Successful Closed Reduction of a Dislocated Constrained Total Hip Arthroplasty

Abstract

This case report and literature review examines whether closed reduction is a viable option to manage hip dislocation when the patient has a constrained liner. Introduction Dislocation after total hip arthroplasty (THA) ranges from less than 1% to 6% of primary cases [1] and from 15% to 30% of revision cases [2]. Unfortunately, the success rate of non-operative treatment of dislocation after THA can be unreliable, and a third of such patients have recurrences [1].Surgical procedures used to treat instability and dislocation include:•Tightening the abductor musculature•Removing sources of impingement•Repositioning malaligned components•Using acetabular liners with elevated rimsSuch treatments fail in 30% to 50% of patients, however [3].The use of constrained liners, which relies on a locking mechanism to capture the femoral head, has been developed to help manage this problem [4]. Despite such efforts, patients continue to be at high risk for instability, and 3% to 18% experience recurrent dislocation even after constrained components have been implanted [5,6]. Generally, open surgical reduction is thought to be the only available treatment for such cases. However, this compromises the integrity of the joint and exposes the patient to the additional risk of surgery [7]. Several authors have reported closed reduction for dislocation of a constrained liner [7-13].Constrained acetabular liners are currently available in various designs, with differences in the locking mechanisms. To our knowledge, ours is the first reported case of a successful closed reduction of a dislocated constrained THA using a Trilogy Acetabular System Constrained liner (Zimmer, Inc, Warsaw, Indiana, USA).The study protocol adhered to the ethics guidelines of the 1975 Declaration of Helsinki, and the study was approved by the Institutional Review Board of Stanford University.