Is dual mobility cup total hip replacement associated with increased incidence of heterotopic ossification compared to conventional total hip replacements in fracture neck of femur patients?

INTRODUCTION: The incidence of heterotopic ossification after total hip replacement is variable in the literature. If symptomatic, it may cause pain and reduced range of motion. Dual mobility total hip replacements have been considered a valuable option for the treatment of femoral neck fractures in the active patients, achieving good range of motion with reduced risk of dislocation. The occurrence of HO may have detrimental effect on this type of articulation and may accelerate polyethylene wear and predispose to intra-prosthetic dislocation. We compared the incidence of HO in DMC versus conventional THR in femoral neck fracture patients across 3 large trauma institutes PATIENTS AND METHODS: This is a retrospective cohort study which included 334 patients, 223 received DMC replacements, 111 received conventional total hip replacement (THR). Mean age for the DMC group was 72.3 ± 9.9 years and was 72.1 ± 6.8 years for the THR group. Patients were stratified according to specific inclusion and exclusion criteria, and the 1-year follow up X rays were evaluated for the presence of heterotopic ossification by 3 assessors. RESULTS: The incidence of HO in the DMC group was 27.1% compared to 12.2% in the THR group (χ2 p value = 0.0001, Relative Risk = 2.22, 95% CI 1.22-4.03, p value = 0.0091). There was no significant effect of gender or age on the incidence of HO in both groups CONCLUSIONS: Patients receiving DMC hip replacements are more likely to develop HO as compared to patients receiving conventional THR for femoral neck fractures. Further prospective studies are required to confirm our findings and to assess the indication of HO prophylaxis in patients receiving DMC hip replacements, and the long-term outcomes in these patients.

Functional outcome and health related quality of life after dual mobility cup total hip replacement for displaced femoral neck fractures in middle aged Egyptian patients.

AIM: This study was done to assess the functional and clinical results after one year of cemented THR with dual mobility cup for the treatment of fracture neck femur in active middle-aged patients in Egypt (Middle Eastern population). PATIENTS AND METHODS: This study included 31 patients (32 hips) with displaced femoral neck fractures that were admitted to El Hadara University Hospital, Alexandria, Egypt. Their mean age was 66.4 ±â€¯5.9 years. Fifteen patients were females. All the patients were treated with total hip replacement using a cemented dual mobility cup (Ecofit® 2 M, Implantcast GmbH, Germany) total hip replacement through the standard posterior approach. Functional assessment was done using Harris Hip Score (HHS), SF-36 questionnaire for health related quality of life (HRQoL) with assistance of a physiotherapist. RESULTS: The mean HHS improved over the follow up period from 79.04 ±â€¯7.9 at 12 weeks to an average of 92.8 ±â€¯11.1 at 1 year follow up. HRQoL measures showed a pattern of initial drop at 3 months postoperatively, then a steady rise to be restored at 1 year as compared to the preoperative baseline measures. There were no dislocations encountered in this series over one year follow up. The following complications were encountered; 1 deep infection, 2 deep vein thrombosis, 2 heterotopic ossifications, and 1 patient died within one year after surgery. CONCLUSIONS: Dual mobility cup total hip replacement is an acceptable method for treatment of displaced femoral neck fracture in active middle aged patients in Egypt as it provides pain relief and good function without compromising the stability.