Dual-mobility bearings in complex revision hip arthroplasty

Background: Revision total hip arthroplasty (rTHA) is associated with an increased dislocation risk. Dual-mobility (DM) bearings have been used to address this issue. Such constructs offer increased range of motion and enhanced stability whilst avoiding some issues associated with fully-constrained devices. DM bearings have been used in our unit since 2013. Methods: All rTHA cases since 2013 were reviewed using the following criteria: (1) use of a DM bearing; (2) extensive soft tissue or bone loss resulting from ARMD, infection or multiple revisions, or requiring custom or megaprosthetic reconstruction; (3) minimum 2-month follow-up. Results: 52 cases were identified with a median of 2 previous operations (range 1–6) and mean follow-up of 14 (2–41) months. The Novae-Stick component was used in 50 cases, the Avantage in 2 and the Trident MDM in 1 case. 19 required acetabular reconstruction using trabecular metal and four required custom acetabular components. 19 required femoral reconstruction with a proximal or total femoral replacement. Postoperatively, 8 patients (15.4%) sustained a dislocation at a mean of 1.6 (range 1–3) months. 3 (5.8%) requiring re-revision. 1 required excision arthroplasty and 2 a constrained liner, 1 of which went on to have further instability. There were no intraprosthetic dislocations. Conclusions: Dual-mobility components are a viable option in the complex rTHA setting. Early dislocations can occur but the rate of instability is acceptable in this high-risk group.