Tumb MCP Dislocation ICD-10
A- initial encounter
D- subsequent encounter
Tumb MCP Dislocation ICD-9
- 834.01 Closed dislocation, metacarpophalangeal joint
- 834.11 Open dislocation, metacarpophalangeal joint
Tumb MCP Dislocation Etiology / Epidemiology / Natural History
Tumb MCP Dislocation Anatomy
- Thumb MCP joint is stabilized by proper collateral ligaments, accessory collateral ligaments, the joint capsule, intrinsic musculature, and extrinsic tendons.
- Sesamoids are embedded in the volar plate and lie anterior to and articulate with the metacarpal head
- Flexor pollicis brevis and abductor pollicis brevis muscles partially insert into the sesamoids
Tumb MCP Dislocation Clinical Evaluation
- Pain and swelling in the thumb
Tumb MCP Dislocation Xray / Diagnositc Tests
- A/P, lateral and oblique views of the thumb indicated.
Tumb MCP Dislocation Classification / Treatment
- Simple dislocation of the mcp joint of the thumb will show proximal phalanyx to be nearly perpendicular to the metacarpal. Reducible closed. Rx:thumb spica cast. Failed closed reduction indicates volar plate is interposed in the joint or metacarpal head is buttonholed through the palmar structures: requires open reduction. Consider ulnar collateral ligament repair if unstable after CR
- Closed reduction for dorsal dislocation: flex the wrist and the PIP joint to relax the flexor tendons. Apply pressure from dorsal to volar to the base of the proximal phalanx.
- Closed reduction for volar dislocation: Wrist and MCP joint is flexed, and gentle pressure applied to the volar surface of the proximal phalanx as it is brought into extension.
- Complex dislocation prox phalanyx and metacarpal are parallel, volar plate is interposed, irreducible closed
Tumb MCP Dislocation Associated Injuries / Differential Diagnosis
Tumb MCP Dislocation Complications
- Early degenerative arthritis
- Osteonecrosis of the metacarpal head
- Neurovascular injury
Tumb MCP Dislocation Follow-up Care
- Early ROM with a dorsal blocking splint preventing extension beyond neutral.
Tumb MCP Dislocation Review References
- Bohart PC, JBJS 56A:1459;1974
- Dinh P, JAAOS 2009:17;318-324