Return-to-play probabilities following new versus recurrent ankle sprains in high school athletes

Objectives: Although ankle sprains have the highest recurrence rate of any musculoskeletal injury, objective estimates of when an athlete is likely to return-to-play (RTP) are unknown. The purpose was to compare time to return-to-play probability timelines for new and recurrent ankle sprains in interscholastic athletes. Design: Observational. Methods: Ankle sprain data were collected at seven high schools during the 2007-2008 and 2008-2009 academic years. Ankle sprains were categorized by time lost from participation (same day return, next-day return, 3-day return, 7-day return, 10-day return, >22-day return, no return [censored data]). Time-to-event analyses were used to determine the influence of ankle injury history on return-to-play after an ankle sprain. Results: 204 ankle sprains occurred during 479,668 athlete-exposures, 163 were new (4 censored) and 35 recurrent (1 censored). There was no significant difference (p = 0.89) between the time-to-event curves for new and recurrent ankle sprains. The median (inter-quartile rage) time to return-to-play for new sprains (inter-quartile range) = 3 days (same day to 7 day return); recurrent sprains = next day return (next day to 7 day return). Noteworthy probabilities [95% CIs] include: same day return (new = 25.2[18.7, 31.9], recurrent = 17.1[6.6, 30.3]); next-day return (new = 43.6[35.3, 52.7], recurrent = 51.4[32.5, 67.5]); and 7-day return (new = 85.9[73.8, 94.4], recurrent = 94.3[47.8, 99.5]). Conclusions: Previous injury history did not affect time until return-to-play probabilities for ankle sprains. Time until return-to-play analyses that describe the likelihood of return-to-play are useful to clinicians by providing prognostic guidelines and can be used for educating athletes, coaches, and parents about the likely timeframe of being withheld from play. (C) 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.