Kneeling is safe for patients implanted with medial-pivot total knee arthroplasty designs

Nine ADVANCE (Wright Medical Technology, Arlington, TN)) Medial-Pivot (MP) and 9 ADVANCE Double-High total knee arthroplasties were analyzed under radiographic surveillance at standing, mid kneeling, and full kneeling. In vivo tibiofemoral contact positions were obtained using the 3- to 2-dimensional image registration technique. The contact in Double-High knee was always more posterior than that in the MP knee presumably because of the presence of the posterior cruciate ligament. The contact positions in both the designs moved anterior from standing to mid kneeling, moved posterior from mid kneeling to full kneeling, and remained within the intended articulation range of the implants. This study indicates that kneeling is safe in MP total knee arthroplasty even in the absence of a cam-post or posterior cruciate ligament.