Knee Function, Strength, and Resumption of Preinjury Sports Participation in Young Athletes Following Anterior Cruciate Ligament Reconstruction.

BACKGROUND

Following anterior cruciate ligament reconstruction (ACLR), young athletes demonstrate deficits in knee function and strength whose association with successful return to preinjury sports participation is not well understood.

OBJECTIVES

To examine differences in knee function and strength at the time of return-to-sport clearance between young athletes who successfully resumed preinjury sports participation, those who did not resume preinjury sports participation, and those who sustained a second anterior cruciate ligament (ACL) injury by 1 year following return-to-sport clearance.

METHODS

This prospective cohort study collected data in 124 young athletes (mean ± SD age, 17.1 ± 2.4 years) at the time of return-to-sport clearance post ACLR. Measures included the Knee injury and Osteoarthritis Outcome Score (KOOS), single-leg hop tests, isokinetic quadriceps and hamstring strength, and limb symmetry during hop tests and strength tests. Participants were allocated to 3 groups: resumed preinjury sports participation (Tegner score), did not resume preinjury sports participation, or sustained a second ACL injury. Group differences were compared using Kruskal-Wallis tests and Mann-Whitney U post hoc tests.

RESULTS

Seventy (56%) participants successfully resumed preinjury sports participation and 26 (21%) sustained a second ACL injury by 1 year post return-to-sport clearance. Participants who successfully resumed preinjury sports participation demonstrated greater absolute performance at return-to-sport clearance in the involved and uninvolved limbs on the triple hop (P = .007 and P = .004, respectively) and the crossover hop (P = .033 and P = .037, respectively), and in the involved limb on the single hop (P = .043), compared to those who did not (n = 28). Participants who sustained a second ACL injury demonstrated greater absolute performance at return-to-sport clearance in the involved and uninvolved limbs on the triple hop (P = .034 and P = .027, respectively) compared to those who did not resume preinjury sports participation. There were no group differences between those who successfully resumed preinjury levels of sports participation and those who sustained a second ACL injury.

CONCLUSION

Following ACLR, the small proportion of young athletes who successfully resumed preinjury levels of sports participation 1 year after return to sport demonstrated greater absolute functional performance at the time of return-to-sport clearance. No differences were identified between those who successfully resumed preinjury sports participation and those who sustained a second ACL injury. Measures of limb symmetry did not differ among any of the groups.

LEVEL OF EVIDENCE: Prognosis, level 2b. J Orthop Sports Phys Ther 2019;49(3):145-153. doi:10.2519/jospt.2019.8624.