Orthopaedic Surgery - Femoral Neck Fracture

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Basics

A femoral neck fracture is one of the most common injuries referred to clinically as a “broken hip.”

The femoral neck is the intracapsular portion of the proximal femur connecting the femoral head to the trochanteric region.

These fractures occur most frequently in elderly patients after relatively minor trauma, although younger patients may sustain them after high-energy injuries.

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Clinical Importance

In older adults, the consequences extend beyond the fracture itself.

Pain and immobility can lead to cardiopulmonary complications, venous thromboembolism, pressure injuries, delirium, loss of independence, substantial morbidity, and increased mortality.

Early stabilization and mobilization are therefore important goals.

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Classification

Femoral neck fractures can be broadly categorized as stable or unstable.

A stable fracture is nondisplaced and may be impacted or incomplete.

An unstable fracture is complete and displaced.

The degree of displacement strongly influences treatment and prognosis because disruption of the femoral head blood supply becomes more likely as displacement increases.

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Epidemiology

Reported incidence is approximately 27.7 per 100,000 person-years in males and 63.3 per 100,000 person-years in females.

Rates have stabilized or declined in some populations, possibly because of improved osteoporosis diagnosis and the use of antiresorptive therapy.

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Age and Sex Distribution

Among younger patients, femoral neck fractures occur more commonly in males because they are usually caused by high-energy trauma.

Among elderly patients, women are affected approximately two to three times more frequently than men, largely because of the higher prevalence of postmenopausal osteoporosis.

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Risk Factors

The most important risk factor in older adults is osteoporosis.

Any condition that increases the likelihood of falling also increases fracture risk.

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Fall-Related Risk Factors

Important contributors include unsteady gait, impaired balance, poor vision, physical inactivity, urinary urgency or incontinence, polypharmacy, syncope, sedating medications such as benzodiazepines, Parkinson disease, and other neurologic disorders.

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Demographic Risk Factors

Additional recognized risk factors include female sex after menopause and Caucasian ancestry, largely through associations with reduced bone mineral density.

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Etiology

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Younger Patients

In patients younger than approximately 50 years, femoral neck fractures usually result from high-energy trauma, such as a motor vehicle collision or significant fall.

The mechanism often involves a strong axial force transmitted along the femoral shaft.

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Older Patients

In elderly individuals, the fracture commonly occurs after low-energy trauma, particularly a fall from standing height.

Underlying osteoporosis allows relatively minor forces to produce intracapsular fracture.

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Associated Conditions

Femoral neck fractures in older adults are strongly associated with osteoporosis and medical conditions that increase fall risk.

Associated problems may include visual impairment, balance disorders, polypharmacy, Parkinson disease, syncope, urinary frequency, and other neurologic conditions.

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Diagnosis

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Signs and Symptoms

Patients usually present with severe groin or hip pain after trauma.

Patients with displaced fractures are often unable to stand or walk.

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Limb Position

With an unstable displaced fracture, the affected leg commonly appears shortened and externally rotated.

Patients may hold the hip slightly flexed because this position reduces discomfort.

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Pain With Movement

Pain worsens with attempted hip motion, particularly internal rotation.

Axial loading of the limb also reproduces pain.

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Stable Fractures

Patients with impacted or nondisplaced fractures may not demonstrate obvious shortening or external rotation.

Some may still be able to bear limited weight, which can delay diagnosis.

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History

A history of hip or thigh pain preceding the traumatic event should raise concern for an underlying pathologic process such as metastatic disease.

The clinician should also determine the mechanism of injury, preinjury ambulatory status, baseline function, osteoporosis history, and relevant medical comorbidities.

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Physical Examination

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Hip Examination

Gentle passive range of motion should be assessed.

Pain with internal rotation is particularly common.

Forceful examination should be avoided when fracture is strongly suspected.

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Limb Alignment

Displaced fractures typically produce shortening and external rotation of the affected leg.

This deformity may be absent in stable fractures.

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Pelvic Examination

The pelvis should be palpated and assessed radiographically when appropriate to exclude a concomitant pelvic fracture.

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Straight-Leg Raise

An active straight-leg raise typically produces significant hip or groin pain and may be impossible.

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Neurovascular Examination

Distal motor, sensory, and vascular function should be documented, particularly after high-energy trauma.

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Laboratory Evaluation

Patients being admitted for operative treatment generally undergo routine preoperative laboratory testing.

This commonly includes a complete blood count, metabolic studies, coagulation testing when indicated, and blood type and screen.

Additional studies depend on age and medical status.

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Cardiopulmonary Assessment

Older adults may require an electrocardiogram, chest imaging when clinically indicated, and prompt medical evaluation to optimize perioperative status without unnecessarily delaying surgery.

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Imaging

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Plain Radiographs

Initial imaging should include an AP pelvis radiograph and dedicated AP and cross-table lateral views of the affected hip.

The entire femur should also be imaged when the mechanism suggests associated injury.

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Occult Femoral Neck Fracture

If radiographs are negative but clinical suspicion remains high, an occult nondisplaced fracture should be assumed until excluded.

MRI is the most sensitive imaging study for detecting an occult femoral neck fracture.

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CT

Dedicated CT can be helpful when MRI is unavailable or when more detailed bony definition is needed.

CT is particularly useful in patients with an ipsilateral femoral shaft fracture, in whom a femoral neck fracture may be subtle or missed.

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Pathological Findings

In elderly patients, especially those with osteoporosis, the fracture may be comminuted.

Comminution is particularly common in the subcapital region.

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Differential Diagnosis

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Occult Femoral Neck Fracture

An occult nondisplaced fracture should remain a major consideration in any patient with post-traumatic hip pain and normal initial radiographs.

MRI is often diagnostic.

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Pelvic Fracture

Pelvic fractures can produce groin pain and inability to bear weight and should be considered after falls or high-energy trauma.

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Intertrochanteric Fracture

Intertrochanteric fractures occur extracapsularly and may produce a similar clinical appearance.

Radiographs usually distinguish them from femoral neck fractures.

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Infection

Septic arthritis or osteomyelitis may cause severe hip pain and inability to bear weight, especially when no clear traumatic event is present.

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Greater Trochanteric Pain

Greater trochanteric bursitis or other lateral hip disorders may produce pain but generally do not cause the severe functional loss associated with a displaced fracture.

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Metastatic Disease

Pathologic fracture through metastatic bone should be considered when pain preceded the injury or imaging demonstrates an abnormal underlying lesion.

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Treatment

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General Principles

Treatment depends on patient age and physiologic status, fracture displacement, bone quality, preinjury function, fracture pattern, and associated medical conditions.

The goals are to restore mobility, reduce complications of immobility, and either preserve the native femoral head or replace it when preservation is unlikely to succeed.

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Stable Femoral Neck Fracture

Stable nondisplaced fractures are generally treated with internal fixation, commonly using multiple cannulated screws.

The objective is to prevent displacement while preserving the patient’s native femoral head.

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Displaced Fracture in Younger Patients

In younger, active patients, particularly those younger than approximately 50 years, a displaced femoral neck fracture should be treated urgently with anatomic reduction and internal fixation.

The reduction may be performed by closed or open techniques.

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Importance of Urgent Treatment

Femoral head preservation is particularly important in young patients.

Because the blood supply to the femoral head may be compromised by displacement, these injuries are considered orthopaedic emergencies or urgent injuries, with emphasis on prompt reduction and stable fixation.

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Polytrauma

In multiply injured patients, treatment of the femoral neck fracture must be coordinated with management of associated life-threatening injuries.

Trauma, anesthesia, and other surgical teams may need to participate simultaneously.

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Older Patients

In older patients with displaced fractures, particularly those of advanced physiologic age or with limited functional demand, arthroplasty is generally favored over internal fixation because of the high risks of nonunion and osteonecrosis.

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Patients Favoring Arthroplasty

Arthroplasty may be particularly appropriate in older sedentary patients or those with conditions such as Parkinson disease, hemiplegia, or severe pre-existing joint disease.

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Medical Optimization

Prompt medical assessment is essential in elderly patients.

Necessary medical problems should be corrected rapidly, but excessive delay in surgery increases the risks associated with prolonged immobilization.

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Activity

Before surgery, the patient is generally maintained at bed rest with protected positioning.

Routine traction is not usually beneficial for pain control and may cause skin complications.

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Nursing Care

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Pressure-Injury Prevention

Older immobilized patients are at risk for pressure ulcers involving the sacrum, buttocks, and heels.

Frequent repositioning, heel protection, pressure-relieving surfaces, and careful skin monitoring are important.

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Delirium Prevention

Postoperative and hospital-associated delirium is common in older adults.

Preventive measures include frequent reorientation, visible clocks and calendars, preservation of sleep-wake cycles, early mobilization, correction of sensory impairment, and avoidance of unnecessary deliriogenic medications.

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Physical Therapy

Physical therapy should begin as early as medically appropriate, usually on the first postoperative day.

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Older Patients

Most elderly patients are encouraged to bear weight as tolerated after fracture fixation or arthroplasty when the construct permits.

Early mobilization decreases the complications of prolonged bed rest.

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Younger Patients

Young patients treated with internal fixation may require restricted weight bearing until adequate fracture healing has occurred.

The exact duration depends on fracture stability and fixation.

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Medication

Analgesia is required throughout the acute and postoperative period.

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Opioid Considerations in Older Adults

Narcotic analgesics may cause delirium, respiratory depression, sedation, nausea, and constipation in elderly patients.

Pain control should therefore be adequate but carefully monitored.

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Younger Patients

Younger patients with high-energy fractures often require sufficient analgesia to permit safe rehabilitation and participation in therapy.

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Surgery

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Positioning and Imaging

Internal fixation may be performed with the patient supine on a fracture table under fluoroscopic guidance.

Alternative positioning on a radiolucent table may also be used depending on the surgical approach and fracture pattern.

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Cannulated Screw Fixation

In young patients and in stable nondisplaced fractures, fixation frequently consists of three cannulated screws placed across the femoral neck into the femoral head.

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Screw Configuration

The screws are typically distributed in a triangular configuration to maximize stability.

They should obtain secure purchase within the subchondral bone of the femoral head while avoiding joint penetration.

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Importance of Reduction

Precise reduction is critical.

Poor alignment increases the risk of mechanical failure, nonunion, and loss of femoral head viability.

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Basicervical Fractures

Fractures occurring near the base of the femoral neck, closer to the trochanters, have different mechanical characteristics and may require a sliding hip screw and side plate or another fixed-angle construct rather than isolated cannulated screws.

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Ipsilateral Femoral Shaft Fracture

Approximately 6–9% of patients with femoral shaft fractures may also have an ipsilateral femoral neck fracture.

Careful imaging is therefore required.

When both injuries are present, stabilization of the femoral neck generally receives priority because a missed or displaced neck fracture can have severe consequences.

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Arthroplasty

Prosthetic replacement may be performed through lateral, anterolateral, or posterior surgical approaches depending on surgeon preference and patient factors.

Both cemented and uncemented femoral components may be used.

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Hemiarthroplasty

Hemiarthroplasty replaces the femoral head and neck while preserving the native acetabulum.

It is commonly chosen for older, lower-demand patients with displaced fractures and without significant pre-existing acetabular disease.

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Total Hip Arthroplasty

Total hip arthroplasty replaces both the femoral and acetabular sides of the joint.

It may be favored in active older adults with good preinjury function or patients with significant pre-existing hip osteoarthritis.

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Follow-Up

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Prognosis

Femoral neck fracture in the elderly is associated with substantial morbidity and mortality.

Historical 30-day mortality rates have ranged from approximately 4–31%, depending on patient age, medical comorbidity, preinjury function, and treatment setting.

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Period of Highest Risk

Mortality is greatest during the first several months after fracture, particularly in medically frail patients or those who remain immobilized for prolonged periods.

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Younger Patients

Young patients generally have better overall survival but remain at significant risk for femoral head osteonecrosis, nonunion, and later reconstructive surgery.

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Complications

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Osteonecrosis

Osteonecrosis of the femoral head is one of the most important complications after displaced intracapsular fracture.

It results from compromise of the femoral head blood supply.

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Nonunion

Failure of the fracture to unite is particularly concerning in displaced fractures treated with internal fixation.

Revision fixation or arthroplasty may eventually be required.

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Malunion

Healing in poor alignment can alter hip biomechanics and produce persistent pain, shortening, or functional impairment.

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Prosthetic Dislocation

Hip arthroplasty carries a risk of postoperative dislocation.

Risk varies according to surgical approach, implant design, patient factors, and soft-tissue stability.

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Prosthetic Loosening

Long-term aseptic loosening or wear can occur after arthroplasty.

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Infection

Deep or superficial surgical infection can complicate either internal fixation or arthroplasty.

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Persistent Pain

Persistent pain may result from nonunion, osteonecrosis, implant problems, soft-tissue dysfunction, arthritis, or infection.

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Cardiopulmonary Complications

Older immobilized patients are at risk for pneumonia, cardiac complications, pulmonary embolism, and deconditioning.

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Postoperative Delirium

Delirium is a frequent complication in elderly patients, particularly those with pre-existing cognitive impairment or multiple medical problems.

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Venous Thromboembolism

Deep venous thrombosis and pulmonary embolism are important postoperative risks.

Appropriate thromboprophylaxis should be provided unless contraindicated.

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Patient Monitoring

Patients with substantial medical comorbidity or multiple traumatic injuries may require intensive cardiovascular and respiratory monitoring throughout the perioperative period.

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Follow-Up After Internal Fixation

Patients treated with internal fixation should undergo serial radiographs until union is established.

Imaging should assess fracture alignment, fixation stability, healing, collapse, and evidence of osteonecrosis.

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Follow-Up After Arthroplasty

Patients treated with arthroplasty require clinical and radiographic surveillance to assess implant position, dislocation, loosening, infection, and recovery of mobility.

Follow-up intervals vary according to surgeon preference and patient factors.