Arcuate sign—fibular head avulsion fracture and associated injuries in the pediatric and adolescent population



To describe the first “arcuate sign” case series in the pediatric population, radiologic features of the associated injuries, management, and how they compare with the adult population.


Retrospective study included patients under 18 years of age with a classic “arcuate sign” on radiographs. Data collected included patient demographics, mechanism of injury, and management. Radiographs and advanced imaging (MRI, CT) were reviewed by two musculoskeletal radiologists in a blinded fashion and findings recorded.


Seven patients (4 males, 3 females) with mean age 15 years (range 14–17 years) were included in the study. All 7 injuries were related to sports, 5/7 (71%) being non-contact injuries. Five patients had MRI done-1 LCL injury, MPFL sprain, and MCL sprain were reported; 3 popliteofibular ligament and popliteus sprains were seen; and 3 bone contusions were present on imaging. None of the patients had meniscus or cruciate ligament tears. One patient had an additional fracture of the lateral tibial plateau at the ilio-tibial band attachment and an associated peroneal nerve injury. Five out of seven (71.4%) were treated non-operatively and were able to return back to activity at a mean of 7.2 weeks from injury. Two out of seven (28.6%) needed operative intervention for the fracture but not arthroscopic repair.


Pediatric patients with a radiographic arcuate sign tend not to have ACL, PCL, or meniscal injuries, and treatment is predominantly non-operative in contrast to literature reported in adults.

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Correspondence to Siddharth P. Jadhav.

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Kushare, I., Ghanta, R.B., Ditzler, M. et al. Arcuate sign—fibular head avulsion fracture and associated injuries in the pediatric and adolescent population. Emerg Radiol (2021).

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  • Arcuate sign
  • Fibula head fracture
  • Knee
  • Magnetic resonance imaging
  • Posterior cruciate ligament
  • Posterolateral corner injury