TY - JOUR T1 - The effect of osseous ankle configuration on chronic ankle instability JF - British Journal of Sports Medicine JO - Br J Sports Med SP - 420 LP - 424 DO - 10.1136/bjsm.2006.032672 VL - 41 IS - 7 AU - Arno Frigg AU - Olaf Magerkurth AU - Victor Valderrabano AU - Hans-Peter Ledermann AU - Beat Hintermann Y1 - 2007/07/01 UR - http://bjsm.bmj.com/content/41/7/420.abstract N2 - Background: 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. Aim: To study the effect of osseous ankle configuration on CAI. Design: Case–control study, level III. Setting: Radiological examination with measurement of lateral x rays by an independent radiologist using a digital DICOM/PACS system. Patients: 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. Main outcome measures: The radius of the talar surface, the tibial coverage of the talus (tibiotalar sector) and the height of the talar body were measured. Results: The talar radius was found to be larger in patients with CAI (21.2 (2.4) mm) than in controls (17.7 (1.9) mm; p<0.001, power >95%). The tibiotalar sector, representing the tibial coverage of the talus, was smaller in patients with CAI (80° (5.1°)) than in controls (88.4° (7.2°); p<0.001, power >95%). No significant difference was observed in the height of the talar body between patients with CAI (28.8 (2.6) mm) and controls (27.5 (4.0) mm; p = 0.055). Conclusion: 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. ER -