Comparison Of Mobile-bearing And Fixed-bearing Total Knee Arthroplasthy For Valgus Deformity

Objective:The purpose of this study was to provide an evidence-based clinical and radiographic evaluation of mobile-bearing prosthesis in total knee arthroplasty for valgus deformity by comparing it with a fixed-bearing posterior stabilized prosthesis, to provide the reference for clinical orthopedists, and to evaluate the efficacy and safety of mobile-bearing prosthesis for valgus knees.Methods:From January2007to June2011, we performed a retrospective study in the Second Affiliated Hospital of Zhejiang University. According to inclusion and exclusion criteria,75patients (77knees) were included. There were40patients (42knees) in the fixed-bearing group which included12knees of type Ⅲ valgus performed with NexGen LPS-FLEX prosthesis (Zimmer, USA). There were35patients (35knees) in the mobile-bearing group which included7knees of type Ⅲ valgus performed with PFC-Simga RPF prosthesis (Depuy, USA). The follow-up was at least one year. The patients were assessed clinically and radiographically. KSS Score and Feller Score for Patella was assessed as a primary outcome. All dates were analyzed using SPSS16.0software, significant statistical difference was P<0.05.Results:Although there was significant improvement in both groups of knee, there was no significant difference between the fixed-bearing and mobile-bearing with regard to the postoperative Knee Society knee clinical score, Knee Society knee functional score, Feller score or Visual Analogue Scale score. Compared with the fixed-bearing group, the mobile-bearing group had more blood loss, but the difference of postoperative transfused blood volume was no significant.In the fix-bearing group, one knee was suspected of having peroneal nerve palsy. In addition there was no lining prolapse, spin out, unstable, osteolysis, prosthesis loosening or other complication occured in any of the patient. No knee needed to be revised.Conclusion:Early-term of both fixed-bearing and mobile-bearing total knee arthroplasthies were encouraging in patients with valgus knee. The efficacy and safety of rotating prosthesis for valgus knee was as good as fix-bearing. However, the mobile bearing had showed no superior. The middle and long-term efficacy needs to be evaluated further.