Detection of bone erosions in knee osteoarthrosis by serum biomarkers

Abstract

Introduction: Osteoarthrosis (OA) is a degenerative chronic disease characterized by destruction of joint articular cartilage and subchondral bone with formation of osteophytes and usuries on joint surface. Quantitative and dynamic changes in remodeling of joint tissue reflect matrix molecules that dismiss as fragments in joint liquid, blood and urine where they can be detected. Human cartilage glycoprotein (YKL-40) is synthesised by chondrocytes and synovial cells and plays a significant role in remodel tissue. Objective: The aim of the paper was the parallel analysis and determination of the degree of correlation between ultrasound indicators destruction of joints, bone erosion (usuries), and serum YKL-40 concentrations in patients with primary osteoarthrosis of the knee. Methods: The analysis included 88 patients with the diagnosis of knee OA. Ultrasound review of knees was done by two rheumatologists. The analysis of serum samples determined the concentration of YKL40 by ELISA method. Results: The average age of patients was 69.97±9.37 years, duration of knee OA 6.46±6.73 years. The mean value of age in 59 patients with usuries was 72.05±7.74, at 29 without usuries 65.75±11.00 (p=0.003). The average value (median) thickness cartilage in medial condyl femur (front access) in patients with usuries was 1.25 mm (1.12-1.36 mm), without usuries 1.35 mm (1.20-1.51 mm) (p=0.016). The central YKL40 value of biomarkers in the patients without usuries was 81 ng/ml (46.5-120.5 ng/ml), with usuries the medial condyil 138 ng/ml (89.5-175.0 ng/ml), the lateral 106 ng/ml (63.0-201.5 ng/ml) and both condyl 86 ng/ml (69.75-140.5 ng/ml) (p=0.004). The central value YKL40 after 5 year-duration of disease was 83.68±33.65 ng/ml, after 10 years 138.22±48.88 ng/ml, after 15 years 209.30±79.36 ng/ml, and after 20 years 218.50±106.51 ng/ml (p=0.000). The biomarker YKL 40 may be a marker for usuries (area 0.691, p=0.004; confidence interval 0.574-0.808). If you took the optimal cut-off of 84.5 ng/ml, then YKL40 sensitivity to the usuries was 69.5%, and specificity 51.7%. Conclusion: Increased concentrations of biomarkers YKL40 may be an indicator of the degree of destructive changes in the knee osteoarthrosis.