Meniscus Injury and its Surgical Treatment Does not Increase Initial Whole Knee Joint Friction

Abstract

While it is generally accepted that traumatic meniscus pathologies lead to degenerative articular cartilage changes in the mid-to long-term and consecutively to post-traumatic osteoarthritis (PTOA), very little is known about how such injuries initiate tribological changes within the knee and their possible impact on PTOA acceleration. Therefore, the aim of this study was to investigate the influence of three different medial meniscus states (intact, posterior root tear, total meniscectomy) on the initial whole knee joint friction. Six ovine knee joints were tested in a passive pendulum friction testing device under an axial load of 250 N and an initial deflection of 12°, representing swing phase conditions, and under an axial load of 1000 N and an initial deflection of 5°, simulating stance phase conditions. To additionally consider the influence of the time-dependent viscoelastic nature of the knee joint soft tissues on whole joint friction, the tests were performed twice, directly following load application and after 20 min creep loading of either 250 N or 1000 N axial load. On the basis of a three-dimensional joint kinematic analysis, the energy loss during the passive joint motion was analyzed, which allowed considerations on frictional and damping processes within the joint. The so-called “whole knee joint” friction was evaluated using the boundary friction model from Stanton and a viscous friction model from Crisco et al., both analyzing the passive joint flexion-extension motion in the sagittal plane. Significantly lower friction coefficients were observed in the simulated swing phase after meniscectomy (p < 0.05) compared to the intact state. No initial whole joint friction differences between the three meniscus states (p > 0.05) were found under stance phase conditions. Soft tissue creeping significantly increased all the determined friction coefficients (p < 0.05) after resting under load for 20 min. The exponential decay function of the viscous friction model provided a better fit (R2∼0.99) to the decaying flexion-extension data than the linear decay function of the boundary friction model (R2∼0.60). In conclusion, this tribological in vitro study on ovine knee joints indicated that neither a simulated posterior medial meniscus root tear nor the removal of the medial meniscus resulted in an initially increased whole joint friction.

Assessing the friction properties of synovial joint lubrication by tracking pendulum motion

“…In motion (3) and motion (4), there are some parts where the COF is measured as a negative value. Negative values of COF have not been measured in any previous studies on the friction properties of knee joints using pendulum tests (e.g., Mabuchi et al, 1994;Teeple et al, 2007;de Roy et al, 2021). We strongly recognize that negative COF is unthinkable in common sense of modern physics.…”

“…In recent studies, the pendulum test was applied to assess the relation between glycosaminoglycan content and COF (Lakin et al, 2016). The influence of three different medial meniscus states (intact, posterior root tear, total meniscetomy) was compared using the method of exponential fitting (de Roy et al, 2021). A pendulum test was used to investigate low-intensity pulsed ultrasound and platelet-rich plasma (Tavakoli et al, 2022).…”

Impact of hyaluronic acid injection on the knee joint friction

“…Friction tests on aged human knee joints with signs of mild or moderate OA were performed using a passive pendulum friction setup and a dynamic pin-on-plate tribometer [ 19 , 22 ] to investigate whole joint friction and the tribological effect of HA supplementation at the joint level and on extracted meniscus and cartilage samples at the tissue level, respectively (Fig. 1 ).…”

“…Subsequently, the skin, fat and muscle tissue were removed, while the collateral ligaments, the patellar ligament at the tibia and the joint capsule were maintained intact. The bony ends of the femur and tibia were embedded in custom-made bone cylinders using polymethyl-methacrylate (Technovit 3040, Heraeus Kulzer GmbH, Wertheim, Germany) for fixation of the knees in the pendulum setup [ 22 ]. Two customized bone screws were bi-cortically anchored in the femur and tibia, while coordinate systems were aligned along the anatomical axes of the bones for kinematic measurements.…”

“…Following preparation, the knee joint was mounted vertically inverted in an inclined mounting block on a base plate of a previously introduced pendulum setup [ 22 ]. The tibia was allowed to freely oscillate relative to the femur with the pendulum arm attached.…”