Likelihood of Scar Tissue from Peroneal Brevis Injury Irritating the Sural Nerve Without Tendon Pain
While theoretically possible, scar tissue from a peroneus brevis tendon injury causing isolated sural nerve irritation without any tendon-related pain is uncommon but anatomically plausible, particularly if the injury occurred distally near the fibular tip where these structures are in closest proximity.
Anatomical Considerations
The anatomical relationship between the peroneal tendons and sural nerve is critical to understanding this scenario:
The distance between the peroneal tendon sheath and sural nerve decreases significantly from proximal to distal 1. At 5 cm proximal to the fibular tip, the average distance is 29.6 mm, but this narrows dramatically to only 7.8 mm at 1.5 cm distal to the fibular tip 1.
The average distance from the fibular tip to the sural nerve is approximately 16.6 mm 1, placing these structures in relatively close proximity where scar tissue could theoretically bridge the gap.
Clinical Reality and Evidence
However, several important clinical factors make isolated nerve irritation without tendon pain unlikely:
Why This Scenario Is Uncommon:
Peroneal tendon pathology typically presents with tendon-related symptoms. The literature consistently describes peroneus brevis injuries presenting with:
- Lateral ankle pain and swelling 2
- Posterolateral ankle pain 3
- Pain during weight-bearing 4
- Instability symptoms 2, 3
Documented Case of Nerve Entrapment in Scar:
There is one documented case of scar tissue causing nerve symptoms after muscle injury: A gastrocnemius strain resulted in sural nerve entrapment in scar tissue beneath the deep fascia, causing progressive calf pain and paresthesias 5. Importantly, this patient had:
- Sensory loss in the sural nerve distribution
- Positive Tinel's sign at the injury site
- Electrodiagnostic confirmation of nerve involvement
- Complete symptom resolution after surgical release 5
Clinical Assessment Algorithm
If you suspect this scenario, evaluate systematically:
Location specificity: Is the pain purely in the sural nerve distribution (lateral foot/ankle) without any retromalleolar tenderness over the peroneal tendons?
Quality of symptoms: Are symptoms primarily sensory (burning, tingling, numbness) rather than mechanical tendon pain (pain with eversion, weight-bearing)?
Physical examination findings:
Electrodiagnostic studies: Consider nerve conduction studies showing sural nerve abnormalities (prolonged latency, reduced amplitude) 5
Advanced imaging: MRI can demonstrate both tendon pathology and surrounding scar tissue 6, 7, though up to 34% of asymptomatic patients may have peroneus brevis tears 8, emphasizing that imaging findings must correlate with clinical examination.
Important Caveats
MRI has a 48% positive predictive value for clinically significant peroneal tendon pathology 8, meaning imaging abnormalities don't always correlate with symptoms.
Delayed peroneal muscle response can occur from traction injury to the peroneal nerve during ankle injuries 9, which could theoretically occur alongside tendon injury.
The proximity of structures distally means any significant scar formation from a peroneus brevis injury would likely affect both the tendon and potentially the nerve, making completely isolated nerve symptoms without any tendon involvement unusual.
Bottom Line
The likelihood is low but not zero. If the original injury was distal (within 2 cm of the fibular tip where structures are closest), and current symptoms are purely sensory without mechanical tendon pain, consider sural nerve entrapment in scar tissue as a differential diagnosis. Electrodiagnostic studies and careful physical examination focusing on nerve-specific findings (Tinel's sign, sensory deficits) rather than tendon loading tests would help differentiate this from ongoing tendon pathology.