Magnetic resonance imaging of normal anatomy and injury of the peroneal tendon

Abstract

Objective: To explore the MR characteristics of normal anatomy and injured peroneal tendon and the diagnostic value of MR in the peroneal tendon injuries. Methods: From February 2018 to December 2018, a total of 20 healthy volunteers (40 ankle joints) were selected, 10 males and 10 females, with an age range of 20-30 (26±3) years. Retrospective analyzed 62 patients with ankle sprain and peroneal tendon injuries confirmed by operation, 34 males and 28 females, with an age range of 14-78(41±14) years. All volunteers and patients underwent MR examination. The MRI characteristics of the normal anatomy of peroneal tendon were analyzed. The patients were classified according to the MR diagnostic criteria of injury. Then the MRI features of different types of injured peroneus longus tendon and peroneus brevis tendon were analyzed. At last, imaging findings were compared with surgical results. Results: The peroneal tendon of 20 healthy volunteers showed oval and elliptical band-like structures on T(1)WI and PD-FS sequences, with natural alignment, clear boundary and uniform low signal. The whole length of the peroneal tendon can't be displayed completely on the same imaging plane. It needed multi-dimensional observation combined with axial, coronal and sagittal directions. There were 62 cases of peroneal tendon injury, including 46 cases of peroneal tendon tear (7 cases of partial-thickness tear, 11.3% of the total injuries, 39 cases of full-thickness tear, 62.9% of the total injuries), 16 cases of peroneal tendon dislocation (15 cases of intrathecal dislocation, 24.2% of the total injuries, 1 case of extrathecal dislocation, 1.6% of the total injuries). In 7 cases of partial-thickness tear (4 cases of peroneus brevis tendon tear, 3 cases of peroneus longus tendon tear), MR showed irregular tendon shape and local continuity interruption. In 39 cases of full-thickness tear (31 cases of peroneus brevis tendon tear, 8 cases of peroneus longus tendon tear), MR showed that the tear was penetrated through the whole layer of tendon from dorsolateral side to plantar side of foot, and the range of tear was different. The torn tendon could be accompanied by tendinitis or effusion of tendon sheath; 15 cases of intrathecal dislocation (3 cases of type A, 12 cases of type B), MR findings of type A dislocation showed that the peroneus longus tendon was located in the deep part of the peroneus brevis tendon, MR findings of type B dislocation showed that the peroneus longus tendon was displaced into the longitudinal tear of peroneus brevis tendon. In 1 case of extrathecal dislocation (type Ⅲ), MR showed that the SPR and the attached cortex of lateral malleolus were avulsed together, and the peroneal tendon was displaced under the avulsed fracture piece. Conclusion: MR can accurately demonstrate the fine anatomical structure of peroneal tendon and the imaging features of injuries. It has important clinical application value for the early diagnosis and accurate treatment of peroneal tendon injuries.