Center of pressure during stance and gait in subjects with or without persistent complaints after a lateral ankle sprain.

STUDY AIM: To investigate differences in the center of pressure (COP) during gait and single leg stance between subjects with persistent complaints (PC) and without persistent complaints (NPC) after a lateral ankle sprain.

METHODS: 44 patients who consulted the general practitioner, 6-12 months prior to inclusion, with a lateral ankle sprain were included for the current study purpose. Using a 7-point Likert scale patients were divided into the PC or NPC group. All subjects filled out an online questionnaire, walked along a walkway and performed a single leg stance, both on the RSscan. Primary outcomes included the COP displacement, range and percentage used in mediolateral and anterioposterior direction.

RESULTS: There was a trend (p<0.05) towards a more medially COP trajectory during walking at 34-46% and 83-96% and more anteriorly at 21-31% and 91-100% of the stance phase in the PC group compared to NPC group. Additionally, the COP was more laterally located in the sprained leg compared to the non-sprained leg in the PC group in the loading response phase (p<0.05). An interaction was found for the percentage of anterior-posterior range used in single leg stance without vision.

CONCLUSION: The COP trajectory discriminates between patients with PC and NPC. This indicates that roll off during gait might play an important role in the recovery of patients after a lateral ankle sprain and could be used to monitor treatment.