Osteochondromatosis is a kind of non-inflammatory disease of articular cartilage and epiphyseal cartilage, and intrachondral ossification disorder, which mainly occurs in the epiphysis of rapid growth period, 4-8 months old. There are the following common osteochondromatosis: i. Separated osteochondromatosis: the articular cartilage is abnormally thickened and cracked, and then separated from the subchondral bone to form a cartilage flap or free cartilage sheet, which is mainly seen in shoulder arthropathy, elbow, knee and tarsal joints. ii. Non-closure of elbow eminence: the ossification center of elbow eminence and proximal metaphysis of ulna are not closed, and the cartilage of epiphyseal growth plate is not ossified, so that the elbow joint is unstable, and osteoarthropathy of elbow joint is secondary. Splitting of ulnar coronoid process: the ulnar coronoid process splits into several pieces and does not heal with the ulna, which is easy to induce osteoarthropathy. Four, epiphyseal growth plate ossification retardation: the epiphyseal growth plate of the secondary ossification center of the long bone, for example, the distal ossification center of the ulna is retarded, resulting in asynchrony with the growth of the radius bone, which leads to radial-ulnar angular deformity or elbow joint subluxation. Its treatment is more rest, less exercise, analgesic drugs are given when the pain is severe, and when there are cartilage pieces and small bone pieces in the joint, they must be removed by surgery, and the angular deformity can be corrected by surgery, and the symptoms are usually relieved gradually after adulthood, but it can be secondary to osteoarthropathy, so it is not very likely for the function to be fully restored, and the cause of the disease is unclear, and it may be related to the congenital factors.