Gender optimized patellar component designs are needed to better match female patellar anatomy

Background: Avoidance of both over-resection of the native patella, and over-stuffing of the patello-femoral joint are advocated to reduce the risk of patellar complications following patellar resurfacing. Female gender, due to thinner native patella, and use of patellar prostheses from one specific manufacturer that were thicker for comparable diameters than the patellar prostheses from a second manufacturer were hypothesized to be risk factors for these undesirable technical outcomes. Methods: A retrospective review was undertaken of 803 consecutive knee replacements, performed by one surgeon, during which the same patellar resurfacing technique had been used, but with two different patellar implant designs. Results: Female gender, and use of one specific design of patella prostheses were associated with both increased risk of patellar over resection to ≤ 13. mm residual patellar thickness, and creation of a patella construct that was thicker than the native patella (p < 0.001). Conclusions: Patellar prostheses design can contribute to compromises in surgical technique during patellar resurfacing in TKA in female patients with thinner patellae. Modifications to current patellar prosthesis dimensions may be considered to allow surgeons to more accurately resurface the thinner, native female patella.