MRI overestimates the full-thickness tear of distal triceps tendon rupture

Injury to the distal triceps brachii tendon is rare. Imaging radiographs are used to confirm the findings of physical examination, classify the extent of injury, and guide treatment. Magnetic resonance imaging (MRI) is considered the gold standard of diagnostic imaging. However, no previous study has reported on the accuracy of differentiation between partial- and full-thickness triceps tendon tears. Our study's aim was to define the accuracy of MRI in differentiating partial- from full-thickness tear of the distal triceps tendon. We hypothesized that MRI has low accuracy in differentiating partial- from full-thickness tears.

A total of eight patients with nine triceps tendon tears underwent surgical repair from 2011 to 2015. MRI of the elbows were retrospectively reviewed for the presence and type of tear, tendon involvement, and location of the tear, and later correlated with surgical findings.

Of the three surgically confirmed complete tears, MRI correctly reported a complete tear in all patients. Of the six partial tears confirmed at surgery, MRI correctly identified four tears. In two cases, MRI described a complete tear, but only a partial tear was noted at surgery.

False-positive MRI assessment of distal triceps injury is not rare. Surgeons should rely on clinical examination in assessing distal triceps tendon injury, with imaging studies providing an adjunctive role in the diagnosis and decision-making.