THE EFFECT OF TROCHLEAR DESIGN ON PATELLOFEMORAL SHEAR AND COMPRESSIVE FORCES IN TOTAL KNEE ARTHROPLASTY

Biomechanical testing was performed on 5 cadaveric knees to evaluate t he effect of patellofemoral design on shear and compressive force at t he patellar component-bone interface. Three patellofemoral designs wit h identical tibiofemoral articular surfaces were tested. The knees wer e tested under dynamic loading conditions from 0 degrees to 100 degree s flexion. A transducer that measured 3 orthogonal force components wa s mounted between the patellar component and the patella. The combinat ion of an oval dome patella with a 2-mm deeper trochlear groove and as sociated increased femoral resection was compared with a biconcave pat ella with standard trochlea and normal femoral resection. Alignment of the trochlear groove in 7 degrees valgus (anatomic) decreased medial- lateral shear by 10% to symmetric trochlear groove alignment.