THE LUNOTRIQUETRAL JOINT - KINEMATIC EFFECTS OF SEQUENTIAL LIGAMENT SECTIONING, LIGAMENT REPAIR, AND ARTHRODESIS

This experiment was conducted to study the effects of sequential secti oning of the ligaments of the lunotriquetral (LT) joint and the effect s of simulated repair or arthodesis on kinematics of the wrist joint u sing an x-ray stereophotogrammetric technique. A 3-dimensional coordin ate software program calculated relative motion between bodies as scre w axis displacement and rotation about each axis. Sectioning of the pr oximal and dorsal component of the LT ligament had little effect on ca rpal kinematics, but sectioning of the proximal and palmar components of the ligament resulted in flexion of both the lunate and triquetrum, producing a volar intercalated segment instability (VISI) pattern. Th e triquetrum supinated away from the I lunate after sectioning of the entire LT ligament. Greater VISI occurred after sectioning the dorsal radiotriquetral and scaphotriquetral ligaments. Progressive destabiliz ation of the LT joint results in increasing kinematic alterations; how ever, these may not exactly mimic the clinical situation. Moving the w rist through 1,000 cycles increased the instability.: Dorsal repair of the LT ligament realigned the lunate and triquetrum, and LT fusion co rrected triquetral supination. The latter, however, resulted in overco rrection into extension, which prevented a full wrist extension. The r epair used may be insufficient to restore the palmar ligamentous integ rity. Lunotriquetral arthodesis was difficult to simulate, providing s ome insight into the cause of clinical nonunions. Severe VISI is not c orrectable by repair or arthrodesis and requires further study using r econstructive procedures not discussed here. Copyright (C) 1998 by the American Society for Surgery of the Hand.