Medium-term comparison of results in obese patients and non-obese hip prostheses with Metha® short stem

Introduction: Total hip arthroplasty is one of the most successful orthopedic surgeries in terms of results. However, the prevalence of obesity has nearly doubled between 1980 and 2008. There is limited and controversial data on hip replacement results in obese patients. The Metha® prosthesis, introduced in 2004, is a short stem midway between devices maintaining the femoral neck and metaphyseal implants. The purpose of this study was to evaluate the influence of obesity on clinical and radiological results at medium term. Materials and methods: Eighty-two patients were retrospectively divided into two cohorts based on their BMI. Mean BMI were, respectively, 35.22 kg/m2 in the obese group [30.02–57.79] and 26.15 [23.25–28.72] in the other cohort. Follow-up were 47.16 [26.10–74.33] and 54.06 [28.17–77.73]. The mean ages at surgery were 55 years [39.8–67.8] and 54 [31.3–70.4]. We used self-assessment questionnaires WOMAC and Oxford; two clinical scores Harris Hip Score and Postel-Merle d’Aubigné. ARA score was used for osseointegration evaluation. Results: Operative times were comparable. The self-assessment questionnaires and clinical scores showed significant poorer results in the obese cohort. HHS were 87.54 [56–100] and 92.49 [25–100]. However, the clinical improvement obtained between pre- and postoperative was identical in both groups: 52 [19–73] and 52 [−6 to 90]. Radiological ARA scores were good or excellent for 97.56 and 92.68 %. Survival analysis was comparable with more than 0.96 at 50 months follow-up. Conclusion: The Metha® prosthesis can be implanted at the forefront of primary total hip arthroplasty in normal subjects as well as in obese subjects. However, we cannot yet claim we will reach the same durability we experience with standard prostheses. © 2014, Springer-Verlag France.