History: Female, 55 years old, felt ankle discomfort for more than 2 years, sometimes stuck with pain when walking, and improved after sitting down and resting and moving the ankle joint, recently the attacks were more frequent than before. X-rays showed a free body in the ankle joint, and CT confirmed a free body of about 6 mm in diameter in the anterior ankle. Diagnosis: Ankle osteoarthritis with free body Shanghai Oriental Hospital Joint and Orthopedic Specialists Junfeng Cai Treatment: Ankle arthroscopy and free body removal Surgical approach: Anterior internal and anterior external incision Posterior internal and posterior external incision Pre-operative images Surgical photos Incision markings 2, free body seen microscopically during surgery 3, free body removed 4, anterior ankle free body disappeared on postoperative X-ray