Superior functional outcome with dual mobility THR as compared to conventional THR in fracture neck femur: a prospective cohort study.

Introduction: Total Hip Replacement (THR) in displaced Fracture Neck of Femur (FNOF) is associated with higher dislocation rates. Conventional THR with a large femoral head and anterior approach has reduced the instability, but it remains higher than THR done for other aetiology. Recent studies have shown reduced dislocation rates with dual mobility THR (DMTHR) for FNOF; however, there is a lack of comparative research to show its superiority over conventional THR. Further, its role in the Asian subcontinent, where the patient requires sitting cross-legged or squatting, has not been studied.

Methods: A prospective cohort study of 103 elderly patients with displaced FNOF with a minimum follow-up of 1-year. Fifty-two patients were operated on with DMTHR and fifty-one patients with conventional THR. Both the groups were matched in terms of demographic data, surgical approach, and postoperative protocol. Radiological and functional outcomes in terms of Harris Hip Score (HHS), Range of motion, Patient Reported Outcome Measures (PROM), and Dislocation rate were compared between the two groups.

Results: Mean HHS of the DMTHR group was 76.37 at three months and 87.02 at the end of the 1-year postoperatively, which was significantly better than the conventional THR group 65.65 at three months and 72.96 at 1-year. The range of motion was significantly better in the DMTHR group than the conventional THR group. There was no significant difference in radiological outcomes and postoperative dislocation rate between the two groups.

Conclusion: Dual mobility implants give better results than conventional implants for primary THA in elderly patients of displaced FNOF regarding better function and greater range of motion.