Large head metal-on-metal cementless versus traditional total hip arthroplasty:One-year follow-up / 中国组织工程研究

ABSTRACT

BACKGROUND: Common complication of traditional joint replacement is hip joint dislocation and large head joint implant can effectively solve this problem. OBJECTIVE: To investigate the preliminary efficacy of large head metal-on-metal implants for patients undergoing total hip arthroplasty. DESIGN, TIME AND SETTING: Prospective cohort study. The patients were selected from Department of Joint Surgery, Xinjiang Hospital of Traditional Chinese Medicine between February 2007 and January 2008. PARTICIPANTS: A total of 65 patients (71 hips) undergoing large head metal-on-metal implantation in Xinjiang Hospital of Traditional Chinese Medicine were selected, including 21 females and 44 males with an average age of 54.6 years (ranging 19 to 77 years). Of them, there were 28 cases of necrosis of the femoral head, 24 of hip osteoarthritis, 9 of femoral neck fracture and 4 of acetabular dysplasia. METHODS: According to age, sex, cause of disease and preoperative joint function, the patients were divided into traditional prosthesis (n=30, 33 hips, metal-on-polyethylene implant) and large head M-O-M group (n=35, 38 hips, ASR/XL prosthesis, DePuy, Motech, Warsaw, IN, USA). MAIN OUTCOME MEASURES: The pre and postoperative Harris scores for the hip, range of motion, periprosthetic radiolucency, leg-length inequality and complications were recorded and compared. RESULTS: All patients were followed-up. The traditional group was followed up for 20 months (ranging 13-28 months), and the large head M-O-M group was followed up for 17 months (ranging 10-26 months). The mean Harris score was 89 points (ranging 59-98) in traditional group, and 94 points (ranging 71-100) in large head M-O-M group (P=0.014). The range of motion of hip was improved, and the large head M-O-M group (34?) was superior to traditional group (26?, P=0.004) at 6 months after surgery; the range of motion was improved 27? in traditional group and 37? in large head M-O-M group (P=0.009) over 1 year of follow up. The leg-length inequality was 4 mm (2-11 mm) in large head M-O-M group and 7 mm (5-16 mm) in traditional group (P=0.005). Both groups exhibited periprosthetic radiolucency (≤1 mm, 2 cases in traditional group and 3 cases in large head M-O-M group). One patient in the traditional group suffered dislocation. CONCLUSION: The large head M-on-M implants in total hip arthroplasty has excellent short-term effects on patients compared with traditional prosthesis. They offer the more stability and better restoration of hip articulation function and biomechanical reconstruction.