To investigate the causes and preventive measures of hip inversion and tension screw cutting prolapse after Gamma nail fixation of intertrochanteric fractures of the femur. METHODS From February 2002 to December 2005, 174 AO/OTA classified A2 femoral rotor fractures were treated with Gamma nail (AP type, stryker company). Results Follow-up was obtained in 125 of 174 patients. Hip inversion occurred in 37 cases, and inversion with cutting and dislocation in 2 cases. Both cases were elderly (78 and 92 years), obese (69 and 74 kg) women. They were partially weight-bearing and walked out of bed one week after surgery. At 3 and 7 months postoperatively, respectively, the fracture was found to be inwardly rotated and the tension screw cut into the femoral head and prolapsed posteriorly and superiorly. The deformity healed after 10 weeks, and in the first case, all the internal fixation was removed, while in the second case, only the tension screw was removed for medical reasons. Postoperative functional recovery was poor and much worse than before the fracture. Conclusion For A2.2 or A2.3 fractures in elderly, obese women, it is not advisable to allow the patient to walk with weight too early after Gamma nail fixation, and the interval between radiographic examinations should be shortened. Findings of tension screw movement within the femoral head or mild inversion of the fracture should result in bed rest until signs of fracture healing occur. Up