To investigate the imaging characteristics and treatment of the wedge effect of basicervical intertrochanteric fracture with proximal femoral nail anti-rotation (PFNA).

In this study, 386 cases of intertrochanteric fracture treated by surgery from 2013 to 2018 were analyzed retrospectively, including 39 cases of basicervical intertrochanteric fracture treated by PFNA. According to the imaging data of the hip joint after surgery, the wedge effect was seen in some cases. Distances from the bilateral neck-shaft angle and the femoral head to the lateral femoral cortex were measured, respectively. The affected side was treated as the wedge effect group and the healthy side was seen as the control group. Then the imaging characteristics of fractures in the wedge effect group and the efficacy of PFNA were analyzed.

There were 39 cases (13 males and 26 females) of basicervical intertrochanteric fracture treated with PFNA, with an average age of (72±5). The wedge effect was found in 21 cases, including 10 males and 11 females, with an average age of (74±6). The average femoral neck-shaft angle in the wedge effect group was (129.4±3.7)°, which was significantly smaller than that in the control group (P<0.05). The average distance from the femoral head to the lateral cortex in the wedge effect group was (63.2±6.8) mm, which was also significantly longer than that in the control group (P<0.05). The features of radiographic anatomy for posterior-lateral fractures in the wedge effect group can be divided into 4 subtypes. One year after surgery, the Harris Hip Score in the wedge effect group was significantly less than that in the PFNA group without wedge effect (P<0.05).

The imaging characteristics and the cause of wedge effect in the treatment of basicervical intertrochanteric fracture with PFNA are identified. Developed a better understanding of the wedge effect, that will help to improve the restoration of intertrochanteric fractures with intramedullary fixation and reduce the complications associated with implants.