Working Diagnosis:
Right peroneal brevis muscle avulsion injury at the proximal fibular attachment point.

Treatment:
The patient was initially managed with immobilization in a tall walking boot and progressive weight bearing on crutches as tolerated for the first two weeks. The boot was weaned as tolerated over 1 week, at which point the patient initiated physical therapy focusing on restoring muscle strength and mobility for 14 weeks. Adjunctive therapies included dry needling and cupping to facilitate recovery.

Outcome:
At eight weeks post-injury, the patient returned to skating. Follow-up ultrasound at nine weeks demonstrated significant healing of the peroneal brevis avulsion and the patient reported 80-90% symptom improvement. At fourteen weeks post-injury, ankle strength testing showed limb similarity indices of 88% for inversion, 120% for eversion, 100% for dorsiflexion, and 97% for plantarflexion [Photo2]. She has returned to hockey and remains pain free.

Case Photo #2

Author's Comments:
The peroneus brevis originates from the distal two-thirds of the lateral fibula and adjacent intermusclar septa before transitioning distally into its tendon. To our knowledge, reports describing acute proximal peroneus brevis muscle avulsion at the fibular origin are exceedingly limited within the sports medicine literature. Most described soft-tissue avulsion injuries involve the hamstring, rectus femoris, or adductor longus muscles(1-3). Management for these injuries can be either surgical or nonoperative. Prior studies regarding proximal hamstring avulsions have shown superior outcomes with surgical repair, however the complication rate was high at 23.17%. In contrast, both operative and nonoperative treatment have produced excellent patient-reported outcomes for proximal adductor longus avulsion injuries (2).

Injuries to the peroneus brevis and peroneus longus are more commonly described as tendon tears, tendinopathy, or tendon subluxation, typically occurring following ankle inversion or chronic lateral ankle instability(4,5). These injuries are generally managed nonoperatively with immobilization and progressive rehabilitation, while surgical intervention is typically reserved for significant tendon tears, recurrent instability, or failed conservative treatment(5). In contrast, the present case involved a proximal muscle avulsion at the fibular attachment site without tendon involvement, representing a distinct injury pattern from those more commonly reported.

The mechanism of injury and symptom distribution initially obscured the diagnosis. Although the patient sustained direct blunt trauma to the posterior calf, the injury was ultimately identified as a proximal peroneus brevis avulsion at the lateral fibular origin, while her pain was predominantly diffuse and localized to the anterolateral leg. Early imaging was unrevealing, likely due in part to the incongruity between the location of injury and presenting symptoms, which limited the scope of the initial ultrasound evaluation.

This case highlights proximal peroneus brevis avulsion as an uncommon but important cause of persistent anterolateral leg pain following blunt lower-extremity trauma. Discordance between the site of impact, symptom location, and initial imaging findings may obscure the diagnosis. Clinicians should maintain suspicion for lateral compartment muscular injury when symptoms persist despite unrevealing radiographs and targeted ultrasound examination. MRI may be necessary for definitive diagnosis. In this case, structured nonoperative treatment resulted in successful healing and return to competitive hockey without surgical intervention.

Editor's Comments:
This is an uncommon injury that presented with an atypical pattern of pain following a common mechanism of lower-extremity trauma. The discordance between the site of impact, location of symptoms, and initially unrevealing imaging made the diagnosis challenging. This case highlights the importance of maintaining a broad differential for persistent anterolateral leg pain and including lateral compartment muscle injury even when the initial trauma occurs elsewhere. MRI may be necessary when symptoms persist despite unrevealing radiographs and ultrasound. This case also demonstrates that proximal peroneus brevis avulsion injuries can be successfully managed nonoperatively with structured rehabilitation and return to sport.

References:
1. Bodendorfer BM, Curley AJ, Kotler JA, et al. Outcomes After Operative and Nonoperative Treatment of Proximal Hamstring Avulsions: A Systematic Review and Meta-analysis. Am J Sports Med. 2018;46(11):2798-2808. doi:10.1177/0363546517732526
2. Best R, Gild A, Huth J, Beckmann J. Patient-related outcome measurements after operative and conservative management of traumatic proximal adductor longus avulsion injuries. Int Orthop. 2020;44(5):965-971. doi:10.1007/s00264-020-04510-3
3. Neetz C, Linhart W. [Proximal avulsion of the tendon of the rectus femoris muscle : Case description and literature review]. Unfallchirurg. Jun 2020;123(6):491-495. Proximaler Ausriss der Sehne des M. rectus femoris : Fallbeschreibung und Literaturübersicht. doi:10.1007/s00113-020-00786-7
4. Demir MT, Kultur Y, Davulcu CDD, Ertan Birsel S. Immobilization with a Short Leg Cast in Acute Peroneus Brevis Tendon Tears. Med Sci Monit. 2025;31:e948836. Published 2025 Jul 6. doi:10.12659/MSM.948836
5. Heckman DS, Reddy S, Pedowitz D, Wapner KL, Parekh SG. Operative treatment for peroneal tendon disorders. J Bone Joint Surg Am. 2008;90(2):404-418. doi:10.2106/JBJS.G.00965

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