Effectiveness comparison of mobile-bearing and fixed-bearing prostheses in total knee arthroplasty for ten years follow-up

Abstract

To compare the clinical results of mobile-bearing and fixed-bearing prostheses in total knee arthroplasty (TKA) during 10 years follow-up so as to provide a reference for clinical selection of TKA prosthesis. Between January 2002 and December 2005, 113 patients with osteoarthritis of the knee joint underwent primary TKA, and the clinical data were retrospectively analyzed. Mobile-bearing prosthesis was used in 47 cases (group A) and fixed-bearing prosthesis in 66 cases (group B). There was no significant difference in age, gender, body mass index, varus and flexion deformity of the knee, range of motion (ROM) of the knee, knee society score (KSS), and Western Ontario and McMaster University Osteoarthritis Index (WOMAC) between 2 groups before operation ( P>0.05), so the data were comparable. The operation time of groups A and B was (88.1±6.5) and (90.3±7.2) minutes respectively, showing no significant difference ( t=1.666, P=0.099). The wounds healed by first intention in all patients of both groups, and no postoperative early complications of incision infection and deep venous thrombosis occurred. The follow-up time was 10.2-12.3 years (mean, 10.8 years) in group A, and was 10.2-12.6 years (mean, 11.3 years) in group B. Revision was performed in 3 cases of group A and 4 cases of group B; the survival rates of prosthesis were 93.6% and 93.9% in groups A and B respectively, showing no significant difference ( χ2=0.005, P=0.944). The postoperative knee ROM, KSS score, and WOMAC score were significantly improved when compared with preoperative ones ( P<0.05). The knee ROM and KSS score of group B were significantly better than those of group A at 6 weeks after operation ( P<0.05), but no significant difference was found between 2 groups at 1, 3, and 10 years after operation ( P>0.05). The WOMAC score of group A was significantly better than that of group B at 10 years after operation ( t=2.086, P=0.037), but no significant difference was shown at 6 weeks, 1 year, and 3 years after operation ( P>0.05). At 10 years after operation, the excellent and good rate of KSS score was 87.2% in group A and was 84.8% in group B, showing no significant difference ( χ2=0.018, P=0.893). Good medium- and long-term clinical results can be achieved in TKA with both mobile-bearing and fixed-bearing prostheses. The TKA with fixed-bearing prosthesis is relatively simple with better early effectiveness of rehabilitation; and the TKA with mobile-bearing prosthesis could provide better long-term degree of satisfaction in WOMAC score, but a higher surgical skill and soft tissue balance techniques are needed.