Effect of lesser trochanter posteromedial wall defect on the stability of femoral intertrochanteric fracture using 3D simulation

This study investigated the effects of posteromedial fracture fragments on the postoperative stability of intertrochanteric fractures of the femur by analyzing the quantity and range of fragments in CT 3D reconstruction. Patients diagnosed with femoral lesser trochanter fractures were collected from September 2015 to February 2018. CT 3D reconstruction was applied to evaluate the quantity and extension of posteromedial fragments and the presence of isolated medial fragments. The stability of postoperative fracture was evaluated by comparing the changes of "neck-shaft angle" and "telescoping" from 1 week to 1 year after operation. A total of 143 patients were finally confirmed, in which 63 patients contained isolated fragments on the medial side, and the average number of fragments in the posteromedial side was 1.93 ± 0.34, which accounted for an average of about 86.11% ± 8.20% in the whole posteromedial wall. When the number of posteromedial fragments was > 2 and the range of posteromedial fragments was > 75%, then the changes in the neck-shaft angle and "telescoping" showed statistical significance (12.27 ± 4.18 mm and 10.13 ± 6.17°, respectively), and when there were isolated medial isolated fragments, then the change in the neck-shaft angle was 10.66 ± 4.27°, showing statistical significance. These findings revealed a certain correlation between the quantity and the range of posteromedial fragments and the postoperative "shortening" and "collapse" of femoral intertrochanteric fractures.