Define Scaphoid Fracture. Describe its clinical features and management.

The scaphoid receives its blood supply retrogradely, the vessels entering distally, so a fracture of the waist or proximal pole risks avascular necrosis and non-union of the proximal fragment. Snuffbox tenderness with a normal initial X-ray must be treated as a fracture until proven otherwise.

Importance and Mechanism

The scaphoid is the commonest carpal bone to fracture, typically in a young adult who falls on the outstretched, dorsiflexed hand. It matters because of its peculiar retrograde blood supply: the nutrient vessels (from the radial artery) enter the bone distally and run proximally, so a fracture through the waist (the commonest site) or the proximal pole deprives the proximal fragment of its blood supply — leading to avascular necrosis and non-union.

Clinical Features and the Diagnostic Pitfall

The hallmark is tenderness in the anatomical snuffbox, with pain on axial compression of the thumb and on wrist movement. The crucial pitfall is that the initial X-ray is frequently normal even when a fracture is present. Therefore any patient with snuffbox tenderness after a fall is treated as having a scaphoid fracture: the wrist is immobilised in a scaphoid (thumb-spica) cast and the X-ray is repeated at 10–14 days (by which time bone resorption at the fracture line makes it visible), or an MRI is obtained for early definitive diagnosis.

Management

Undisplaced fractures are treated in a scaphoid (thumb-spica) cast for 6–12 weeks. Displaced fractures, and most proximal-pole fractures, are treated by internal fixation with a compression (Herbert) screw, which also allows earlier mobilisation. Complications are non-union, avascular necrosis of the proximal pole, and — if untreated — a pattern of secondary wrist osteoarthritis (SNAC wrist: scaphoid non-union advanced collapse).

• Commonest carpal fracture; FOOSH in a young adult; commonest site is the waist.
• Retrograde blood supply (vessels enter distally) → waist/proximal-pole fractures risk avascular necrosis and non-union of the proximal fragment.
• Snuffbox tenderness with a normal initial X-ray = treat as a fracture: scaphoid cast + repeat X-ray/MRI at ~2 weeks.
• Undisplaced → thumb-spica cast; displaced or proximal-pole → Herbert screw fixation. Untreated non-union → SNAC-wrist osteoarthritis.