovascular Injury

In severely displaced fractures, the digital neurovascular bundles located on either side of the metacarpal head may be injured.

Neurovascular status should therefore be carefully documented in all significantly displaced injuries.

Fight-Bite Injury

A particularly important associated injury is a fight bite, which occurs when the dorsum of the MCP joint contacts another person’s tooth.

The tooth can create a small laceration that penetrates deeply into the extensor mechanism or MCP joint.

Such injuries require urgent recognition because they can lead to serious infection, including septic arthritis.

Importance of Injury History

Patients injured during a fight may be reluctant to disclose the exact mechanism.

A small wound over the MCP joint should therefore raise concern for a possible human bite even when the initial history is unclear.

Extensor Mechanism Injury

When substantial angulation or displacement is present, the overlying extensor mechanism may also be damaged.

Extensor tendon injury should be considered when there is weakness, abnormal tendon tracking, or difficulty extending the affected finger.

Diagnosis

Signs and Symptoms

Patients typically present with pain and tenderness over the involved metacarpal head or neck.

Swelling and bruising may be present.

The normal knuckle prominence may appear flattened or depressed compared with the opposite hand.

Physical Examination

The dorsal skin should be examined carefully for puncture wounds, abrasions, lacerations, or evidence of an open fracture.

This is particularly important when the injury followed punching another person.

A small dorsal wound should not be assumed to be superficial.

Assessment of Rotational Alignment

Rotational deformity is clinically more important than modest angular deformity.

Rotation is best assessed by flexing the MCP and PIP joints while keeping the DIP joint extended.

The fingers should point toward a common area near the scaphoid tubercle without crossing or overlapping.

Finger Cascade

When the patient flexes the fingers, the digits should form a smooth and symmetric cascade.

Scissoring or overlap of one finger over another suggests malrotation and is an indication for specialist assessment and often operative treatment.

Knuckle Depression

With sufficient volar displacement of the metacarpal head, the normal dorsal prominence of the affected knuckle becomes less visible.

Some residual loss of knuckle contour may remain even after successful healing.

Imaging

Plain Radiographs

Standard radiographic evaluation includes posteroanterior, lateral, and oblique views of the hand.

These views define the fracture location, degree of displacement, angulation, comminution, and possible associated injury.

Measuring Angulation

The degree of volar angulation is most accurately assessed on the lateral radiograph.

The amount of angulation helps guide decisions regarding observation, reduction, or surgery.

MRI

MRI is not routinely required for an uncomplicated boxer’s fracture.

It may be considered if there is concern for significant injury to the extensor mechanism or neurovascular structures that cannot be adequately assessed clinically.

Differential Diagnosis

Conditions that may resemble or accompany a boxer’s fracture include MCP joint dislocation, extensor mechanism injury, fracture of the base of the proximal phalanx, transverse metacarpal shaft fracture, and articular fracture of the metacarpal head.

Careful examination and appropriate radiographs help distinguish these injuries.

Treatment

Open Fracture or Fight Bite

Any associated open fracture or fight-bite injury should be treated as a potentially contaminated wound.

These injuries require intravenous antibiotics and urgent surgical irrigation and debridement.

Failure to recognize a penetrating human bite may lead to deep infection or septic arthritis.

Indications for Hand-Surgery Referral

Referral to a hand surgeon is appropriate when there is malrotation, severe comminution, major angulation, open injury, tendon injury, neurovascular compromise, or significant uncertainty regarding stability.

Nonoperative Treatment

Closed fractures without malrotation can often be treated nonoperatively.

For the ring finger, fractures with less than approximately 30° of volar angulation may often be accepted.

For the small finger, up to approximately 40° of volar angulation may be acceptable in selected patients.

Ulnar Gutter Splint

Stable fractures within acceptable alignment can be immobilized in an ulnar gutter splint or cast.

The hand is generally positioned in the intrinsic-plus position, with MCP flexion and appropriate positioning of the interphalangeal joints.

This helps maintain alignment and reduce stiffness.

Buddy Taping

The injured digit may also be buddy-taped to the adjacent finger beneath the splint or cast.

This helps control rotational alignment during healing.

Indications for Closed Reduction

Closed reduction is considered when volar angulation exceeds acceptable limits.

Reduction may also be required when deformity significantly affects function or finger alignment.

Analgesia for Reduction

Reduction can be performed after appropriate local anesthesia, such as a hematoma block or ulnar nerve block.

Children, highly anxious patients, or patients unable to tolerate manipulation may require procedural sedation.

Jahss Reduction Maneuver

A commonly used reduction technique is the Jahss maneuver.

The MCP and PIP joints of the injured finger are flexed to approximately 90°.

A dorsally directed force is then applied along the proximal phalanx while counterpressure is placed over the metacarpal shaft to correct the angulation.

Contemporary Nonoperative Approaches

More recent evidence suggests that, in many uncomplicated boxer’s fractures without malrotation, formal reduction and rigid casting may not provide superior outcomes compared with functional treatment using a soft wrap or less restrictive support.

Treatment should therefore be individualized according to fracture alignment, stability, symptoms, and patient demands.

Physical Therapy

After approximately 4–6 weeks of immobilization, hand therapy may be started when clinically appropriate.

Both active and passive range-of-motion exercises can be used to restore movement at the MCP and PIP joints.

The goal is to prevent stiffness and regain grip function.

Medication

Pain is usually managed with a combination of acetaminophen and NSAIDs, provided there are no contraindications.

A hematoma block may also be used during acute fracture manipulation in the emergency department or clinic.

Surgical Management

Surgery may be required for significant malrotation, severe comminution, unacceptable angulation, open fractures, or unstable injuries.

Some patients may also request correction of a marked cosmetic loss of knuckle contour, although cosmetic concerns alone should be weighed against operative risks.

Fixation Methods

Operative fixation can be achieved using various combinations of Kirschner wires, screws, or other internal fixation techniques.

Stable fixation may allow earlier controlled motion and reduce the risk of stiffness.

Follow-Up

Most boxer’s fractures heal uneventfully.

Clinical and radiographic follow-up is used to confirm maintenance of alignment and progression toward union.

Prognosis

The prognosis is generally very good.

Most patients experience only temporary loss of motion and hand function.

A mild residual depression of the affected knuckle is common and usually has little effect on hand performance.

Healing Time

Clinical healing usually occurs within approximately 6 weeks.

Strength and full motion may continue to improve after fracture union.

Delayed Presentation

Delayed presentation is relatively common because some patients underestimate the injury or are reluctant to explain the circumstances.

If the fracture is already healing and there is no significant malrotation, functional deficit, or unacceptable deformity, nonoperative treatment may still be appropriate.

Complications

Potential complications include loss of reduction, infection in an open fracture, stiffness, extensor tendon injury, and injury to the digital neurovascular bundles.

Patients undergoing surgical fixation may occasionally require later hardware removal.

Loss of Reduction

Fracture alignment may change during the early healing period.

This is one reason that follow-up examination and radiographs are important, particularly when the initial fracture was substantially displaced.

Infection

Infection is primarily a concern in open fractures and fight-bite injuries.

Deep infection can involve the tendon, MCP joint, or bone and may result in significant long-term hand dysfunction if treatment is delayed.

Patient Monitoring

Repeat radiographs are commonly obtained approximately 1 week after injury to confirm maintenance of alignment.

Further radiographs may be obtained at roughly 2-week intervals until clinical healing, depending on the stability and treatment method.

Clinical monitoring should also assess rotation, motion, tenderness, skin condition, and neurovascular status.

Boxer’s Knuckle

A boxer’s knuckle should not be confused with a boxer’s fracture.

Boxer’s knuckle refers to rupture of the sagittal band over the MCP joint, leading to instability or subluxation of the extensor tendon.

The tendon may displace radially or ulnarly during finger motion.

Clinical Features of Boxer’s Knuckle

Patients may describe painful snapping or popping of the extensor tendon over the knuckle during active or passive motion.

Pain is often reproduced when attempting to extend the MCP joint against resistance while the interphalangeal joints are held extended.

Imaging of Boxer’s Knuckle

Because sagittal band injuries do not usually produce abnormalities on plain radiographs, MRI may be required to confirm the diagnosis and define associated soft-tissue injury.

Management of Boxer’s Knuckle

Suspected sagittal band rupture should be referred to a hand surgeon.

Some injuries can be managed with appropriate splinting, whereas others require operative repair, particularly when extensor tendon instability is persistent or severe.

Orthopaedic Surgery - Boutonniere Deformity

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Basics

Boutonniere deformity is characterized by flexion of the proximal interphalangeal joint (PIPJ) together with hyperextension of the distal interphalangeal joint (DIPJ).

The deformity develops as a consequence of injury or failure of the central slip of the extensor mechanism.

It may occur after acute trauma or develop gradually in association with inflammatory disease such as rheumatoid arthritis.

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General Prevention

The main preventive measure is appropriate medical control of rheumatoid arthritis, which can reduce chronic synovitis and subsequent attrition of the central slip.

Traumatic cases are not always preventable, but early recognition and treatment of a central slip injury can reduce the risk of progression to a fixed deformity.

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Risk Factors

The most important medical risk factor is rheumatoid arthritis.

Chronic inflammation of the PIP joint can weaken and gradually damage the central slip, eventually producing the characteristic deformity.

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Etiology

Boutonniere deformity results from a central slip injury.

The central slip may fail because of direct rupture, gradual attenuation, or avulsion from its bony insertion.

Inflammatory synovitis of the PIP joint, particularly in rheumatoid arthritis, can also cause attritional failure of the central slip.

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Pathophysiology

The central slip normally extends the PIP joint.

When it is disrupted, the PIP joint begins to fall into flexion.

As the deformity progresses, the extensor mechanism migrates proximally and volarly relative to the PIP joint.

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Lateral Band Migration

Stretching or disruption of the triangular ligament allows the lateral bands to move volarly around the sides of the PIP joint.

Once the lateral bands subluxate below the axis of rotation of the PIP joint, they act as flexors rather than extensors at that joint.

This further reinforces the PIP flexion deformity.

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DIP Hyperextension

As the extensor mechanism migrates proximally, increased tension is transmitted distally through the lateral bands and terminal tendon.

This produces the characteristic hyperextension deformity of the DIP joint.

The combined pattern of PIP flexion and DIP hyperextension creates the classic boutonniere appearance.

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Diagnosis

History

The history may reveal either a chronic inflammatory process or an acute traumatic injury.

Patients with rheumatoid arthritis may describe a slowly progressive deformity.

In traumatic cases, there is often a history of sudden hyperflexion or direct injury to the PIP joint, followed by immediate difficulty actively extending the joint.

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Signs and Symptoms

The classic clinical appearance consists of PIP joint flexion with DIP joint hyperextension.

In early central slip injury, the deformity may not yet be fully developed.

Patients may initially present only with swelling, pain, and an extensor lag at the PIP joint.

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Physical Examination

Examination should determine whether the deformity is flexible or fixed.

Active and passive motion of both the PIP and DIP joints should be assessed.

The integrity of the central slip and lateral bands can be further evaluated using specialized clinical tests.

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Elson Test

The Elson test is commonly used to confirm a central slip injury.

The PIP joint is flexed to approximately 90°, and the patient is asked to extend the PIP joint against resistance.

The examiner simultaneously assesses the behavior of the DIP joint.

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Elson Test Interpretation

If the central slip remains intact, the DIP joint remains relatively supple or lax during resisted PIP extension.

If the central slip is ruptured, the extensor force is redirected through the lateral bands and terminal tendon.

As a result, the DIP joint becomes rigid or stiff in extension during the maneuver.

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Boyes Test

The Boyes test evaluates whether the lateral bands have become shortened or contracted.

The PIP joint is held in full extension while the patient is asked to actively flex the DIP joint.

If the DIP joint flexes fully, the extensor mechanism remains relatively supple.

If active DIP flexion is limited, contracted lateral bands are likely present.

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Limitations of the Boyes Test

The Boyes test may be negative during the acute phase because significant lateral band contracture has not yet developed.

It becomes more useful in chronic deformity when soft-tissue shortening is established.

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Laboratory Tests

No laboratory study is required to diagnose an isolated boutonniere deformity.

Laboratory investigations may be appropriate only when an underlying systemic inflammatory disorder, such as rheumatoid arthritis, is suspected or already known.

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Imaging

Plain Radiographs

Radiographs are useful for identifying associated structural abnormalities.

They can help exclude a bony avulsion fracture, joint dislocation, or degenerative or inflammatory arthritis.

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Radiographic Technique

Imaging should include the entire involved ray so that the metacarpophalangeal joint, PIP joint, and DIP joint can all be evaluated.

This is especially useful when there is concern for more extensive trauma or underlying arthropathy.

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Differential Diagnosis

The main differential diagnosis is pseudoboutonniere deformity.

This condition also produces inability to fully extend the PIP joint, but the mechanism is different.

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Pseudoboutonniere Deformity

Pseudoboutonniere deformity usually follows a hyperextension injury of the PIP joint.

The problem results from scarring or adhesions involving the volar plate and flexor structures rather than central slip disruption.

Unlike true boutonniere deformity, the DIP joint remains functionally normal and does not develop the characteristic hyperextension pattern.

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Treatment

Acute Injuries

Acute central slip injuries are generally treated with the PIP joint held continuously in full extension for approximately 6 weeks.

During this period, the DIP joint should remain free so that active motion can be performed.

This allows the central slip to heal while minimizing stiffness of the distal joint.

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DIP Motion During Splinting

Active DIP flexion and extension exercises are important while the PIP joint remains immobilized.

These exercises help maintain mobility of the lateral bands and reduce the risk of adhesions or contracture.

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Transition After Initial Immobilization

After approximately 6 weeks of continuous PIP extension splinting, patients typically transition to night splinting.

Progressive PIP joint motion is then introduced.

The amount and pace of motion should be advanced gradually to avoid recurrent deformity.

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Chronic Injuries

Chronic boutonniere deformity should first be assessed for passive correctability.

If full passive PIP extension can still be achieved with stretching or progressive splinting, treatment can often proceed similarly to that used for an acute injury.

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Fixed Chronic Deformity

If the deformity is fixed, serial splinting or casting may be required to gradually restore passive PIP extension before definitive treatment.

Surgery is generally reserved for patients in whom splinting fails or who have a meaningful functional deficit.

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Surgical Expectations

Surgical treatment of chronic boutonniere deformity has guarded results.

Complete correction of the extensor lag should not always be expected.

Because of this, surgery is usually considered only when the deformity produces substantial functional impairment.

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Activity

Heavy lifting and sports activities should be avoided until healing is adequate.

Premature loading or repeated flexion stress may disrupt healing of the central slip and lead to recurrent deformity.

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Occupational Therapy

Occupational or hand therapy plays an important role in management.

Treatment may include custom splinting, stretching, edema control, and progressive motion exercises.

Therapy is particularly important in chronic cases and after surgery.

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Acute Central Slip Injury With Bony Avulsion

When the central slip injury includes a bony avulsion fragment, treatment may involve fracture fixation, splinting, or temporary joint pinning in full extension.

Immobilization is generally maintained for approximately 6 weeks.

The exact approach depends on the size and displacement of the fragment and the stability of the joint.

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Acute Central Slip Injury Without Bony Avulsion

When no fracture is present, many injuries can be treated with extension splinting alone.

In selected cases, temporary joint pinning may be used.

Direct repair of the central slip, including fixation with a suture anchor, may be considered when the tendon has been clearly disrupted and operative treatment is appropriate.

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Open Injuries

Open central slip injuries require irrigation and debridement because of the risk of contamination.

Definitive repair or fixation is then performed as indicated.

Temporary pinning of the PIP joint in extension may be used to protect the repair.

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Chronic Passively Correctable Deformity

A chronic deformity that can still be fully corrected passively may be treated in a manner similar to an acute injury.

Approximately 6 weeks of extension splinting or joint pinning may allow soft-tissue rebalancing.

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Terminal Tendon Tenotomy

In selected chronic cases, a terminal tendon tenotomy may be performed.

The purpose is to reduce excessive extension force at the DIP joint and redirect more of the extensor force toward the PIP joint.

This can improve the balance of the extensor mechanism.

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Fixed Contracture With Tight Lateral Bands

When a fixed PIP flexion contracture is accompanied by shortened lateral bands, treatment often begins with serial casting or progressive splinting.

The goal is to restore passive PIP extension.

Once full extension is achieved, treatment can then proceed using principles similar to those for an acute boutonniere injury.

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Fixed Contracture With Volar Plate or Collateral Tightness

If the deformity includes contracture of the volar plate or collateral ligaments, surgical release of the joint contracture may be required.

Soft-tissue rebalancing may then be performed, sometimes in a staged fashion.

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Boutonniere Deformity With PIP Arthrosis

When a fixed boutonniere deformity is associated with substantial PIP joint arthritis, reconstruction of the extensor mechanism alone may not provide adequate pain relief or function.

In such cases, treatment may require PIP joint arthrodesis or arthroplasty.

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Follow-Up

Conservative treatment generally requires at least 12 weeks of follow-up to ensure that splinting and rehabilitation are completed appropriately.

Patients treated surgically require regular postoperative review to monitor healing, alignment, motion, and recurrence.

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Indications for Referral

Referral to a hand or orthopaedic specialist is appropriate for an acute central slip rupture, especially when the diagnosis is uncertain or a bony avulsion is present.

Referral is also appropriate for a chronic boutonniere deformity that produces significant functional impairment.

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Prognosis

The prognosis is generally better when the injury is recognized and treated early.

Chronic fixed deformities have a more guarded outcome.

Even after surgery, some degree of residual PIP extensor lag may persist.

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Complications

Potential complications include recurrent boutonniere deformity, loss of PIP flexion, and development of a mallet-type deformity at the DIP joint.

Stiffness may also result from prolonged immobilization or chronic joint contracture.

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Recurrent Deformity

Recurrence can occur if the central slip fails to heal adequately or if the PIP joint is mobilized too aggressively.

Continued nighttime splinting and gradual rehabilitation may help reduce this risk.

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Limited PIP Flexion

Prolonged extension splinting or surgical scarring may lead to reduced PIP flexion.

Therapy should therefore balance protection of the central slip with preservation of joint mobility.

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DIP Complications

Alteration of the extensor mechanism can occasionally produce a mallet-type deformity at the DIP joint.

This may occur particularly after certain reconstructive procedures or if distal extensor balance becomes abnormal.

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Patient Monitoring

Patients should be monitored closely for recurrent PIP flexion, increasing DIP hyperextension, loss of motion, or persistent extensor lag.

Early detection of recurrent deformity allows adjustment of splinting or rehabilitation before the deformity becomes fixed.

Orthopaedic Surgery - Bite to the Hand

Basics

Bite injuries to the hand are common and potentially serious. They may occur directly, such as from a dog, cat, or intentional human bite, or indirectly through a clenched-fist injury.

If these wounds are not recognized and treated appropriately, they can lead to significant morbidity involving the soft tissues, tendons, joints, and bones of the hand.

Clenched-Fist Injury

The classic indirect human bite injury, commonly called a “fight bite” or “clenched-fist injury,” occurs when a closed fist strikes another person’s teeth.

The injury most commonly affects the skin over a metacarpophalangeal (MCP) joint.

Although the external wound may appear small and harmless, the underlying damage may be extensive.

Deep Structural Injury

A tooth can penetrate the skin and injure the extensor tendon, joint capsule, or MCP joint itself.

Deep structural involvement has been reported in a substantial proportion of clenched-fist injuries.

Because the fist is flexed at the time of impact, the skin wound and deeper injury may not remain aligned when the fingers are subsequently extended.

Hidden Nature of Fight-Bite Wounds

When the injured finger is returned to an extended position, the skin shifts relative to the underlying tendon and joint.

As a result, the deeper injury may lie proximal to the visible skin laceration.

This can make the wound appear more superficial than it actually is and contributes to delayed diagnosis.

Synonyms

Common synonyms include clenched-fist injury and fight bite.

General Prevention

Patients should be advised to avoid unnecessary contact with unfamiliar or potentially aggressive animals and to avoid fistfighting.

The complications of clenched-fist injuries can be reduced by recognizing them early as serious wounds and initiating prompt irrigation, debridement, and appropriate antibiotic therapy.

Epidemiology

Bite injuries to the hand account for a large number of emergency department visits.

Approximately 330,000 emergency visits annually in the United States have been attributed to hand bites.

More than half of the population is estimated to experience an animal bite at some point in life, with many occurring during childhood.

Dog Bites

Approximately 4.5 million dog bites occur annually in the United States.

Dog bites may produce crushing injury, puncture wounds, lacerations, fractures, or tendon damage.

Although infection is possible, the infection rate is generally lower than that associated with cat bites.

Human Bites

Human bite injuries are less common than animal bites, and their true incidence is difficult to determine.

Some patients with fight bites do not initially disclose that the injury occurred during an altercation, which can delay diagnosis and appropriate treatment.

Risk Factors

Risk factors include alcohol misuse, fighting, exposure to unfamiliar animals, and delayed presentation for treatment.

Cat bites have a particularly high risk of infection because their sharp, narrow teeth can penetrate deeply into tissue.

Approximately 30–50% of cat bites may become infected, whereas dog bites have a lower infection rate.

Etiology

Common mechanisms include fistfights, dog bites, cat bites, and bites from other mammals.

The mechanism is important because different bite types cause different patterns of tissue damage and expose the patient to different organisms.

Associated Injuries

Hand bites may be associated with fractures, extensor tendon lacerations, joint capsule penetration, and retained foreign material such as tooth fragments.

Infectious complications may include cellulitis, abscess formation, septic tenosynovitis, septic arthritis, osteomyelitis, and systemic sepsis.

Diagnosis

Signs and Symptoms

The most obvious finding is usually a puncture wound or laceration of the hand.

Swelling and erythema may develop around the injury.

If infection occurs, cellulitis or lymphangitis may spread beyond the original wound.

Tendon Injury

If the extensor tendon has been injured, the patient may have difficulty extending the affected finger.

However, apparent finger extension does not completely exclude extensor injury because the intrinsic muscles can sometimes extend the proximal interphalangeal joint even when part of the extensor mechanism has been disrupted.

Symptoms

Patients may report pain at the wound, along the affected digit or ray, or around the adjacent MCP joint.

Hand function may be reduced, with difficulty gripping objects or moving an individual finger.

Pain and swelling that progressively worsen after the initial injury suggest developing infection.

History

The history should identify whether the wound resulted from a human bite, animal bite, or clenched-fist impact against another person’s mouth.

The clinician should ask about increasing erythema, swelling, pain, drainage, fever, and reduced hand function.

Immunocompromising conditions should also be identified because they increase the risk and severity of infection.

Delayed Presentation

Patients with clenched-fist injuries may minimize or conceal how the injury occurred.

Some may also fail to appreciate the seriousness of a small dorsal hand wound.

Delayed presentation is associated with a higher rate of infection, tissue destruction, joint damage, and poor functional outcome.

Physical Examination

The hand should be examined carefully for every puncture or laceration.

Special attention should be paid to wounds over the third and fourth MCP joints, which are common locations for clenched-fist injuries.

Even a small wound in this area should be considered potentially deep until proven otherwise.

Neurovascular Examination

Motor, sensory, and vascular function should be assessed in the entire hand and in each individual digit.

Capillary refill, pulse examination when appropriate, sensation, and active movement should be documented before treatment.

Examination in the Injured Position

When a clenched-fist injury is suspected, the patient should be asked to make a fist if tolerated.

Flexing the MCP joint may realign the superficial wound with the underlying tendon or joint injury and improve visualization of the true depth of penetration.

Extensor Mechanism Assessment

The extensor tendons should be examined carefully.

Because the intrinsic muscles can contribute to extension of the proximal interphalangeal joint, a patient may appear to have preserved extension despite injury to the central slip or more proximal extensor tendon.

Individual tendon function should therefore be tested systematically.

Laboratory Tests

Laboratory evaluation may include a white blood cell count, erythrocyte sedimentation rate, and C-reactive protein when infection is suspected.

These tests can assist in assessing and monitoring inflammatory activity but do not replace clinical examination.

Wound Cultures

When operative debridement is required, cultures should preferably be obtained from deep tissue specimens rather than superficial swabs.

Tissue cultures generally provide more meaningful information regarding the causative organisms.

Imaging

Plain Radiographs

Radiographs of the hand should be obtained when a significant bite injury is suspected.

They can identify fractures, bone impaction, retained tooth fragments, or other foreign bodies.

Delayed Imaging Findings

In patients presenting later, radiographs may demonstrate changes associated with osteomyelitis.

Bone destruction, periosteal reaction, or other abnormalities may indicate progression of infection beyond the soft tissues.

Ultrasound

Ultrasound can be useful for detecting fluid collections or abscesses.

It may also assist in evaluating selected soft-tissue abnormalities when the physical examination is uncertain.

Differential Diagnosis

The differential diagnosis includes a simple superficial laceration and a retained foreign body.

However, apparently minor wounds over the MCP joint after an altercation should always raise concern for deeper bite injury.

Treatment

Tetanus Prophylaxis

Tetanus immunization status should be reviewed in every patient.

If immunization is not up to date, appropriate tetanus-containing vaccination should be administered.

Patients with an incomplete prior vaccination series may also require tetanus immune globulin, depending on the wound and immunization history.

Rabies Considerations

Rabies exposure should be assessed according to the animal involved and the circumstances of the bite.

In the United States, rabies is most commonly associated with animals such as bats, raccoons, skunks, and foxes.

When significant exposure has occurred and the animal cannot immediately be confirmed to be free of rabies, appropriate post-exposure prophylaxis should be considered.

Irrigation and Debridement

The most important early treatment is aggressive irrigation and debridement.

The goal is to remove bacteria, devitalized tissue, contaminated material, and retained foreign bodies.

Copious irrigation with normal saline is commonly performed initially.

Wound Exploration

The wound may need to be extended surgically to determine its true depth.

In clenched-fist injuries, careful exploration is particularly important to assess the extensor tendon, joint capsule, cartilage, and MCP joint.

Failure to identify joint penetration can result in septic arthritis.

Wound Management

After adequate irrigation and debridement, deeper structures may be loosely covered as necessary.

The wound is generally left open rather than primarily sutured, particularly when contamination or infection is present.

Packing and regular dressing changes may be used depending on the wound.

Immobilization and Elevation

The hand should initially be immobilized and elevated.

This decreases soft-tissue stress, swelling, and pain while the acute wound is being monitored.

Prolonged immobilization should be avoided once the infection is controlled because stiffness can develop rapidly.

Antibiotic Prophylaxis

Because hand bites carry a substantial infection risk, prophylactic antibiotics are generally recommended.

Amoxicillin-clavulanate is commonly used as a first-line oral agent when the patient is not allergic.

A typical prophylactic course lasts approximately 5–7 days, depending on the injury and clinical circumstances.

Follow-Up After Initial Treatment

The wound should be reassessed early, commonly within approximately 24 hours.

If packing has been used, it can be removed or changed at this visit.

Warm soaks and local wound care may then be initiated when appropriate.

Management of Established Infection

If infection is present, repeat irrigation and debridement may be necessary.

Patients with significant infection may require hospital admission and intravenous antibiotic therapy.

Septic arthritis, deep-space infection, tendon sheath infection, or systemic illness requires particularly aggressive management.

Physical Therapy

Formal therapy is usually unnecessary during the immediate acute phase.

However, once the wound is stable and infection is controlled, finger range-of-motion exercises should begin relatively early, often within the first week.

Early motion helps prevent stiffness, particularly at the MCP joints.

Common Organisms in Human Bites

The human mouth contains numerous bacterial species.

Common organisms associated with human bite wounds include Eikenella corrodens and streptococcal species, along with staphylococci and anaerobic organisms.

Because the flora are polymicrobial, antibiotic coverage should address both aerobic and anaerobic bacteria.

Common Organisms in Animal Bites

Animal bite infections may involve Pasteurella species, Staphylococcus aureus, streptococci, Bacteroides, and other anaerobic organisms.

Pasteurella is particularly associated with cat and dog bites.

First-Line Oral Antibiotic

Amoxicillin-clavulanate provides broad coverage against many organisms encountered in both human and animal bites.

It is therefore commonly selected as first-line oral therapy in patients who can tolerate penicillin-class antibiotics.

Intravenous Antibiotics

Clinically apparent deep infection may require intravenous therapy.

An agent such as ampicillin-sulbactam may be used empirically before culture results are available.

Treatment should subsequently be adjusted according to culture and sensitivity results.

Blood-Borne Viral Transmission

Although uncommon, human bites involving blood exposure can potentially transmit hepatitis B, hepatitis C, or HIV.

The risk depends on whether blood was present in the mouth or wound and on the infectious status of the individuals involved.

Appropriate exposure assessment should therefore be performed when significant blood contact has occurred.

Hepatitis B Prophylaxis

Hepatitis B vaccination status should be reviewed after a human bite involving blood exposure.

An accelerated vaccination schedule or other post-exposure measures may be considered according to the patient’s immunity and exposure risk.

Surgical Management

Surgical irrigation and debridement involve removing contaminated and nonviable tissue and thoroughly cleaning infected spaces.

All potentially involved structures should be assessed during exploration.

Joint Involvement

If the joint capsule has been penetrated, formal joint irrigation and debridement are required.

This is essential to reduce the risk of septic arthritis and subsequent cartilage destruction.

Cultures During Surgery

Deep cultures should be obtained intraoperatively before definitive antibiotic adjustment whenever possible.

Tissue specimens are preferred because they more accurately represent the organisms responsible for deep infection.

Wound Closure

Bite wounds requiring operative treatment are generally left open and managed with dressing changes rather than closed primarily.

Delayed closure may be considered later when contamination and infection have resolved.

Tendon Reconstruction

Extensor tendon injuries or other structures requiring definitive reconstruction are often not repaired immediately if active infection is present.

The initial priority is controlling infection.

Definitive tendon repair or reconstruction can be addressed after the wound has become clean and infection has resolved.

Follow-Up

Close follow-up is essential.

The wound should be reassessed early to ensure that swelling, erythema, pain, and drainage are improving rather than worsening.

Hand function and neurovascular status should also be monitored.

Prognosis

The prognosis is generally good when bite injuries are recognized and treated early.

Prompt irrigation, debridement, antibiotics, and appropriate follow-up can prevent most serious complications.

Late presentation substantially worsens the prognosis.

Delayed Presentation

Patients presenting very late, particularly after more than approximately 8 days, have a higher risk of severe infection, tissue loss, joint destruction, and even amputation.

This emphasizes the importance of early recognition and treatment.

Complications

The most important complication is infection, which may involve the soft tissues, tendon sheaths, joints, or bone.

Other complications include stiffness, persistent pain, tendon injury, loss of motion, and reduced hand function.

Septic Arthritis

Penetration of a bite wound into the MCP joint may result in septic arthritis.

Without prompt treatment, infection can rapidly damage the articular cartilage and lead to chronic pain, stiffness, and loss of function.

Osteomyelitis

Untreated or delayed infection can spread into bone and produce osteomyelitis.

This complication may require prolonged antibiotic treatment and additional surgical debridement.

Stiffness

Hand stiffness may develop because of pain, edema, infection, prolonged immobilization, or tendon and joint injury.

Early supervised range-of-motion exercises are therefore important once the wound is sufficiently stable.

Patient Monitoring

If packing is used, it should generally be removed or changed at approximately 24 hours.

The patient should continue to be followed until the wound is healing satisfactorily and there is no evidence of progressive infection.

When there is uncertainty regarding wound stability or infection, reassessment at 24–48-hour intervals is appropriate.

Orthopaedic Surgery - Bisphosphonates

Basics

Bisphosphonates are medications that reduce bone resorption by suppressing osteoclast activity.

They are commonly used in the treatment of osteoporosis, metastatic bone disease, Paget disease of bone, and malignancy-associated hypercalcemia.

Bisphosphonates can be administered either orally or intravenously, depending on the clinical indication, patient factors, and specific medication being used.

Oral Bisphosphonates

Commonly used oral bisphosphonates include alendronate, risedronate, and ibandronate.

These agents are frequently prescribed for osteoporosis and other conditions characterized by excessive bone turnover.

Because oral bisphosphonates can irritate the upper gastrointestinal tract, specific administration instructions are important.

Intravenous Bisphosphonates

Frequently used intravenous agents include zoledronate and pamidronate.

Intravenous therapy is particularly useful in patients with metastatic bone disease, multiple myeloma, malignancy-related hypercalcemia, or those who cannot tolerate oral treatment.

Epidemiology and Clinical Use

Patients with metastatic bone disease or multiple myeloma often have increased osteoclast-mediated bone destruction.

As a result, most such patients receive therapy that suppresses osteoclast function, either with a bisphosphonate or another antiresorptive agent such as denosumab, which inhibits osteoclast formation, function, and survival.

High Bone-Turnover Disorders

Bisphosphonates are also commonly used in disorders associated with increased bone turnover.

These include osteoporosis, Paget disease, and selected cases of polyostotic fibrous dysplasia.

By reducing osteoclastic activity, these medications can decrease excessive bone resorption and improve skeletal stability.

Risk Factors and Dental Considerations

One of the most important concerns before starting bisphosphonate therapy is poor dental health.

Patients with significant dental disease may be at greater risk of developing osteonecrosis of the jaw, particularly when potent intravenous bisphosphonates are used for prolonged periods.

Pretreatment Dental Evaluation

Before beginning long-term or high-potency bisphosphonate therapy, patients should undergo appropriate dental evaluation.

Any necessary tooth extractions, treatment of active dental infection, or major reconstructive dental procedures should ideally be addressed before therapy begins.

Good oral hygiene and regular dental follow-up remain important during treatment.

Pathophysiology

Bisphosphonates reduce skeletal resorption by interfering with the normal function and survival of osteoclasts, the cells responsible for breaking down bone.

Their action ultimately decreases the rate at which mineralized bone is removed.

Mevalonate Pathway

Many bisphosphonates act by interfering with enzymes in the mevalonate pathway.

Disruption of this pathway impairs intracellular processes required for normal osteoclast function.

This reduces the ability of osteoclasts to adhere to and resorb bone effectively.

Osteoclast Ruffled Border

Active osteoclasts form a specialized ruffled border against the bone surface.

This structure is essential for creating the acidic environment and releasing enzymes required for bone resorption.

Bisphosphonates interfere with this resorptive apparatus and thereby diminish osteoclastic activity.

Osteoclast Apoptosis

Bisphosphonates can also promote apoptosis, or programmed cell death, of osteoclasts.

The resulting reduction in osteoclast number and activity decreases bone turnover and limits further bone loss.

Complications

The adverse effects of bisphosphonate therapy vary according to whether the medication is administered orally or intravenously and according to treatment duration.

Important complications include gastrointestinal irritation, acute systemic reactions, osteonecrosis of the jaw, and atypical femoral fractures.

Gastrointestinal Adverse Effects

The most common complication of oral bisphosphonate therapy is upper gastrointestinal irritation or gastric upset.

Patients may experience dyspepsia, reflux symptoms, esophageal irritation, or abdominal discomfort.

Proper administration helps reduce these complications.

Administration of Oral Bisphosphonates

Oral bisphosphonates should generally be taken on an empty stomach with a full glass of water.

The patient should remain upright after taking the medication, traditionally for approximately 30–60 minutes depending on the specific preparation, to reduce the risk of esophageal irritation.

Food and other medications may interfere with absorption and should be avoided for the recommended period after dosing.

Intravenous Adverse Effects

The most common early adverse effects of intravenous bisphosphonates include fever, bone pain, and muscle aches.

These acute-phase reactions may occur in approximately one-quarter of patients, particularly after an initial infusion.

Symptoms are usually temporary.

Osteonecrosis of the Jaw

One of the most important long-term complications of bisphosphonate therapy is osteonecrosis of the jaw.

This complication is characterized by impaired healing and exposed or necrotic jaw bone, often after dental extraction or other invasive dental treatment.

The risk is particularly relevant in patients receiving high-dose intravenous therapy for malignancy.

Prevention of Jaw Osteonecrosis

Preventive measures include addressing major dental problems before treatment, maintaining good oral hygiene, and obtaining regular dental care.

Patients should inform their dentist that they are receiving bisphosphonate therapy.

Any invasive dental procedure during treatment should be planned carefully.

Atypical Femoral Fractures

Long-term bisphosphonate use is also associated with atypical stress fractures of the femur.

These fractures commonly involve the subtrochanteric or femoral shaft region and may develop gradually because of prolonged suppression of bone remodeling.

Prodromal Symptoms

Before an atypical femoral fracture becomes complete, patients may experience thigh or groin pain during walking or weight-bearing.

This discomfort may precede fracture by weeks or months.

Patients receiving prolonged bisphosphonate therapy should report new persistent thigh or groin pain promptly.

Radiographic Findings

Early radiographs may be normal.

When abnormalities are present, they may include periosteal reaction, cortical thickening, or localized beaking of the lateral femoral cortex.

These findings can represent an incomplete or impending atypical fracture.

Duration of Therapy

Because the risk of atypical femoral fracture increases with prolonged treatment, the need for continued bisphosphonate therapy should be reassessed periodically.

Long-term treatment should be individualized according to the patient’s fracture risk, response to therapy, and potential complications rather than continued automatically.

Drug Holiday Consideration

In selected patients whose fracture risk has fallen after several years of therapy, a temporary bisphosphonate drug holiday may be considered.

The timing and duration depend on the specific medication, bone density, previous fractures, and overall osteoporosis risk.

Patients at very high fracture risk may require continued therapy or an alternative treatment strategy.

Patient Monitoring

Patients receiving bisphosphonates are commonly monitored with serial dual-energy X-ray absorptiometry (DEXA) scans.

DEXA testing provides an estimate of bone mineral density and helps assess the response to osteoporosis treatment over time.

Additional Monitoring

Follow-up should also include assessment for new fractures, changes in height or posture, medication tolerance, dental problems, and symptoms suggestive of atypical femoral fracture.

Persistent thigh or groin pain should prompt further evaluation even when the initial radiograph is normal.

Patient Education

Patients should understand why bisphosphonate therapy has been prescribed and how to take the medication correctly.

Those receiving oral therapy should follow administration instructions carefully to reduce gastrointestinal complications.

Patients should also maintain good dental care and promptly report jaw symptoms, persistent thigh or groin pain, or other new skeletal complaints.

Prognosis

When used appropriately, bisphosphonates can substantially reduce excessive bone resorption and help lower fracture risk in patients with osteoporosis and other high-turnover skeletal disorders.

The benefits of therapy should be balanced against uncommon but potentially important complications, especially during prolonged treatment.

Regular reassessment allows treatment to be adjusted according to changing fracture risk and patient response.

Orthopaedic Surgery - Biceps Tendon Rupture

Basics

The biceps tendon may rupture either proximally near the shoulder or distally near the elbow.

Most biceps tendon ruptures occur proximally.

At the shoulder, the long head of the biceps contributes to stabilization and depression of the humeral head. Distally, the biceps is the principal supinator of the forearm and also contributes significantly to elbow flexion.

Epidemiology

Biceps tendon rupture occurs most commonly in men between 40 and 60 years of age.

The dominant upper extremity is affected more frequently.

Although the condition is classically seen in middle-aged adults, rupture can also occur in younger athletes. In younger individuals, a history of anabolic steroid use should be considered because steroid exposure may weaken tendon structure.

Risk Factors

Important risk factors include male sex, age between 40 and 60 years, tendon degeneration, and anabolic steroid use.

For proximal ruptures, associated rotator cuff impingement or rotator cuff disease increases the risk of tendon failure.

For distal ruptures, chronic degenerative changes within the tendon predispose it to avulsion during a sudden high-load eccentric contraction.

Pathophysiology

Most biceps tendon ruptures occur through a background of degenerative tendon change.

This degeneration may be symptomatic or may remain clinically silent until rupture occurs.

In the proximal tendon, degeneration may result from reduced vascularity or chronic mechanical impingement beneath the coracoacromial arch.

Distal Tendon Pathophysiology

The distal biceps tendon commonly fails near its attachment to the radial tuberosity.

A degenerated tendon may avulse when subjected to a sudden and powerful eccentric force, particularly when the elbow is flexed and the muscle is attempting to contract against resistance.

This mechanism is often seen when a person suddenly tries to hold or lower a heavy object.

Associated Conditions

Biceps tendon rupture is commonly associated with rotator cuff disease, particularly when the rupture is proximal.

The presence of associated shoulder pathology should therefore be assessed during evaluation.

Diagnosis

Signs and Symptoms

Symptoms depend on whether the rupture is proximal or distal.

A sudden tearing sensation may be followed by pain, bruising, swelling, weakness, and visible change in the contour of the biceps muscle.

History in Proximal Rupture

Patients with a proximal biceps tendon rupture may complain of pain in the anterior shoulder, upper arm, or antecubital region.

Pain may be acute initially but can improve relatively quickly.

Some patients primarily notice a change in arm appearance rather than major functional loss.

History in Distal Rupture

Patients with a distal rupture commonly report antecubital pain together with weakness during forearm supination or elbow flexion.

The injury often follows a clear history of a sudden heavy eccentric load applied to a contracting biceps muscle.

Patients may describe a pop or tearing sensation at the time of injury.

Physical Examination

Proximal Rupture

Proximal tears may produce bruising and swelling around the shoulder, arm, or antecubital fossa.

The biceps muscle belly may retract distally, creating an abnormal contour of the arm.

This can produce the characteristic “Popeye” deformity.

Distal Rupture

With a distal tendon rupture, the biceps muscle belly retracts proximally toward the shoulder.

The normal tendon may no longer be palpable in the antecubital fossa.

A clearly absent distal tendon strongly suggests a complete distal rupture.

Strength Testing

Weakness may be present with both elbow flexion and forearm supination.

The loss of strength is usually more clinically significant after a distal rupture because the distal biceps plays a major role in supination.

Pain during resisted flexion or supination may occur in partial tears.

Popeye Sign

The Popeye sign describes visible bunching or distortion of the biceps muscle belly after tendon rupture.

It is more classically associated with proximal long-head biceps rupture, although changes in muscle contour may also occur with distal injury.

The location of muscle retraction helps distinguish proximal from distal rupture.

Imaging

MRI

MRI is the most useful imaging study when the diagnosis is uncertain or when the extent of injury must be defined.

It can identify complete or partial tendon disruption, tendon retraction, associated rotator cuff pathology, and surrounding soft-tissue injury.

MRI is particularly useful for planning surgery in distal ruptures or symptomatic partial tears.

Differential Diagnosis

Important differential diagnoses include rotator cuff impingement and rotator cuff tear.

Other causes of shoulder or antecubital pain should also be considered when the examination does not clearly demonstrate tendon rupture.

Treatment

General Principles

Management depends primarily on whether the rupture is proximal or distal, as well as the patient’s age, activity level, functional demands, cosmetic concerns, and associated pathology.

Proximal ruptures are often successfully treated nonoperatively.

Distal ruptures are more commonly treated surgically because untreated injury can result in meaningful loss of strength.

Proximal Biceps Tendon Rupture

Initial treatment of an isolated proximal rupture is usually nonoperative.

Many affected patients are older than 40 years and experience only modest weakness or functional limitation.

Pain often settles with conservative care, and many patients adapt well to the cosmetic deformity.

Candidates for Surgery After Proximal Rupture

Surgical treatment may be considered in patients who are younger, highly active, athletic, concerned about the appearance of the arm, or seeking maximal restoration of function.

Persistent cramping or pain may also support operative treatment.

Distal Biceps Tendon Rupture

For complete distal ruptures, surgical repair generally provides the best functional outcome, particularly in active patients.

Because the distal biceps is an important supinator, nonoperative treatment can result in persistent weakness, especially during activities requiring forceful supination.

Partial Distal Rupture

Partial distal biceps tears may initially be treated nonoperatively when symptoms are mild.

However, persistent pain or weakness despite conservative management may require surgical treatment.

Operative management may involve completing the partial release and then repairing the tendon back to the radial tuberosity.

Nonoperative Management

Conservative treatment includes rest, activity modification, analgesia, and gradual rehabilitation.

During the acute phase, the arm should be rested until pain and swelling decrease.

Gentle range-of-motion exercises can then begin.

Activity is gradually advanced as tolerated.

Physical Therapy

Physical therapy focuses initially on maintaining comfortable shoulder, elbow, and forearm motion.

As pain improves, strengthening can be introduced progressively.

In nonoperatively treated patients, rehabilitation aims to maximize the function of remaining muscles and compensate for any persistent weakness.

Medication

NSAIDs and acetaminophen may be used during the acute phase for pain relief.

Medication should be combined with rest and gradual restoration of function.

Surgical Management of Proximal Rupture

For selected proximal ruptures, the biceps tendon may be treated with tenodesis.

In this procedure, the tendon is fixed to the humerus to restore a more normal muscle contour and reduce cramping or discomfort.

Tenodesis is often performed mainly for functional or cosmetic reasons.

Proximal Rupture With Rotator Cuff Disease

When a proximal biceps rupture occurs together with significant rotator cuff or impingement pathology, surgery may address both conditions.

Procedures may include biceps tenodesis together with treatment of rotator cuff disease, and in selected cases acromioplasty may also be performed.

Surgical Management of Distal Rupture

Distal biceps repair involves reattaching the tendon to the radial tuberosity.

This can be performed through a single anterior incision or through a two-incision muscle-splitting approach.

The objective is to restore the normal insertion and regain elbow flexion and forearm supination strength.

Surgery for Symptomatic Partial Tears

A symptomatic partial distal tear may be treated surgically when pain or weakness persists.

The damaged tendon may be released and then formally reattached to the radial tuberosity.

This can improve both pain and function in appropriately selected patients.

Follow-Up

Follow-up should assess pain, swelling, range of motion, strength, and restoration of functional use of the arm.

Patients treated surgically require progressive rehabilitation according to tendon healing and the repair technique used.

Strengthening should be advanced carefully to protect the repair.

Prognosis

Patients undergoing successful surgical repair of a distal biceps rupture can generally expect a near-complete return of flexion and supination strength.

Outcome is typically best when repair is performed before substantial chronic retraction or scarring develops.

Prognosis After Proximal Tenodesis

Patients undergoing tenodesis for a proximal rupture can generally expect good pain relief and improvement in arm contour.

The procedure also helps reduce the prominence of the Popeye deformity.

Complications of Nonoperative Treatment

Without surgery, some patients may continue to experience activity-related pain, cramping, or weakness.

This is usually more clinically important after distal rupture than proximal rupture.

Loss of Supination Strength

The most important functional deficit after an untreated distal biceps rupture is reduced forearm supination strength.

Patients may notice difficulty with activities such as turning a screwdriver, opening a jar, using tools, or performing repetitive lifting with the palm facing upward.

Elbow flexion strength may also decrease, but the loss is generally less pronounced because other muscles can assist with flexion.

Patient Monitoring

Patients should be monitored for recovery of pain-free motion, strength, and functional use of the extremity.

Persistent weakness, ongoing pain, or difficulty with supination should prompt reassessment, particularly in patients with suspected distal rupture or symptomatic partial tendon injury.

Orthopaedic Surgery - Back Pain in Children

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Basics

Pediatric back pain is less common than back pain in adults but becomes increasingly frequent with age.

The estimated prevalence is approximately 6% among children aged 7–10 years and approximately 18% among adolescents aged 14–16 years.

Participation in competitive sports has been associated with a higher risk of pediatric back pain. Behavioral, emotional, and psychological difficulties may also be associated with a greater frequency of symptoms.

Although most pediatric back pain is musculoskeletal and self-limiting, persistent or severe symptoms require careful evaluation because infection, tumor, structural abnormalities, and neurologic disorders may also present with back pain.

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Etiology

The differential diagnosis of pediatric back pain is broad.

Important causes include spondylolysis, spondylolisthesis, tethered cord syndrome, neoplasms, spondyloarthropathies, Bertolotti syndrome, discitis, pyogenic sacroiliitis, Scheuermann disease, lumbar disc herniation, and musculoskeletal strain.

Age, pain characteristics, neurologic findings, systemic symptoms, and activity history help distinguish among these conditions.

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Spondylolysis

Spondylolysis is a defect or stress fracture involving the pars interarticularis, the portion of the vertebral arch located between the superior and inferior facet joints.

It usually develops as a fatigue injury caused by repeated lumbar extension and rotational movements.

Sports involving repetitive hyperextension, such as gymnastics and certain throwing or kicking activities, can increase mechanical stress on the pars.

The estimated prevalence in children is approximately 4.4%.

The fifth lumbar vertebra (L5) is affected most commonly.

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Spondylolisthesis

Spondylolisthesis refers to anterior displacement of one vertebral body relative to the vertebra beneath it.

In children and adolescents, it frequently occurs in association with a pars defect or spondylolysis.

Its estimated prevalence is approximately 0.9%.

Low back pain is the most common clinical manifestation, although some patients may also develop radicular pain or neurologic symptoms if neural structures are affected.

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Primary Tethered Cord Syndrome

Primary tethered cord syndrome is caused by abnormal fixation of the lower spinal cord to surrounding tissues.

This abnormal attachment restricts normal movement of the cord during growth and may progressively impair the lumbosacral nerve roots.

The estimated prevalence is approximately 0.1%.

Tethered cord syndrome may occur together with other congenital spinal abnormalities, including spina bifida.

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Clinical Features of Tethered Cord Syndrome

Symptoms may include low back pain, lower-extremity muscle wasting, clubfoot deformity, leg-length discrepancy, scoliosis, weakness, and sensory loss.

Bladder or bowel dysfunction may also occur in clinically significant cases.

Progressive neurologic abnormalities should prompt further spinal cord evaluation.

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Neoplastic Causes

Tumors are a rare cause of pediatric back pain, accounting for approximately 0.1% of cases.

Both benign and malignant bone or spinal cord tumors may present with back pain.

Pain that is persistent, occurs at night, is associated with systemic symptoms, or is accompanied by neurologic abnormalities warrants further investigation.

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Osteoid Osteoma

An osteoid osteoma is a benign primary bone tumor that may involve the spine.

Up to approximately 20% of osteoid osteomas can occur in spinal locations.

A characteristic clinical feature is back or neck pain that is worse at night and responds markedly to NSAIDs.

The lesion may also cause painful scoliosis when located asymmetrically in the posterior spinal elements.

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Ewing Sarcoma

Ewing sarcoma is an important malignant bone tumor occurring in children and adolescents.

It may present with localized pain together with systemic or constitutional symptoms such as fever, fatigue, and weight loss.

Persistent unexplained back pain associated with constitutional symptoms should therefore raise concern for malignancy.

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Spinal Cord Tumors

Spinal cord tumors may be benign or malignant.

Clinical manifestations depend on the location and extent of the lesion.

Children may develop back pain, progressive motor weakness, sensory abnormalities, gait disturbance, or bowel and bladder dysfunction.

Neurologic deterioration requires prompt imaging.

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Spondyloarthropathies

Pediatric spondyloarthropathies include ankylosing spondylitis, psoriatic arthritis, enthesitis-related arthritis, reactive arthritis, and arthritis associated with inflammatory bowel disease.

Their estimated prevalence is approximately 0.2%.

Common manifestations include inflammatory back pain, sacroiliitis, enthesitis, and dactylitis.

Many affected children are HLA-B27 positive, although HLA-B27 positivity alone does not establish the diagnosis.

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Associated Features of Spondyloarthropathies

Reactive arthritis may occur in association with urethritis and conjunctivitis.

Psoriatic arthritis may be associated with cutaneous or nail manifestations of psoriasis.

Enteropathic arthritis occurs in association with inflammatory bowel disease.

Recognition of these associated features can help identify an inflammatory cause of back pain.

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Bertolotti Syndrome

Bertolotti syndrome occurs when a lumbosacral transitional vertebra becomes symptomatic.

A lumbosacral transitional vertebra is an anatomical variant in which the lowest lumbar vertebra has an enlarged transverse process that partially or completely articulates or fuses with the sacrum.

The estimated prevalence of this anatomical variant is approximately 4–10%.

When the abnormal articulation is responsible for low back pain, the condition is termed Bertolotti syndrome.

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Clinical Features of Bertolotti Syndrome

Pain is commonly mechanical and may worsen during lumbar extension.

Some patients also develop radicular symptoms caused by altered lumbosacral mechanics or nerve compression.

Radiographs may demonstrate an enlarged transverse process articulating with the sacrum.

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Discitis

Discitis is an inflammatory or infectious disorder of the intervertebral disc space and is seen most commonly in children younger than approximately 5 years.

Young children may present with back pain, irritability, refusal to walk, or reluctance to sit or bend.

Many affected children remain afebrile, and the peripheral white blood cell count may be normal.

The erythrocyte sedimentation rate (ESR) is elevated in many cases and can support the diagnosis.

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Pyogenic Sacroiliitis

Pyogenic sacroiliitis is a bacterial infection involving the sacroiliac joint.

Patients may complain of pain in the lower back, buttock, hip, or abdomen.

The ESR is often elevated, although the white blood cell count may remain normal.

Because symptoms may be poorly localized, diagnosis can be delayed without a high index of suspicion.

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Scheuermann Disease

Scheuermann disease is a developmental disorder involving the thoracic or thoracolumbar vertebrae.

Its estimated prevalence is approximately 0.2%.

The classic radiographic criterion is anterior wedging greater than 5° in at least three consecutive vertebral bodies.

The precise cause is uncertain, although a hereditary component with autosomal dominant inheritance and incomplete penetrance has been proposed.

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Clinical Features of Scheuermann Disease

Patients commonly present during adolescence with back pain and a rigid focal kyphotic deformity.

Pain may worsen with prolonged sitting, standing, or activity.

Unlike postural kyphosis, the deformity is relatively rigid and does not fully correct with voluntary posture.

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Herniated Nucleus Pulposus

Lumbar disc herniation is uncommon in younger children but may occur in adolescents, sometimes after trauma.

The lumbar spine is affected most frequently.

Symptoms often include low back pain radiating into one or both lower extremities, depending on the nerve root involved.

Neurologic deficits may develop when compression is substantial.

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Musculoskeletal Back Pain

Muscular strain and ligamentous sprain are the most common causes of pediatric back pain.

Symptoms are generally related to activity and improve with rest.

Musculoskeletal back pain is typically self-limiting.

When the history and examination are reassuring and no red-flag features are present, additional imaging may not be necessary.

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Diagnosis

History

History should focus on defining the location, quality, severity, duration, and pattern of pain.

The clinician should ask about trauma, sports participation, repetitive activities, aggravating movements, and previous episodes.

Particular attention should be paid to features that suggest more serious pathology.

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Concerning Symptoms

Red-flag symptoms include motor or sensory deficits, persistent nocturnal pain, bowel or bladder dysfunction, progressive weakness, and gait disturbance.

Constitutional symptoms such as fever, unexplained weight loss, and fatigue may suggest infectious, inflammatory, or neoplastic disease.

These findings usually warrant further investigation.

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Psychological Assessment

Mental and emotional well-being should also be considered.

Anxiety, depression, behavioral problems, and emotional distress have been associated with a higher prevalence of pediatric back pain.

These factors should be evaluated without assuming that the pain is purely psychological.

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Physical Examination

A complete examination should include inspection, palpation, provocative maneuvers, lumbar range of motion, gait assessment, and a detailed neurologic examination.

The findings should be interpreted together with the history.

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Inspection

The child’s posture should be evaluated in both the coronal and sagittal planes.

The examiner should look for scoliosis, excessive kyphosis, abnormal lordosis, pelvic asymmetry, or other deformity.

Skin findings such as dimples, hairy patches, masses, or other congenital markers over the spine may suggest occult spinal dysraphism.

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Gait Assessment

Gait should be observed for abnormalities such as Trendelenburg gait, limping, weakness, or ataxia.

An abnormal gait may indicate hip pathology, neurologic dysfunction, pain, or muscular weakness.

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Palpation

The spinal column, paraspinal muscles, and sacroiliac joints should be palpated.

Midline spinal tenderness raises concern for fracture, infection, or other structural pathology.

Paraspinal tenderness is more commonly associated with muscular strain.

The examiner should also assess for swelling, edema, or a palpable mass.

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Straight Leg Raise Test

The straight leg raise test helps assess possible lumbar disc herniation with nerve root irritation.

With the patient lying supine, the examiner passively raises the leg while maintaining the knee in extension.

Reproduction of radicular pain when the hip is flexed approximately 30–70° supports irritation of the lumbosacral nerve roots and raises suspicion for disc herniation.

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FABER Test

The FABER test evaluates pathology involving the sacroiliac joint or hip.

With the patient supine, the tested hip is flexed, abducted, and externally rotated so that the ankle rests over the opposite thigh.

Downward pressure is then applied to the flexed knee while the contralateral pelvis is stabilized.

Pain around the sacroiliac region may suggest SI joint pathology, including sacroiliitis.

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Lumbar Range of Motion

Lumbar range of motion does not always identify the specific cause of pain, but it can help assess functional limitation and disease progression.

Average pediatric lumbar flexion is approximately 52°, with extension around 19°.

Average axial rotation is approximately 33° to the left and 32° to the right.

Average lateral flexion is approximately 30° to the left and 31° to the right.

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Neurologic Examination

A detailed bilateral neurologic examination should assess motor strength, sensation, and reflexes.

Neurologic abnormalities may help localize a disc herniation or identify spinal cord or nerve root pathology.

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Disc Herniation Findings

An L4–L5 disc herniation may cause weakness involving ankle or great-toe dorsiflexion, depending on the affected nerve root.

An L5–S1 disc herniation may produce a diminished or absent Achilles tendon reflex.

Sensory changes should also be mapped according to the involved dermatome.

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Neurologic Red Flags

Progressive weakness, abnormal reflexes, sensory loss, gait disturbance, or bowel and bladder dysfunction should raise concern for significant neurologic compression or a spinal cord lesion.

Neoplastic and congenital neurologic disorders must also be considered.

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Imaging

The three principal imaging modalities are plain radiographs, CT, and MRI.

The decision to image should be based on the patient’s symptoms and examination while considering radiation exposure and the possible need for sedation in younger children.

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When Imaging Is Not Required

When the neurologic examination is normal and there are no concerning features such as fever, weight loss, persistent night pain, or neurologic changes, immediate imaging is often unnecessary.

Children with uncomplicated musculoskeletal pain may be managed initially with observation and conservative care.

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Plain Radiographs

Plain radiographs are often the initial imaging study when structural pathology is suspected.

They are useful for evaluating vertebral alignment, deformity, spondylolysis, spondylolisthesis, transitional vertebrae, Scheuermann disease, and some tumors.

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CT

CT provides excellent visualization of bone detail.

It can help define pars defects, fractures, congenital abnormalities, and other osseous lesions.

Three-dimensional reconstructions can be useful when detailed anatomical assessment is required.

Because CT exposes children to ionizing radiation, its use should be selective.

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MRI

MRI provides detailed visualization of the spinal cord, nerve roots, intervertebral discs, bone marrow, ligaments, and soft tissues.

It is particularly useful for evaluating infection, tumors, tethered cord, disc herniation, sacroiliitis, and neurologic abnormalities.

MRI avoids ionizing radiation but may require sedation in some young children.

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Imaging in Spondylolysis

Plain radiographs may demonstrate a radiolucent defect through the pars interarticularis.

When radiographs are normal but clinical suspicion remains high, advanced imaging may be considered.

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Imaging in Spondylolisthesis

Radiographs demonstrate anterior displacement of one vertebral body relative to the vertebra below.

Standing lateral radiographs are particularly useful for assessing the degree of slip.

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Imaging in Tethered Cord Syndrome

MRI is the preferred study.

Findings may include abnormalities of the filum terminale, a low-lying cord, or dorsal adherence of the spinal cord.

Associated congenital abnormalities may also be identified.

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Imaging in Osteoid Osteoma

Radiographs or CT may demonstrate a small focal lesion, often with surrounding sclerosis.

CT is particularly useful for identifying the central nidus when osteoid osteoma is suspected.

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Imaging in Ewing Sarcoma

Radiographs may show a destructive bone lesion with a mixture of lytic and sclerotic features.

MRI is useful for defining marrow involvement and soft-tissue extension.

Further oncologic imaging is required if malignancy is suspected.

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Imaging of Spinal Cord Tumors

MRI is the investigation of choice for suspected spinal cord tumors.

Lesions may demonstrate abnormal signal intensity, often appearing hyperintense on T2-weighted imaging, depending on tumor type.

MRI also demonstrates the degree of cord or nerve compression.

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Imaging in Bertolotti Syndrome

Radiographs may reveal an enlarged transverse process of the lowest lumbar vertebra contacting or articulating with the sacrum.

The imaging abnormality must correlate with the patient’s symptoms before it is considered the source of pain.

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Imaging in Discitis

Plain radiographs may eventually demonstrate narrowing of the intervertebral disc space, although early studies can be normal.

MRI is more sensitive for early infection and for evaluating adjacent vertebral and soft-tissue involvement.

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Imaging in Pyogenic Sacroiliitis

MRI may demonstrate inflammation, edema, or fluid around the sacroiliac joint.

It is useful for identifying associated abscess formation or surrounding bone involvement.

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Imaging in Scheuermann Disease

The radiographic diagnosis requires anterior wedging of more than 5° in at least three consecutive vertebrae.

Other findings may include irregular endplates and Schmorl nodes.

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Imaging in Disc Herniation

MRI may demonstrate disc bulging, protrusion, extrusion, reduced disc height, or nerve root compression.

It is the preferred imaging modality when neurologic symptoms suggest clinically important disc disease.

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Imaging in Musculoskeletal Pain

Imaging is usually normal in uncomplicated muscular or ligamentous back pain.

When the history and examination are reassuring, normal imaging is not required to establish a clinical diagnosis of musculoskeletal strain.

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Treatment

Treatment depends on identifying the underlying cause.

Management options include activity modification, rest, physical therapy, medication, and surgery.

Most uncomplicated musculoskeletal causes can be treated conservatively.

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Rest and Activity Modification

Rest from the provoking activity is often the first step in treating spondylolysis and low-grade spondylolisthesis.

Repetitive extension, rotation, and impact activities may need to be temporarily avoided.

Activity is gradually resumed after pain improves and strength and flexibility have been restored.

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Physical Therapy

Physical therapy is beneficial for many causes of pediatric back pain.

Treatment may focus on core strengthening, flexibility, hamstring stretching, posture, spinal stabilization, and correction of biomechanical abnormalities.

The program should be tailored to the child’s diagnosis and activity demands.

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Medication

NSAIDs and acetaminophen can be used for symptomatic treatment of many conditions, including musculoskeletal pain, Bertolotti syndrome, and disc herniation.

Medication should be combined with treatment of the underlying cause rather than used as the sole therapy.

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Spondyloarthropathy Treatment

NSAIDs are commonly used as initial treatment for inflammatory spondyloarthropathies.

Patients with persistent active inflammatory disease may require biologic therapy, including tumor necrosis factor inhibitors, under specialist rheumatologic care.

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Osteoid Osteoma Treatment

Pain from osteoid osteoma often responds markedly to NSAIDs.

Definitive treatment may be considered when symptoms persist or medication is undesirable for long-term use.

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Treatment of Discitis

Discitis is generally treated with appropriate antimicrobial therapy when bacterial infection is suspected or confirmed.

Empiric therapy commonly includes coverage against Staphylococcus aureus, with subsequent adjustment according to cultures and clinical response.

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Treatment of Pyogenic Sacroiliitis

Pyogenic sacroiliitis also requires antibiotic therapy directed toward the causative organism.

Staphylococcus aureus is an important pathogen to cover initially when bacterial infection is suspected.

Drainage may be required if an abscess or persistent collection is present.

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Treatment of Neoplasms

Tumors require treatment according to their histologic diagnosis and stage.

Malignant conditions such as Ewing sarcoma may require systemic chemotherapy together with local control by surgery and/or radiotherapy.

Spinal cord tumors require specialist oncologic and neurosurgical evaluation.

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Surgical Management of Spondylolysis

Most cases of spondylolysis are treated nonoperatively.

Persistent symptomatic lesions that fail conservative treatment may occasionally require direct repair of the pars defect using internal fixation and bone grafting.

Fusion may be considered in selected patients with associated instability or advanced spondylolisthesis.

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Surgery for Spondylolisthesis

Progressive or high-grade spondylolisthesis may require spinal fusion, particularly when there is persistent pain, progression of the slip, deformity, or neurologic compromise.

The exact procedure depends on the severity and level of the deformity.

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Surgery for Bertolotti Syndrome

Most patients with Bertolotti syndrome are initially treated conservatively.

Persistent symptoms attributable to the transitional articulation may occasionally require resection or fusion, depending on the anatomical abnormality and pain generator.

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Surgery for Tethered Cord Syndrome

Symptomatic tethered cord syndrome may require surgical detethering.

The goal is to release abnormal attachments and prevent further neurologic deterioration.

Surgery is particularly considered when progressive weakness, sensory loss, deformity, or bladder dysfunction is present.

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Surgery for Disc Herniation

Most pediatric disc herniations are initially managed nonoperatively when neurologic function is preserved.

Persistent radicular pain, progressive neurologic deficit, or significant neural compression may require discectomy, sometimes combined with limited decompression such as laminotomy or laminectomy.

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Follow-Up

Follow-up should be individualized according to the underlying diagnosis.

Children with uncomplicated musculoskeletal pain should demonstrate progressive improvement with activity modification and rehabilitation.

Persistent pain, worsening deformity, new neurologic abnormalities, or constitutional symptoms require reassessment.

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Prognosis

The prognosis is generally favorable for uncomplicated musculoskeletal causes of pediatric back pain.

Many stress-related and mechanical conditions improve with appropriate activity modification and physical therapy.

Prognosis for infection, tumors, neurologic disorders, and structural deformities depends on the underlying condition and how early treatment is initiated.

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Red Flags Requiring Further Evaluation

Features that should prompt more urgent investigation include night pain, persistent or progressive pain, fever, weight loss, fatigue, neurologic deficit, gait disturbance, bowel or bladder dysfunction, and significant spinal tenderness.

Back pain in very young children also deserves a lower threshold for further investigation.

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Patient Monitoring

Children should be monitored for improvement in pain, spinal motion, posture, gait, muscle strength, and neurologic function.

Return to sport should occur gradually after pain has resolved and normal strength, flexibility, and movement have been restored.

Failure to improve as expected should prompt reconsideration of the diagnosis and possible further imaging or specialist referral.

Orthopaedic Surgery - Back Pain

Basics

Low back pain (LBP) is one of the most common musculoskeletal complaints and is a major cause of disability. It accounts for a substantial number of years lived with disability and is responsible for a very large amount of lost work productivity.

An estimated 149 million workdays per year are lost because of low back pain, and approximately 70–80% of adults experience a significant episode of back pain at some point during their lives.

Back pain may involve the bones, joints, ligaments, discs, or muscles of the spine. It occurs most frequently in middle-aged adults but may also affect children and adolescents.

Classification

Back pain can be broadly classified as traumatic or atraumatic.

Pathologic pain may originate directly from the spine, including spondylogenic or neurogenic causes, or may arise from structures outside the spine, including visceral, vascular, or psychogenic sources.

Because low back pain is a symptom rather than a single disease, careful clinical assessment is necessary to determine its underlying cause.

Synonyms

Common terms include backache and low back pain (LBP).

Epidemiology

Low back pain is extremely common in adults.

It is less common in children, and significant back pain in a child should prompt careful investigation.

Children or adolescents with scoliosis may report mild discomfort, but severe or persistent pain should raise concern for conditions such as infection, tumor, fracture, or another structural abnormality.

Age Considerations

The prevalence of chronic low back pain increases with age and is highest during approximately the fifth and sixth decades of life.

Most surgical procedures performed for low back pain occur in patients between approximately 35 and 55 years of age.

Sex Distribution

Back pain has historically been reported more frequently in males, partly because of greater exposure to manual labor, motor vehicle trauma, and industrial accidents.

However, low back pain affects both sexes and is common across the general population.

Incidence

Approximately 25% of adults in the United States report experiencing low back pain over a given period.

The burden of disease is substantial because symptoms may interfere with work, exercise, mobility, sleep, and activities of daily living.

Prevalence

The point prevalence of chronic low back pain among adults aged approximately 20–69 years has been reported at around 13%.

The likelihood of chronic symptoms rises with age.

Risk Factors

Important risk factors include obesity, cigarette smoking, manual labor, and traumatic accidents.

Repeated heavy lifting, prolonged mechanical loading, poor physical conditioning, and certain occupational exposures may also contribute.

Genetics

There is no single established genetic predisposition that explains most cases of nonspecific low back pain.

However, inherited factors may contribute indirectly to certain disorders, such as degenerative disc disease or inflammatory spondyloarthritis.

Pathophysiology

There is no single pathologic process responsible for all forms of back pain.

The mechanism depends on the underlying disorder and may involve mechanical strain, disc degeneration, nerve compression, inflammation, fracture, infection, neoplasm, or referred pain from other structures.

Etiology

Traumatic Causes

Traumatic causes include vertebral fractures or microfractures, fracture-dislocations, intervertebral disc herniation, and ligamentous injuries.

Fractures and major structural injuries usually produce sudden and often severe pain following trauma.

Atraumatic Causes

Atraumatic causes include degenerative disc disease, degenerative spinal stenosis, inflammatory arthritis, osteoporosis, spondylolysis, spondylolisthesis, infection, and neoplasms.

Tumors may be primary bone lesions or metastatic disease.

Associated Conditions

Low back pain may occur in association with ankylosing spondylitis, rheumatoid arthritis, sciatica, and cauda equina syndrome.

Neurologic symptoms accompanying back pain require particular attention because they may indicate nerve root or spinal canal compromise.

Diagnosis

Signs and Symptoms

Common symptoms include low back pain, stiffness, and numbness.

Patients may also experience radiating pain into the buttocks or lower extremities when nerve roots are involved.

Neurologic Signs

Potential examination findings include paravertebral muscle spasm, motor weakness, loss of deep tendon reflexes, sensory loss, clonus, and a positive Babinski sign.

The presence of upper motor neuron findings or significant neurologic deficits should prompt further investigation.

History

A detailed history is essential because routine diagnostic studies are often unnecessary in uncomplicated low back pain.

The clinician should determine the onset, location, severity, duration, and character of pain, together with aggravating and relieving factors.

A history of trauma, systemic illness, malignancy, infection risk, osteoporosis, or neurologic symptoms is particularly important.

Pain Mapping

Rather than relying only on verbal descriptions, asking the patient to identify or map the exact distribution of pain can improve localization.

The pattern may help distinguish localized mechanical pain from radicular, referred, or systemic causes.

Red Flag History

Important concerning features include night pain, unexplained weight loss, fever, recent serious trauma, history of malignancy, immunosuppression, intravenous drug use, progressive neurologic deficit, or bowel and bladder dysfunction.

These findings may indicate serious structural disease and require urgent investigation.

Physical Examination

Examination begins with inspection of the spine and overall posture.

The clinician should assess for asymmetry of the ribs, flanks, pelvis, or shoulders, and should observe the normal sagittal spinal curves.

Deformities such as scoliosis, excessive kyphosis, or abnormal lumbar lordosis should be documented.

Range of Motion

Lumbar motion should be assessed in flexion, extension, lateral bending, and rotation.

Pain suddenly reproduced during a specific movement may suggest a mechanical abnormality.

Restriction of motion may occur because of pain, muscle spasm, degenerative disease, inflammation, or structural deformity.

Palpation

The lumbar spine and surrounding muscles should be palpated for tenderness.

Paravertebral muscle spasm may be present in acute mechanical pain.

Percussion tenderness over the spine may raise concern for fracture, infection, or other osseous pathology.

Neurologic Examination

The neurologic examination is a crucial component of assessment.

It should include motor strength, sensory testing, deep tendon reflexes, and gait evaluation.

The distribution of weakness or sensory loss may help identify the involved nerve root.

Motor Testing

Major muscle groups of the lower extremities should be examined systematically.

Weakness may indicate nerve root compression, spinal cord involvement, severe pain inhibition, or another neurologic disorder.

Reflexes

Deep tendon reflexes should be assessed and compared bilaterally.

Abnormal or absent reflexes may indicate nerve root involvement, whereas hyperreflexia, clonus, or a positive Babinski response may suggest spinal cord pathology.

Gait Examination

The patient’s gait should be observed for antalgia, weakness, foot drop, imbalance, or other neurologic abnormalities.

Difficulty with heel or toe walking may provide additional information regarding specific nerve root or muscle dysfunction.

Laboratory Tests

There are no routine laboratory tests required for uncomplicated mechanical low back pain.

Investigations should be guided by clinical suspicion.

Evaluation for Infection

When infection is suspected, a complete blood count and erythrocyte sedimentation rate (ESR) may be obtained.

Inflammatory markers are commonly elevated in spinal infection, with ESR often being particularly useful.

C-reactive protein may also assist in assessing inflammatory activity.

Evaluation for Multiple Myeloma

In older patients, particularly those over approximately 50 years of age with unexplained persistent back pain, laboratory investigations may be used to screen for disorders such as multiple myeloma when clinically indicated.

HLA-B27 Testing

In younger patients with marked spinal stiffness and symptoms suggestive of inflammatory back pain, testing for HLA-B27 may support evaluation for ankylosing spondylitis.

It should not be used as a stand-alone diagnostic test.

Imaging

Plain Radiographs

Routine radiographs are not necessary for every first episode of uncomplicated low back pain, particularly when symptoms follow a minor mechanical event such as lifting and there are no concerning findings.

Imaging should be considered when history or examination suggests a significant structural abnormality.

Indications for Imaging

Radiographs may be appropriate when there is suspicion of fracture, ankylosing spondylitis, severe deformity, malignancy, infection, or another important structural disorder.

The decision to image should be based on clinical findings rather than pain alone.

CT

Computed tomography is particularly useful for evaluating bony abnormalities.

It can provide detailed assessment of fractures, pars defects, osteoid osteoma, and other osseous lesions.

CT is also helpful when complex anatomy must be defined before surgery.

MRI

MRI provides excellent visualization of bone marrow, discs, ligaments, neural structures, and surrounding soft tissues.

It is particularly useful for detecting disc herniation, spinal stenosis, infection, metastatic disease, marrow abnormalities, and nerve compression.

MRI is generally the preferred advanced imaging modality when neurologic symptoms or serious spinal pathology are suspected.

Bone Scintigraphy

Technetium bone scanning can help detect areas of increased skeletal activity.

It may be useful for identifying early bone infection, stress injury, occult fracture, or metastatic lesions.

Its use has decreased in many situations because MRI often provides more detailed anatomic information.

Differential Diagnosis in Adults

Traumatic Causes

Important traumatic causes include herniated disc, compression fracture, fracture-dislocation, and traumatic spondylolysis.

A clear traumatic history increases suspicion for these conditions.

Atraumatic Causes in Adults

Atraumatic causes include degenerative disc disease, spinal stenosis, inflammatory arthritis, spondylolysis, spondylolisthesis, ligamentous or muscular strain, and neoplasm.

Malignant causes include metastatic bone disease and multiple myeloma.

Differential Diagnosis in Children

Back pain in children deserves careful attention because serious causes are relatively more important.

Traumatic causes include fracture and disc herniation.

Atraumatic causes include scoliosis, disc-space infection, vertebral osteomyelitis, and tumors.

Persistent severe pain should not automatically be attributed to muscular strain.

Treatment

General Measures

Most patients with uncomplicated low back pain can be managed nonoperatively.

Treatment may include short-term rest, appropriate analgesia, NSAIDs when indicated, activity modification, and physical therapy.

The overall aim is to restore mobility and prevent deconditioning.

Bed Rest

Prolonged bed rest is generally not beneficial.

In patients with severe acute spasm or pain, a very short period of rest—often no more than 2–3 days—may be reasonable.

During the first several days, activity may be temporarily restricted, but progressive mobilization should begin as symptoms improve.

Early Mobilization

If no serious structural abnormality is identified, patients should gradually resume activity.

Early mobilization helps prevent muscle weakness, stiffness, loss of cardiovascular fitness, and prolonged disability.

Physical Therapy

Physical therapy and structured exercise can improve back strength, flexibility, range of motion, posture, and general fitness.

Therapy should be tailored to the underlying diagnosis and the patient’s functional limitations.

Exercise Programs

Traditional exercise approaches include the Williams flexion program and McKenzie extension-based exercises.

No single exercise method is appropriate for every patient.

Programs emphasizing coordination, stabilization, strength, and resistance training are particularly useful in chronic low back pain.

Core and Stabilization Training

Exercises targeting the abdominal, paraspinal, pelvic, and hip muscles can improve spinal stability.

Motor-control and stabilization programs may reduce recurrent symptoms and improve function in patients with chronic mechanical low back pain.

Activity Modification

Patients should be educated regarding safe lifting techniques, posture, gradual return to activity, and strategies for preventing recurrent injury.

Temporary modification of work or sporting activity may be required during painful episodes.

Work-Hardening Programs

Patients injured at work may benefit from a structured work-hardening program.

These programs progressively reproduce occupational tasks in a controlled setting and help restore strength, endurance, and confidence before return to full duty.

Passive Therapies

Massage, acupuncture, electrical stimulation, and other passive modalities may provide temporary symptom relief.

However, they generally provide less durable benefit than active exercise and strengthening programs.

They should therefore be considered adjuncts rather than the primary long-term treatment.

Medication

NSAIDs

Nonsteroidal anti-inflammatory drugs are commonly used for short-term symptomatic relief.

They may reduce pain and inflammation sufficiently to allow earlier mobilization and participation in rehabilitation.

Treatment should be individualized according to gastrointestinal, renal, cardiovascular, and other patient-specific risks.

Duration of Medication

NSAIDs may be prescribed for several weeks when necessary, but treatment should be reassessed regularly.

Once symptoms improve, medication can usually be reduced or discontinued.

Muscle Relaxants

Muscle relaxants have a limited role in routine management.

They may be useful for short-term relief in patients with severe muscle spasm, especially during an acute episode.

They are generally not recommended for prolonged use.

Treatment of Spinal Infection

When infection is present, treatment requires appropriate antimicrobial therapy and management of the infected spinal segment.

Intravenous antibiotics are commonly required initially.

Inflammatory markers such as ESR and CRP may be followed to assess response to treatment.

Surgical Management

Only a minority of patients with low back pain require surgery.

Approximately 1–5% may ultimately become candidates for operative treatment, depending on the underlying pathology.

Surgery is generally reserved for clearly defined structural problems that fail to respond to appropriate conservative care or threaten neurologic function.

Surgical Principles

The principal surgical goals include decompression of compressed nerve roots or the spinal cord, stabilization of an unstable spine, and correction of significant deformity.

The exact procedure depends on the diagnosis.

Decompression

Nerve root or spinal cord compression may require surgical decompression.

Examples include significant disc herniation, spinal stenosis, tumor, infection, or traumatic compression associated with neurologic deficits.

Spinal Fusion

Fusion may be used when instability is present or when decompression would otherwise leave the spine unstable.

It can also be considered for selected cases of deformity, spondylolisthesis, or severe degenerative disease.

Fusion solely for nonspecific low back pain is relatively uncommon.

Deformity Correction

Patients with significant spinal deformities such as scoliosis or spondylolisthesis may require realignment combined with fusion.

Correction is generally considered when deformity is progressive, symptomatic, unstable, or neurologically compromising.

Instrumentation

Modern spinal fusion may use a variety of fixation systems.

Examples include pedicle screws, rods, plates, and interbody devices.

Instrumentation provides mechanical stability and increases the likelihood of obtaining a solid fusion.

Lumbar Disc Arthroplasty

Lumbar disc replacement has been developed as an alternative to fusion for selected patients with persistent discogenic low back pain.

The objective is to remove the painful disc while preserving motion at the involved spinal level.

Short-term outcomes have been encouraging in appropriately selected patients.

Limitations of Disc Arthroplasty

Longer-term studies have demonstrated that prosthetic disc motion may gradually decrease over time.

Because of concerns regarding durability, patient selection, adjacent-segment effects, and revision surgery, lumbar disc arthroplasty remains controversial in some settings.

Follow-Up

Patients with uncomplicated low back pain should be reviewed according to symptom severity and functional limitation.

Follow-up at approximately 4–6-week intervals may be appropriate until substantial improvement occurs.

Persistent or worsening symptoms should prompt reconsideration of the diagnosis.

Prognosis

The prognosis is generally good in patients without major structural abnormalities.

Many episodes improve with activity modification, appropriate medication, exercise, and rehabilitation.

However, recurrent or chronic symptoms are common in some patients.

Prognosis After Fusion

Patients who undergo major spinal fusion can often return to many routine activities.

However, heavy manual work and repeated high-load activities may remain difficult because spinal motion is reduced and adjacent segments experience greater mechanical demand.

Complications

Potential complications of spinal disease and its treatment include infection, neurologic injury, surgical failure, pseudarthrosis, loss of fixation, and persistent unexplained pain.

Complication risk varies according to the underlying disorder and surgical procedure.

Pseudarthrosis

Pseudarthrosis refers to failure of a planned spinal fusion to unite.

It may result in persistent pain, hardware failure, deformity, or instability and may occasionally require revision surgery.

Cauda Equina Syndrome

Cauda equina syndrome is a neurologic emergency caused by severe compression of the cauda equina nerve roots.

It may result from a large disc herniation, tumor, infection, fracture, or other space-occupying lesion.

Signs of Cauda Equina Syndrome

Concerning findings include progressive bilateral leg weakness, saddle anesthesia, urinary retention or incontinence, bowel dysfunction, and severe neurologic loss.

Untreated compression can result in permanent paralysis and irreversible loss of bladder and bowel function.

Urgent imaging and surgical evaluation are required.

Patient Monitoring

Patients should demonstrate gradual improvement with rest, activity modification, appropriate medication, and rehabilitation.

Range of motion, strength, gait, neurologic function, and ability to perform daily activities should be monitored.

If pain fails to improve as expected or new neurologic or systemic symptoms develop, a significant structural or systemic cause should be reconsidered.

Orthopaedic Surgery - Atypical Stress Fractures

Basics

Atypical stress fractures most commonly involve the subtrochanteric region or femoral shaft and are strongly associated with prolonged bisphosphonate therapy.

These fractures occur distal to the lesser trochanter and proximal to the supracondylar region of the femur.

They generally result from a low-energy mechanism, such as a fall from standing height, and some patients report no preceding traumatic event at all.

A characteristic radiographic feature is localized thickening or beaking of the lateral femoral cortex.

The fracture is usually transverse or short oblique, is generally noncomminuted, and may occasionally demonstrate a medial cortical spike.

Epidemiology

The reported incidence of atypical femoral fractures is approximately 50–130 cases per 100,000 patient-years.

The true incidence may be lower because epidemiologic studies sometimes have difficulty consistently identifying fractures that meet formal atypical femoral fracture criteria.

These fractures remain substantially less common than typical osteoporotic hip fractures.

They appear to occur more frequently in women and individuals of Asian ethnicity.

Risk Factors

The most important risk factor is long-term bisphosphonate use.

The risk increases with longer duration of treatment and becomes more significant after approximately 4 years of continuous therapy, although atypical fractures have been reported after as little as 1.5 years of treatment.

Other recognized risk factors include Asian ethnicity, prolonged glucocorticoid therapy, autoimmune disease, obesity with a BMI greater than 30 kg/m², age younger than approximately 70 years, and earlier menopause.

Etiology and Pathophysiology

The principal proposed mechanism is prolonged suppression of normal bone remodeling caused by bisphosphonates.

The femur is exposed to repetitive mechanical loading during everyday activities. This produces microscopic damage, particularly along the lateral cortex, which normally undergoes continuous remodeling and repair.

Bisphosphonate therapy can markedly reduce bone turnover. When remodeling is excessively suppressed, microdamage may accumulate rather than being repaired.

Over time, small cortical cracks may propagate and eventually develop into an incomplete or complete atypical fracture.

Mechanical Factors

The lateral femoral cortex experiences considerable tensile stress during weight-bearing.

Certain anatomical characteristics can increase these stresses, including lateral femoral bowing and varus alignment of the proximal femur.

These mechanical factors may concentrate forces along the lateral cortex and increase susceptibility to fracture.

Genetic Factors

A genetic predisposition has also been reported in some patients.

The precise genetic contribution remains incompletely understood, but inherited differences in bone remodeling or femoral geometry may influence susceptibility.

Associated Conditions

Atypical femoral fractures are frequently encountered in patients with osteoporosis receiving prolonged bisphosphonate treatment.

They may also occur in individuals with autoimmune disorders who have required prolonged glucocorticoid therapy, which can adversely affect bone quality and healing.

Diagnosis

Signs and Symptoms

Some patients are completely asymptomatic before sustaining a complete fracture.

Others experience characteristic prodromal pain for weeks or months before the fracture becomes complete.

The pain is often described as a dull or aching discomfort involving the groin or thigh, particularly during weight-bearing.

Symptoms may be vague or sharply localized.

History

The clinical history should specifically assess the duration of bisphosphonate use.

Although the greatest concern traditionally involves treatment extending beyond 4–5 years, atypical fractures can occur earlier.

A history of long-term glucocorticoid use should also be documented.

Patients should be questioned about preceding thigh or groin pain and whether symptoms worsen with walking or prolonged standing.

Physical Examination

Patients with an incomplete fracture may have localized tenderness along the thigh and pain during weight-bearing.

Hip range of motion may reproduce discomfort, particularly internal rotation.

A complete displaced fracture usually results in inability to bear weight.

Visible deformity and shortening of the affected limb may also be present.

Imaging

Plain Radiographs

Initial evaluation should include an anteroposterior radiograph of the pelvis together with AP and lateral views of the hip, entire femur, and knee.

It is important to image the entire femur because the lesion may occur anywhere from the subtrochanteric region to the distal shaft.

Early Radiographic Findings

Before a complete fracture develops, radiographs may show focal periosteal reaction, cortical thickening, or beaking along the lateral femoral cortex.

These changes may represent an impending atypical fracture.

A transverse radiolucent line extending inward from the lateral cortex may indicate an incomplete fracture.

Complete Fracture Pattern

Complete atypical femoral fractures are typically transverse or short oblique.

The fracture pattern is usually simple and demonstrates little or no comminution.

A characteristic medial cortical spike may occasionally be present.

These features help distinguish atypical fractures from typical high-energy femoral shaft fractures.

Contralateral Femur Imaging

Atypical femoral fractures are frequently bilateral or sequential.

Therefore, radiographs of the contralateral femur should routinely be obtained when an atypical fracture is identified.

The opposite femur should be examined for cortical thickening, beaking, periosteal reaction, or a transverse radiolucent line.

MRI

MRI is generally unnecessary when a complete fracture is clearly visible on radiographs.

However, it is the preferred imaging study for detecting an occult or incomplete atypical fracture when plain radiographs are normal or equivocal but clinical suspicion remains high.

Typical findings include bone marrow edema and a linear low-signal fracture line.

MRI is particularly useful in patients receiving long-term bisphosphonates who present with unexplained thigh or groin pain.

Bone Scintigraphy

Bone scintigraphy may detect increased metabolic activity at an impending fracture site.

However, it is less specific than MRI and is not generally required when a complete fracture is already visible radiographically.

It may be useful when MRI cannot be performed.

CT

CT is also usually unnecessary for complete atypical fractures.

It has lower sensitivity than MRI for detecting early stress reactions and incomplete fractures.

Its use is therefore generally reserved for selected cases in which detailed cortical anatomy is required.

Dual-Energy X-Ray Absorptiometry

Dual-energy X-ray absorptiometry may occasionally identify cortical abnormalities such as periosteal reaction or lateral cortical beaking during monitoring of patients receiving prolonged bisphosphonate therapy.

Its primary purpose remains assessment of bone mineral density rather than diagnosis of atypical fracture.

Differential Diagnosis

The differential diagnosis includes insufficiency fracture, intertrochanteric or peritrochanteric fracture, typical osteoporotic hip fracture, and femoral neck stress fracture.

Musculoskeletal conditions such as overuse tendinopathy may also produce thigh or groin pain and can mimic prodromal symptoms.

Treatment

General Measures

Long-term bisphosphonate therapy should be reassessed in patients at increased risk of atypical femoral fracture.

A drug holiday may be considered in appropriate patients after balancing the risk of atypical fracture against the continuing risk of osteoporotic fragility fracture.

Patients receiving bisphosphonates for approximately 3–5 years or longer should be monitored for symptoms suggestive of an atypical femoral fracture.

Monitoring for Prodromal Symptoms

Patients on prolonged bisphosphonate treatment should be questioned about new groin or thigh pain, particularly pain occurring during weight-bearing.

When such symptoms develop, imaging should be obtained promptly.

Early identification of an incomplete lesion may allow prophylactic treatment before displacement occurs.

Laboratory Evaluation

Bone turnover markers may occasionally be assessed when excessive suppression of remodeling is suspected.

Potential investigations include serum or urine N-telopeptide or C-telopeptide levels and bone-specific alkaline phosphatase.

These tests may provide information about bone turnover but do not establish the diagnosis of an atypical fracture.

Weight-Bearing Restrictions

Patients with prodromal pain and radiographic or imaging evidence of an incomplete fracture should reduce loading of the affected limb.

Partial or non-weight-bearing may be recommended while definitive treatment is arranged.

The objective is to reduce the risk of progression to a complete displaced fracture.

Surgical Management

Intramedullary Nailing

Intramedullary nailing is the preferred treatment for most complete atypical femoral fractures.

It is also commonly recommended for incomplete fractures that are painful or demonstrate features indicating a high risk of progression.

The intramedullary device provides load-sharing fixation along the length of the femur and allows early mobilization.

Incomplete Fractures

Incomplete atypical fractures have a substantial risk of progressing to complete displaced fractures.

This risk is particularly high when a visible radiolucent fracture line, lateral cortical beaking, and persistent prodromal pain are present.

Observation alone may therefore be inappropriate in high-risk lesions.

Prophylactic Intramedullary Nailing

Prophylactic intramedullary fixation may be recommended for patients with an incomplete atypical lesion before a displaced fracture occurs.

Important indications include lateral cortical beaking combined with persistent thigh or groin pain.

Preventive fixation can reduce the likelihood of sudden complete fracture and may allow a more predictable recovery.

Plate Fixation

Intramedullary nailing may be technically difficult in patients with substantial femoral bowing.

In such situations, lateral plate fixation may be considered.

The choice of fixation should take femoral geometry, fracture location, and surgeon experience into account.

Contralateral Femur Management

Management of the opposite femur is controversial.

Routine prophylactic fixation of an asymptomatic contralateral femur is not recommended for every patient.

However, prophylactic intramedullary nailing may be considered when multiple high-risk features are present.

High-Risk Contralateral Features

Factors that may support prophylactic fixation of the opposite femur include Asian ethnicity, prodromal thigh pain, varus proximal femoral geometry, marked femoral bowing, and radiographic abnormalities such as cortical beaking or a transverse radiolucent line.

The decision should be individualized according to overall fracture risk and symptoms.

Follow-Up

Patients require close follow-up after both operative and nonoperative management.

Serial radiographs are used to assess healing, implant position, and possible progression of incomplete lesions.

The contralateral femur should also be monitored because a second atypical fracture may develop later.

Prognosis

Intramedullary fixation generally permits relatively early or immediate protected weight-bearing and facilitates return to function.

However, atypical femoral fractures often heal more slowly than typical traumatic femoral fractures.

They have a higher incidence of delayed union, nonunion, and revision surgery compared with more typical hip or femoral fractures.

Delayed Healing

Suppressed bone remodeling and the chronic stress-fracture nature of the injury may contribute to prolonged healing.

Radiographic union can therefore take considerable time even after technically successful fixation.

Patients should be counseled that recovery may be slower than after a conventional femoral fracture.

Complications

An incomplete atypical fracture may progress to a complete displaced fracture, particularly if weight-bearing continues despite prodromal symptoms.

Other important complications include delayed union, nonunion, implant-related problems, and the development of an atypical fracture in the contralateral femur.

Contralateral Fracture

Patients who sustain one atypical femoral fracture have an increased risk of developing a similar lesion on the opposite side.

Persistent or new contralateral thigh pain should therefore be investigated promptly.

Long-term surveillance of both femora may be appropriate in high-risk individuals.

Patient Teaching

Patients receiving long-term bisphosphonate therapy should understand that atypical femoral fractures are uncommon but recognized complications of prolonged treatment.

They should be advised to report new groin or thigh pain during weight-bearing, even if there has been no trauma.

Early Warning Signs

Patients should understand that an atypical fracture may initially produce no symptoms.

When symptoms do occur, vague aching pain in the thigh or groin may precede complete fracture by weeks or months.

Radiographs may show lateral cortical thickening or beaking before the fracture becomes complete.

Importance of Early Evaluation

Early recognition of an impending atypical femoral fracture can prevent progression to a displaced injury.

Patients with significant prodromal symptoms, radiographic abnormalities, or other high-risk findings should undergo prompt orthopedic evaluation.

Patients with a complete atypical fracture, or those with an incomplete lesion at high risk of progression, commonly require surgical stabilization.

Orthopaedic Surgery - Arthroscopy

Basics

Arthroscopy is a minimally invasive surgical technique that allows direct visualization and treatment of structures within a joint through small portal incisions.

The procedure should be performed only after a complete clinical history, thorough physical examination, and appropriate imaging studies have been obtained.

Most arthroscopic procedures can be performed on an outpatient basis, although the postoperative course depends on the joint involved and the complexity of the procedure.

General Principles

Arthroscopy uses a small camera, or arthroscope, inserted through one portal while surgical instruments are introduced through one or more additional portals.

The technique allows the surgeon to inspect articular cartilage, ligaments, tendons, menisci, labral structures, synovium, and other intra-articular tissues.

In addition to diagnostic evaluation, many abnormalities can be treated during the same procedure.

Knee Arthroscopy

Indications

Common indications for knee arthroscopy include meniscal repair or debridement, treatment of meniscal cysts, management of osteochondral lesions, and reconstruction or debridement of anterior or posterior cruciate ligament injuries.

It may also be performed for synovial biopsy, synovectomy, evaluation of unexplained knee pain or instability, and selected cases of degenerative joint disease requiring debridement.

Procedure

Knee arthroscopy is usually performed through two or more small portal incisions, each measuring approximately 0.5 cm.

One portal is used for the arthroscope, while the remaining portals permit insertion of surgical instruments.

The technique allows systematic visualization of all three major compartments of the knee: the patellofemoral, medial, and lateral compartments.

Articular Cartilage Assessment

The articular cartilage of the femur, tibia, and patella can be directly inspected.

The surgeon can evaluate cartilage for degeneration, fissuring, osteochondral defects, loose fragments, or traumatic injury.

Selected cartilage lesions may be treated arthroscopically during the same procedure.

Meniscal Assessment

Both the medial and lateral menisci can be visualized and probed.

Probing helps determine the location, configuration, stability, and extent of a meniscal tear.

Depending on the tear pattern and vascularity, treatment may involve meniscal repair or selective debridement.

Cruciate Ligament Assessment

The anterior cruciate ligament and posterior cruciate ligament can also be visualized and probed arthroscopically.

Their integrity, tension, attachment sites, and associated injuries can be assessed.

ACL and PCL reconstruction can be performed with arthroscopic assistance.

Postoperative Weight-Bearing

After uncomplicated knee arthroscopy, many patients can begin partial or full weight-bearing with crutch assistance soon after surgery.

The exact amount of permitted weight-bearing depends on the procedure performed.

For example, rehabilitation after simple debridement may progress more rapidly than after meniscal repair, cartilage restoration, or ligament reconstruction.

Rehabilitation After Knee Arthroscopy

The duration of rehabilitation varies according to the underlying injury and surgical procedure.

Physical therapy commonly focuses on restoring range of motion, gait, core stability, quadriceps strength, and hamstring strength.

The rehabilitation protocol should be individualized rather than based solely on the fact that arthroscopy was performed.

Shoulder Arthroscopy

Indications

Shoulder arthroscopy may be performed for a wide variety of conditions.

Common indications include shoulder instability, synovial or tissue biopsy, removal of loose bodies, subacromial impingement, rotator cuff tears, and superior labral anterior-posterior (SLAP) lesions.

It can provide both diagnostic assessment and definitive surgical treatment.

Procedure

Shoulder arthroscopy typically requires two or more portals, generally measuring approximately 0.8 cm.

The arthroscope is introduced into the glenohumeral joint to inspect the articular surfaces and surrounding soft tissues.

Additional portals provide access for probing, debridement, repair, and fixation.

Articular Cartilage Assessment

The articular surfaces of the glenoid and humeral head can be inspected directly.

Arthroscopy may identify abnormalities such as osteoarthritis, cartilage defects, osteochondral fragments, or loose bodies.

The severity and distribution of cartilage damage can therefore be assessed accurately.

Glenohumeral Ligament Assessment

The major soft-tissue stabilizers of the shoulder can be examined arthroscopically.

These include the inferior, middle, and superior glenohumeral ligament complexes.

Their integrity is particularly important when evaluating recurrent instability or previous dislocation.

Labral Assessment

The glenoid labrum can be inspected throughout its circumference.

Arthroscopy can identify Bankart lesions, SLAP tears, degenerative labral changes, and other labral injuries.

The stability of the labrum can also be assessed with a probe.

Subacromial Assessment

When rotator cuff or impingement symptoms are present, arthroscopy can be extended into the subacromial space.

The rotator cuff, bursa, undersurface of the acromion, and surrounding structures are examined for causes of mechanical impingement or tendon injury.

Arthroscopic Stabilization

Recurrent shoulder instability can often be treated arthroscopically.

Procedures may include Bankart repair or capsulolabral stabilization, in which the detached labrum and capsule are restored to the glenoid rim.

These procedures aim to restore stability while preserving shoulder motion.

Acromioplasty

Arthroscopic acromioplasty may be performed in selected cases of mechanical subacromial impingement.

The procedure involves reshaping part of the acromion and removing impinging tissue to increase the available space for the rotator cuff.

Rotator Cuff Repair

Many rotator cuff tears can be repaired arthroscopically.

The torn tendon is mobilized and reattached to its insertion on the greater tuberosity, commonly using suture anchors.

Arthroscopic repair allows treatment through small portals while minimizing disruption of the surrounding deltoid muscle.

SLAP Lesions

SLAP lesions may be treated with arthroscopic repair or debridement, depending on the tear pattern, patient age, activity level, and associated pathology.

Direct visualization allows accurate evaluation of the superior labrum and biceps anchor.

Rehabilitation After Shoulder Arthroscopy

Physical therapy is an essential component of recovery after shoulder arthroscopy.

Early rehabilitation usually emphasizes restoring appropriate motion while protecting repaired tissues.

Later stages focus on strengthening the rotator cuff, scapular stabilizers, and other dynamic stabilizers of the shoulder.

The duration and progression of rehabilitation depend on the operation performed.

Hip Arthroscopy

Indications

Hip arthroscopy may be used for synovial biopsy, synovectomy, removal of loose bodies, and treatment of labral tears.

Because the hip is a deep, constrained joint, specialized traction and instrumentation are generally required.

Labral Treatment

Hip arthroscopy allows direct inspection of the acetabular labrum.

Symptomatic labral tears may be treated with repair, selective debridement, or other arthroscopic techniques, depending on the pattern and quality of the tissue.

Loose-Body Removal

Intra-articular loose bodies can produce pain, locking, catching, and restricted motion.

Arthroscopy permits their removal without requiring a large open surgical exposure.

Ankle Arthroscopy

Indications

Ankle arthroscopy may be performed for synovial biopsy or synovectomy, removal of loose bodies, excision of bone spurs, and treatment of osteochondral lesions.

It is particularly useful for disorders causing mechanical impingement, locking, or persistent intra-articular pain.

Osteochondral Lesions

Osteochondral lesions of the talus can be evaluated directly during ankle arthroscopy.

Depending on the size and characteristics of the lesion, treatment may include debridement, stabilization of unstable cartilage, or marrow-stimulation techniques.

Bone-Spur Removal

Anterior or posterior ankle osteophytes can produce painful impingement during motion.

Arthroscopic excision of selected osteophytes can improve movement and relieve mechanical symptoms.

Elbow Arthroscopy

Indications

Elbow arthroscopy may be used for synovial biopsy, synovectomy, loose-body removal, and debridement of cartilage lesions or osteophytes.

It can be especially useful in patients with mechanical locking, restricted motion, or symptomatic intra-articular pathology.

Cartilage and Osteophyte Debridement

Degenerative cartilage fragments and osteophytes may restrict elbow motion and cause pain.

Arthroscopic debridement can remove these structures while minimizing soft-tissue disruption compared with some open procedures.

Wrist Arthroscopy

Indications

Wrist arthroscopy may be performed for synovial biopsy, synovectomy, removal of loose bodies, and diagnosis or treatment of triangular fibrocartilage complex (TFCC) injuries.

It provides detailed visualization of small intra-articular structures that may be difficult to assess using imaging alone.

TFCC Assessment

The triangular fibrocartilage complex can be directly inspected and probed arthroscopically.

Tears may be assessed according to their location, stability, and tissue quality.

Depending on the lesion, treatment may involve debridement or repair.

Advantages of Arthroscopy

Arthroscopy generally requires smaller incisions than traditional open surgery.

Potential benefits include less disruption of surrounding soft tissues, improved visualization of intra-articular structures, and the ability to diagnose and treat several abnormalities during the same procedure.

Many procedures can also be performed without overnight hospitalization.

Limitations

Arthroscopy is not appropriate for every joint disorder.

The decision to operate should be based on the patient’s symptoms, physical examination, imaging, functional impairment, and likelihood that the identified pathology is responsible for the symptoms.

Abnormal imaging alone does not necessarily justify arthroscopic surgery.

Postoperative Rehabilitation

Rehabilitation should always be tailored to the specific procedure performed.

Simple diagnostic arthroscopy or debridement may allow rapid progression of activity.

Procedures involving meniscal repair, ligament reconstruction, labral repair, rotator cuff repair, or cartilage treatment generally require more prolonged protection and structured rehabilitation.

Patient Monitoring

Postoperative follow-up should assess wound healing, pain, swelling, joint range of motion, strength, and functional recovery.

Patients should also be monitored for complications such as infection, stiffness, neurovascular symptoms, or persistent mechanical complaints.

Progression of weight-bearing, strengthening, and return to sport should follow the requirements of the specific arthroscopic procedure rather than a single universal protocol.