Impact of hyaluronic acid injection on the knee joint friction

Abstract

Purpose: The purpose of this in vitro study was to investigate whether or not hyaluronic acid supplementation improves knee joint friction during osteoarthritis progression under gait-like loading conditions.

Methods: Twelve human cadaveric knee joints were equally divided into mild and moderate osteoarthritic groups. After initial conservative preparation, a passive pendulum setup was used to test the whole joints under gait-like conditions before and after hyaluronic acid supplementation. The friction-related damping properties given by the coefficient of friction µ and the damping coefficient c (in kg m²/s) were calculated from the decaying flexion-extension motion of the knee. Subsequently, tibial and femoral cartilage and meniscus samples were extracted from the joints and tested in an established dynamic pin-on-plate tribometer using synthetic synovial fluid followed by synthetic synovial fluid supplemented with hyaluronic acid as lubricant. Friction was quantified by calculating the coefficient of friction.

Results: In the pendulum tests, the moderate OA group indicated significantly lower c₀ values (p < 0.05) under stance phase conditions and significantly lower µ₀ (p = 0.01) values under swing phase conditions. No degeneration-related statistical differences were found for µ_end or c_end. Friction was not significantly different (p > 0.05) with regard to mild and moderate osteoarthritis in the pin-on-plate tests. Additionally, hyaluronic acid did not affect friction in both, the pendulum (p > 0.05) and pin-on-plate friction tests (p > 0.05).

Conclusion: The results of this in vitro study suggested that the friction of cadaveric knee joint tissues does not increase with progressing degeneration. Moreover, hyaluronic acid viscosupplementation does not lead to an initial decrease in knee joint friction.

Keywords: Cartilage; Degeneration; Friction; Hyaluronic acid; Meniscus.

Fig. 1

Study design overview; (A) Hyaluronic acid (HA) supplementation at the joint level was examined using a passive pendulum friction setup (upper row), while the load application for the stance and swing phases were derived from a human gait cycle [24]. A viscous friction model was applied on the decaying passive knee joint motion in flexion–extension to calculate the damping time (tD) and to quantify the energy loss in terms of viscous damping (c) and friction processes (µ). (B) Testing of HA supplementation at the tissue level where meniscus against cartilage (tribosystem Meniscus) and tibial against femoral cartilage (tribosystem Cartilage) samples were examined using a dynamic pin-on-plate tribometer under gait-like loading conditions [19], while the coefficient of friction (CoF) was separately calculated for both, the stance and swing phases

Fig. 2

Results of Whole-organ arthroscopic knee score (WOAKS); Box-plots (min., mean, max., 25% and 75% percentiles) of the mild and severe OA knee joints according to the International Cartilage Research Society [21] and the Pauli degeneration score [28] with according, representative images of the cartilage surfaces and the menisci for both degeneration groups. Unpaired t-tests; n = 6; *p ≤ 0.05

Fig. 3

Results of the pendulum tests under stance phase conditions; Boxplots (min., max., median, 25% and 75% percentiles) of the damping time (tD_0/end in s), friction coefficient (µ_0/end) and viscous damping coefficient (c_0/end in kg m²/s) of the mild (green) and moderate OA knee joints (red) in the native condition (Native) and after hyaluronic acid supplementation (+ HA) determined under stance phase loading conditions. Wilcoxon and Mann–Whitney test; n = 6

Fig. 4

Results of the pendulum tests under swing phase conditions; Boxplots (min., max., median, 25% and 75% percentiles) of the damping time (tD_0/end in s), friction coefficient (µ_0/end) and viscous damping coefficient (c_0/endin kg m²/s) of the mild (green) and moderate OA knee joints (red) in the native condition (Native) and after hyaluronic acid supplementation (+ HA) determined under swing phase loading conditions. Wilcoxon and Mann–Whitney test; n = 6

Fig. 5

Results of the pin-on-plate tests; Boxplots (min., max., median, 25% and 75% percentiles) of the coefficient of friction (CoF) under stance (A) and swing phase (B) conditions. Results of the tribosystem Meniscus (n = 18) and Cartilage (n = 6) are shown for the samples with mild OA (green) and moderate OA (red), lubricated with synthetic synovial fluid (sSF) or with sSF and hyaluronic acid (HA) (sSF + HA). Wilcoxon and Mann–Whitney test