An Examination of Anatomic Variants and Incidental Peroneal Tendon Pathologic Features: A Comprehensive MRI Review of Asymptomatic Lateral Ankles

Intraoperatively, foot and ankle surgeons will encounter peroneal pathologic features in patients with asymptomatic lateral ankles. The purpose of the present study was to review the ankle magnetic resonance imaging (MRI) scans of patients without a history of ankle trauma or lateral ankle pain to determine which anatomic variants correlate with peroneal tendon pathologic features and noted pathophysiology. A total of 500 MRI scans were screened, 108 (41.90 ± 20.42) of which met the inclusion criteria. The peroneus brevis tendon was intact in 104 MRI scans (96.30%), and the peroneus longus tendon was intact in 108 (100.00%). The results of the present study have confirmed statistically significant correlations between the presence of an os perineum and tendinopathy of the peroneus longus [rs(106) = 0.27], undulating peroneal grooves and the severity of peroneal brevis tears [rs(106) = 0.32], a boomerang-shaped peroneus brevis tendon and increasing tendinopathy of the peroneal tendons [brevis (rs(106) = 0.37; longus rs(106) = 0.33], and low-lying muscle bellies and chronic injuries of the superior peroneal retinaculum (rϕ = 0.19). However, the present study did not find evidence to support the presumed correlations between peroneal tendon pathologic findings and hypertrophied peroneal tubercles, low-lying muscle bellies, or the peroneus quartus muscle. Adding to the published data, the present study found a statistically significant correlation between undulating peroneal grooves and an increasing prevalence of osteophytes within the peroneal groove [rs(106) = 0.32]. MRI findings of anatomic variants or peroneal pathologic features might be useful for injury prevention; however, we advise caution from using the findings alone to advocate surgical intervention. To definitively assess causation, prospective, long-term cohort studies are warranted.