Abstract
Background:
Safe return to sport (RTS) after anterior cruciate ligament (ACL) reconstruction is difficult to determine in adolescent patients. Return of strength and dynamic knee stability can be assessed with functional single-leg hop testing as part of a formal RTS assessment. However, it is unclear whether performance during single-leg hop testing can predict future ACL graft rupture.
Hypothesis/Purpose:
To investigate differences in single-leg hop testing between adolescent patients who experienced a graft rupture after ACL reconstruction and those that did not.
Methods:
A retrospective review of adolescent patients whom underwent primary ACL reconstruction with a hamstring (HS) autograft identified 16 patients (10 girls, 6 boys) with single-leg hop testing data prior to graft failure. A nearest neighbor match algorithm was used to age-, sex-, surgeon-, and graft-match 16 patients without graft rupture. All patients followed a standardized rehabilitation protocol following surgery. As part of a formal RTS test, assessment of function and dynamic strength/stability was performed using 4 different single-leg hop tests: single hop for distance, triple hop for distance, triple crossover hop for distance, and timed hop. The recovery of muscle strength was defined by a limb symmetry index (LSI) ≥ 90%. Bivariate analyses were performed to compare the two groups.
Results:
The mean age of the entire cohort at the time of surgery was 14.6 ± 1.5 years. Patients completed their RTS test at 29.0 ± 5.4 weeks. There were no statistically significant differences in demographics, graft size, or time to RTS test between groups. There were no statistically significant differences in LSIs on the single hop (p=0.90), triple hop (p=0.36), crossover hop (p=0.41), or timed hop (p=0.48). The mean LSIs on each of the four hop tests were 92.3 ± 14.7, 95.1 ± 6.1, 95.8 ± 7.1, and 98.6 ± 7.9, respectively. Passing rates were similar between groups (p=0.54).
Conclusion:
Performance on single-leg hop tests 6 months after surgery is not predictive of graft rupture following ACL reconstruction with HS autograft in adolescent patients. Further investigation of alternative RTS measures and different time frames for testing in this high-risk population is needed.