INTRODUCTION It has been suggested that abnormal lower extremity kinematics during running are related to patellofemoral pain (PFP). Specifically, during the first half of stance when the knee is loaded, excessive internal rotation of the femur may result in lateral patellae maltracking [1,2]. Similarly, the patellofemoral joint may also be influenced by excessive knee valgus, which may be part...

Patellar tendon moment arm length (PTma) changes at different knee flexion angles have not been determined in invivo studies. We aimed to determine PTma in four different knee angles using Magnetic Resonance Imaging (MRI) topredict in vivo changes in the moment arm length from different knee angles during running.PTma was measured as the perpendicular distance from muscle–tend...

Simulation results suggest that the primary mechanism for improvement in knee flexion after surgery is reduction of the muscle’s knee extension moment, rather than conversion to a knee flexion moment. Scarred transfer simulations resulted in an average peak knee flexion improvement (14° ± 5°) comparable to the average increase in knee flexion range of motion (13° ± 11°) in the subjects’ postope...

PURPOSE The purpose of this study was to compare the bundle tension curves and resultant knee kinematics between 2 tensioning protocols in anatomic double-bundle anterior cruciate ligament (ACL) reconstruction. METHODS Anatomic double-bundle ACL reconstruction was performed in 7 male cadaveric knees. Each graft was tensioned to 22 N under 2 conditions: (1) both bundles tensioned at 20 degrees...

Achieving high flexion is an objective of contemporary total knee arthoplasty; however little is known on the knee biomechanics at high flexion under weight-bearing conditions. This study investigates the 6DOF kinematics and tibiofemoral cartilage contact biomechanics of the knee during weight-bearing flexion from full extension to maximal flexion. Eight knees from seven healthy subjects with n...

This study compared the effects of solid and hinged ankle-foot orthoses (AFOs) on the gait of children with spastic diplegic cerebral palsy (CP) who ambulate with excessive ankle plantar flexion during stance. Twelve children with spastic diplegic CP wore no AFOs for an initial 2-week period, solid AFOs for 1 month, no AFOs for 2 weeks, and hinged AFOs for 1 month. Lower extremity muscle timing...

BACKGROUND Knee osteoarthritis is common in people who have undergone partial meniscectomy, and a higher external knee flexion moment during gait may be a potential contributor. Although the peak external knee flexion moment has been shown to increase from 3 months to 2 years following partial meniscectomy, mechanisms underpinning the increase in the peak knee flexion moment are unknown. METH...

CONTEXT The importance of the sensorimotor system in maintaining a stable knee joint has been recognized. As individual entities, knee-joint proprioception, landing kinematics, and knee muscles play important roles in functional joint stability. Preventing knee injuries during dynamic tasks requires accurate proprioceptive information and adequate muscular strength. Few investigators have evalu...