Avulsion of the flexor retinaculum associated with dislocation of the posterior tibialis and flexor digitorum longus tendons – Don't let a fracture make you miss the diagnosis

Abstract

Introduction: Traumatic dislocation of the posterior tibial tendon (PTT) is portrayed as a rare and challenging to diagnose lesion, even more so in association with flexor digitorum longus tendon (FDL) dislocation. This article aims to bring awareness to this condition and present a reasonable and reproducible surgical solution.Case report: A 19-year-old male was admitted after a car accident. An isolated posterior malleolus fracture was identified among other lesions, and surgery was proposed. A cord-like structure over the medial malleolus was identified during surgery, and a PTT and FDL dislocation was diagnosed. The flexor retinaculum was avulsed and was re-inserted with suture anchors, and the tendons remained stable without any additional gesture. At follow-up, good results were obtained.Discussion: PTT dislocations probably occur more frequently than thought, but the association with flexor digitorum longus tendon dislocation seems even rarer. This entity should be known by the common trauma professional since it can be mistaken for an ankle sprain or not noticed in a polytrauma patient. This case brings awareness to vital signs to not miss the diagnosis and a reliable, easy, and reproducible surgical option.

Keywords

• Ankle trauma
• Posterior tibial tendon dislocation
• Flexor retinaculum
• Flexor digitorum longus tendon dislocation