Objective: To evaluate the relationship between serum chondroitinsulphate WF6 (CS- WF6) and hyaluronate (HA) and the severity of knee OA according to Kellgren-Lawrence (K/L) grades of radiographic severity and minimal joint space width (JSW).

Material and Method: One-hundred and twenty-six patients with OA (knee) according to K/L grades were classified into four groups. The JSW of the tibiofemoral joint were measured from standing PA radiographs. Serum CS-WF6 and HA were analyzed by the ELISA based technique. One-way analysis of variance, Bonferroni’s method and Kendall’s tau coefficient relation test were performed to evaluate the association of K/L grades and JSW with levels of CS-WF6 and HA, respectively.

Results: Serum CS-WF6 levels in grade 4 were significantly increased when compared with the other grades (p<0.05). The serum HA level did not show any significant difference among the grades of severity. The serum CS-WF6 level showed a significant negative correlation with the JSW and its levels rose rapidly to the level beyond 300 ng/ml. There was no correlation found between the levels of serum HA and JSW.

Conclusion: WF6 levels may be useful in identifying patients at risk of rapid progression reflected by a point of an abruptly high WF6 level. The determination of WF6 in the serum showed increasing levels in more severe grades, so it could be useful in monitoring the effectiveness of treatment. There were some limitations because of broad distribution and overlap with the normal range. Thus, it may not be suitable as a diagnostic tool.

Keywords: Biomarkers, Cartilage, Osteoarthritis, Chondroitin sulphate WF6