Osteoarthritis, the most common type of arthritis, is a chronic and degenerative joint disease. It has been reported to affect more than 300 million adults and elderly individuals worldwide. The joint most commonly affected by osteoarthritis is the knee joint and this condition is called gonarthrosis.

The goal of treatment is to reduce symptoms and ultimately slow the progression of the disease with various treatment options throughout the course of the disease.Current clinical studies prepared by the working groups of the International Osteoarthritis Research Society (OARSI) and the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) According to the guidelines, treatment typically includes physiotherapy interventions with the use of non-steroidal anti-inflammatory drugs (NSAIDs) and analgesics, including intra-articular injections of corticosteroids. Exercise-oriented physiotherapy is one of the main approaches for the conservative treatment of gonarthrosis. The curative clinical effect of exercise therapy on pain and functional disability in gonarthrosis is important.

The use of PRP in the treatment of gonarthrosis is based on the ability of platelets to release biologically active proteins and promote tissue healing. Since the cartilage tissue mainly affected in gonarthrosis has low healing potential, this feature of platelets becomes more important for the target tissue. Existing studies show that PRP is superior to hyaluronic acid in intermediate and initial gonarthrosis; on the other hand, less satisfactory results are reported in severe gonarthrosis, similar to viscosupplementation.

Topically or orally administered NSAIDs form the backbone of pharmacological treatment in gonarthrosis.

It is seen that both exercise, PRP and topical NSAID agents are among the recommendations in the treatment of gonarthrosis. However, there is insufficient evidence regarding the superiority and therapeutic efficacy of these three treatment approaches. The aim of this study is to determine the effectiveness of "exercise", "PRP" and "NSAID-specific topical agents" in the treatment of patients with gonarthrosis; pain, function, quality of life, and patient satisfaction.

Voluntary participants who have been diagnosed with gonarthritis will be included in the study. Signed voluntary consent will be obtained from participants. Participants will be divided into tree groups. Study groups will be as follows: a) exercise, b) topical diclofenac, c) platalet-rich-plasma (PRP).

Inclusion Criteria:

• Diagnosed with gonarthrosis according to the criteria of the American Society of Rheumatology (ACR)
• Stage 2 or 3 according to Kellgren Lawrence radiological staging criteria,
• Those between the ages of 40 and 65,
• Body mass index below 30 kg/m2,
• Pain intensity defined by the patient in the last 3 months is at least 3 out of 10 according to NPRS,
• Patients who do not have any barriers to being included in the exercise program

Exclusion Criteria:

• Being in stage 4 according to Kellgren Lawrence radiological staging criteria,
• Hemoglobin level <11.5 g/dL
• Platelet level <100,000/μL
• Thrombocytopenia, coagulopathy, crystal arthropathy, hemophilia or hematological malignancy,
• Presence of active infection or tumor,
• Chronic antiaggregant use or taking immunosuppressive therapy,
• Pregnancy or lactation,
• Viscosupplementation or steroid injection in the related knee in the last 3 months, or using systemic steroids,
• To have received a physiotherapy program for the relevant knee in the last 3 months,
• Having a valgus or varus deformity greater than 15°,
• Presence of neurological diseases and/or deformity leading to lower extremity muscle weakness
• Having serious systemic and cardiovascular diseases that interfere with exercise

The investigator administering the treatment and the investigator performing the evaluations will be different. The evaluator will not know about the interventions that the participants received.