Correlation Analysis of C‐terminal telopeptide of collagen type II and Interleukin‐1β for Early Diagnosis of Knee Osteoarthritis

OBJECTIVE To analyze the correlation between the Kellgren-Lawrence (K-L) score of knee osteoarthritis (KOA) patients with different degrees and their urine concentration of C-terminal telopeptide of collagen type II (CTX-II) and interleukin-1β (IL-1β), and to further evaluate the diagnostic value of CTX-II and IL-1β during the pathological process by producing an experimental osteoarthritis (OA) model in rabbits. METHODS From 1 January 2017 to 31 December 2018, a total of 34 subjects (7 mild, 9 moderate, 9 severe arthritis patients, and 9 healthy individuals) comprising 16 men and 18 women were included in this study. Patients were diagnosed according to the American College of Rheumatology (ACR) criteria. The urine of all subjects was collected to detect the concentration of CTX-II and IL-1β. The rabbits in the KOA group were subjected to protease (control group with saline) injection into the articular cavity of their right knees and immobilization with gypsum. We used radiological and histological examination to identify the KOA model. ELISA was applied to investigate the concentrations of CTX-II and IL-1β in urine and serum, and Spearman's rank correlation analysis was used to analyze the correlation. RESULTS There was no significant difference in the mean ages and body mass index (BMI) between groups. The mean ages of mild, moderate, and severe arthritis patients and healthy individuals were 54.29 ± 5.76, 58.44 ± 6.44, 59.89 ± 6.75, and 56.67 ± 4.18 years, respectively. The mean BMI of mild, moderate, and severe arthritis patients and healthy individuals were 23.59 ± 1.56, 23.57 ± 2.06, 24.46 ± 1.64, and 23.42 ± 1.35 kg/m2 , respectively. The Kellgren-Lawrence (K-L) score was higher with the aggravation of KOA. The K-L scores of mild, moderate, and severe KOA patients were 1.14 ± 0.38, 2.56 ± 0.53, and 3.63 ± 0.52, respectively. The KOA symptoms of patients became more severe, with not only increased K-L scores but also elevated concentrations of CTX-II and IL-1β. Moreover, there was a positive correlation between CTX-II and IL-1β of all subjects (r = 0.974, P