FIGURE 1.

Schematic overview of the study design. In total, three meniscus states were tested to examine the influence of the menisci on initial whole knee joint friction: intact, with posterior medial meniscus root tear (PMMR tear) and after medial meniscectomy. Each meniscus state was tested under simulated swing and stance phase conditions derived from an ovine gait cycle (Taylor et al., 2006; Taylor et al., 2011), each under two time settings: directly following loading the joints and after 20 min resting under the axial load using a passive pendulum friction testing device. Joint kinematics were recorded using a motion capturing system. The flexion-extension motion in the sagittal plane was used to calculate whole joint friction by applying a boundary friction model (Stanton, 1923) and a viscous friction model (Crisco et al., 2007).