Glycosaminoglycan loss from cartilage after anterior cruciate ligament rupture: Influence of time since rupture and chondral injury

Abstract

Objective: To quantify the concentration of sulfated glycosaminoglycans (GAGs) concentration in the synovial fluid (SF) of knees with chronic anterior cruciate ligament (ACL) rupture and to identify possible associations between GAG concentration in SF and the time elapsed since rupture and degree of chondral injury. Method: Fourteen adult male subjects with total unilateral ACL rupture, which had occurred between 5 and 144 months earlier, were assessed. All subjects underwent joint aspiration; it was possible to collect SF from ten individuals. The samples were quantified to determine the GAG concentration using dimethylmethylene blue (DMMB) staining. The degree of chondral injury was macroscopically evaluated using the modified Mankin histological scale. Spearman correlation test (p≤ 0.05) was used to evaluate the association between GAG concentration and chondral injury, and Pearson correlation test (p≤ 0.05) was used to evaluate the association between GAG concentration and the time elapsed since rupture. Results: The GAG concentration in SF showed a mean variation of 73.84 ± 40.75 μg/ml, with a mean time of 40.4 ± 40.3 months since the rupture. There was no correlation between GAG concentration and time since the rupture (r= -0.09, p= 0.81). The chondral injury grades found were 0, 1, 4 and 5. There was no correlation between chondral injury grade and GAG concentration in SF (r= -0.41, p= 0.24). Conclusion: After at least 5 months, the GAG concentration in SF from knees with ACL rupture is independent of the time elapsed since rupture and/or the severity oi chondral injury.