Chronic ankle instability (CAI) is a common orthopaedic entity in sport. Although other risk factors have been studied extensively, little is known about how it is influenced by the osseous joint configuration. The aim of this research was to study the effect of osseous ankle configuration on CAI. A group of 52 patients who had had at least three recurrent sprains was compared with an age-matched and sex-matched control group of 52 healthy subjects. The radius of the talar surface, the tibial coverage of the talus (tibiotalar sector) and the height of the talar body were radiographically measured. The talar radius was found to be larger in patients with CAI than in controls. The tibiotalar sector, representing the tibial coverage of the talus, was smaller in patients with CAI than in controls. No significant difference was observed in the height of the talar body between patients with CAI and controls. The authors concluded that CAI is associated with an unstable osseous joint configuration characterised by a larger radius of the talus and a smaller tibiotalar sector. There is evidence that a higher talus might also play some part, particularly in women.
British Journal of Sports Medicine 2007, 41, 420-424.