Choosing Your Implant: Cementless, Patella Sparing and Posterior Cruciate Ligament Retaining

Clinical results of total knee arthroplasty with osteointegration techniques for fixation of the femoral and tibial components in a series of 192 patients (255 knees) followed up for 15 to 18 years are comparable with the best series reported with cemented fixation. Although functional scores declined as the patients aged, pain scores did not worsen, and the mechanical failure rate remained low through follow-up. Preservation of the posterior cruciate ligament offered knee stability, especially in knees that required ligament balancing. Results with unresurfaced patellas in total knee arthroplasty are superior to resurfaced patellas in qualities related to quadriceps function such as stair climbing, likely because of femoral component design. Femoral implants with a shallow patellar groove and wide intercondylar notch produce the highest stresses on the unresurfaced patella. Those with deeper patellar grooves and supporting lateral flange surfaces have low contact stress similar to that of the normal patellofemoral joint.