Treatment of a Scientifically Neglected Ankle Injury: The Isolated Medial Malleolar Fracture. A Systematic Review.

Isolated medial malleolar fractures are frequently encountered injuries. Literature regarding their treatment, though, is scarce and contradicting. The aim of this systematic review is to compare surgical and conservative treatment of isolated medial malleolar fractures considering complication rates and functional outcomes. PubMed, Embase, Cochrane, and CINAHL were searched for this review. Articles from 1980 or later, written in English, French, German, or Dutch, reporting any outcome of 10 or more isolated medial malleolar fractures in skeletally mature patients were included. Study quality was assessed using the Methodological Index for Non Randomized Studies (MINORS) instrument. Eighteen studies were included involving 2566 isolated medial malleolar fractures, which showed a mean (± SD) MINORS score of 8 ± 2. Mean nonunion rate was 1.7% after surgical treatment and 3.5% after conservative treatment. Overall, comparable functional outcomes were found after both treatment methods. Only 2 of the included studies reported the exact amount of fracture displacement. One study-comparing surgical and conservative treatment-showed similar functional outcomes for 1- and 2-mm displaced isolated medial malleolar fractures, and the other, a nonunion rate of 3.5% and a good mean functional outcome in 57 conservatively treated isolated medial malleolar fractures with a mean displacement of 3.8 mm. The available evidence is scarce and of low quality but suggests that conservative treatment of isolated medial malleolar fractures displaced ≤2 mm is safe. No study exists that compares surgical and conservative treatment in isolated medial malleolar fractures displaced >2 mm. Therefore, further research is needed. Until then, the eventual choice of treatment for isolated medial malleolar fractures displaced >2 mm, might be mainly dependent on the patients' characteristics and demands.