Triquetral Motion Is Limited In Vivo After Lunocapitate Arthrodesis

PURPOSE: Lunocapitate arthrodesis is a motion-preserving salvage procedure for painful wrist osteoarthritis. Because the arthrodesis is limited to the capitate and the lunate, the adaptive motion of the triquetrum is theoretically maintained. We aimed to examine whether triquetral motion is sustained in vivo after lunocapitate arthrodesis. METHODS: We examined 7 patients after lunocapitate arthrodesis at least 1 year earlier, with computed tomography at 2 wrist positions: maximal radial extension and maximal ulnar flexion. Triquetral motion in vivo was analyzed using volume registration technique of the paired computed tomography scans and compared with the contralateral side. RESULTS: The triquetrum moved in all patients, but the degree of motion was small compared with the nonsurgical wrist. A minor degree of motion of the hamate relative to the fused lunocapitate could also be demonstrated. CONCLUSIONS: Triquetral motion is limited after lunocapitate arthrodesis. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.