Femoral head fracture
Anatomy of the pelvis and hip joint showing the femoral head inserting into the acetabulum

Definition

A fracture of the femoral head is defined as a break of the larger femur extremity or head, which fits at the pelvis into the acetabulum.

A fractured femoral head exposed during surgical treatment

Pathology

A femoral head fracture is a rare pathology most often arising with high energy traumas and associated with hip dislocations, fractures to the femoral neck, femoral shaft, acetabulum, pelvis, as well as hip arthritis and osteonecrosis. This fracture is complicated by the rupture of the hip capsule - defined as an intracapsular hip fracture – which often compromises a successful healing. A superior femoral head fracture occurs concurrently with anterior dislocations, whereas an inferior femoral head fracture is mostly associated with posterior dislocations. A femoral head fracture requires immediate management in the Emergency Department to perform reduction and if necessary surgery. Fractures of the femoral head are frequent in younger individuals. In elderly patients it is often associated with femoral neck fractures.

Comminuted fracture of the femoral head seen in a CT scan image

Classification

Fractures of the femoral head are detected on X-ray following closed reduction of a dislocated hip. They are divided into:

Type 1 - Single fragment fractures (single bone break)

Type 2 - Comminuted fractures (multiple bone fragments)

The fracture to the femoral head can be displaced when the bone integrity has been disrupted or non-displaced when the break does not separate the femoral head.

A more detailed characterisation of femoral head fractures is summarised in the Pipkin classification

A - Type I, fracture inferior to the fovea (concave depression of the femoral head without cartilage layer)

B - Type II, fracture extending superior to the fovea

C - Type III, any femoral head fracture associated with femoral neck fracture

D - Type IV, any femoral head fracture associated with acetabular fracture

Left: Distal radius intraarticular, displaced fracture; Middle: Older distal radius fracture with callus formation; Right: Distal radius and ulna fracture, extraarticular and displaced

No 2.

Intra-articular fracture extends to the wrist joint (or articulation)

Extra-articular fracture is located outside of the wrist joint

Open fracture when bone fragments perforate the skin

Comminuted fracture when the bone breaks into multiple fragments

Non-displaced when the anatomical alignment of the bone is maintained or displaced when the bone fragments move apart.

Melone’s classification describes the characteristics of intra-articular fractures of the radius:

i    Stable fracture

ii    Unstable "die-punch"

iii   "Spike" fracture

iv Split fracture

v   Explosion injuries

Acetabular fracture of the pelvis

Acetabular fractures

These fractures are divided into:

Anterior pillar (not weight bearing part of joint)

Posterior pillar (often associated with dislocation of the hip including the weight bearing part of joint)

Transverse

Comminuted involving both column type 

Sacral / coccygeal fractures

The sacrum is a triangular-shaped bone formed by 5 fused vertebrae, which provide a posterior wall to the pelvic ring. At each side of the sacrum, the ala structures articulate with the ilium bones forming the sacro-iliac joints. Sacral fractures are usually parallel to the spine and can involve the ala. Less frequently sacral fractures may display an “H” shape, including a transversal fracture uniting both sides of the sacrum. Three zones are described where sacral fractures can occur that are along vertical lines relative to the alignment of the foramina. Sacral fractures may result in sacral instability and require treatment via sacroplasty (injection of bone glue into the fracture). Surgery is necessary in case of associated neurological symptoms.

Fractures of the coccyx involve the tailbone, the terminal portion of the spine situated below the sacrum formed by 3 to 5 fused vertebrae. Coccyx fractures occur when falling on a seated position. They are more common in elderly women and seldom require surgical treatment.

A frontal crash with impact onto the knee / femur and lead to a fracture of the femoral head

Causes

High-energy traumas and falls are the most frequent cause of a fracture to the femoral head:

Motor vehicle accidents (dashboard trauma: posterior hip dislocation and femoral head fracture)

Sport injuries

Falls from height

Industrial accidents

A pathologic fracture to the femoral head is rare and mostly observed in postmenopausal women due to bone weakening by osteoporosis and comorbidities such as diabetes, obesity or conditions requiring cortisone therapy. Bone degeneration of the femoral head over time causes its collapse. Pathologic fractures do not require a traumatic impact or a fall to occur.

Avascular necrosis of the femoral head can precede a fracture

Risk factors

Leading risk factors for a femoral head fracture include:

Frequent driving

Working at height (carpenters, electricians, builders, painters)

High speed contact sports

Elderly age

Female gender: loss of bone density after menopause

Osteoporosis

Avascular necrosis of the femoral head

Chronic medical conditions (diabetes, obesity)

Medications e.g. steroids that weaken bone density

Lack of physical fitness

Use of tobacco and alcohol

Severe pain and inability to move following a femoral head fracture requires immediate paramedic care and transport to the Emergency Department

Symptoms

A fractured femoral head caused by trauma triggers an immediate, severe pain in the hip region. The patient is likely unable to move, bear weight and walk.

The leg of the fractured femoral head appears shorter and the rotation of both limbs becomes asymmetrical. When concurrent to posterior dislocation of the hip, the limb appears flexed, adducted with an internal rotation. With anterior dislocation the limb is flexed, abducted and rotated externally. In case of severe trauma the patient may suffer from transient sciatic nerve damage. On the hip side of the injury or fall the patient may present a bruise, swelling and stiffness.

Imaging including X-rays, CT and MRI scans are used for the diagnosis of a femoral head fracture. Here a CT scan with a 3D reconstruction of the fractured femoral head

Diagnosis

The diagnosis of a femoral head fracture occurring after trauma is executed after transport to the Emergency Department. Following admittance to the hospital, the treating physician will acquire information on the history of injury and past medical conditions. The patient is firstly treated with painkillers (analgesics) and fluid replacement in case of dehydration, prior to radiologic evaluation with X-rays.

Often a CT scan or an MRI is performed to better characterise the fracture type and the presence of associated fractures around the hip, pelvis and lower limb. The orthopaedic surgeon will assess the images obtained and opt for the best treatment suitable to the type of fracture in relation to the general condition of the patient. 

Treatment

With a hip dislocation causing a femoral head fracture, the patient requires closed reduction of the hip under anaesthesia

Nonoperative treatment

If a femoral head fracture is caused by a hip dislocation and is not associated with other fractures (Pipkin I and II) or release of bone fragments, it is managed conservatively. Treatment consists of a closed reduction of the hip under general anaesthesia. This should occur within 6 hours from the accident and followed by a control CT scan to confirm correct repositioning of the femoral head in the hip joint. The patient is advised to avoid weight bearing (Touch Down Weight Bearing, TDWB, whereby only the toes are placed on the floor) for 4-6 weeks.

Treatment of a Pipkin type III femoral head fracture involving fracture of the trochanter

Surgical treatment

Surgery via open reduction internal fixation (ORIF) is recommend for complex femoral head fractures (Pipkin II with over 1mm step off, presence of intra-articular bone fragments or other fractures to femoral neck, acetabulum (Pipkin III, IV) or in case of multiple trauma. Surgical approach can be anterior or anterolateral. Two or more special screws are placed through the femoral head (headless compression or bioabsorbable screws) to prevent vascular damage and consequent avascular necrosis of the femoral head. 

Example of hip arthropasty with a prosthetic replacement of the femoral head

Arthroplasty or hip replacement is performed in elderly patients in case of  more complicated, comminuted and displaced femoral head fractures with osteoporotic bone conditions.

Complications

Complications that may occur following a fracture to the femoral head include:

Local infection - requiring antibiotic treatment as a preventative measure

Sciatic nerve neuropraxia - transient loss of neural function following injury

Avascular necrosis – with an intracapsular hip fracture the vessels supplying the femoral head may be injured compromising blood flow and causing bone death. Avascular necrosis of the femoral head can lead to chronic pain of the hip region

Degenerative joint disease -gradual deterioration of the articular cartilage of the bones forming the hip joint, leading to osteoarthritis

Reduced internal rotation of the hip

Heterotopic ossification - growth of bone tissue in regions distant from the fracture

Deep vein thrombosis (DVT) and pulmonary embolism – thrombosis mostly occurs in the deep veins of the lower limbs due to prolonged immobility. Patients are usually treated with early anti-clotting medications (warfarin, aspirin)

Blood loss - can occur during or after surgery. Rarely, a blood transfusion is needed

Hydrotherapy is a gentle form of rehabilitation following a femoral head fracture

Rehabilitation

Following arthroplasty particularly in elderly patients, it is critical to begin rehabilitative exercise through gradual and assisted walking to prevent medical complications. This phase may require the patient to be admitted to a cared facility or receive regular in-home visits by an occupational therapist. A wheelchair, crutches, walking stick, or a walker may be necessary to support the patient during the first weeks up to 12 months after a femoral head fracture.  Physiotherapy during the first 6-12 weeks post surgery include:

Ice/heat treatment

Antiinflammatory therapy

Exercise to strengthen quadriceps, hamstrings and gluteal muscles

Hydrotherapy

Massage

Joint mobilisation

Guided return to activity

Use of high chairs and walking devices

Weight loss in overweighed patients

In the elderly the risk of falls and injuries is reduced with the use of walking devices

Prevention

A femoral head fracture can be prevented by reducing the risk of accidents in young people and falls in elderly patients. In osteoporotic patients bone strength can be improved with the administration of the bisphosphonate group of drugs and additional supplement of calcium and vitamin D. Other preventive measures include:

Adherence to occupational health and safety regulation and use of road traffic safety equipment (harness, balustrades, seatbelt)

Use of walking devices in the elderly

Removal of carpets or other items facilitating falls

Modify habits (laced shoes, illuminate house at night, install railings, non-skid tiles in bathroom)

Physical exercise and maintenance of muscular strength in the elderly (walking, swimming)

Frequent monitoring of chronic diseases and pharmacological use (blood pressure medications)