1, joint twin: muscle strength loss across. Mild wear prosthesis can be corrected. 2, stump pain and phantom limb pain: due to infection, nerve adhesion. Severe cases need treatment. 3.Bone spur: improper treatment of the stump during surgery. 4.Children patients: fibula grows faster than tibia; bone grows faster than soft tissue. 5, scar: improper surgery or inflammatory changes. Causes tissue adhesions or contractures. 6, synovial bursa: enlarged by pressure and friction. Excessive size must be treated. 7, residual limb ulcer: poor blood circulation. Cannot be fitted with a prosthesis without healing. 8.Dermatological disease: folliculitis, dermatophytosis, etc. Receiving cavity is not ventilated caused.