Metacarpophalangeal Dislocations



Metacarpophalangeal Dislocations


Joseph A. Rosenbaum

Hisham M. Awan



INTRODUCTION



  • Pathoanatomy



    • Dislocation of the metacarpophalangeal (MCP) joint secondary to trauma


    • Force applied to the MCP joint exceeds the strength of its capsuloligamentous support.


  • Mechanism of injury



    • Mechanisms of injury include torsional, angular, and tractional forces across joint.


    • Dorsal dislocations may be caused by forced hyperextension.


    • Dislocation may be part of a more severe overall injury pattern including soft tissue injury to ligament, tendon, nerve, and/or vessels.


  • Epidemiology/background



    • Dislocations of MCP joints are not very common.


    • Often seen in laborers or athletes


    • Males are affected more than females.


EVALUATION



  • History



    • Typically caused by trauma, either direct or indirect


    • Presentation is usually acute due to deformity and pain.


    • May be overlooked initially in polytrauma cases


  • Physical examination



    • Digit may be held in extension at the MCP with flexion at proximal interphalangeal and distal interphalangeal.


    • Palmar skin puckering indicates a complex dislocation.



    • Assess for edema, angular deformity, rotational deformity, and quality of soft tissues.


    • Identify any lacerations, and rule out open dislocation.


    • Assess sensation and capillary refill distally.


    • Assess the other digits as well as the hand and wrist.


  • Imaging/assessment



    • Obtain hand radiograph if MCP joint dislocation is suspected.


    • Brewerton view may help to identify fractures or joint dislocation.


    • Identify any fractures if present.


  • Classification



    • As with other dislocations, the nomenclature of direction of dislocation is based on which way the distal bone dislocates relative to the proximal bone.


    • Dorsal dislocations—P1 is dislocated dorsally relative to the metacarpal head.


    • Volar dislocations (uncommon)—The proximal phalanx (P1) is dislocated volarly relative to the metacarpal head.


ACUTE MANAGEMENT

May 7, 2019 | Posted by in ORTHOPEDIC | Comments Off on Metacarpophalangeal Dislocations
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