A 24 year old male rugby player presents to your ED with a severely painful, swollen left hand which occurred during a tackle and subsequent ruck.
These are his x-rays….
[DDET What about the lateral ??]
[DDET What’s going on here ??]
[DDET The Anatomy…]
- The carpometacarpal (CMC) joints form the base of the metacarpal arch of the hand.
- The metacarpal bases articulate with each other & with the distal carpal row.
- This is a complex structural configuration.
- Supported by volar, dorsal and interosseous ligaments.
- Reinforced by broad insertions of wrist flexors and extensors as well as the deep transverse metacarpal ligament.
- The ring & little finger MCs articulate with the hamate.
- These are more mobile and hence more susceptible to dislocation (5th >> 4th digit).
[DDET The Injury…]
- Dislocations of the carpometacarpal (CMC) joints are rare.
- Often the diagnosis is missed.
- Most commonly a dorsal dislocation.
- Commonly associated with fractures.
- Occurs as a result of MVAs, falls, crush injuries and closed-fist trauma.
- Marked swelling and deformity with pain over the dorsum of the hand.
- Thorough neurovascular examination is mandatory.
- Assess deep motor branch of ulnar nerve
- Passes adjacent to hook of hamate & can be directly injured.
- Beware of compartment syndrome.
- Fractures may be subtle on x-ray.
- Superimposed carpal & metacarpal bones.
- Extra-oblique films may be helpful.
- Analgesia & limb elevation initially.
- Closed reduction can be attempted (following adequate sedation +/- regional anaesthesia)
- Traction & flexion with simultaneous longitudinal pressure on the MC base.
- Followed by extension of the MC head.
- Requires Hand-Surgeon referral & will likely need surgical fixation (K-wire).
- Volar dislocations are very rare and require Hand-Surgery involvement.
- Rosenʼs Emergency Medicine. Concepts and Clinical Approach. 7th Edition
- Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 7th Edition.
- Wheeless’ Textbook of Orthopaedics