RESUMO
PURPOSE: We wanted to evaluate the efficacy of performing preoperative 3D computed tomography scanning in treatment of Jensen's type 4 intertrochanteric fractures of the femur for predicting the stability of fractures. MATERIALS AND METHODS: From March 2001 to February 2005, 56 patients, who were at least 65 years old, with Jensen's type 4 intertrochanteric fractures were included in our study. We divided them into two groups; group 1 (the control group, 34 cases) and group 2 (the experimental group, 22 cases). The average age of the patient was 78.7 years (range: 65~95) in group 1 and 77.8 years (range: 65~89) in group 2. We measured the volume of each fragments in the 3-part fractures by performing preoperative 3D computed tomography scanning. The criteria of unstable fracture were that the ratio of the volume of the greater trochanter to the the volume of the proximal femur was less than 25% and the ratio of the volume of the lesser trochanteric fragment to the volume of the greater trochanter was above 0.5. Dynamic compression screws alone were used in 30 cases (group 1) and 19 cases (group 2). Additional fixation by employing a greater trochanter stabilizing plate was done in 4 cases (group 1) and in 3 cases (group 2). We compared the radiological results and the rates of the fixation failure at the last follow-up between the two groups. RESULTS: There were four cases of fixation failure in group 1: varus &cut-out (2 cases), nonunion (1 case) and excessive backout of the screw (1 case). But there was no case of fixation failure in group 2. The neck shaft angle was 131.6+/-5.2 in group 1 and 134.7+/-4.3 in group 2. The sliding length of the lag screw was 8.4+/-3.2 mm in group 1 and 5.5+/-2.7 mm in group 2 (p<0.05). CONCLUSION: The volumetric measurement of each of the fragments in Jensen's type 4 intertrochanteric fracture by preoperative 3D computed tomography scanning for predicting the stability of fracture is useful in preventing fixation failures. Yet the radiation hazard or cost effectiveness should be considered for the risk vs benefit.