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The Use of Constrained Acetabular Sockets

Summary Recurrent instability after total hip replacement is a complex problem with extensive literature detailing multiple etiologies and solutions. It has been shown that the success of surgical management depends on the identification of the etiology. Unfortunately, in certain situations, there may not be an optimal solution for dealing with the cause, or the etiology may remain unidentified. In these cases, the success rate of surgical management of unstable total hip replacement is only 40 to 50%. Constrained acetabular liners were developed to address the problem of recurrent instability by holding the femoral head captive within the socket. The authors’ experience with attaining joint stability using one type of constrained liner has far surpassed the success rates achieved by other means. The intermediate follow-up after implantation of a constrained liner has not demonstrated significant rates of component wear or loosening. The authors reserve the use of a constrained liner for situations in which there are inadequate soft tissue, a deficient abductor mechanism, or neuromuscular disorders. Poor patient compliance or instability without a clear etiology are relative indications for its use.