Approximately 120 patients who have been diagnosed with knee osteoarthritis but have not previously operated due to this disease and who are in Kellgren Lawrence stage 2 and 3 will be compared with the KOOS scale and Short Form-36 (Short Form-36: SF-36) scales to investigate the validity and reliability of the Turkish version of KOOS-12.

Osteoarthritis (OA) is a chronic degenerative disease characterized by the loss of articular cartilage, causing destruction in periarticular bone tissue, leading to a decrease in daily life and quality of life due to pain despite its slow progression.

When the knee osteoarthritis Looking at the prevalence among people living in Turkey, compared to males more can be seen, 14.8% of the 50 and older population in knee OA incidence, 22.5% of the incidence in women, while men were determined to be 8%.

Risk factors that affect the development of knee OA include obesity, traumas, chondrocalcinosis, nutritional factors, genetics, smoking, estrogen replacement, muscular weakness, and professional or sports activities. The individual with knee OA especially; It is applied to the physician with the complaints of increased pain during walking, climbing and climbing stairs, stiffness in the joint, crepitation and limited range of motion.

Diagnosis is determined based on knee OA, clinical and radiological evaluations; According to the radiological changes seen, the stage of the disease is determined by Kellgren Lawrence staging (Stage 0-4). Purposes in the treatment of knee OA; patient education, pain control, increasing functionality and reducing the impact of disability on daily life. The optimal treatment approach involves the application of non-pharmacological and pharmacological treatments together.

Functional evaluation methods are of great importance in planning the right treatment approach and evaluating treatment effectiveness due to the negative impact of individuals on daily life activities. Functional evaluation of the individual; daily life activities, professional activities, leisure activities, social relationships and their skills in performing these tasks are carried out with objective, generic or disease-specific scales. Various scales have been developed in individuals with knee OA that allow an objective evaluation of functions. Among these scales, Western Ontario and McMaster Universities Osteoarthritis Index (Western Ontario and McMaster Universities Osteoarthritis Index: WOMAC), Lequesne Index, Knee-Hip Osteoarthritis Life Quality Scale (Osteoarthritis of Knee Hip Quality Of Life Questionnaire: OAKHQOL), Knee osteoarthritis and Knee Injury and Knee Injury and Osteoarthritis Outcome Score: KOOS.

These questionnaires, which are reported by the patients, are not routinely used in the clinic due to the length of the questionnaires, which are used to determine the problems caused by joint problems in daily life and quality of life. Therefore, patient-based scales that can be used in the clinic should be short, and include questions that can evaluate pain, function and quality of life. Although the short form of the KOOS questionnaire has been developed, KOOS-PS only measures the effects of knee osteoarthritis on physical function. Consisting of 12 questions considering that the KOOS scale is long in routine, clinic use; A short form of KOOS-12 was created, which included the assessment sections of pain, function and knee-specific quality of life. The application of the KOOS-12 scale takes 2 minutes. The short form of KOOS-12 was found to be a valid and reliable scale in individuals who underwent total knee arthroplasty. The purpose of our study; Turkish reliability and validity of the Knee Osteoarthritis and Knee Injury and Osteoarthritis Result Score-12 scale.

Inclusion Criteria:

• The study resides in the province of Istanbul
• 18 years and older
• Who have been diagnosed with knee osteoarthritis
• In Kellgren Lawrence Staging; Stage 2 and 3 detected
• Not operated after knee osteoarthritis after diagnosis
• Literate
• 120 individuals who agree to participate in the study will be included. For the validity of the questionnaire, it must be applied to at least 10 times the number of questions in the questionnaire. In this context, it is planned to be included in the study with at least 120 people.

Exclusion Criteria:

• Those diagnosed with hip and ankle OA
• Those with neurological diseases affecting their lower extremities
• Those with knee pain due to rheumatoid arthritis, anterior cruciate ligament injury and menisectomy
• Those who had a total knee arthroplasty operation in the last 6 months

In determining the individuals who will participate in the study; face to face interviews and social media groups (whatsapp, facebook, instagram etc.) will be used. Individuals diagnosed with osteoarthritis by the physician at the Alptekin Physical Therapy Clinic will be included.