Limitation of magnetic resonance imaging in diagnosing longitudinal peroneal tendon tears.

The purpose of this case study was to highlight a potential limitation of magnetic resonance imaging in diagnosing longitudinal tendon tears and to emphasize the importance of clinical examination for peroneal tendinopathy. We describe a 15-year-old female with lateral ankle pain, who was negative for peroneal tendon tear on magnetic resonance imaging. Owing to high clinical suspicion of peroneal tendon pathology, we opted to take the patient to the operating room and found a 6.5-cm longitudinal tear and a low-lying muscle belly of the peroneus brevis tendon. A low-lying muscle belly of the peroneal tendon has been shown to be associated with increased tendon tears.