Work

Tribological impact of synovial fluid alterations in osteoarthritis: Correlation analyses between cartilage friction and synovial fluid properties

Year: 2025

Type: article

Abstract: Objective To better understand how patient-specific alterations in the synovial fluid composition and its viscosity affect cartilage friction of samples with mild and advanced signs of degeneration. Design Synovial fluid, mild and advanced degenerated cartilage samples were collected from twelve patients undergoing knee replacement surgery. Friction tests were performed under simulated gait conditions, with each sample lubricated with its patient-specific synovial fluid. Cartilage degeneration was assessed macroscopically and microscopically. Synovial fluid samples were analyzed for viscosity and biochemical composition and the Spearman method was used to assess relationships between all parameters. Results Friction of mildly degenerated cartilage samples negatively correlated with the proteoglycan 4 concentration in the synovial fluid (µ endStance : ρ = −0.9, 95% CI [-1.0, −0.8], p < 0.01), µ endSwing : ρ = −0.7, 95% CI [-0.9, −0.3], p=0.01). For advanced degenerated samples, significant positive correlations were found between friction during swing phase of gait (µ endSwing ) and synovial fluid viscosity values (η 0.01(25 °C) : ρ = −0.7, 95% CI [-0.9, −0.2], p=0.01; η 1000(25 °C) : ρ = −0.8, 95% CI [-0.9, −0.4], p=< 0.01). Conclusion The impact of SF alterations on AC friction depends on the tissue's degeneration severity. These findings might provide valuable information when selecting appropriate patient populations and timing of treatment options, particularly tribosupplementation approaches, which address the knee joint's tribology.

Source: Osteoarthritis and Cartilage

DOI: 10.1016/j.joca.2025.11.002