① Soft knee brace: made of strong elastic fabric. Hard struts can also be used to increase strength; ② Plastic knee brace: made of thermoplastic material to prevent knee flexion and lateral instability; ③ Frame-type knee brace: The structure is very simple, consisting of two side braces, upper and lower leather hoops and patella pads, and there is no hinge. Used for temporary fixation of quadriceps femoris muscle weakness; ④ Traditional knee brace: equivalent to the middle part of metal knee ankle foot orthosis, with hinges; ⑤ Swedish knee flexion brace: it is specially used for knee flexion. _ The belt of the socket can be adjusted, and the knee joint can be kept straight or slightly flexed by three-point fixation.