Return to sport following syndesmosis injuries in 64 elite athletes - factors affecting need for stabilization and presentation of a modified classification

J. Calder, R. Bamford, G. McCollum

Introduction: Isolated syndesmosis injuries lead to a prolonged time away from sport. Stable injuries respond well to conservative management whilst unstable injuries with diastasis require fixation. However, grade II injuries may have latent instability which is only present on stressing the syndesmosis during loading. They are difficult to identify with the current classification system and inappropriate treatment can lead to late morbidity.

Methods: A prospective series of 64 isolated grade II syndesmosis injuries in professional athletes are reported. Clinical and MRI findings were used to determine whether the injury was stable (grade IIa) or unstable requiring arthroscopic assessment and possible surgical stabilization (grade IIb).

Results: 38/64 athletes had a possible grade IIb injury. 36/38 were deemed unstable at arthroscopy and stabilized with a Tightrope. At a minimum of 12 months all athletes returned to their previous level of sport - grade IIa injuries returned to play significantly earlier that grade IIb (64 versus 45 days; p< 0.001). Injury to both AITFL and deltoid ligaments had a significant chance of being unstable whereas concomitant injury to the ATFL appeared protective leading to an earlier mean time to return to sport and were less likely to be suggesting a different mechanism of injury. Although the external rotation test was sensitive it was less specific than a positive squeeze test which was associated with increased severity of injury with a longer return to sport and increased need for stabilization.

Conclusions: We have identified specific clinical and radiological findings to increase accuracy of differentiating stable from unstable grade II syndesmosis injury enabling appropriate management, predictable time of return to sport and minimizing the risk of later symptoms. Those athletes with no diastasis but AITFL rupture, injury to the deltoid and/or a positive squeeze test are more likely to have an unstable syndesmosis and may warrant arthroscopic assessment.