By: Dr. Laura Wenger, PT, OCS, FAAOMPT
When I was completing my initial doctorate degree at the University of Utah, I focused the efforts of my doctoral project on identifying risk factors for individuals to sustain a repeat or opposite-leg knee anterior cruciate ligament (ACL) injury after undergoing an ACL-reconstruction surgery. Nearly 10 years later, researchers are still working to identify risk factors for a second ACL injury and to either validate or invalidate previously identified factors. One such recent research article by Beischer et al.(1) sought to further understand the factors that may impact the likelihood of somebody sustaining a second ACL injury after going through surgery and returning back to sport.
The main reason why this topic is so heavily investigated is because the rate of reinjury has been shown to be concerning for young athletes. According to the literature review in the Beischer et al. study, “approximately 1 in 4 patients who are 25 years of age or younger and return to high-risk sport after primary ACL reconstruction sustain a second ACL injury.”(1) For the amount of time and energy it takes to have and recover from this surgery, I don’t like the sounds of those odds and I certainly try to prepare my patients as much as possible to have success when returning to their sport.
This research study focused on three specific factors: 1- the amount of time to return to a knee-strenuous sport after ACL-reconstruction, 2- symmetrical muscle function as assessed by a variety of strength and hopping tests to compare the injured leg to the non-injured leg, and 3- symmetrical quadriceps muscle strength at the time of return to sport.(1) After analyzing data from 159 athletes, this research group found that athletes who returned to knee-strenuous sport earlier than 9 months had an approximately 7-fold higher rate of new ACL injury- of either the same leg or the opposite leg- compared with those who returned at 9 months or later after surgery.(1) They did not find associations with muscle function or symmetry of quadriceps strength in relation to new ACL injury.(1)
The results of this study reinforce the results of many prior studies showing that returning to strenuous sport “too soon” after an ACL-reconstruction is risky. Ultimately, time is on your side when it comes to properly rehabilitating after an ACL-reconstruction surgery, and getting back into play is not to be taken lightly. For those patients of ours who are recovering from an ACL-reconstruction, we will continue to be diligent in educating them about the importance of time throughout the rehab process.
1. Beischer S, Gustavsson L, et al. Young Athletes Who Return to Sport Before 9 Months After Anterior Cruciate Ligament Reconstruction Have a Rate of New Injury 7 Times That of Those Who Delay Return. J Orthop Sports Phys Ther. 2020 Jul;50(7):411.