Effects of Implant Alignment on Passive Knee Envelope

INTRODUCTION: A successful surgical outcome in total knee arthroplasty (TKA) depends on multiple factors, including proper rotational and translational alignment of the femoral and tibial components. Small variation in surgical alignment of an implant could potentially have a large impact on knee performance. Several authors have studied the effects of tibial and femoral component’s internal-external (IE) rotational alignment on tibiofemoral kinematics; however, the variation in implant alignment and its effects on knee kinematics have not been studied. It is important to understand the relationship and interaction between various implant alignment factors and their resultant effect on post-surgery knee kinematics. The objective of the present study was to measure the effects of variation in the implant’s rotational alignment on the tibiofemoral passive envelope using principal component (PC) analysis.