Metacarpal Neck Frx

- See: metacarpal frx menu

- Discussion:
    - frxs through neck & shaft of metacarpals usually angulate w/ apex dorsal, displacing the metacarpal head into the palm;
    - ring and little neck frx: (see boxer's frx);
            - corresponding CMC joints are mobile (in contrast to 1st & 2nd CMC) w/ flexion extension arc of between 20-30 deg in little finger and 10-15 deg in 4th metacarpal;
            - will tolerate up to 20 deg dorsal angulation;
            - amount of acceptable angulation will be greater when frx occurs more distally in the neck;
    - index and long metacarpal neck frx:
            - minimal angulation can be accepted because there is no compensatory motion at the CMC joints;
            - any residual angulation of these bones will cause problems;
            - in these joints angulation of 10-15 deg should be corrected;

- Exam:
    - look for malrotation of injured ray;
    - look for loss of ability to hyperextend the MCP joint;

- Closed Reduction:
    - easy to reduce by difficult to maintain;
    - MCP & PIP joints are both flexed 90 deg to gain control of distal fragment & then exert dorsally directed force on metacarpal to push metacarpal head dorsally (& metacarpal shaft volarly) to achieve reduction;
            - immobilization in this position is not allowed, however, as flexion contracture will develop;
    - more proximal frxs (ie, shaft frx) are more likely to produce noticable dorsal angulation & clawing, and therefore less angulation can be accepted in midshaft fractures than in neck frx

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

Last updated by Data Trace Staff on Thursday, October 4, 2012 2:09 pm