Should the patella be replaced in total knee replacement?

In 170 total knee arthroplasties for osteoarthritis 71 did not receive a patellar replacement (group A), while 99 knees had a cemented polyethylene patella (group B). The mean follow-up time was 36 months (30-50 months). In group A 10 patients underwent second-stage patellar resurfacing and in group B 2 knees underwent revision of the patellar component. Radiologically the average patellar congruency was similar. In both groups there were 21 non-congruent knees. In group A 8 were symptomatic and had low scores compared to 2 in group B (P<0.05). The mean HSS score and patellar score were higher in group B than in group A (P<0.05).