Ankle bone bulge has the following reasons: 1, may be normal anatomical structure, such as inside and outside the ankle, generally located in the ankle joint, left and right symmetry exists, there is no local pain, swelling performance; 2, is the local bone congenital developmental deformity, usually from childhood, with no obvious changes over time; 3, there is a local fracture deformity healing, there will be a clear history of trauma and fractures 4, other causes are ankle joint free body, osteochondroma, bone cysts and other lesions, free body will move, sometimes may disappear, and osteochondroma may be accompanied by local pain or pressure pain, you can through the ankle joint lateral radiographs to check and determine the nature of the bulge. If it is a normal anatomical structure, no special treatment is needed; if it is a joint free body, it can be removed arthroscopically; if it is an osteochondroma, etc., it can be treated with local surgical resection.