The Association Between Femoroacetabular Impingement and Internal Fixation of Femoral Neck Fractures

Abstract

Objective: Congenital deformities, slipped capital femoral epiphysis and Legg-Calve-Perthes disease have been suggested as possible causes for femoroacetabular impingement (FAI). The aim of our study is to describe the radiographic signs of FAI after femoral neck fractures and to compare these data with those of the contralateral hip. Method: Our institutional medical records database was retrospectively searched for patients 18-50 years old with a history of femoral neck fractures (OTA 31-B) between 2010-2019. Fifty-two patients were identified. After exclusion criteria, we detected 37 fractures in 37 patients. The mean age of 29 male and 8 female patients was 32,7 (range 18-48) years. The antero-posterior and cross- table lateral views of bilateral hip joints for all 37 patients were reviewed preoperatively and at final follow-up. The mean follow-up period was 48 months (range 6-98 months). In addition, postoperative CT-scans of these patients were also reviewed. Results: According to OTA classification subtypes, 2 subcapital (31B1), 25 transcervical (31B2) and 10 basicervical (31B3) fractures were detected. The mean alpha angle on lateral X-ray of the operated side was statistically significantly higher than the unaffected side. The mean alpha angle on CT was higher on the operated side than the unaffected side. In addition, the acetabular version angle on CT was higher on the unaffected side while acetabular depth on CT was higher on the operated side. The lateral CE angle on the AP X-ray was not different on the unaffected side compared to the operated side. Conclusion: Symptoms of impingement can be seen in patients undergoing internal fixation after femoral neck fracture, and a decrease in acetabular version and an increase in acetabular depth may be predisposing to femoral neck fracture.