Performance evaluation of surgical techniques for treatment of scapholunate instability in a type II wrist.

Abstract

We investigated the performance of three tenodesis techniques, modified Brunelli (MBT), Corella and scapholunate axis (SLAM) methods in repairing scapholunate interosseous ligament (SLIL) disruption for a type II wrist using Finite Element based virtual surgery and compared the results to those of a previous investigation for a type I wrist. In addition, a comparison of the carpal mechanics of type I and type II wrists was undertaken in order to elucidate the difference between the two types. For the type II wrist, following simulated SLIL disruption, the Corella reconstruction technique provided a superior outcome, restoring dorsal gap, volar gap and SL angle to within 3.5%, 7.1% and 8.4% respectively of the intact wrist. Moreover, application of the ligament reconstruction techniques did not significantly alter the motion pattern of the type II and type I wrists. For the type I wrist, SLIL disruption resulted in no contact between scaphoid-lunate cartilage articulation, whereas for the type II wrist, some contact was maintained. We conclude that the Corella ligamentous reconstruction technique is best able to restore SL gap, angle and stability following scapholunate ligament injury for both type II and type I wrists and is able to do so without altering wrist kinematics. Our findings also support the view that type I wrists exhibit row behaviour and type II wrists column behaviour. In addition, our analysis suggests that the extra articulation between the lunate and hamate in a type II wrist may help to improve stability following scapholunate ligament injury.