Introduction and Objective. The Cartilage Oligomeric Matrix Protein (COMP) is a glycoprotein that is elevated in patients with osteoarthritis. The elevation increases linearly with the radiological grade of osteoarthritis. The objective of this study was to study the levels of COMP in knee osteoarthritis in the Indian population and to correlate (establish ranges) with the specific radiological grade of osteoarthritis (Kellgreen and Lawrence grading). Since the radiological classification is subjective, the COMP levels would serve as a more objective way of classifying osteoarthritic joints. Materials and Methods. We analysed the COMP levels by the Enzyme Linked Immunosorbent Assay (ELISA) method in 100 patients presenting to the outpatient clinic of our hospital, after obtaining due approvals. The radiographs of these patients were classified according to the Kellgreen-Lawrence grading by a senior orthopaedic surgeon. Results. We found a linear correlation with the COMP levels and the radiological classification as established in the previous studies. We were also able to establish a range of COMP levels for each classification stage. Conclusions. This study would provide means to classify osteoarthritis without the need for radiographs thus minimising radiation to the patient. It would also help us to predict the radiological findings thus serving as a guide for further treatment planning

Abstract. Objectives. The ability to predict which patients will improve following routine surgeries aimed at preventing the progression of osteoarthritis is needed to aid patients being stratified to receive the most appropriate treatment. This study aimed to investigate the potential of a panel of biomarkers for predicting (prior to treatment) the clinical outcome following treatment with microfracture or osteotomy. Methods. Proteins known to relate to OA severity, with predictive value in autologous cell implantation treatment or that had been identified in proteomic analyses (aggrecanase-1/ ADAMTS-4, cartilage oligomeric matrix protein (COMP), hyaluronic acid (HA), Lymphatic Vessel Endothelial Hyaluronan Receptor-1, matrix metalloproteinases-1 and −3, soluble CD14, S100 calcium binding protein A13 and 14-3-3 protein theta) were assessed in the synovial fluid (SF) of 19 and 13 patients prior to microfracture or osteotomy, respectively, using commercial immunoassays. Levels of COMP and HA were measured in the plasma of these patients. To find predictors of postoperative function, multiple linear regression analyses were performed. Results. Linear regression analyses demonstrated that a lower concentration of HA in pre-operative SF was predictive of improved knee function (higher Lysholm score) following microfracture surgery. Further, lower pre-operative activity of ADAMTS-4 in SF was a significant, independent predictor of higher post-operative Lysholm score (improved joint function) following osteotomy surgery. Conclusion. This study is novel in identifying biomarkers with the potential to predict clinical outcome in patients treated with microfracture or osteotomy of the knee. Lower concentrations of HA and undetectable activity of ADAMTS-4 in the joint fluid of individuals with cartilage defects/early-OA may be used in algorithms to stratify patients to the most appropriate surgery. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project