Patellar resurfacing in total knee arthroplasty remains controversial. We report the medium term results of patients who had Scorpio total knee replacement for osteoarthritis between January 2002 and September 2004. A retrospective review of 118 patients was undertaken. All patients during the first half of this time period had no resurfacing of the patella, and all patients in the later half of this period underwent resurfacing of the patella. The mean follow-up in the non-resurfaced group was 30 months and the mean follow-up in the resurfaced group was 17 months. The two groups were similar in age, gender and the grade of the surgeon. Knee society clinical rating score, patient satisfaction, anterior knee pain, patellofemoral questionnaires, patellofemoral revision rates and success in returning to normal daily activities were noted.

There was a significant difference between the two groups in the patellar revision rates, anterior knee pain and Euroquol scores. The incidence of anterior knee pain in the patella non-resurfaced group was 23%, compared to 6% in the resurfaced group [p<0.05]. The rate of revision in the non-resurfaced group was 11% compared to 0% in the resurfaced group [p=0.03]. The mean Euroquol score in the resurfaced group was 86.44 compared to 80.35 [p=0.04]. Knee Society score, patient satisfaction, symptoms of patellar apprehension and knee instability, return to pre-op functional level, ability to kneel, use of a walking aid, presence of limp and satisfaction with operation as not statistically different between the two groups.

In view of the statistically significant difference in the incidence of anterior knee pain and the rate of revision in the group of patients without patellar resurfacing, the authors suggest that retaining the patellar surface may not be a viable option. Although an appropriate design for the femoral prosthetic trochlea is an important factor, a good surgical technique with patellar resurfacing is more likely to result in predictable satisfactory results. We feel that high contact pressures between the non-resurfaced patellae and the prosthetic femoral trochlea can be generated after a total knee replacement when the patella is not resurfaced, and can thus result in patients having anterior knee pain.