BACKGROUND:Intertrochanteric fracture showed shattered state of different degrees in the clinic. The medial cortex is often a lack of continuity. Indentation and lesser trochanter displacement often cause destruction of biomechanics of femoral calcar to different degrees. Under this condition, it is very important to perform detailed classification of fractures and to strictly master indication of dynamic hip screw. OBJECTIVE:To further analyze the reasons for failure of internal fixation with dynamic hip screw for intertrochanteric fracture. METHODS:Data of 82 patients with intertrochanteric fracture repaired by internal fixation with dynamic hip screw, who were treated at the Department of Orthopedics, Kangtai Branch of the Second Hospital of Lanzhou University from March 2004 to December 2013, were retrospectively analyzed. The reason for failure of internal fixation and prevention method were explored. RESULTS AND CONCLUSION:Al patients were fol owed up for 4-48 months. Time of fracture healing was 12-38 weeks. Fixation failure was found in 12 cases, with an incidence of 15%. Of 12 failure cases, 7 cases affected hip screw cutting out femoral head neck (including 1 case combined with avascular necrosis of the femoral head), 1 case suffered from compression screw slipping out of the tube, 3 cases experienced screw pul ing out and breaking, plate loosening, and 1 case affected steel plate breakage. There were 1 case of Evans II type (8%), 3 cases of type III (25%), 5 cases of type IV (42%), and 3 cases of type V (25%). Lesser trochanter was not completely reset in 5 cases (42%). There were tip-apex distance>25 mm in 7 cases (58%) and early weight loading (3 weeks after fixation) in 1 case (8%). These data confirmed that the selection of indications, the degree of stability after reduction, accuracy of implant position and postoperative unreasonable exercise wil cause fixation failure of dynamic hip screw. Preoperative careful and comprehensive analysis, intraoperative precise operation and postoperative reasonable functional exercise are the keys to ensure success of fixation.