Hand and Wrist Trauma: Fractures, Dislocations, Tendon and Nerve Injuries
Core concepts
A candidate must know the injury patterns that dominate hand surgery. For the wrist, understand scaphoid fractures: the blood supply is retrograde, entering distally and running proximally, so proximal-pole fractures carry the highest risk of nonunion and avascular necrosis. Snuffbox tenderness with a negative radiograph does not exclude fracture; immobilize and obtain CT or MRI. Distal radius fractures require assessment of articular step-off, volar versus dorsal tilt, ulnar variance, and DRUJ integrity. In the digits, distinguish mallet finger (terminal extensor tendon avulsion, treated with continuous DIP extension) from Jersey finger (FDP avulsion, requiring early repair), and boutonniere (central slip) from volar plate injury.
Tendon injuries are described by zone: flexor zone II at Camper's chiasm historically had the worst results, and extensor zone I is the terminal tendon. Nerve injuries are graded by Seddon and Sunderland; sharp lacerations are repaired primarily, tension-free, with epineurial or grouped fascicular technique.
Traps
Questions favor occult scaphoid fracture, missed Jersey finger, and "safe" observation of a fight bite over the MCP joint. Radiographs underestimate articular incongruity; remember the die-punch fragment and the need for post-reduction imaging.
Rule of thumb
Any snuffbox tenderness after a fall is a scaphoid fracture until proven otherwise: immobilize and re-image at two weeks or obtain early MRI.