COMPARING TRANSVERSE PLANE BIOMECHANICS BETWEEN FIXED- AND MOBILE-BEARING TOTAL KNEE ARTHROPLASTY DURING LEVEL WALKING, STAIR NEGOTIATION AND PIVOTING

Abstract

Compared with fixed-bearing (FB) total knee arthroplasty (TKA), mobile-bearing (MB) TKA may promote knee rotation and reduce rotational load at bone–implant interface. Unfortunately, this hypothesis has not been examined with neither knee rotation during stance of pivoting nor knee rotational moment during activities other than level walking. This study used 3D motion analysis to obtain the rotation of tibia relative to the femur and knee rotation moment during stance phase of level walking, stair ascent/descent, step and spin turn for 17 FB, 20[Formula: see text]MB and 28 healthy knees. Statistical comparisons revealed that transverse plane biomechanics was similar between MB and FB knees. Compared with healthy knees ([Formula: see text]), both FB ([Formula: see text]) and MB knees ([Formula: see text]) reduced internal rotation during step turn at early stance. During spin turn, FB knees ([Formula: see text] vs. [Formula: see text]) reduced internal rotation at late stance, whereas MB knees ([Formula: see text] versus [Formula: see text]) reduced external rotation at early stance. MB knees (0.064% and 0.126% body weight [Formula: see text] height) had lower peak external rotation moments during early stance phase of both level walking and spin turn than healthy knees (0.108% and 0.238% body weight [Formula: see text] height). Using FB for TKA surgery without bias and step-turn strategy for pivoting were recommended.