Orthopaedic Surgery - Subtrochanteric Fracture

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Basics

A subtrochanteric fracture is a fracture of the proximal femur occurring between the:

Lesser trochanter

and a point approximately:

5 cm distal to it.

This region is subjected to very high:

Compressive

and

Tensile forces

during normal weight bearing.

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Classification

Numerous classification systems have been described.

From a practical and prognostic standpoint, one of the most important characteristics is:

Fracture stability.

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Stable Versus Unstable Fracture

Stability depends largely on preservation of the:

Medial

and

Posteromedial cortices.

These regions normally resist substantial:

Compressive loading.

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Unstable Fracture

Comminution of the:

Medial or posteromedial cortex

removes an important structural buttress and makes the fracture:

Mechanically unstable.

This increases the risk of:

Varus collapse

Loss of fixation

and

Nonunion.

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General Prevention

Preventive measures include:

Fall prevention in older adults

and

Seat-belt use in motor vehicles.

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Bone Health

Because many low-energy subtrochanteric fractures occur in patients with weakened bone, appropriate evaluation and treatment of:

Osteoporosis

and other metabolic bone disorders can reduce future:

Fragility fracture risk.

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Epidemiology

Subtrochanteric fractures demonstrate a:

Bimodal age distribution.

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Younger Patients

Approximately:

One-third

occur in patients younger than or equal to:

50 years.

These injuries are typically caused by:

High-energy trauma.

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Older Patients

In geriatric patients, subtrochanteric fractures more commonly follow:

Low-energy trauma

such as a:

Fall from standing height.

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Incidence

Historical series report that subtrochanteric fractures account for approximately:

10–34% of proximal femoral or hip fractures.

Reported percentages vary according to how the:

Subtrochanteric region

is defined.

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Risk Factors

Any disorder that decreases:

Bone strength

may predispose to subtrochanteric fracture.

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Generalized Bone Weakness

Examples include:

Osteoporosis

Osteomalacia

and other:

Metabolic bone diseases.

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Focal Bone Weakness

Local structural weakening may occur with:

Metastatic disease

Primary bone tumor

Fibrous dysplasia

or other focal:

Bone lesions.

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Etiology

The injury mechanism differs according to:

Age

and

Bone quality.

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High-Energy Trauma

In young patients with normal bone, common mechanisms include:

Motor vehicle collisions

Falls from significant height

and

Gunshot wounds.

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Low-Energy Trauma

In older patients with osteoporotic bone, a minor fall may generate sufficient force to produce a:

Subtrochanteric fracture.

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Pathological Fracture

A pathological fracture may occur when structurally abnormal bone can no longer tolerate:

Normal physiologic loading.

Potential causes include:

Metastatic carcinoma

Multiple myeloma

Primary bone tumor

and

Metabolic bone disease.

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Biomechanics

The subtrochanteric region experiences some of the highest mechanical forces in the:

Femur.

This contributes to both:

Fracture instability

and the risk of:

Fixation failure.

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Associated Injuries

High-energy subtrochanteric fractures may occur with injuries involving:

The ipsilateral femur

Hip

Pelvis

Spine

Head

or other body regions.

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Trauma Evaluation

Patients with a high-energy mechanism require a:

Complete trauma assessment.

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Hemorrhage

Femoral fractures can be associated with substantial:

Blood loss.

Patients should be monitored for:

Hemodynamic instability

and

Hypovolemic shock.

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Thigh Compartment Syndrome

Compartment syndrome of the thigh is:

Rare

but possible after severe trauma.

Increasing pain, tense swelling, and neurologic abnormalities should prompt:

Urgent evaluation.

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Suspicion for Pathological Fracture

An underlying neoplasm or bone disorder should be considered when the fracture occurs after:

Minimal trauma

or when the patient reports preceding:

Thigh pain

Hip pain

or

Limp.

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Biopsy

If a pathological lesion is suspected, the diagnostic plan should be established before definitive fixation.

In selected cases, this may include:

Biopsy

performed in a manner consistent with future:

Oncologic treatment.

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Diagnosis

The clinical presentation often resembles a:

Femoral shaft

or

Intertrochanteric fracture.

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Signs and Symptoms

Typical findings include:

Severe proximal thigh or hip pain

Swelling

Deformity

and inability to:

Bear weight.

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Nondisplaced Fractures

Some fractures may initially be:

Nondisplaced

and therefore produce less obvious:

Deformity.

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History

The usual history includes:

Trauma

or

Fall.

In pathological fractures, trauma may be:

Minimal or absent.

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Physical Examination

The injured extremity often appears:

Shortened

and the thigh may be:

Swollen.

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Deformity

Varus and rotational deformity may be apparent because of the powerful:

Muscle forces

acting across the fracture.

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Neurovascular Examination

A complete neurovascular examination should document:

Motor function

Sensation

Peripheral pulses

and

Capillary refill.

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Open Fracture

The skin should be examined carefully to exclude:

Open injury.

Even a small wound may communicate with the:

Fracture.

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Laboratory Tests

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Complete Blood Count

A CBC is useful to evaluate:

Hemoglobin

and

Hematocrit

because significant blood loss may accompany:

Femoral fractures.

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Preoperative Testing

Patients likely to undergo surgery should receive appropriate:

Preoperative laboratory evaluation

based on age and:

Medical comorbidity.

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Multiple Myeloma Evaluation

When a pathological fracture is suspected, selected testing may include:

Serum protein electrophoresis

and

Urine protein electrophoresis

to evaluate for:

Plasma-cell disorders.

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Imaging

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Plain Radiographs

Imaging should include:

AP pelvis

AP hip

Lateral hip

and

Full-length AP and lateral femur radiographs.

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Entire Femur Imaging

The entire femur should be visualized because associated fractures may occur and because definitive fixation often requires knowledge of:

Femoral anatomy.

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Femoral Neck

The femoral neck should be assessed carefully for an associated:

Ipsilateral femoral neck fracture.

This is particularly important after:

High-energy trauma.

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Cross-Table Lateral

A:

Cross-table lateral hip view

is preferred in the acute setting.

A frog-leg lateral should generally be avoided because positioning can cause:

Pain

and potentially worsen:

Fracture displacement.

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CT

CT may be useful in selected complex injuries to define:

Fracture morphology

or associated:

Pelvic or proximal femoral injury.

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Pathophysiology of Deformity

Characteristic deformity occurs because the proximal and distal fragments are pulled in different directions by:

Muscle forces.

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Proximal Fragment

The proximal femoral fragment is typically pulled into:

Flexion

Abduction

and

External rotation.

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Flexion

The:

Iliopsoas

pulls the proximal fragment into:

Flexion.

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Abduction

The:

Gluteus medius and minimus

contribute to proximal fragment:

Abduction.

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External Rotation

The short external rotators contribute to:

External rotation

of the proximal fragment.

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Distal Fragment

The distal fragment is pulled:

Proximally

and often into:

Adduction and varus.

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Shortening

Muscular pull across the fracture produces:

Femoral shortening.

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Varus Deformity

Loss of medial support and muscular forces predispose the fracture to:

Varus malalignment.

Recognition of these predictable deforming forces is important during:

Fracture reduction.

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Differential Diagnosis

The major distinction is between:

Traumatic fracture

and

Pathological fracture.

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Additional Differential Considerations

Other proximal femoral injuries include:

Intertrochanteric fracture

Femoral neck fracture

and

Proximal femoral shaft fracture.

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Treatment

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General Measures

Initial management follows standard principles of:

Trauma stabilization.

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ATLS

For patients with major trauma, evaluation should follow:

ATLS principles

with treatment of immediately life-threatening conditions before definitive:

Fracture fixation.

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Temporary Stabilization

Temporary immobilization may help reduce:

Pain

Bleeding

and further:

Soft-tissue injury.

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Traction

Skeletal traction was historically used when definitive fixation was delayed or when nonoperative treatment was planned.

Modern practice generally favors:

Early surgical fixation

when medically feasible.

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Nonoperative Treatment

Nonoperative management is uncommon and is usually reserved for:

Patients who cannot tolerate surgery

or other exceptional situations.

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Limitations of Nonoperative Care

Traction or cast bracing frequently leads to:

Shortening

Rotational deformity

Varus malunion

Delayed union

or

Nonunion.

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Medical Optimization

Important perioperative issues include:

Fluid and blood-volume management

Venous thromboembolism prophylaxis

Pain control

and treatment of:

Pre-existing medical conditions.

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Venous Thromboembolism Prevention

Appropriate prophylaxis should be planned while considering the timing of:

Definitive surgery.

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Activity

Before definitive stabilization, the patient is generally:

Non-weight-bearing.

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Postoperative Weight Bearing

Weight-bearing recommendations depend on:

Fracture stability

Quality of reduction

Fixation construct

and

Bone quality.

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Younger Patients

Historically, younger patients were often started with:

Toe-touch or protected weight bearing

using:

Crutches

or

A walker

during the early postoperative period.

Progression toward full weight bearing was guided by:

Clinical and radiographic healing.

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Older Patients

Older patients are often allowed:

Weight bearing as tolerated

after stable fixation because prolonged restriction may be difficult and can increase:

Medical complications.

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Physical Therapy

Rehabilitation should begin early after stabilization.

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Range of Motion

Patients can usually begin:

Hip

and

Knee range-of-motion exercises

during the early postoperative period.

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Strengthening

Progressive strengthening emphasizes:

Hip abductors

Quadriceps

and overall:

Lower-extremity function.

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Gait Training

Physical therapy also includes:

Transfer training

Walking with assistive devices

and progression toward:

Independent mobility.

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Medication

Significant acute pain often requires:

Short-term opioid analgesia.

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Multimodal Pain Control

Whenever possible, pain treatment should use:

Multimodal analgesia

including:

Acetaminophen

and other appropriate adjuncts to reduce reliance on:

Opioids.

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Surgery

Operative fixation is the treatment of choice for most:

Subtrochanteric fractures.

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Goals of Surgery

The major objectives are to restore:

Femoral length

Rotational alignment

and

Coronal alignment

while preserving the:

Hip abductor lever arm.

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Varus Prevention

Avoidance of:

Varus malreduction

is particularly important because varus increases mechanical stress across:

The fracture

and

Implant.

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Intramedullary Fixation

Modern treatment most commonly uses a:

Cephalomedullary intramedullary nail.

This fixation method places the implant closer to the mechanical axis of the:

Femur

and is advantageous for many:

Unstable fracture patterns.

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Cephalomedullary Nail

A cephalomedullary nail usually includes:

Proximal fixation into the femoral head and neck

and

Distal locking screws.

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Posteromedial Comminution

Cephalomedullary fixation is particularly useful when there is:

Loss of posteromedial cortical support.

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Interlocking Nail

Static interlocking nails may be used in selected patterns when the:

Proximal trochanteric anatomy

permits stable fixation.

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Plate Fixation

A:

95° angled blade plate

is a historical and still occasionally useful option for selected complex fractures or:

Revision procedures.

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Mechanical Environment

Because the subtrochanteric femur experiences high:

Tensile

and

Compressive forces

implant fatigue is a major concern when reduction is poor or healing is:

Delayed.

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Reduction Quality

Successful fixation depends heavily on obtaining:

Near-anatomic alignment

especially restoration of the:

Medial cortex

and avoidance of:

Varus.

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Pediatric Considerations

Subtrochanteric femur fractures are relatively uncommon in:

Children.

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Mechanism in Children

Unless bone is weakened by disorders such as:

Simple bone cyst

Fibrous dysplasia

or

Osteoporosis

these fractures generally result from:

High-energy trauma.

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Femoral Head Blood Supply

Unlike femoral neck fractures, typical pediatric subtrochanteric fractures do not directly endanger the:

Femoral head blood supply.

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Leg-Length Discrepancy

Children may develop:

Leg-length discrepancy

even when no obvious physeal injury is present.

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Rotational Alignment

Attention to:

Leg length

and

Femoral rotation

is especially important during pediatric treatment.

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Pediatric Treatment Options

Treatment may include:

Closed reduction with spica casting

External fixation

or

Internal fixation

depending on:

Age

Fracture pattern

and

Body size.

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Pediatric Intramedullary Nailing

In skeletally immature patients, traditional piriformis-entry rigid nails may endanger the:

Femoral head blood supply.

Alternative entry points or fixation methods are therefore preferred when the:

Proximal femoral physis remains open.

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Follow-Up

Patients should be reviewed soon after:

Surgical fixation.

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Early Review

An initial follow-up around:

1–2 weeks

may assess:

Wound healing

Alignment

and

Implant position.

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Serial Follow-Up

Subsequent visits monitor:

Pain

Weight-bearing progression

Fracture callus

and evidence of:

Union.

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Radiographic Monitoring

Radiographs are typically repeated at regular intervals until:

Solid healing

is demonstrated.

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Prognosis

With appropriate reduction and stable fixation, many patients can return toward their:

Preinjury level of activity.

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Older Patients

In frail geriatric patients, prognosis is also strongly influenced by:

Age

Comorbidities

and

Prefracture mobility.

Historical series of low-energy fractures have demonstrated substantial:

One-year mortality

and loss of:

Independence.

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Historical Outcomes

One older series of patients treated with cephalomedullary nails reported approximately:

34.5% mortality at 1 year.

Among survivors, increased use of:

Walking aids

and greater:

Social dependence

were common.

These values reflect a frail historical population and should not be interpreted as a universal prognosis for every patient.

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Residual Pain

Some survivors continue to experience:

Hip discomfort

although severe disabling pain is less common.

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Reoperation

Historical data have reported reoperation in approximately:

9%

of patients in some geriatric cohorts.

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Nonunion

Nonunion is uncommon with appropriate fixation but remains an important complication because of the high mechanical stresses in this region.

Historical reports have described rates around:

2%

in some modern nail series.

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Complications

The principal complications include:

Nonunion

Malunion

Shortening

and

Implant failure.

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Nonunion

Nonunion should be suspected when there is persistent:

Pain

Tenderness

and lack of radiographic progression toward healing over:

Several months.

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Timing

Persistent symptoms and absent healing at approximately:

3–6 months

may raise concern for:

Delayed union or nonunion.

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Risk Factors for Nonunion

Important factors include:

Varus malreduction

Medial cortical deficiency

Poor fixation

Smoking

Poor bone biology

and premature:

Excessive loading.

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Malunion

Malunion may result in:

Limp

Rotational deformity

Varus alignment

and

Leg-length discrepancy.

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Shortening

Loss of fracture alignment may produce:

Femoral shortening

and compromise:

Gait mechanics.

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Implant Failure

Hardware failure is more likely when the fracture remains:

Unstable

or develops:

Nonunion.

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Plate Failure

Plate constructs may fail through:

Screw pullout

especially in:

Osteoporotic bone.

Revision may require conversion to an:

Intramedullary device

with restoration of:

Alignment and biology.

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Intramedullary Nail Failure

Potential causes include:

Inadequate distal locking

Undersized nail

Poor reduction

and

Fracture extension near the entry site.

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Distal Cortical Penetration

An intramedullary nail may occasionally penetrate the:

Anterior distal femoral cortex

particularly when there is a mismatch between the:

Femoral bow

and

Implant geometry.

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Revision Surgery

Symptomatic nonunion or malunion may require:

Revision fixation

Bone grafting

and occasionally:

Corrective valgus osteotomy.

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Osteotomy

A valgus-producing osteotomy may improve mechanical loading by converting excessive:

Shear forces

into more favorable:

Compressive forces.

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Pediatric Osteonecrosis

Osteonecrosis of the femoral head is uncommon in the fracture itself but may occur in a child if a rigid intramedullary nail is introduced through the:

Piriformis fossa

while the proximal femoral blood supply remains vulnerable.

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Patient Monitoring

Follow-up should assess:

Pain

Wound healing

Neurovascular status

Alignment

Leg length

Rotation

Weight-bearing ability

and progression toward:

Fracture union.

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Key Principle

A subtrochanteric fracture is a proximal femoral fracture extending from the lesser trochanter to approximately 5 cm distally.

The region experiences very high:

Mechanical forces, and loss of the medial or posteromedial cortex makes the fracture particularly:

Unstable.

Young patients usually sustain these injuries through:

High-energy trauma, whereas older patients typically sustain them after:

Low-energy falls in osteoporotic bone.

Most fractures are treated surgically, commonly with a:

Cephalomedullary intramedullary nail, with the goals of restoring:

Femoral length, rotation, and alignment while avoiding varus deformity.

Important complications include:

Nonunion, malunion, shortening, implant failure, and persistent functional impairment.