- See:
metacarpal frx menu:
- Discussion:
- frxs thru 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;
