This study will compare Hight Tibial Osteotomy with or without arthroscopically repair intra-articular knee lesions in patients with early stages of Osteoarthritis.The purpose of this study is evaluate if addition of arthroscopy to HTO provides better clinical, radiological and laboratory outcomes.

Intraarticular knee lesions are often in patients with early stages of osteoarthritis. The most frequent findings are degenerative meniscus/meniscal tears and cartilage degeneration. Degenerative meniscal lesions or meniscal tears are often incidental findings without any complains from patients. In the current literature there is no evidence for good clinical outcomes after arthroscopically treatment degenerative meniscus. Cartilage injuries are common in osteoarthritic knee and depending on grading of chondromalacia are usually treated by microfractures. By this time the choice of performed surgery depends on surgeons personal assessment. The investigators believe that concomitant intraarticular procedures added to HTO will provide better clinical outcomes.

Inclusion Criteria:

• Knee medial compartment or patellofemoral osteoarthritis in medical interview and physical examination
• Intraarticular lesions in MRI
• Confirmation of cartilage degeneration/damage and knee malalignment in radiological tests

Exclusion Criteria:

• no informed consent to participate in the study
• age under 18 years or above 65
• multilligament injury or single plane knee instability
• another musculoskeletal disorders in lower limb
• lower limb deformity requiring axis correction below 4o or above 12.5o • joints inflammatory diseases
• ASA score > II