PURPOSE: To evaluate trochanter stabilizing plate and compression hip screw can prevent excessive impaction and cutting-out in unstable intertrochanteric fractures. MATERIALS AND METHODS: One hundred twenty-one patients with intertrochanteric fractures were treated between December 1999 and March 2002. Of the patients, twenty-four patients were treated with an additional TSP on the CHS. Nineteen patients were followed for more than six months. The fractures were classified according to the AO classification. Impactions of compression lag screw were measured immediate postoperatively and postoperatively three months later on simple radiographs. Functional results were followed Salvati-Wilson assessment score at postoperative six months later. RESULTS: The group consisted of seven men and twelve women, and the mean age was 73 years. Two were classified as A2.2, six A2.3, one A3.2, and ten A3.3 fractures. Mean impaction was 5.4 mm (range 1.8 to 11.4 mm). Functional results were excellent in 32% and good in 53%. Eighteen patients had healed after operation. One complication required a bipolar hemiarthroplasty due to cutting-out of lag screw. CONCLUSION: In three-part and four-part intertrochanteric fractures with lateral cortex breakage or vertical fracture in greater trochanter, the addition of TSP to CHS can prevent abductor muscle weakness due to fracture impaction, limb shortening and additional lateral cortical fracture. It also helps early weight bearing and bone healing.