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.