# Reducing ACL Reinjury in Athletes: Strategies, Statistics, and Key Insights

> In this blog post, we delve into the latest research and offer valuable insights, complete with percentages, to help athletes minimize the risk of ACL reinjury and confidently return to the field.

## Overview of the Blended Intensive Program (BIP)
In week 43 of 2023, Savonia University of Applied Sciences (Finland) hosted a Blended Intensive Program (BIP) focused on Evidence-Based Physical Therapy (EBP). Over 40 physiotherapy students and 7 teachers from Savonia University of Applied Sciences (Finland), Universidade da Coruña (Spain), and Charles University Prague (Czech Republic) participated. Students collaborated on articles covering themes such as McKenzie therapy, back pain, spinal cord injuries, aquatic therapy, ergonomics, Nordic walking, and sports injury prevention.

## The Challenge of ACL Reinjury
Anterior Cruciate Ligament (ACL) injuries are among the most daunting challenges for athletes, often requiring surgery and extensive rehabilitation. Understanding the factors contributing to reinjury is essential for a safe return to sport.

## Statistical Insights on Reinjury
*   **Reinjury Rates:** Approximately 25% of athletes who return to sports after ACL reconstruction (ACLR) experience a second ACL injury (Wong et al., 2023).
*   **Psychological Factors:** Surprisingly, 70% of athletes who experienced a second ACL injury had a more positive psychological outlook, suggesting that higher psychological readiness can sometimes lead to premature return or overconfidence (Zarzycki et al., 2023).
*   **Expectations vs. Reality:** 63% of patients expect to return to their preinjury level of sport before revision surgery, but after 12 months, only 12% achieve this. 14% give up on sports entirely, with 71% of those cases citing fear of reinjury as the primary reason (Webster and Feller, 2019).
*   **Adolescent Risk:** Adolescent patients (15–20 years) are at a remarkably high risk, with up to 30% requiring a new ACL reconstruction within the first two years after returning to sport (Beischer et al., 2018).

## Key Strategies for Prevention
*   **Timing:** Returning to high-intensity sports before nine months significantly increases the risk of reinjury (Cronström et al., 2023).
*   **Muscle Function:** Restoring muscle function is critical. A Limb Symmetry Index (LSI) of over 90% for both leg muscle strength and hop performance is recommended to reduce risk (Grindem et al., 2016).
*   **Safe Exercise Protocols:** According to Aspetar guidelines (Kotsifaki et al., 2023), open kinetic chain exercises (like knee extensions) are safe in a limited range (90°–45°) starting from the fourth week post-surgery. Avoiding the 15°–30° range is advised initially, as this is where peak ACL strain occurs.
*   **Return to Running Criteria:** Decisions should be based on performance and clinical criteria rather than time alone. Key criteria include:
    *   95% knee flexion ROM and full extension ROM.
    *   No effusion.
    *   LSI >80% for quadriceps strength.
    *   LSI >80% eccentric impulse during countermovement jump.
    *   Pain-free aqua jogging/Alter-G running and repeated single-leg hopping.

## Authors
*   **Kalander, Juho**, Physiotherapy student, Savonia University of Applied Sciences, Kuopio, Finland
*   **Karvonen, Oona**, Physiotherapy student, Savonia University of Applied Sciences, Kuopio, Finland
*   **López García, Jorge**, Physiotherapy student, University of Coruña (UDC), A Coruña, Spain
*   **Ráž, Jiří**, Physiotherapy student, Faculty of Physical Education and Sport at Charles University, Prague, Czech Republic
*   **Stuchlíková, Kateřina**, Physiotherapy student Faculty of Physical Education and Sport at Charles University, Prague, Czech Republic
*   **Timonen, Jussi**, Physiotherapy student, Savonia University of Applied Sciences, Kuopio, Finland
*   **Marja Äijö**, PhD, Principal lecturer of gerontology and rehabilitation, Savonia University of Applied Sciences, Finland
*   **Mari Tuppurainen**, physiotherapy lecture, Savonia University of Applied Sciences, Kuopio, Finland
*   **Dagmar Pavlu**, Physiotherapist, Assoc. Prof. Charles University, Czech Republic
*   **Ivana Vláčilová**, Professor, Charles University, Czech Republic
*   **Jamile Vivas Costa**, PhD, MSc, PT. Lecturer at Department of Physical Therapy, Medicine and Biomedical Sciences, Faculty of Physiotherapy and Researcher at Psychosocial intervention and functional rehabilitation group, Universidade da Coruña, Spain
*   **Montserrat Fernández Pereira**, MSc, PT. Lecturer at Department of Physical Therapy, Medicine and Biomedical Sciences, Faculty of Physiotherapy and Physiotherapist at Spinal Cord Injury Unit, A Coruña Hospital (CHUAC), Spain
*   **Verónica Robles García**, PhD, MSc, PT, OT. Lecturer at Department of Physical Therapy, Medicine and Biomedical Sciences, Faculty of Physiotherapy and Researcher at the Neuroscience and motor control group, Universidade da Coruña and Biomedical Institute of A Coruña, Spain

## References
*   Beischer, Susanna, et al. (2018). Young athletes return too early to knee-strenuous sport, without acceptable knee function after anterior cruciate ligament reconstruction. https://doi.org/10.1007/s00167-017-4747-8
*   Buckthorpe, Matthew & Della Villa, Francesco (2019). Optimising the ‘Mid-Stage’ Training and Testing Process After ACL Reconstruction. https://doi.org/10.1007/s40279-019-01222-6
*   Cronström, Anna, et al. (2023). Return to Sports: A Risky Business? A Systematic Review with Meta-Analysis of Risk Factors for Graft Rupture Following ACL Reconstruction. https://doi.org/10.1007/s40279-022-01747-3
*   Davies, George, et al. (2017). ACL Return to Sport Guidelines and Criteria. doi: 10.1007/s12178-017-9420-9
*   Du, Tianshu, et al. (2022). Current study on the influence of psychological factors on returning to sports after ACLR. DOI: 10.1016/j.heliyon.2022.e12434
*   Escamilla, Rafael F, et al. (2012). Cruciate ligament loading during common knee rehabilitation exercises. DOI: 10.1177/0954411912451839
*   Grindem, Hege, et al. (2016). Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: the Delaware-Oslo ACL cohort study. DOI: 10.1136/bjsports-2016-096031
*   Kostifaki, Roula, et al. (2022). Aspetar clinical practice guideline on rehabilitation after anterior cruciate ligament reconstruction. DOI: 10.1136/bjsports-2022-106158
*   McPherson, April, et al. (2019). Psychological Readiness to Return to Sport Is Associated With Second Anterior Cruciate Ligament Injuries. https://doi.org/10.1177/0363546518825258
*   Rambaud, Alexander JM, et al. (2017). Criteria for return to running after anterior cruciate ligament reconstruction: a scoping review. DOI: 10.1136/bjsports-2017-098602
*   Webster, Kate E & Feller, Julian A (2019). Expectations for Return to Preinjury Sport Before and After Anterior Cruciate Ligament Reconstruction. DOI: 10.1177/0363546518819454
*   Wong, Choi-Yan, et al. (2023). Secondary Anterior Cruciate Ligament Injury Prevention Training in Athletes: What Is the Missing Link? https://doi.org/10.3390/ijerph20064821
*   Zarzycki, Ryan, et al. (2023). Female Athletes with Better Psychological Readiness Are at Higher Risk for Second ACL Injury After Primary ACL Reconstruction. https://doi.org/10.1177/19417381231155120