- Frx Malrotation:
- tend to shorten & rotate rather than angulate;
- may telescope because of proximal pull of extrinsic muscles;
- effect of malrotation:
- if 5 deg of malrotation is accepted, then displacement will
override 10 mm;
- Frx Shortening:
- long & ring metacarpals tend to shorten less because of tethering effect
of deep transverse metacarpal ligament;
- index and little metacarpals tend to have more shortening & rotation;
- look for loss of normal contour of metacarpal head with MCP joint flexion;
- shortening of upto 3 mm is well tolerated;
- Reduction:
- malrotation is minimized by passive flexion of all fingers while stabilizing frx;
- Operative Treatment:
-
cross pinning
- w/ unacceptaable shortening, length may be regained w/ closed reduction
& cross pinning to adjacent metacarpal;
-
screw fixation:
- single screw is not adequate to withstand rotational and shear stress,
and therefore consider use of neturalization plate;
-
plate fixation:
- seek to place 2 screws (4 cortices) distal & proximal to plate;
- in midshaft one quarter tubular plate applied dorsally w/ 2.7 mm
screws may be used in adults;
- if frx is at proximal 1/3 of metacarpal,
T or L plate may be used;
- lag screw may be placed thru or independent of the plate;
