Effect of decreasing patella thickness on patellofemoral joint function after total knee arthroplasty

Objective To investigate the effect of decreasing patella thickness on patellofemoral joint function after total knee arthroplasty. Methods From July 2014 to July 2016, 122 patients underwent unilateral primary total knee arthroplasty in our hospital were divided into routine patellar polishing group and reduced patellar thickness group. The patients were followed up for 2 years. The general condition, preoperative and postoperative knee function score (HSS score), patellar score (Feller score), visual analogue pain score (VAS) were observed and compared between the two groups. Patellar tilt angle and suitable angle were observed by X-ray. Results There was no difference in general data between the two groups before operation. There was no significant difference in HSS and Feller score between the two groups before operation. The HSS score, Feller score, VAS and knee joint mobility of the two groups at 3 months, 6 months, 1 year and 2 years after surgery were analyzed by variance analysis with repeated measurements (P<0.05). There was interaction between groups and time points, and difference was significant between the group of reducing patellar thickness and the group of routine patellar polishing at all time points except 1 month after operation. Conclusions Total knee arthroplasty can significantly improve the function of the knee joint.If the thickness of patella is reduced properly, the pressure of patellofemoral joint is reduced, the patellofemoral joint function can be improved better than that of conventional patellar polishing. But the long-term efficacy and possible complications of reducing patellar thickness need further follow-up. Key words: Arthroplasty, Replacement, Knee; Patellofemoral joint; Anterior knee pain