A comparison of dart thrower's range of motion following radioscapholunate fusion, four-corner fusion and proximal row carpectomy

Dart thrower's motion is the functional coupled movement of the wrist from radial extension to ulnar flexion. The aim of this study was to evaluate dart thrower's motion following three surgeries: radioscapholunate fusion, four-corner fusion and proximal row carpectomy. Six fresh-frozen cadaver forearms were dissected. Sequential loading of tendons resulted in radial extension and ulnar flexion allowing dart thrower's motion measurements at end range before and then again after each surgery. After radioscapholunate fusion, 74% of both radial extension and ulnar flexion were maintained. After four-corner fusion, radial extension decreased to 53% and ulnar flexion to 84% of control motion. Proximal row carpectomy did not statistically significantly alter radial extension, but decreased ulnar flexion to 87%. We found that dart thrower's motion is well maintained in three of these commonly used surgical treatments. These results may aid surgeons in managing patients by providing comparative functional movement following these procedures.