HP23: SALVAGE OF UNSTABLE TOTAL HIP REPLACEMENTS USING A “DUAL MOBILITY” SOCKET

Abstract

Reoperations for total hip arthroplasty instability are reported with high failure rates. The “dual mobility” socket is an attractive option in such cases. The goal of this retrospective study was to assess the clinical and radiographic features associated with such a design.

Fifty four unstable total hip arthroplasties (35 females, 19 males) were revised using a “dual mobility” socket at our institution between March 2000 and June 2005. Mean age at reoperation was 66.5 year old (range, 35.7 to 98.7). Harris Hip Score was used to assess the revision procedures’ outcome, and complications were determined by detailed review of the patient’s records. Anteroposterior and lateral radiographs of the involved joint were reviewed to assess the position of the prosthesis and to look for osteolysis and signs of loosening of the implant.

Mean follow-up was 4 years (range, 26 to 81 months). At last review 4 patients had died and one was lost to follow up. Postoperatively there was a significant improvement of the Harris Hip Score. Among the surviving patients, one (2%) redislocated and was successfully managed with closed reduction. This patient remained stable at latest follow-up. There were 3 revisions for deep infection, and 2 for dissociation of the bipolar component. Technical errors were found to be conducive to these dissociations. No cup required a revision for aseptic loosening. No radiolucent lines around the components and no osteolysis were observed at latest follow up.

The “dual mobility” socket is a highly effective option to manage unstable total hip arthroplasty. Unlike constrained devices, such components did not raise any concern regarding the potential for loosening and for osteolysis. Longer follow up is needed to confirm these results.