Step-by-step recognition of peroneal tendon dislocation in association with calcaneal fractures

J. Wong-Chung, W.D. Marley, S. McKenna, D. O'Longain

Introduction: Although dislocation of the peroneal tendons (PT's) in association with calcaneal fractures has been described over 25 years ago, it frequently passes unrecognised by radiologists and orthopaedic surgeons. This retrospective study aims to determine the prevalence of PT dislocation in association with calcaneal fractures at a single institution and describe systematic steps to avoid missed diagnosis at each stage of management.

Methods: CT scans of all patients with calcaneal fractures from the Picture Archiving and Communications System (PACS) from 2010 were systematically reviewed. The senior author and a Musculoskeletal Radiologist analysed the images for concomitant dislocation or subluxation of the PT's, utilizing criteria as defined by Ho et al. Further to this we included patients who sustained calcaneal fractures with associated PT dislocation prior to June 2010 and were referred either for primary open reduction or later with post-traumatic osteoarthrosis of the subtalar joint.

Results: Over three years and nine months beginning in June 2010, 71 calcaneal fractures were identified on PACS. 15 of those had associated subluxation or dislocation of the peroneal tendons either on CT scan or at surgery (21%). 10 of our 71 patients exhibited a fleck sign on plain anteroposterior ankle x-ray (14.1%) suggesting potential avulsion of the superior peroneal retinaculum.
The combined cohort comprised 28 patients, 23 men and 5 women, aged 21 to 82 years (average, 46.3 years). 22 (79%) of PT dislocations were not recognised at the original injury. In six patients undergoing operative fixation, five (83.3%) had dislocated PT's noted on CT scan. In one case (16.7%) the peroneal tendons were clinically dislocated.

Conclusion: The PT dislocation rate in this paper is comparable with the literature. Patients should undergo careful clinical examination, radiological assessment with x-ray and CT followed by probing at surgery to ensure the diagnosis is not missed.