Effectiveness of triangular stabilization system for patients with postoperative nonunion of femoral neck fracture

Objective To explore the effectiveness of triangular stabilization system in the treatment of postoperative nonunion of femoral neck fracture. Methods The clinical data of 30 patients with postoperative nonunion of femoral neck fracture who met the selection criteria between December 2014 and December 2019 were retrospectively analyzed. There were 21 males and 9 females with an average age of 40.7 years (range, 15-65 years). The Pauwels angle at the time of injury was 51°-79°, with an average of 63.6°. According to the Pauwels classification, they were all type Ⅲ. The time from the first operation to this revision operation was 5-24 months, with an average of 9.7 months. The preoperative visual analogue scale (VAS) score was 4.2±1.3, the Harris score was 31.2±5.3, the neck-shaft angle was (116.3±7.9)°, and the lower limb shortening length was (1.73±0.53) cm. Triangular stabilization system, which was made of dynamic condylar screw and medial anatomical buttress plate, combined with the window bone grafting at the fracture site was used for bone nonunion revision. The postoperative lower limb shortening length, neck-shaft angle, fracture healing time, and complications were recorded; the Harris score was used to evaluate the hip joint function, and the VAS score was used to evaluate the pain improvement before and after operation. Results All patients were followed up 12-60 months, with an average of 27.7 months. There was no clear sign of femoral head necrosis and collapse after operation; 1 patient developed infection at 4 months after operation, and the incision healed after debridement and removal of internal fixator. All patients achieved bone healing, and the healing time was 2.8-6.0 months, with an average of 3.9 months. At last follow-up, the lower limb shortening length was (0.30±0.53) cm, which was significantly corrected when compared with preoperative one ( t=16.721, P=0.000); the neck-shaft angle was (133.9±5.7)°, which was significantly recovered when compared with preoperative one ( t=-11.239, P=0.000). The VAS score was 0.7±0.9, the Harris score was 88.3±5.9, both of which were significantly improved when compared with preoperative scores ( t=16.705, P=0.000; t=-40.138, P=0.000). Conclusion Triangular stabilization system combined with window bone grafting can provide a stable and balanced mechanical environment, promote fracture healing, and achieve satisfactory effectiveness in the treatment of postoperative nonunion of femoral neck fracture.