Self-reported outcomes are associated with knee strength and functional symmetry in individuals who have undergone anterior cruciate ligament reconstruction with hamstring tendon autograft

Background: The aim of this study was to investigate the relationship between self-reported knee outcomes and limb symmetry indices (LSIs) for hip and knee strength, postural control and single-leg hop distance in individuals who had undergone an anterior cruciate ligament (ACL) reconstruction via hamstring tendon autograft (HTG).

Methods: A total of 72 participants with a history of unilateral ACL reconstruction via HTG (mean ± standard deviation (SD) age: 28.0 ± 7.6 years; height: 178.4 ± 6.7 cm; mass 76.9 ± 14.9 kg) were included. International Knee Documentation Committee 2000 Subjective Knee Form (IKDC), Lysholm, Knee Osteoarthritis Outcomes Scores (KOOS) and Tampa scores were used to evaluate self-reported outcomes. Concentric and eccentric knee extensor and flexor, and hip strength, postural control and single leg hop distance were evaluated for performance-based outcomes. The relationships between the LSI scores and the performance measures were explored using the Pearson correlation coefficient.

Results: The IKDC, Lysholm and KOOS scores were positively correlated with knee extensor and flexor strength LSIs (P < 0.05, r = 0.34 to r = 0.50), and the Tampa score was negatively correlated with eccentric extensor LSI (P = 0.02, r = -0.34). Single-leg hop distance LSI was correlated with IKDC and Lysholm scores (P = 0.003, r = 0.50; P = 0.04, r = 0.29) respectively, while postural control was only correlated with the KOOS scores (P < 0.001, r = 0.51 to r = 0.52).

Conclusions: Compared to Lysholm and Tampa scores, KOOS and IKDC scores were more likely to be correlated with performance-based outcomes. Therefore, KOOS and IKDC scores may help clinicians in return to sport decision making when there is a limited time to perform extensive evaluations or access equipment.