Metacarpal Extra-articular Base Frx

- See: Extra-articular Thumb Metacarpal Fractures

- Discussion:
    - interosseous muscles & intrinsically strong carpometacarpal capsular and interosseous ligaments provide intrinsic stability to extra-articular fractures at the metacarpal bases;
    - mechanism of frx of little CMC:
          - stability of CMC joint derives from articulation w/ carpal bones,
          - convex bases metacarpals are displaced dorsally losing stability of articulation and causing extrinsic tendon power to be unbalanced;
          - ECU is a deforming force since it inserts onto base of 5th metacarpal;
          - overpull of ECU along w/ interposition of capsule may complicate reduction;
          - most common presentation is the dorsal avulsion frx of metacarpal base;
     - associated frx: CMC joints dislocation is associated w/ this injury;

- X-Rays:
     - isolated metacarpal views are not possible;
     - 30 deg pronated lateral: for index and long metacarpals;
     - 30 supinated lateral: for ring and little metacarpals;

- Non operative treatment:
     - extra-articular fractrues may be impacted and clinically stable when they occur from direct trauma;
           - these may be treated w/ splints;

- Operative treatment:
     - unstable fractures may result from violent trauma and may require & internal fixation w/ K wires;
     - more stable fixation can be gained w/ 2.0 mm or 2.7 mm condylar plate;
     - note associatted soft tissue injuries, may preclude plate fixation


Clinical results of intraarticular fractures of the base of the fifth metacarpal treated by closed reduction and cast immobilization.
Intra-articular fractures at the base of the fifth metacarpal. A clinical and radiographical study of 64 cases.
The surgical treatment of fractures of the base of the fifth metacarpal bone
Management of Intra-Articular Metacarpal Base Fractures of the Second Through Fifth Metacarpals
Fracture-subluxation of base of fifth metacarpal
The ‘mirrored’ Bennett fracture of the base of the fifth metacarpal

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Tuesday, February 3, 2015 1:45 pm