A systematic review on how to treat deltoid ligament injuries - are we missing a uniform standard?

There is an vivid, ongoing discussion on whether injuries to the deltoid ligament complex, especially in the setting of ankle fractures, neccessitate surgical treatment. One reason for the conflicting results in literature, could be a missing standard on how acute deltoid ligament injuries are treated. The aim of this systematic review was to analyze the different applied treatment stratagies in studies reporting on the outcome of surgically treated acute deltoid ligament injuries. The herein conducted systematic review was conducted per PRISMA guidelines, the inclusion criteria were framed according to the PICOS criteria. The study was a-priori registered. Three independent reviewers conducted the literature search and data extraction (JS, AMN). The data assessed were study type, level of evidence, included fractures, methods of treating deltoid ligament injuries, differentiation between the superficial and deep layers and associated syndesmotic injuries. Per the therapeutic studies (n = 37), the deltoid ligament repair was mostly conducted using suture anchors (n = 29), either placed in the medial malleolus for superficial deltoid ligament (SDL, n = 11)/ deep deltoid ligament (DDL, n = 7) repair and/ or in the medial talus for DDL repair (n = 10). 10 studies used direct sutures for SDL repair (n = 10) and/ or the DDL repair (n = 1). One study each used either a tibialis anterior tendon graft, a temporary arthrodesis of the ankle joint, or augmented the deltoid ligament. A missing standard for treating injuries to the deltoid ligament complex was observed. Although most studies used suture anchors, there is a huge heterogeneity regarding the placement, the number of anchors used for repair, and the exact layer(s) that were adressed. Further research is needed to establish evidence-based guidelines on how to treat acute deltoid ligament injuries.