- See: Diff Dx
- Discussion:
- when the volar lip fracture of the middle phalanx involves 20% or more of the articular surface, the remainder of the middle phalanx
subluxes dorsally;
- this unstable injury requires more sophisticated treatment than the simple volar plate avulsion;
- Radiographs:
- can misleadingly suggest that very simple frx has occured w/ only small fragment of the bone involved;
- this fragment, however, is often the major attachment of a collateral ligament, the volar plate, or a tendon;
- this small frx may render joint grossly or potentially unstable;
- when volar triangular frx frag of middle phalanx involves > 1/4 of articular surface, dorsal dislocation of middle phalanx may occur
late because the volar plate and a significant portion of the collateral ligaments are attached to the small fragment;
- since many of these acticular fractures were actually dislocations at the time of injury, the x-ray film may not indicate the true degree of
original displacement;
- this injury often involves volar plate & collateral ligaments;
- dislocations of digital joints may stretch the collateral ligaments w/o completely disrupting them, while still rupturing the volar capsule or
volar plate