Subperiosteal hematoma of the ilium: a characteristic traction injury pattern causing acute groin pain in adolescent athletes

Abstract Purpose Subperiosteal hematoma of the ilium is an underrecognized traction injury causing acute groin pain in adolescent athletes and is often occult on plain radiographs. This study aimed to clarify the imaging features, clinical presentation, injury mechanisms, and return-to-sport course in a consecutively evaluated cohort. Methods This retrospective case series included adolescent athletes diagnosed at a single sports orthopaedic center between 2015 and 2025. Among 164 consecutive patients aged 22 years or younger presenting with acute sports-related groin pain and evaluated using a standardized MRI workflow, 20 met predefined MRI criteria. Demographics, skeletal maturity, sport, injury mechanism, ability to continue activity, treatment, and time to return to sport were analyzed descriptively. Results Mean age was 13.9 (SD 1.5) years; 95% were male and 90% had open physes. Soccer was the most common sport (65%). Injury mechanisms included kicking (50%), sprinting (20%), sudden deceleration (15%), and player contact (15%). Eighty-five percent were unable to continue sports immediately after injury. All patients were treated conservatively and returned to sport at a mean of 4.5 (SD 2.2) weeks. This condition accounted for 12.2% of adolescents evaluated with MRI for radiograph-negative acute groin pain in this cohort. Conclusion Subperiosteal hematoma of the ilium represents a reproducible traction injury pattern in skeletally immature athletes, particularly male soccer players, associated with kicking and sprinting. Awareness of this radiograph-occult but MRI-detectable entity may improve diagnostic accuracy and guide appropriate management of acute groin pain in adolescents.