Clinical measures associated with knee function over two years in young athletes after ACL reconstruction

The purpose of this study was to investigate how patient-reported knee function changed over a two-year period in young athletes after anterior cruciate ligament reconstruction (ACLR) and return-to-sport (RTS), and to determine the impact of clinical measures, after controlling for demographic and surgical covariates.

At the time of RTS after primary, unilateral ACLR, the following data were collected in 67 young athletes: Quadriceps (QF), hamstring (HS), and hip abduction (HA) strength; knee range-of-motion, effusion, and anterior laxity; and patient-reported function using the Knee injury and Osteoarthritis Outcome Score (KOOS). At two years post-RTS, patient-reported function was reevaluated using the KOOS. Absolute KOOS scores and proportions of participants meeting functional recovery cutoffs were compared between time-points. Multivariable linear regression was used to determine clinical measures at RTS associated with two-year post-RTS KOOS scores.

KOOS scores for all subscales were higher at two years post-RTS (all p < 0.003), and the proportions of participants demonstrating functional recovery were higher at two years post-RTS for the KOOS-Symptoms, KOOS-Sport, KOOS-QOL, and all KOOS subscales combined (all p < 0.03). After controlling for graft type, clinical measures at RTS associated with higher two-year post-RTS KOOS scores were: KOOS-Pain (lower HA peak torque); KOOS-Symptoms (higher QF strength symmetry and higher QF peak torque); and KOOS-ADL (lower HA peak torque).

In this cohort, after controlling for graft type, higher QF strength symmetry, higher involved-limb QF peak torque, and lower involved-limb HA peak torque from the time of RTS were associated with higher function at two years post-RTS.