Objective: To improve the results of the treatment of unstable types of intertrochanteric fractures of the femur (ITFF) by intal fixation.rnMethods: A L-trapezoid compression plate system (L-TCP) was designed and compared to the AO/ASIF angle plates of 95° and 130° (L-AP) with mechanical tests. An Evans Type Ⅲ model was made, the simulation electrical test with loading on single and both legs were done. The results demonstrated that the stability of the L-TCP fixation was significantly greater, and the stress concentration at the upper screw hole was relevantly smaller than that of L-AP. From June 1986 to June 1998, 82 patients of ITFF were treated with L-TCP fixation. The average age was 67.4 years old (26-91). Seventy-four of those fractures were unstable. Fifty-eight patients were treated with open reduction, and 24 cases were treated by closed reduction rnrnand limited open (only lateral aspect of upper femur was exposed) fixation with L-TCP under X-ray monitoring.rnResults: Sixty-six patients were followed up for 6-69months. Complications, including 3 wound infection, 1 non-union, 3 coxa varus and 2 implant breakage (9complications of 7 cases ), all occurred in the open reduction group. No complication was found in the dosed reduction group.rnConclusions: In the treatment of ITFF, the results of closed reduction and limited open fixation with L-TCP is significantly better than that of open reduction and fully exposed fixation.rn