LUNATE IMPLANT ARTHROPLASTY - EVALUATION OF 19 PATIENTS

Lunate implant arthroplasty are unpredictable and many postoperative problems are encountered. A retrospective review of 19 patients operated on for lunatomalacia (Kienbock''s disease) by Silastic (HP) implant arthroplasty suggests that prevention of postoperative scapholunate dissociation seems to be the key to successful results. Knowledge of the predominant role played by the palmar ulnolunate and radiolunate ligaments is important to the understanding of this mechanism. The intrinsic stability accomplished by the geometry of the carpal bones requires adequate ligamentous support. This restraint, however, may be weakened by pre-existing absence of certain palmar fibers, by the disease process or by the surgery. Three operative methods were assessed: dorsal approach and implant stem fixation; dorsal approach, removal of implant stem and Kirschner-wire fixation and volar approach, removal of implant stem, no internal fixation but palmar capsuloligamentous reinforcement. Consistently, good results were obtained using the latter technique. It seems as if most of the usual postoperative problems of lunate implant arthroplasty can be avoided by this method which warrants continued trial.