Characteristics

• Traditionally described as a nightstick fracture, as the ulnar shaft is usually fractured by a direct blow.

• Potential for open injury as the ulna is a subcutaneous structure along most of its length.

Clinical features

• Pain, swelling, bruising, fracture crepitus.

• Deformity and angulation depending on fracture displacement.

• Always suspect radio-capitellar dislocation – Monteggia pattern – see below.

Radiological features

• AP and lateral views of the forearm including elbow/wrist.

• Carefully examine the views of elbow for normal alignment. A line drawn along the axis of the radius should pass though the centre of the capitellum on the lateral, AP and oblique views (see diagram below). This is known as the radiocapitellar line.

Management

• Assess soft tissues, neurovascular status and immobilise with above elbow backslab initially.

• Undisplaced – Non-operative treatment with above elbow cast approximately 2 weeks, then short arm cast or functional brace until union.

• Displaced – > 10° angulation or 50% shaft displacement should be treated with ORIF with compression plating, or flexible intramedullary nail/POP in children.

• Both bone forearm fractures should be treated with radial and ulna ORIF and early mobilisation in the adult and flexible intramedullary nail/above-elbow POP in children.