Background: Osteochondritis dissecans (OCD) of the knee is rare in adult patients, and there is no standardized treatment protocol for managing such cases. Treatment options range from conservative therapy and internal fixation to advanced cartilage restoration techniques. In recent years, mechanical axis correction has gained importance, especially in cases involving cartilage lesions in weight-bearing joints. Case Report: We report a rare case of a 51-year-old active male with a Grade 2 OCD lesion (ICRS classification) in the weight-bearing region of the medial femoral condyle, accompanied by varus malalignment. The patient desired a return to athletic activity. He was successfully treated using a combination of Osteochondral Autograft Transplantation (OATS) and Medial Opening Wedge High Tibial Osteotomy (MOWHTO). At 9 months postoperatively, he returned to sport with significant improvement in pain and function. Conclusion: This case emphasizes the importance of comprehensive clinical and radiological evaluation in diagnosing OCD in adults. Correction of limb alignment is critical for surgical success and long-term graft survival. Implant-free techniques such as OATS with MOWHTO can offer excellent outcomes while avoiding secondary procedures.