KINEMATIC COMPARISON OF A FIRST- AND SECOND-GENERATION BCS TKA DURING A DEEP KNEE BEND

IntroductionThe Bi-Cruciate Stabilized (BCS) total knee arthroplasty (TKA) incorporates two cam-post mechanisms to reproduce the functionality and stability provided by the anterior cruciate ligament and posterior cruciate ligament in the native knee. The anterior cam-post mechanism provides stability in full extension and early flexion (≤20°) while the posterior cam-post mechanism prevents anterior sliding of the femur during deeper flexion (≥60°). Recently (2012), a second generation BCS design introduced more normal shapes to the femur and tibial bearing geometries that provides delayed lateral femoral condyle rollback and encourages more stable positioning of the medial femoral condyle. The purpose of this study was to compare the in vivo kinematics exhibited by the two generations during weight bearing flexion.MethodsIn vivo kinematics were derived for 126 patients. Eighty-six subjects were implanted with a first generation BCS (BCS 1) TKA and 40 with the second generation BCS (BCS 2) TKA. Fluoroscop...