Risk Factor of Proximal Lag Screw Cut-Out After Cephalomedullary Nail Fixation in Trochanteric Femoral Fractures: A Retrospective Analytic Study

Abstract

Objective: A cephalomedullary nail is the treatment of choice for trochanteric fractures; however, a lag screw cutout is one of the most devastating complications. The lag screw cut-out rate was reported to be around 2.5%–8.3%. This study aimed to evaluate the prevalence of lag screw cut-outs and identify the associated risk factors. Materials and Methods: A retrospective review of 267 trochanteric fracture patients treated with cephalomedullary nail fixation from January 2007 to December 2017 was conducted. The demographic variables were documented, comprising age, gender, fracture pattern, and AO/OTA classification. Immediate postoperative radiographs were assessed for quality of reduction and implant position. Lag screw cut-outs or radiographic union were determined using the final follow-up radiograph. Prognostic factors associated with lag screw cut-out were determined using univariate and multivariate logistic regression analyses. Results: Of the 175 patients, 154 were successfully treated, and 21 had a lag screw cut-out. There were no significant differences in mean ages or genders of the union and cut-out groups. No lag screw cut-outs were observed in patients with AO/OTA 31-A1. Patients with AO/OTA 31-B2.1 had a higher rate of screw cut-out (OR 10.5, [3.22, 34.25] p < .001). The disintegration of basicervical fragments was significantly associated with lag screw cut-out (OR 5.51, [2.01, 15.12] p = .001). The highest cut-out rate was found in the superoanterior and superoposterior positions of the lag screw. However, the screw position did not reach the significance level in a multivariate analysis (p = .094). Conclusion: The prevalence of lag screw cut-out after cephalomedullary nail fixation for trochanteric fractures was 12%. A simple, two-part, basicervical trochanteric fracture hads a significantly higher risk of lag screw cut-out.

Keywords

• Trochanteric fracture
• pertrochanteric fracture
• hip fracture
• cut-out
• cephalomedullary nail