The purpose was to evaluate clinical and radiographical outcome of 1777 patella non-resurfacing in two major centres. Patella management in total knee arthroplasty (TKA) is of concern when resurfaced (multiple problems) or when non-resurfaced (pain). Reports in the literature are frequently non-specific regarding surgical approach, femoral rotation alignment, and femoral design.

1777 non-resurfaced patella TKAs from two large centres were evaluated with a 2 to 15 year follow-up, using similar selection criterion, operative techniques, and prostheses. Patient demographics included 70% females (mean age 68 years). Diagnoses included 8% rheumatoid. Radiologic skyline view assessment of 200 cases (100 from each centre) with longest (mean 9. 2 years) follow-up, formed a subset group. Clinical success rate was good/excellent in 94. 6%; scores improved from 59 to 87.

Patella-related anterior knee pain requiring re-operation was 1. 1% (19 patients), only 9 (0. 55%) of which had unequivocal improvement following re-surfacing. Twenty-one cases (1. 2%) underwent “incidental” patella resurfacing at revision for other reasons. There were no patella subluxations or dislocations. Two hundred cases with longest follow-up revealed perfect congruent contact in 97. 5% with no lateral deviation (mid-sulcus to patella crown) over 6 mm. Asymptomatic remodelling was noted in 8%, with relative sclerosis and height loss of the lateral facet in 2. 5%. No changes correlated with clinical symptoms.

These data support a success rate of over 98% with non-resurfaced patella in a mobile-bearing (LCS) TKA system that includes a patella friendly design, proper soft tissue management, and femoral component rotational alignment using the tibial shaft axis and balanced flexion tension gap method.