Efficacy of sCOMP and sCTX-I in Diagnosis of Knee Osteoarthritis.

Objective: The aim of this study was to evaluate the efficacy of serum cartilage oligomeric matrix protein (sCOMP) and  serum C-terminal cross-linked telopeptide of type I collagen (sCTX-I) in identifying disease severity in knee osteoarthritis (KOA) cases.
Methods: A total of 150 individuals (100 cases and 50 controls) were recruited. They were assessed clinically and radiologically with WOMAC score and knee radiographs respectively, while biochemical assessment was done by serum COMP and serum CTX-I level.
Results: There were significant differences in serum levels between healthy individuals and KOA patients of both, sCOMP (01.16 ± 0.39 vs 17.38 ± 4.99 U/L; p = 0.01) and sCTX-I (0.35 ± 0.14 vs 4.59 ± 1.69; p = 0.02). There was a statistically significant difference between serum levels of CTX-I between K-L grade I and grade II (4.59 ± 1.69 vs 4.60 ± 1.17 ng/mL; p = 0.03) but no significant difference was seen in the sCOMP levels between K-L grade I and grade II (14.60 ± 6.47 vs 17.47 ± 4.99 U/L; p = 0.14).
Conclusion: Our findings reveal that both sCOMP and sCTX-I are very effective in distinguishing between healthy adults and those affected by KOA. Only CTX-I was also able to distinguish between K-L grades I and II, while sCOMP failed. Further, use of these two biomarkers to differentiate between K-L grade II, III and IV is limited and lacks sufficient discriminating power, hence not recommended. © Indian Orthopaedics Association 2022.