Effectiveness evaluation of a criteria-based rehabilitation algorithm for lateral ankle sprains in professional football

Lateral ankle sprains (LAS) are one of the most common types of injuries in sports, especially in football. The present PhD thesis is an evaluation of the effectiveness of a newly developed rehabilitation protocol. The hypothesis tested in this work is that this criteria-based rehabilitation algorithm will contribute to a reduction in the recurrence rate and positively influence the rehabilitation of LAS in the future. Methods: For the purpose of the evaluation, a mixed-methods study design with continuous longitudinal studies was carried out across four seasons (2021-2025) in German Bundesliga based on the findings of time-loss (15.5 days) and recurrence rate (17.1%) outcomes of a previously performed systematic review and meta-analysis. LAS injury data of an observational study ("treatment as usual", reference) were compared against outcomes of an intervention (application of the rehabilitation algorithm). Follow-up was set for 12 months after return to competition. Additionally, a qualitative survey study was conducted to evaluate user experience of medical staff and players. Results: The observational study included thirty-four teams from 13 German Bundesliga clubs. A total of 130 LAS, categorised according to respective age categories and severity grades were analysed. The overall time-loss was 29.9 (SD=29.9) days. The study found an age-related trend in terms of time loss, with significant longer periods of time-loss in youth players in comparison to adult professional players (15.5 versus 33.0 days; p = 0.001). A substantially elevated recurrence rate was found among competitive player groups of 25% for professional players and 33.8% for U19 players, respectively. The overall recurrence rate was found to be 27.9%. A total of 120 LAS from 12 participating clubs incorporating 31 teams were analysed in the subsequent intervention study. The average time-loss across all players groups was found to be 27.5 days (SD = 16.9). Elite youth players experienced longer mean time-loss (27.9, SD=17.6 days) compared to adult professionals (25.1, SD=12.8 days), respectively. The overall recurrence rate was 10.3%. The medical staff awarded the highest score to the category 'communication', indicating the positive impact of the rehabilitation algorithm on enhancing internal communication and simplifying reporting to non-medical staff. In comparison, the implementation of the rehabilitation algorithm was associated with a significant 62.8% reduction in recurrence rate (27.7% vs. 10.3%; OR 0.313, 95% CI 0.148-0.622; p=.001), while the overall time-loss remained comparable (29.9 vs. 27.5 days; p=.751). Recurrence decreased from 25% to 0% in professional players and from 33.8% to 9.5% in U19 players, respectively. In contrast, time-loss among professional players increased significantly (15.5 vs. 25.1 days; p=.001), particularly for grade I injuries. Conclusion: This dissertation constitutes the first evaluation of a criteria-based rehabilitation algorithm for lateral ankle sprains in professional football. The results of this study support the primary hypothesis. The implementation of a criteria-based rehabilitation algorithm has been demonstrated to result in a considerable decrease in the recurrence rate, particularly among professional football players.