[Pelvic Avulsion Fractures in Children: a Retrospective Study from Four Trauma Centers].

Purpose of the study: Pelvic avulsion fractures in children are rare and usually associated with sports. The study aimed to evaluate the epidemiology, complications, and displacement cutoff value for surgical treatment.

Material and methods: In a retrospective study (2007-2022), we used a group of 201 boys and 20 girls (p < 0.0001). The mean age of boys was 14.9 ± 1.7, and 14.0 ± 1.9 years for girls (p = 0.0129). Injuries included 86 anterior superior iliac spine (ASIS), 83 anterior inferior iliac spine (AIIS), 28 ischial tuberosity (ITU), 13 iliac crest, nine reflected head of the rectus femoris avulsions, and two ipsilateral ASIS + AIIS avulsions. The displacement cutoff value was determined using logistic regression. Complications were assessed using Cox regression and Kaplan-Meier plots.

Results: The mean incidence of avulsions was 21 per 1,000,000 children per year. The highest prevalence of osteosynthesis was in ITU (10 out of 28, 35.71%); iliac crest and reflexed head avulsions were treated conservatively. Running was related to the highest risk of ASIS, football for AIIS, and gymnastics for ITU. Most avulsions occurred in September, the fewest in July. Displacement cutoff values were calculated as 10.5 mm for ASIS, 9.5 mm for AIIS, and 14.5 mm for ITU. The most common healing complication was distraction 31 (14.0%), refracture in 2 ITU and non-union in 1 ITU; ITU complications were treated with osteosynthesis. According to the Cox regression, the following items significantly affected outcomes: fracture type (p < 0.0001), early verticalization (p = 0.0062), and initial displacement (p < 0.0001).

Discussion: Our study had several limitations, such as it was retrospective, there was a loss of patients from follow-up, and a lack of functional evaluations, for example, using Majeed's score modified for pediatric patients. The positives of the study included a relatively large group of patients from multiple hospitals, the use of logistic regression to determine displacement values to help differentiate between OS and conservative treatment, the inclusion of fracture incidence data, and the inclusion of patients with both surgical and conservative treatment.

Conclusions: In the case of ASIS and AIIS avulsions, osteosynthesis can be considered for displacements ≥ 1 cm and ≥ 1.5 cm for ITU avulsions. Early verticalization was associated with a lower risk of healing complications in distraction injuries.