Abstract
Ulna Styloid Fractures have been historically dismissed as a relatively benign injury. However recent clinical and biomechanical research has suggested that primary repair of displaced ulna styloid avulsion fractures is advised as a means of stabilizing the radioulnar joint and preventing the disability associated with chronic radioulnar joint instability.
Optimum fixation method was examined in this study using a human cadaveric model. A custom jig was designed to allow testing in radial/ulna deviation in varying degrees of wrist flexion and extension. Universal materials testing device was used to apply a maximum load of 150 N. Eight pairs of cadaveric wrists were tested. Constructs tested were 1.6mm K-wire fixation, Tension Band wiring and Screw Fixation. Fracture displacement was measured using a venire micrometer.
Results: Displacement on forced radial deviation was maximum in neutral wrist position in all construct configurations. Displacement was minimized in 20 degrees wrist flexion. The optimum fixation method was 2 k-wires with tension band wiring. This study would suggest that the optimum fixation for ulna styloid fractures is a Tension band-wiring construct. If non-operative treatment is used we suggest that the wrist is immobilized in a position of wrist flexion to reduce tension on the ulna carpal ligament and prevent fracture displacement.
The abstracts were prepared by Raymond Moran. Correspondence should be addressed to him at the Irish Orthopaedic Assocation, c/o Cappagh National Orthopaedic Hospital, Finglas, Dublin 11, Ireland.
