Femoral head fracture

Femoral head fractures, also known as femoral head fracture-dislocations, are rare injuries, representing the least common type of proximal femoral fracture and most cases are associated with hip dislocations ^1-6.

Epidemiology

Unlike other proximal femoral fractures which are usually caused by low-energy trauma such as a fall from standing height and primarily affect elderly women, femoral head fractures require high-energy trauma (e.g. motor vehicle accidents) and have a young adult male predominance ^5,6.

Femoral head fractures represent 0.5-1.5% of all femoral fractures ^5,6.

Clinical presentation

The usual presentation is that of a posterior hip dislocation, which has the affected lower extremity shortened, adducted, and internally rotated ^2,4.

Other associated injuries are common, especially of the ipsilateral knee ².

Pathology

The main mechanism of trauma for femoral head fracture is traumatic posterior hip dislocation and most cases described in the literature are associated with hip dislocations ^1-4.

Up to 15% of all posterior hip dislocations are associated with femoral head fractures ^1,4.

Radiographic features

Plain radiograph

Femoral head fracture-dislocations are often evident on plain radiographs, with the dislocated head usually displaced superiorly and causing interruption of the Shenton line ².

The radiograph must be reviewed for intra-articular fragments that may block closed reduction and for associated femoral neck and acetabular fractures ^1,4.

There are many radiographic classifications for femoral head fractures. The most commonly used is the Pipkin classification system ^1-4.

CT

Cross-sectional imaging is recommended after successful closed reduction or before open reduction to assess joint congruency ^2-4.

Treatment and prognosis

Hip dislocation is an orthopedic urgency and emergent closed reduction should be attempted unless the patient presents a clear clinical contraindication. If the joint is irreducible, open reduction should then proceed ^1-4.

After either closed or open reduction of the hip joint, management of the associated femoral head fracture is dependant on it pattern and associated injuries, which can be aided by the Pipkin classification ^1-4.

Given the severity of these injuries they have been widely associated with poor outcomes ³.

Complications

There are numerous possible complications of femoral head fracture-dislocations. However, given the rare nature of these injuries, the rates of each complication are usually imprecise across literature.

The most common complications are heterotopic ossification, avascular necrosis of the femoral head, post-traumatic arthritis, and nerve injuries (sciatic, femoral, and pudendal) ^1-4.