Summary

Psychological readiness and timing of surgery are key predictors of successful return to sport following ACL reconstruction, with only half of the patients achieving pre-injury sports levels.

Abstract

Introduction

Anterior cruciate ligament (ACL) injuries are a common and significant concern for athletes, especially those participating in sports that place a high demand on the knees. ACL reconstruction (ACL-R) aims to restore knee stability and function, yet returning to pre-injury levels of sports participation remains a challenging goal. The SPARX (Sports and Physical Activity after Reconstruction of the Anterior Cruciate X Ligament) study was designed to assess the return to sport (RTS) rates following primary ACL-R as recorded in the Swedish National Knee Ligament Registry (SNKLR) and to identify predictors of successful RTS.

Methods

This longitudinal, prospective, national registry-based cohort study included patients aged 16-40 years who underwent primary ACL-R registered in the SNKLR and had a pre-injury Tegner score of ≥7 during the study period of December 2019 to May 2021. Participants were followed for 24 months post-surgery, with data collected through monthly web-based surveys as well as from the SNKLR. These surveys assessed rehabilitation participation, sports involvement, knee function, and new injuries. Primary outcomes were RTS rates at a Tegner level of ≥7 and RTS to a pre-injury level or higher. Predictive factors such as age, sex, surgical timing, and psychological readiness were analyzed using binary logistic regression models.

Results

A total of 551 participants were included; 56% returned to a Tegner level of ≥7 and 45% returned pre-injury level, with an average time to RTS of 11.9 months post-surgery. There was no significant difference in RTS rate to a Tegner ≥ 7 level (56% vs 55%, p= 0.750) between females and males, but there was a tendency, although not significant, of higher return to pre-injury level in females compared to males (49% vs 41%, p=0.060). The univariate logistic regression analysis revealed several significant predictors of RTS. Patients involved in competitive sports had significantly lower odds of returning to a Tegner level of ≥7 compared to those involved in elite sports (OR 0.51; 95% CI 0.29-0.90; p = 0.020). Those engaged in non-competitive activities or recreational sports had even lower odds (OR 0.18; 95% CI 0.08-0.42; p < 0.001). The presence of an MCL injury was associated with significantly lower odds of achieving RTS at Tegner ≥7 (OR 0.19; 95% CI 0.05-0.75; p = 0.018). Timing of surgery was critical, as patients who underwent surgery more than 12 months after the injury had lower odds of RTS at Tegner ≥7 (OR 0.52; 95% CI 0.27-1.01; p = 0.053), and even lower odds of returning to the same or higher sports level (OR 0.34; 95% CI 0.17-0.66; p = 0.002). Psychological readiness, as measured by the ACL-RSI score at 6 months, was a strong predictor of successful RTS both in reaching Tegner ≥7 (OR 1.03; 95% CI 1.02-1.04; p < 0.001) and returning to the same or higher sports level (OR 1.04; 95% CI 1.03-1.05; p < 0.001).

Conclusion

Following athletes participating in contact and/or pivoting sports before ACL rupture, 56% returned to Tegner ≥7, and 45% returned to the preinjury Tegner level at 1 year after ACL-R. Females tended to have higher RTS rates to pre-injury level and competition level. MCL injuries, delayed ACL-R and psychological readiness influenced RTS success.