Disclosures: Michael Glicksman, MD: No financial relationships or conflicts of interest

Case Diagnosis: Right distal fibula fracture

Case Description or Program Description: A 13-year-old female and cross-country runner with a past medical history of NF1 presented with right lateral leg pain of three weeks duration that limited walking. She denied any known inciting factor. Initial x-rays prior to presentation were negative for fracture. On physical examination, the patient had generalized swelling and tenderness to palpation over the right lateral distal leg, in addition to mild pain with both active and passive ankle dorsiflexion. Ultrasound of the right lateral leg revealed a region of cortical irregularity with exquisite sonopalpation tenderness concerning for a right distal fibula fracture. The patient was recommended to be weight bearing as tolerated and referred for physical therapy.

Setting: Outpatient sports medicine clinic

Assessment/Results: Subsequent X-rays demonstrated the fibular fracture. Two months after presentation to clinic, she no longer endorsed pain to palpation and was able to run short distances painlessly.

Discussion (relevance): NF1 is a relatively common autosomal dominant disease with variable expressivity, resulting in osseous abnormalities in one-third of patients. This includes decreased bone mineral density, which predisposes these individuals to increased rates of fractures. Children with NF1 and high levels of physical activity may be at particularly high risk. X-ray is often the initial modality in diagnosing these fractures, but sonography has demonstrated similar diagnostic capabilities. This comparable diagnostic efficacy while simultaneously avoiding ionizing radiation is especially important in the adolescent population. Sonography offers both superior soft tissue evaluation and the ability to assess unossified structures, in addition to improving both patient comfort and cost-efficiency.

Conclusions: Sonography has demonstrated similar sensitivity and specificity to x-ray in diagnosing fractures while concurrently providing many benefits over the latter – particularly in the adolescent population. Given the increased risk of fractures in children with NF1 and subsequent radiation risk, sonography should be considered as an initial imaging modality in these individuals.

Level of Evidence: Level IV

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/sonography-as-an-initial-diagnostic-modality-for-adolescent-fractures-in-neurofibromatosis-type-1-nf1-a-case-report/