SALVAGE OF A RECURRENTLY DISLOCATING TOTAL HIP-PROSTHESIS WITH USE OFA CONSTRAINED ACETABULAR COMPONENT - A RETROSPECTIVE ANALYSIS OF 56 CASES

Fifty-six constrained acetabular components were placed, between April 1988 and February 1993, in fifty-five patients who had had recurrent dislocations (average, six dislocations; range, two to twenty dislocat ions) of the femoral component after a previous total hip arthroplasty , All patients had additional factors contributing to the instability of the implant, including absence or disruption of the abductor mechan ism, poor health, mental retardation, confusion, and Alzheimer disease . One patient was lost to follow-up. The remaining patients mere follo wed clinically for a minimum of three years (average, sixty-four month s; range, thirty-seven to ninety-seven months) or until the time of de ath. During the follow-up interval, only two (4 per cent) of the fifty -five patients had a subsequent dislocation. The use of this type of c omponent should be considered for patients who have recurrent dislocat ion if other treatment modalities are unlikely to be effective.