The biomechanical and surgical solutions for patella implant in total kneearthroplasty

A basic fault in designs of patella implants that calls for a prompt remedy is the inadequate polyethylene thickness in contact areas. The requirement for thickness of patella implants should be similar to the requirement set up by the FDA in 1993 regarding the tibial implants, that is, a minimal th ickness of 8 mm. A solution is presented for the optimal design of the patella implant and f or the appropriate surgical technique. The implant's undersurface that fixes to hone is concave and has a 1-cm wid e but 5 to 6 mm short central peg that does not risk the integrity of the b one. Fixation of the concave aspect to the convex aspect of the bony patell a strongly enhances resistance to medio-lateral and supero-inferior shear f orces. The circumferential facet of the implant 8 mm thick assures uniform thickne ss of the entire implant and assures optimal mechanical properties of the p olyethylene. The articulating surface is tailored to conform to the corresponding femora l trochlear groove and condyles. It can be made to fit any femoral componen t of any knee implant.