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 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.
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
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
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)
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.
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)
Falls from height
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.
Leading risk factors for a femoral head fracture include:
Working at height (carpenters, electricians, builders, painters)
High speed contact sports
Female gender: loss of bone density after menopause
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
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.
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.
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.
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.
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 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
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:
Exercise to strengthen quadriceps, hamstrings and gluteal muscles
Guided return to activity
Use of high chairs and walking devices
Weight loss in overweighed patients
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)