Patellofemoral knee prosthesis - why is it rarely used?

The aim of this research is to present the initial results of patellofemoral (PF) knee joint prosthesis implantation, as well as a review of recent literature. In the ten-year time period from 2012 to 2021, we implanted 8 PF prostheses, which account for 0.7% of all implanted knee prostheses. Out of the eight patients, two were male and six were female. The average age of the patients was 55.3 (47-70) years, with the average BMI being 26.4 (22.9- 31.9) kg/m2. Four patients had the procedure done on their right leg, and the other four on their left leg. The indication for surgery was secondary osteoarthritis following dysplasia or patellar instability in 5 patients, post-traumatic osteoarthritis in one patient, grade II chondromalacia with chronic anterior knee pain in one patient, and patella baja following surgical treatment in one patient FU was 5.87 (1-10) years. The patients underwent functional testing, Womac, KSS, Tegner and VAS. We analysed 7 patients, one of whom underwent conversion to TEP after 5.5 years. Range of motion was 0/128 (120-135) deg. Through clinical and radiological follow-ups, we found that the prostheses were stable throughout the follow-up period, with a normal patellar tracking. Preoperative WOMAC score was 38.4 , postoperative score was 95.5 points (p < 0.0001); preoperative KKS 1 (pain) score was 34.25, postoperative score was 94 (p < 0.0057); KKS 2 (function) score was 53.75, postoperative score was 95 (p < 0.0485), preoperative Tegner activity level was 1.86, postoperative level was 3 (p < 0.0002); preoperative VAS score was 7.14, postoperative score was 1.86 (p < -0.0001). PF arthroplasty has proven to be a successful option for treating isolated patellofemoral osteoarthritis, In recent years, the design of the prosthesis have been improving, which leaves open the possibility of this method of treatment being used more frequently and the indications being expanded.