Prosthetic dislocation of total hip arthroplasty (THA) is a common cause for revision surgery. Dual-mobility (DM) bearings were introduced to mitigate complications; however, their performance in younger patients is unknown. This study compared results of patients <55 years of age with DM vs fixed-bearing (FB) primary THA.
Our total joint registry was used to evaluate primary THA patients <55 years of age, and then, an age-matched comparative analysis was performed for 136 THAs using third-generation highly cross-linked polyethylene DM bearings and 136 THAs using FB from the same manufacturer with mean follow-up of 3.2 and 3.4 years, respectively. Mean age at surgery was 48.4 and 48.5 years, respectively. There was no difference in gender distribution. Incidence of complications (eg, dislocation) was evaluated and compared statistically. Patient-reported outcomes using the Modified Harris Hip Score were available. Normally distributed continuous data were compared using the Student t test, and discrete data were compared using the Fisher exact test (P < .05).
There were no dislocations or intraprosthetic dissociations (0%) in the DM group and 7 (5.1%) dislocations in the FB group (P = .01) at the mean follow-up of 3 years postoperatively. Two of the 7 unstable patients in the FB cohort were revised for recurrent instability (1.5%). There was no difference in postoperative Modified Harris Hip Score between the DM (87.2 ± 16.6) and the control cohorts (87.9 ± 13.7; P = .78).
DM bearings in patients <55 years of age show excellent results for prosthetic stability when compared with patients who undergo FB.