MANUAL MINORS
A Bennett fracture-dislocation is an intra-articular fracture at the base of the first metacarpal (thumb), affecting the carpometacarpal (CMC) joint. This fracture occurs due to direct trauma, such as a fall onto the thumb or a strong blow, and is characterised by the separation of a bone fragment while the rest of the metacarpal is displaced due to tendon traction.
Diagnosis
Diagnosis is based on a history of acute trauma, with intense pain at the base of the thumb, swelling, and difficulty moving it. X-rays show a fracture at the base of the first metacarpal and displacement of the CMC joint, confirming the fracture-dislocation.
Differential Diagnosis
Condition | Key Differences |
|---|---|
Rolando fracture | Multifragmentary fracture at the base of the first metacarpal, more complex than Bennett’s. |
Simple first metacarpal dislocation | CMC joint displacement without visible fracture on X-rays. |
Gamekeeper’s thumb | Injury to the ulnar collateral ligament without intra-articular fracture. |
Thumb sprain | Pain and swelling without fracture or bone displacement. |
Emergency Management
Immobilisation of the thumb and wrist with a thumb spica splint to prevent movement.
Administration of analgesics and anti-inflammatory medications for pain control.
Radiographic evaluation to confirm the diagnosis and rule out associated injuries.
If significant displacement is present, a closed reduction under local anaesthesia or sedation may be attempted, although these fractures are often unstable.
Definitive Treatment
Most cases require surgical treatment due to the instability of the fracture. Surgery involves fixation with screws, Kirschner wires, or plates to ensure proper alignment of the metacarpal. After surgery, the thumb is immobilised for 4-6 weeks. Once immobilisation is removed, physiotherapy is essential to restore thumb mobility and function.
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