To investigate the influence of patella tracking and thickness for muscle strength after patellar resurfacing in total knee arthroplasty (TKA).
Quadriceps muscle strength of 100 cases 134 knees with osteoarthritis were analysed with isokinetic testing and extension lag after patellar resurfacing in TKA. Result was analyzed statistically through T test.
Significant decreasing of quadriceps muscle strength and endurance were detected on mal-patellofemoral tracking (61 +/- 24, P <0.01) and improper position of patella prosthesis (56 +/- 33, P < 0.01). Anterior knee pain with patella resurfacing was mainly associated with mal-patellofemoral tracking.
Asymptomatic weakness of quadriceps muscle was mainly associated with improper patella thickness.