Single-Legged Hop Tests and Predictors of Self-Reported Knee Functional After Anterior Cruciate Ligament Reconstruction: The Delaware-Oslo ACL Cohort Study
Logerstedt D, Grindem H, Lynch A, Eitzen I, Engebresten L, Risberg MA, Axe MJ, & Snyder-Mackler L. American Journal of Sports Medicine. 2012; 40:12348-2356. doi 10.1177/0363546512457551
Anterior cruciate ligament (ACL) reconstruction is performed regularly with relatively favorable results. However, there remains a lack of evidence to predict who will have favorable outcomes and who may have problems after surgery. Therefore, purpose of this prospective cohort study was to assess the effectiveness single-legged hop tests to predict self-reported knee function 1-year post ACL reconstruction. One hundred twenty patients (mean age = 26) received ACL reconstruction surgery and followed the same pre- and post-operative rehabilitation programs. Patients performed 4 single-legged hop tests (i.e., single hop, crossover hop, triple hop, and 6-m timed hop) at the end of pre-operative rehabilitation and at 6 months post-surgery. Patients also completed the IKDC 2000 (knee outcome survey) 1-year post surgery. Only 84% of the patients completed the preoperative hop testing due to various reasons (e.g., meniscal injuries, missed appointments, quadriceps weakness/poor dynamic stability). There were no significant differences found in IKDC scores between those who did or did not perform the pre-operative hop tests. Among the 79 patients that completed the pre-operative hop tests and 1-year knee outcome survey the authors found that none of the preoperative hop tests could conclusively predict function 1-year post ACL reconstruction. However, among the 85 patients that completed the 6-month post-surgery hop tests and 1-year knee outcome surveys the authors discovered that all of the hop tests successfully predicted self-reported knee function. They noted that the crossover hop and 6-m timed hop indexes were the most accurate at identifying patients who would or would not have normal knee function at 1 year.
Clinically, it appears that the single-legged hop tests performed at 6-months are accurate predictors of self-reported outcomes 1-year post-surgery. However, we are still lacking a tool to assess and potentially identify patients that will likely have favorable surgical outcomes prior to their having the surgery done. While the study controlled for rehabilitation, it contained a variety of graft types. It would be interesting to see if there were any differences among graft types with some sub-analyses. Furthermore, it may be interesting to see if there are certain exercises that could be provided if someone performed poorly at a 6-month assessment. While the results seem favorable, there is still room for more investigation to verify these results and to explore pre-surgery predictors, as well as to evaluate what we can do for the patients that are not performing well on hop tests at 6 months post-surgery. Have you seen other clinical measures that seem to predict favorable (or even not favorable) function after an ACL reconstruction?
Written by: Nicole Cattano
Reviewed by: Jeffrey Driban
Related Posts:Logerstedt, D., Grindem, H., Lynch, A., Eitzen, I., Engebretsen, L., Risberg, M., Axe, M., & Snyder-Mackler, L. (2012). Single-Legged Hop Tests as Predictors of Self-Reported Knee Function After Anterior Cruciate Ligament Reconstruction: The Delaware-Oslo ACL Cohort Study The American Journal of Sports Medicine, 40 (10), 2348-2356 DOI: 10.1177/0363546512457551