Loading
Life sciences · Journal article
Osteoarthritis and Cartilage Open · August 20, 2026
No summary has been generated for this record yet. What follows is drawn from its source metadata only.
Journal article.
No findings were extractable from the material analysed.
Safety was not reported in the material analysed. Check the source before drawing any conclusion about harm.
The source did not state who this applies to in practice.
Graded across the dimensions that decide whether you should act, each from what the source actually supports. There is no single score, and where a dimension was not assessed it says so.
This record has not been graded across any dimension yet. Treat the label above as provisional and read the source.
What is missing. This record has no bottom line, key findings, reported figures, evidence dimensions. That is a gap in the analysis, not a judgement about the study.
Hyaluronic acid (HA) and proteoglycan 4 (PRG4) are the primary lubricants in synovial fluid (SF), critical to its function and overall joint health. SF composition and lubricating ability has been primarily investigated in the context of disease; however, baseline ranges in normal SF remain unclear. This study aimed to quantify PRG4 and HA concentrations and evaluate lubrication performance in human SF without any joint pathology. SF was obtained from 33 cadaveric donors, with samples collected bilaterally in seven donors. Mean donor age was 60 ± 14 years and 51.5% were female. Concentrations of HA and PRG4 were quantified and SF lubrication under static and dynamic fiction conditions was assessed. Sex differences, age correlations, and intra-individual variability in biochemical and frictional properties were analyzed. HA ranged from 0.44 to 10.13 mg/mL (mean: 2.66 ± 2.05 mg/mL), while PRG4 levels ranged from 183.51 to 303.25 μg/mL (mean: 251.15 ± 32.16 μg/mL). Neither lubricant correlated with age (HA: rs = 0.03, p = 0.88; PRG4: r = 0.12, p = 0.52) or sex (both p > 0.5), nor showed intra-individual differences (both p > 0.40). Mean static friction (0.63 ± 0.08) exceeded dynamic friction (0.48 ± 0.04), and both were independent of age, sex, and HA and PRG4 levels (all p > 0.2). Baseline concentrations of HA and PRG4 and SF lubrication properties in normal SF were independent of age and sex, with no significant association between lubricant composition and function. These findings provide a reference for normal SF lubricant composition and lubrication function and will aid in the understanding of SF lubrication dysregulation in disease states.