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Thumb MCP Dislocation S63.116A 834.01

thumb mcp dislocation xray 
ICD-9 Classification / Treatment
Etiology / Natural History Associated Injuries / Differential Diagnosis
Anatomy Complications
Clinical Evaluation Follow-up Care
Xray / Diagnositc Tests Review References


Tumb MCP Dislocation ICD-10

A- initial encounter

D- subsequent encounter

S- sequela


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
  • Stiffness
  • 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