Assessment of Severity of Knee Pain and its Relationship with Serum and Urine Biomarkers in Individuals with Osteoarthritis Knee

Research Objectives: To assess the severity of knee pain in persons with primary osteoarthritis (OA) knee and find out the possible association between severity of knee pain and (serum and urine) biomarkers.

Design: A cross-sectional study

Setting: A tertiary care teaching hospital in India

Participants: Persons presenting with knee pain, with diagnosis of primary osteoarthritis Knee (unilateral/ bilateral) with a Kellgren-Lawrence score of 3

Interventions: Nil

Main Outcome Measures: The severity of knee pain was assessed with a visual analog scale (VAS). Among biomarkers, C-telopeptide type-II Collagen (CTX-II) and N-telopeptide- type-I Collagen (NTX-I) were assessed from urine. From serum, cartilage oligomeric matrix protein (COMP), N-terminal propeptide of collagen type-IIA (PIIANP), and hyaluronic acid (HA) were assessed. Besides these, erythrocyte sedimentation rate (ESR) and C-reactive Protein were assessed. In this study, we calculated the correlation coefficients between pain (VAS) scores and individual biomarkers.

Results: A total of 96 persons (47% were female) with OA knee grade III participated in the study. The mean age and body mass index (BMI) of the participants was 59 years and 26.6 kg/m2. None of the participants were using any walking aids or any orthosis/ knee brace. The mean ESR and uric acids were 14.05 mm/hour and 5.40 mg/dL. Using spearman's correlation coefficient, the study found a correlation among VAS pain and ESR (p < 0.001, r=0.51), CRP (p=0.002, r= 0.31) and HA (p=0.024, r=0.23). However, the study failed to demonstrate any association between the intensity of knee pain and bony biomarkers- CTX-II (p=0.14, r= 0.15), NTX-I (p=0.67, r= 0.43), COMP (p=0.06, r= -0.20) and PIIANP (p=0.26, r= 0.12).

Conclusions: The study confirmed the relationship between the intensity of knee pain and inflammatory markers- ESR, C-reactive protein and HA.

Author(s) Disclosures: The study was supported by extramural research grant (ICMR)