Fixation methods for acute syndesmotic injury: a systematic review and meta-analysis

Abstract

The distal tibiofibular joint is a syndesmotic articulation between the tibia and fibula at the ankle. It is stabilised by a number of ligaments. It is a dynamic articulation which allows fibular motion to accommodate the talus through ankle range of motion. Injuries to the ankle syndesmosis are common and usually occur with an associated ankle fracture. An unstable syndesmosis leads to pain and instability in the short term and posttraumatic osteoarthritis in the long term. As such, surgical stabilisation is recommended for unstable syndesmotic injuries. Various fixation methods exist for stabilisation of these injuries. Metal syndesmotic screws placed in a lateral to medial direction through the fibula into the tibia are considered the current gold standard. The number of screws, their location, the number of cortices engaged, the screw diameter and whether they are removed or retained once the syndesmosis has healed remain controversial and practice depends on surgeon and institutional preference rather than evidence. More recent developments include bioabsorbable screws and suture button fixation with perceived benefits being no requirement for implant removal and in the case of suture button fixation, a dynamic fixation which more closely approximates the normal motion through an uninjured syndesmosis. Published and unpublished studies in English were sought in the CINAHL, Embase, PubMed/Medline, Scopus, Web of Science and other databases. A total of 4493 citations were screened for suitability and 79 articles were read and assessed for eligibility. Fifty-three studies were included in final analysis. Two reviewers using the Joanna Briggs Institute - Meta Analysis of Statistics, Assessment & Review Instrument, assessed the quality of the studies. The effectiveness of syndesmotic injury stabilisation using metal screws, suture button fixation and bioabsorbable fixation was assessed and compared. Composite outcome measures (such as the Olerud-Molander Ankle Score (OMAS) and the American Orthopedic Foot and Ankle Society ankle-hindfoot score (AOFAS), range of motion, pain as measured by visual-analogue scale (VAS), radiological measurements of the syndesmosis, complications and other outcomes were analysed. Single group analysis was performed for all metal screw, suture button or bioabsorbable screw studies where appropriate outcome measures and variance were reported. This analysis was possible for OMAS, AOFAS, VAS, complications and radiological parameters. This review includes 24 descriptive studies, 19 cohort studies, 9 RCTs and 1 quasiexperimental study. Bioabsorbable implants featured in 8 studies, metal screws in 29 and suture button constructs in 20 studies. A total of 3,088 subjects are assessed across the included studies. Five studies were included in meta-analysis. There were no major differences in outcomes across the various fixation methods. All yielded good results with an acceptable complication profile. This review further adds to the assertion that between metal screws, suture button constructs or bioabsorbable screws, there is no significant difference in outcomes following stabilisation of acute syndesmotic injury. The same holds true for the various strategies using metal screws; screw size, number of cortices, screw location, screw number and screw removal have little effect on the final outcome.