INTRODUCTIONOsteoarthritis or degenerative arthritis is the most common non-inflammatory degenerative joint disease. Osteoarthritis occurs more frequently at older ages and affects both gender and post-menopausal women. It commonly affects weight-bearing joints like the knee and hip, where the knee joint is mostly affected in India due to cultural and other practices like sitting on the ground, kneeling, sitting cross-legged, squatting etc . (Jayanth Joshi, Parakashkotwal). In particular, the rural population is more prone to this condition due to activities that involve increased physical stress such as going to the toilet in Indian toilets, sitting cross-legged during meals and heavy manual labor, while the urban population is less prone due to the involvement of technology that replaces and reduces manual loading. As we age, cartilage begins to degenerate, flaking off or forming small cracks. In advanced osteoarthritis, there is a total loss of the cartilaginous cushion between the bones of the joints. Repeated use of worn joints over the years can mechanically irritate and inflame the cartilage, causing joint pain, stiffness and swelling. Osteoarthritis is classified into 2 main groups based on the cause as primary osteoarthritis and secondary osteoarthritis. Primary osteoarthritis is the most commonly diagnosed form of OA. It is believed to be largely due to the "wear and tear" of overtime. Age between 50 and 60 is the most potent risk factor, and the longer a person uses their joints, the more likely they are to suffer from this form of OA. Secondary osteoarthritis results from conditions such as significant trauma, congenital joint anomalies, metabolic defects, diseases and disorders that alter the normal function and structure of the cartilage. Age groups between 45 and 50 are more likely to be affected. Risk factors such as trauma, sedentary lifestyle, excessive use of joints, heredity lead to this type of osteoarthritis. However, the intensity of osteoarthritis symptoms varies between individuals, and they typically become more severe, more frequent, and more debilitating over time. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay In osteoarthritis, pain is the main symptom that has a gradual onset and worsens with activity and after prolonged sitting or standing, with weight-bearing activities. Subsequently it becomes continuous even at rest. The joint swells due to synovitis, and stiffness gradually occurs following severe pain. This makes movement painful and limited, where crepitus is felt when passively moving the joint. There may be some flexion deformities and advanced cases present with genu varus deformity, e.g. Lightness of the bow (Hunter Hsu et al,2018). Treatment of osteoarthritis can be done as either a non-surgical or surgical treatment. Non-surgical treatment options include physiotherapy interventions, lifestyle modifications, weight loss, knee braces and support devices, pharmacological support such as NSAIDs and corticosteroids. surgical management includes osteotomy, unicompartmental knee arthroplasty, and total knee arthroplasty (Hunter Hsu et al,2018). Physiotherapy interventions include physical therapy to strengthen surrounding structures, electrotherapy modalities to relieve pain, thermotherapy, cryotherapy, supportive devices such as braces, bandaging to improve patients' functional ability and quality of life (RiannM.Palmeiri et al 2010) An important aspect in treatment planning is not only the diagnosis of the condition but also the assessment of the level of disability and ability to function. Studies have shown that diagnosis alone cannot predict service needs, length of stay, level of care, or functional outcomes. Although many questionnaires exist to assess the functioning of an individual with osteoarthritis, Western Ontario and McMaster Universities Osteoarthritis (WOMAC) has been found to be commonly used in a clinical setting with good validity and reliability. The Western Ontario and McMaster Universities Osteoarthritis Index is commonly used to evaluate patients with osteoarthritis and includes five questions on pain, two on stiffness, and seventeen on the level of disability in performing ADL (Mohammad H Ebrahimzadeh et al., 2015). Scores for each subscale range from 0-20 for pain, 0-8 for stiffness, 0-68 for physical function. The sum of all subscores gives a total WOMAC score. The higher score indicates a serious condition, e.g. increased pain, stiffness and functional limitation (WOMAC index, 2013). The World Health Organization developed the International Classification of Functioning, Disability and Health, a multipurpose classification that helps organize information on functioning and disability by providing precise details about health and related states. (WHO Geneva 2002). The ICF provides a list of activities and participations similar to activities of daily living. It is useful to people with any form of disability, not only to identify their health and rehabilitation needs, but also to identify and measure the level of disability and the effect of the physical and social environment they experience in their daily life. The functioning of individuals assessed through the ICF is the result of the interaction between bodily functions, body structures, activities and participation and environmental factors. Changes in one component can affect other components. Although the International Classification of Diseases (ICD-10) is the most widely used classification, there is growing interest in the use of the ICF, particularly as it relates to disability. Defining and measuring disability is difficult because it involves many aspects of life and the interaction between people and their environment. Considering this, WHO initiated a project on the assessment and classification of functioning, disability and health by representatives of more than 100 countries, researchers and consumers in an international collaboration, to produce the ICF as a universal framework (WHODAS 2.0 ). Although ICF contains a broad classification of functioning of individuals, which helps to diagnose a health condition by applying ICF before it is diagnosed clinically, the same seems to be a limitation as it is time consuming and tedious to use in clinical practice daily (Sven Bolte et al. al., 2014). Both quantitative and qualitative data can be organized through the ICF. PROCEDURES Sample Collection: Data were collected using the complete International Classification of Functioning, Disability and Health (ICF) core set for OA and WOMAC from subjects diagnosed with knee osteoarthritis, aged over 50 years, regardless of sex, from Saveetha Medical College and Hospital and surrounding communities. A total of 145 subjects diagnosed with knee osteoarthritis were included in the study after meeting the inclusion criteria of subjects in the age group of 50 years and above, including gender and who were able to understand and read Tamil , and at the same time.