Scapholunate instability after distal radius volar plating.

Background: Prior to volar locked plating and early motion protocols, ligamentous injuries incidentally associated with distal radius fractures may have been indirectly treated with immobilization. Our goal was to determine the prevalence of scapholunate instability in our population, while identifying those who may have had progression of instability.

Methods: We retrospectively reviewed 221 distal radius fractures treated with a volar locking plate during a 6-year period. Average patient age was 59 years. Standard posteroanterior and lateral radiographs from the first and last postoperative visits were analyzed for scapholunate instability, using the criteria of scapholunate gap ≥3 mm and scapholunate angle ≥60°.

Results: Six patients (3 %) met neither or only one criterion for instability at the first postoperative visit and did not have ligament repair and then went on to meet both criteria at the last postoperative visit after an early motion protocol. Seven patients (3 %) met both criteria at the first and last postoperative visits and did not have ligament repair. Five patients (2 %) underwent primary scapholunate ligament repair at the time of distal radius fixation.

Conclusions: In our representative population, scapholunate instability was uncommon, either from initial injury or possible progression of occult ligament injury, despite early motion without operative treatment of the ligament. Thus, we did not find strong evidence for routinely delaying motion or pursuing further workup. When early radiographs clearly demonstrate acute scapholunate instability, more aggressive treatment may be appropriate for selected patients.