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

•Technique errors in patellar re-surfacing may contribute to complications in TKA.•Over-resection of the patella and over-stuffing of the patello-femoral joint should be avoided.•Patellar prosthesis design and gender are significant risk factors.•Optimized patella components that are thinner may reduce these errors.

BackgroundAvoidance 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.MethodsA 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.ResultsFemale 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).ConclusionsPatellar 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.Level of EvidenceIII