Timothy Hewett, PhD, and doctoral candidate Christopher Nagelli of the Mayo Clinic in Rochester, Minn., argue that athletes should sit for two full years after tearing their ACLs, according to the study they published in Sports Medicine.
However, many professional athletes return to play after a much shorter timeframe. Here are seven things to know about the study:
1. The study reported that nearly one-third of athletes who return to action within two years after knee reconstruction end up suffering a second ACL injury.
2. Athletes under 20 years old are three to six time more likely to suffer a second injury than older athletes. Those who return within one year of the initial injury are 15 times more likely to re-injure themselves than a healthy athlete with no prior knee injury history.
3. Some of the many risk factors for re-injury are age, female sex, activity level, sport type, neuromuscular and biomechanical factors and surgical characteristics such as graft placement and type.
4. The authors wrote: "The sports medicine community has made significant advances in surgical techniques, postoperative rehabilitation, and identification of risk factors for second injury but this has not translated to a reduction in secondary ACL injury risk."
5. Reconstructed athletes' injuries don't return to baseline levels for at least two years after the operation, impacting neuromuscular control and knee extension strength on a daily basis.
6. NFL players such as Super Bowl-winning quarterback Tom Brady and running back Dion Lewis, in addition to star Minnesota running back Adrian Peterson have all returned to the field in a year or less after their respective ACL injuries. The researchers fear that these players' recoveries will prompt more athletes to prioritize quick returns from ACL injuries over long-term health.
7. Dr. Hewett admitted that the study's findings likely won't keep athletes from returning from their ACL injuries in six months to a year. However, he hopes to reduce the rate of second injuries to one in five or six from the current rate of one in three.
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