Define Fracture of the Shaft of the Femur. Describe its clinical features, investigations, management and complications.

Definition & Importance

A fracture of the shaft of the femur involves the diaphysis between the subtrochanteric region and the supracondylar region. The femur is the largest and strongest bone, so a shaft fracture usually implies high-energy trauma (road-traffic accident, fall from height) in a young adult, or a trivial injury on pathological/osteoporotic bone. It is important for two reasons: substantial blood loss (1–1.5 L into the thigh, more if bilateral or open) that can cause hypovolaemic shock, and the risk of fat embolism syndrome.

Deforming Forces

The powerful thigh muscles displace the fragments predictably. The proximal fragment is flexed (iliopsoas), abducted (glutei) and externally rotated; the distal fragment is pulled into adduction and varus by the adductors and flexed posteriorly by gastrocnemius (a danger to the popliteal vessels in supracondylar extensions). Understanding these forces guides reduction.

Characteristic deforming muscle pull on femoral shaft fragments — the basis of the typical deformity.

Clinical Features

Severe pain, swelling and deformity of the thigh with shortening and inability to bear weight; abnormal mobility and crepitus. Because of the energy involved, assess for shock and always look for associated injuries — ipsilateral hip/neck-of-femur fracture, knee ligament injury, and (critically) distal neurovascular status.

Investigations

AP and lateral radiographs of the whole femur including the hip and knee joints — never image the shaft alone. Assess comminution, segmental patterns and pathological features. Trauma work-up (fast/CT) as indicated by the mechanism.

Management

First aid / resuscitation: ATLS principles, control haemorrhage, splint the limb (Thomas splint) for pain relief and to reduce blood loss and fat embolism, and give analgesia. Definitive: in adults the treatment of choice is closed intramedullary interlocking nailing — it is load-sharing, permits early mobilisation and gives high union rates. Antegrade or retrograde nails are used depending on the fracture and associated injuries. Plating or an external fixator (as damage control in the unstable polytrauma patient or open fracture) are alternatives. In children, treatment is largely conservative/age-dependent — Pavlik harness or hip spica in infants, and titanium elastic nails or submuscular plating in older children.

Complications

Early: hypovolaemic shock, fat embolism syndrome, and (rarely) vascular or nerve injury. Late: delayed/non-union, malunion (shortening, malrotation, angulation), knee stiffness from quadriceps adhesions, and infection after open injury or surgery. Refracture may follow premature implant removal.

• High-energy injury in the young; watch for shock and fat embolism.
• Proximal fragment flexed/abducted; distal fragment adducted (varus) & flexed.
• Always X-ray the whole femur with hip and knee; exclude ipsilateral neck fracture.
• Splint with Thomas splint; definitive Rx = closed interlocking IM nailing in adults.
• Children treated conservatively / age-appropriate (spica, elastic nails).