Published Rates of Reinjury After ACL Reconstruction Show Need for Advanced Neuromuscular Retraining

Sue Barber-Westin

Despite advances in ACL reconstruction techniques and the use of early rehabilitation principles such as immediate knee motion and quadriceps strengthening exercises, some recent studies have reported high failure rates when patients resume athletics after surgery. This problem has been especially noted in athletes under 25 years of age who return to sports that involve jumping, pivoting, and cutting. For instance, one study2 reported that 30% of patients sustained noncontact reinjuries and tore either their ACL graft or the ACL in the contralateral knee within 2 years of surgery. These patients had a 6 x greater ACL injury incidence compared with a healthy control group. Even more concerning was the finding that the rate of a contralateral ACL injury was significantly higher than the rate of ACL graft injury (20.5% and 9%, respectively). Another study4 that involved 788 ACL autograft and 228 ACL allograft patients reported a significant difference in the reinjury rates in patients under the age of 25 (9% and 25%, respectively; p < .0001). This study was the first to show such poor results in young, highly active patients who received allografts and questioned this graft choice for primary ACL reconstruction. A third study3 followed 878 patients who were less that 25 years of age at the time of their ACL autograft reconstruction. These investigators reported that ACL reinjuries occurred to either knee in 62% of men (289 of 465) and 40% of women (167 of 413) after the patients had resumed sports activities.

None of these studies reported on the program of rehabilitation that was followed after surgery, or if the patients underwent advanced neuromuscular retraining and demonstrated a return of normal muscle strength, balance, proprioception, and other athletic indices. There is currently a lack of consensus in the medical community regarding objective criteria that is required before athletes are released to full sports participation after ACL reconstruction. We performed a systematic review1 of 264 studies and found that only 13% discussed objective criteria – such as muscle strength and lower limb symmetry – required for return to athletics. We highly recommend that athletes who wish to resume high-risk sports complete a course of Sportsmetrics neuromuscular retraining and demonstrate normal values on single-leg hop tests (< 15% deficit distance hopped between legs), the video drop-jump test (> 60% normalized knee separation distance), isokinetic strength testing (< 10% deficit), and knee stability (< 3 mm increased anteroposterior displacement on Lachman testing) before they are released to unrestricted activities.


  1. Barber-Westin SD, Noyes FR. Factors used to determine return to unrestricted sports activities after anterior cruciate ligament reconstruction. Arthroscopy. 2011;27(12):1697-1705.
  2. Paterno MV, Rauh MJ, Schmitt LC, Ford KR, Hewett TE. Incidence of Second ACL Injuries 2 Years After Primary ACL Reconstruction and Return to Sport. Am J Sports Med. 2014;42(7):1567-1573.
  3. Shelbourne KD, Gray T, Haro M. Incidence of subsequent injury to either knee within 5 years after anterior cruciate ligament reconstruction with patellar tendon autograft. Am J Sports Med. 2009;37(2):246-251.
  4. Wasserstein D, Sheth U, Cabrera A, Spindler KP. A Systematic Review of Failed Anterior Cruciate Ligament Reconstruction With Autograft Compared With Allograft in Young Patients. Sports Health. 2015;7(3):207-216.