This article addresses the following questions: after scapho-trapezo-trapezoid (STT) fusion in patients, is the wrist center of rotation (COR) modified during flexion/extension and radioulnar deviations? What is the loss of range of motion (ROM) observed after this procedure? To answer these questions, the authors analyzed the COR in the plan using fluoroscopy and an approach by 3D electrogoniometry using the mean point pivot. This 3D COR was studied during circumduction.