Athletes at higher risk of second ACL injury if they don't score 90 pc on various tests

Young athletes who do not score a 90 per cent on various tests that measure their fitness to return to the athletic competition are at a higher risk of second ACL injury, finds a study.

An ACL injury is a tear or sprain of the anterior cruciate ligament (ACL), one of the major ligaments in your knee.

The study presented at the 'American Orthopedic Society of Sports Medicine Annual Meeting' followed 181 patients, average age 16 years, for two years.

Each patient was given a return-to-sport assessment that included six tests: isometric quadriceps strength, four functional hop tests and the International Knee Documentation Committee (IKDC) patient-reported outcome survey.

Limb symmetry index was calculated for strength and hop test assessments. Subjects were classified as patients who successfully passed all six return-to-sport tests at a level of 90 as compared to those who failed to meet all six criteria.

The researchers sought to determine if successfully passing all six measures resulted in a reduced risk of second ACL injury in the first 24 months after returning to their sport, as well as to assess if the ability to successfully pass individual return-to-sport criteria resulted in reduced risk of a second ACL injury.

Of the 181 patients enrolled, 39 suffered a second ACL injury with 18 ipsilateral graft failures and 21 contralateral ACL tears in the first 24 months after RTS following surgery. At the time of the return-to-sport assessment, 57 patients achieved 90 per cent or greater on all testing.

When individual return-to-sport criterion was evaluated, patients who failed to achieve 90 per cent quadricep strength were 84 per cent less likely to suffer an ipsilateral graft failure but three times more likely to suffer a 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 Dr Mark V Paterno, Division of Sports Medicine, Cincinnati Children's Hospital.