Stability evaluation of the “equivalent” ankle bimalleolar fractures

a comparative study

Abstract

With an incidence of 125/100,000/year, the ankle malleolar fractures are often diagnosed in young male and old female. The supination-external rotation fractures (SE), also known as AO Weber B are the most commonly seen in around 80% of them all. To identify the absence or presence of a deltoid ligament injury in an undisplaced isolated lateral malleolar fracture remains the key point to differentiate between the stable and unstable types. We know that the latter, if operated, has a better outcome which might decrease early post-traumatic osteoarthritis. How can we check the competence of the deltoid ligament in an isolated fibular fracture with a normal medial clear space in X-ray? The authors intends to assess the competence of the deltoid ligament in malleolar fracture using Gravity stress radiographs and an external rotation stress test under fluoroscopy as a diagnostic tool. A consecutive series of patients with isolated lateral malleolar fractures (Lauge-Hansen SER type) were prospectively enrolled from 10 February 2016 to 30 November 2017. Patients with unstable fractures (medial clear space (MCS) ≥4 mm on the radiograph was operated. Gravity stress radiographs and an external rotation stress test under fluoroscopy provide a reliable basis to decide about stability and operative treatment in isolated lateral malleolar fractures of the SER type.