Young athletes who do not achieve a 90% score on a battery of tests that measure fitness to return to athletic competition following anterior cruciate ligament (ACL) reconstruction are at increased risk for a second knee injury, according to research presented at the 2019 Annual Meeting of the American Orthopedic Society of Sports Medicine.
Return-to-sport criteria are intended to help orthopaedic surgeons and sports medicine professionals guide patients as they consider participating in athletic competition after injury. One of the tests – strength of the quadriceps – is generally considered to be a key predictor of risk for further injury to ACL.
Researchers from multiple institutions in the US enrolled 181 patients (116 females, 65 males; average age 16) who had been cleared to return to pivoting and cutting sports following ACL reconstruction in a prospective, observational cohort study. Each patient had undergone a return-to-sport assessment that included 6 tests:
- Isometric quadriceps strength
- 4 functional hop tests
- International Knee Documentation Committee (IKDC) patient reported outcome survey.
The patients were divided into 2 groups:
- Those who had successfully passed all 6 return-to-sport criteria at a level of 90%
- Those who had failed to meet all 6 return-to-sport criteria at a level of 90%
The researchers followed these patients for 24 months to determine if successfully passing all 6 return-to-sport criteria resulted in a reduced risk of a second ACL injury (ipsilateral graft tear or contralateral ACL injury), as well as to assess if successfully passing any of the individual return-to-sport tests resulted in reduced risk of a second ACL injury.
Of the 181 patients enrolled, 39 sustained a second ACL injury – 18 ipsilateral graft failures and 21 contralateral ACL tears – in the first 24 months after returning to sports following ACL reconstruction. At the time of return-to-sport assessment, 57 patients had achieved 90% or more on all testing.
Evaluation of individual return-to-sport criterion showed that patients who failed to achieve 90% quadriceps strength were 84% less likely to experience ipsilateral graft failure but 3 times more likely to sustain a contralateral ACL injury.
The researchers said that current criteria to evaluate readiness to return young athletes to pivoting and cutting sports may not identify young, active patients independently at high risk for a future ipsilateral graft tear or contralateral ACL injury.
“Further investigation is needed on the relationship between quad strength and side of future ACL injury and whether other factors may help contribute to a predictive model of future ACL injury specific to limb,” said Mark V. Paterno, PhD, PT, ATC, lead author of the study.
Click here to access the abstract from this presentation.
Paterno MV, Rauh MJ, Thomas S, Hewett TE, Schmitt LC. Quadricep Femoris Strength at Return to Sport Identifies Limb at Increased Risk of Future ACL Injury after ACL Reconstruction in Young Athletes (Paper 84). Presented at the 2019 Annual Meeting of the American Orthopedic Society of Sports Medicine, July 11-14, 2019, Boston, Massachusetts.