Extracapsular Fractures

Also Known as:

Intertrochanteric or extracapsular.

These fractures are rarely associated with avascular necrosis of the femoral head as the retinacular vessels are not affected.

Mechanism of Injury

These fractures usually arise as a result of falls onto the greater trochanter, road traffic accidents or from direct violence.

Classification

Jenson’s classification is most commonly used:

• Type 1 - two part undisplaced fracture
• Type 2 - two part displaced fracture
• Type 3 - three part fracture, loss of posterolateral support
• Type 4 - three part fracture, loss of medial support
• Type 5 - four part fracture.

Clinical Features

They are similar to intra-capsular fractures but differences do occur: the degree of external rotation is usually greater in intertrochanteric fractures and bruising tends to occur late after injury. The patient can’t lift the affected leg.

X-rays are needed to confirm the diagnosis: AP and lateral views. X-rays show a fracture line extending between the lesser and greater trochanters. The result is that the proximal fragment tends to be displaced into varus and there may be a degree of comminution of the postero-medial cortex.

Associated Injuries

Dislocation of the hip or pelvic fractures may also occur.