Early supervised physiotherapy session-completion adherence and outcomes after acute lateral ankle sprain in professional athletes: concurrent indirect associations through kinesiophobia

Acute lateral ankle sprains (LAS) are common in professional athletes and may be followed by delayed return to sport (RTS), ankle instability, residual pain, and psychological barriers. This study examined the associations of early supervised physiotherapy session-completion adherence with RTS and residual symptoms and explored concurrent indirect associations through kinesiophobia. This single-center retrospective cohort study with cross-sectional follow-up included 118 professional athletes with acute LAS. Early rehabilitation adherence was defined as the proportion of prescribed therapist-supervised physiotherapy sessions completed during the first four weeks after injury. Adherence was analyzed continuously in the primary models, with effects reported per 10-percentage-point increase. Groups defined by the cohort median of 78.5% were used only for descriptive presentation and sensitivity analyses. Outcomes included time to qualifying unrestricted RTS, CAIT-defined ankle instability at follow-up, residual pain intensity measured using the Visual Analog Scale (VAS), and concurrent kinesiophobia measured using the TSK-11. Adjusted Cox, logistic, and linear regression models and exploratory indirect-effect analyses with 5000 bootstrap resamples were performed. Overall, 86 athletes (72.9%) achieved qualifying RTS. In the descriptive median-defined comparison, median RTS time was 8.0 weeks in the high-adherence group and 14.5 weeks in the low-adherence group, corresponding to a 6.5-week difference. In the primary continuous analysis of RTS, each 10-percentage-point increase in adherence was associated with a higher rate of achieving RTS (HR = 1.27; 95% CI, 1.16–1.39; p < 0.001). In the primary cross-sectional models, which additionally included concurrent TSK-11 score, each 10-percentage-point increase in adherence was associated with lower odds of CAIT-defined ankle instability at follow-up (OR = 0.70; 95% CI, 0.55–0.90; p = 0.005) and a lower residual VAS pain score (B = − 0.36; 95% CI, − 0.56 to − 0.17; p < 0.001). Higher adherence was also associated with lower concurrent TSK-11 scores (B = − 1.22; 95% CI, − 1.66 to − 0.77; p < 0.001). Significant exploratory concurrent indirect associations through kinesiophobia were observed for both residual outcomes. Greater completion of prescribed supervised physiotherapy sessions was associated with faster achievement of qualifying RTS, lower odds of CAIT-defined ankle instability at follow-up, and less residual pain. Kinesiophobia was an important concurrent psychological correlate, although temporal or causal mediation cannot be inferred. Early rehabilitation adherence should be considered one component of a multidimensional RTS assessment that also incorporates physical function, sport-specific performance, psychological readiness, and reinjury risk.