Endoscopic-assisted percutaneous fixation for displaced anterior inferior iliac spine avulsion fractures: a prospective cohort study.

Introduction: Anterior inferior iliac spine (AIIS) avulsion fractures commonly occur in adolescent patients during sports activities. To systematically evaluate fracture severity and guide management, an adaptation of the Hetsroni classification system was used to categorize fractures on the basis of their displacement relative to the acetabular rim. Traditional open reduction and internal fixation reported satisfactory consolidation rates but complications such as lateral femoral cutaneous nerve (LFCN) neuropathies, heterotopic ossifications (HO), and subspine impingement. The objectives of this work are to (1) report short- and mid-term radiographic and clinical outcomes and (2) propose an adapted classification system based on the risk of subsequent subspine impingement.

Materials and methods: A prospective cohort study was conducted on patients with AIIS avulsion fracture with ≥ 1.5 cm displacement who underwent surgery between 2021 and 2024. Patients with follow-up < 6 months, displacement < 1.5 cm, comminuted fractures, or chronic fractures were excluded. Clinical outcomes, including the subspine impingement test, the modified Harris Hip Score (mHHS), and the University of California Los Angeles Score (UCLA), were evaluated at last follow-up. Postoperative complications, such as LFCN neurapraxia, HO (classified by Brooker), and surgical revisions, are reported.

Results: Eleven male patients with mean age of 14.1 years (range 12.8-15.0 years) were included. Fractures were classified as type I in two patients (18.2%), type II in four patients (36.4%), and type III in five patients (45.4%). The mean surgical duration was 71.4 min (SD 17.1 min), and the average time from injury to surgery was 4.2 days (range 1-11 days). The mean fracture displacement was 18.3 mm (range 15-25 mm). Postoperative scores averaged 89.7 for mHHS (SD 3.1) and 9.7 for UCLA (SD 0.6). Patients were followed for 20.0 months (range 6-47 months, SD 13.3 months). One patient underwent open surgical revision and subsequently experienced temporary LFCN neurapraxia, HO (Brooker 1), and symptoms of subspine impingement.

Conclusions: Endoscopic-assisted percutaneous fixation is an effective technique for treating displaced AIIS avulsion fractures. Preliminary results suggest that this approach offers noninferior results, satisfactory outcomes, and limited complications. Further studies with long-term follow-up are needed to confirm these findings.