Ankle Sensorimotor Control and Eversion Strength after Acute Ankle Inversion Injuries

We performed this study to monitor changes in ankle eversion strength and sensorimotor control functions after acute ankle inversion injury. Forty-four patients with clinical grade II to III first-time ankle inversion sprains were tested for 1) pathologic talar tilt and anterior talar translation at 1 and 12 weeks after injury; 2) isometric eccentric ankle eversion strength and 3) peroneal reaction time to sudden ankle inversion at 3, 6, and 12 weeks after injury; and 4) accuracy of inversion position assessment 1, 3, 6, and 12 weeks after injury. Not all patients could perform all tests at the early follow-up visits. There was mechanical instability in 19 of 40 tested patients at 1 week and in 4 patients at 12 weeks after injury. Eversion strength was 88% of the contralateral side 3 weeks after injury, rising to 96% after 12 weeks. The magnitude of error of inversion position sense was 190% of the contralateral side 1 week after injury; this was still affected after 12 weeks, but fell to 133%. Patients with pathologic talar tilt or anterior talar translation, or both, at 1 week after injury did not show significantly greater error in position assessment or reduction in eversion strength when compared with patients with ankles that remained stable after injury.