Simulated Osteotomy of the Trapezium Reduces Radial Subluxation and Improves Contact Pressure Distribution Across the Thumb Carpometacarpal Joint in Lateral Pinch

Joint laxity and radial subluxation of the metacarpal on the trapezium have been associated with arthritis of the carpometacarpal (CMC) joint of the thumb. In normal flexion and extension of the thumb, the ligaments and the joint are minimally stressed. However, in opposition and lateral pinch (key pinch), the two surfaces rotate on each other, generating an unequal surface stress. Over time, the unequal stresses lead to an asymmetrical wear pattern. This leads to increased strain on the ligaments and may lead to subluxation over time.¹ Surgical treatment of early arthritis of the CMC joint includes ligament reconstruction or first metacarpal extension osteotomy to decrease joint laxity. Once laxity exists, joint degeneration is accelerated.² The long-term impact of painful CMC arthritis on activities of daily living can be debilitating.