Prevention of Dislocation Risk During Hip Revision Surgery with the Dual Mobility Concept; Study of a New Generation of Dual Mobility Cups.

INTRODUCTION

Total hip arthroplasty (THA) is a common surgery presenting well-known failures that may require surgical revision. To reduce the risk of hip dislocation after revision THA, we hypothesize the interest of the use of a new generation dual mobility cup by evaluating its survival and complication rates.

MATERIALS AND

METHODS

We analyzed the survival and the failures rate of 91 patients who underwent revision THAs with a specific dual mobility cup Novae® E TH (SERF, Décines-Charpieu, France). The surgical indication for revision THAs were: 59 aseptic loosening or insert advanced wear (61.5%), 10 recurrent dislocations (10.9%), and 22 deep infections (24.1%). All patients underwent the same surgical technique and received a clinical and radiological examination. Failure of the cup was defined as an aseptic loosening; all failures were reported.

RESULTS

During the follow up, 17 patients died and five were unaccounted for. The mean follow-up of the 86 patients included was 33 months (0-71) with a mean age of 71 years (41-99) at the time of surgery. The Postel Merle D'Aubigné (PMA) increased by 6.8 points from preoperative until the last consultation. No aseptic loosening was reported. The postoperative dislocation rate was 3.5% and 4.6% for deep infections. The overall rate for re-revision THAs was 8.1%.

DISCUSSION: New choice of design and coating for the cup have demonstrated good results to reduce the rate of aseptic loosening compared to other studies. The three hip dislocations concerned two patients who had a history of recurrent dislocation and psychiatric pathologies. The limit of the study is its short follow-up, partially explained by the occurrence of 10 deaths in the first year of follow-up (lowering the mean).

CONCLUSION

The use of a cementless dual mobility tripod cup for revision THA confirms its place in the possible therapeutic range by its excellent results at medium term.