Quadriceps performance following total knee arthroplasty (TKA) is a critical factor in patient satisfaction that can be significantly affected by implant design (Greene, 2008). The objective of this study was to compare quadriceps efficiency (QE) following TKA with a medial-pivot system (EVOLUTION®, MicroPort Orthopedics Inc., Arlington, TN, USA) to non-implanted control measurements. Five cadaveric leg specimens with no prior surgeries, deformities, or disease were obtained. Each was placed in a custom closed chain device and loaded to simulate a heel-up squat from full-extension to deep flexion (approximately 115°) and back to full extension. Quadriceps force (FQ) and ground reaction force (FZ) were measured, and the ratio of the two was calculated as the quadriceps load factor (QLF). QFLs are inversely related to QE, with higher QFLs representing reduced efficiency. Each specimen was then implanted with a medial-pivot implant by a board certified orthopedic surgeon and force measurements were repeated. Mean pre- (represents control values) and post-implantation QFLs were compared to determine any differences in QE throughout the range of motion.Introduction
Methods
