2015 ISAKOS Biennial Congress ePoster #1362

Post ACL Reconstructionn: Do Patient Outcome Scores Correlate with Objective Functional Tests?

Mary Lloyd Ireland, MD, Lexington, KY UNITED STATES
Brian Noehren, PhD, Lexington, KY UNITED STATES
Susan K. Myers, BS, Lexington, KY UNITED STATES

University of Kentucky, Lexington, KY, USA

FDA Status Not Applicable

Summary: When cleared to run after ACL Reconstruction, patients underwent 3 months of rehabilitation.Outcome scores were not related to objective functional tests of strength and balance. Perception was higher than performance.Use of functional tests is critical to educate the athlete on true readiness to return to play.




Reconstructive surgery of the anterior cruciate ligament (ACL) is one of the most common orthopedic procedure performed on the knee. However, following surgery, up to 40% of individuals do not return to their previous activity levels. One potential reason could be due to a discrepancy between patient perceptions of their knee function versus the actual function of the knee following surgery. This relationship could be particularly important before they finish rehabilitation as it represents the best time to address these disparities. Thus we hypothesized that patient reported outcomes would not be correlated to between limb differences in performance on a variety of functional tests typically administered during rehabilitation. Methods: 48 individuals (22 female, 26 male) participated in this study. All participants completed the Knee injury and Osteoarthritis Outcome Score (KOOS) and functional testing following 3 months of rehabilitation at the time they are cleared to start running. Following previously published procedures they then completed the Y balance test. Their knee extensor strength was measured isometrically using a hand held dynamometer and stabilization strap. Finally, the number of step downs that they could perform off of a 20.32cm riser was determined. We then calculated between limb differences by subtracting the values from the no-injured to injured limb. Data was checked for normality and Pearson product moment correlations determined between the functional variables and the KOOS scores. Results: Participants reported an average score of 92.96 (SD= 6.54) on KOOS-ADL and had a between limb differences on the following tests: Y-balance test (mean=-30.19, SD= 75.29 cm), knee extensor strength (mean of 6.05, SD=5.32 Nm/kg), and step down performance (mean=9.75, SD=9.65 steps/minute). We found no significant relationship between the KOOS and between limb differences in the Y balance test (r=0.04, p= 0.79), knee extensor strength ( r=-0.07 p=0.63), and the step downs (r=-0.20, p=0.18). Discussion: Overall we did not find any relationship between the magnitude of between limb differences in strength and functional performance measures to the patients perception of how they were doing. These results have a number of implications. First, there may be a need for greater patient education on the significance of asymmetries in performance at this stage of rehabilitation to performance in sports after completing rehabilitation. Another consequence of lack of a relationship could be an unwarranted level of confidence in their abilities early in rehabilitation that results in decreased compliance with their exercises. These results could also reflect a ceiling affect with current patient reported outcomes within this cohort. There could be a need for new scales that better reflect the higher demand activities these individuals expect to return to. Conclusion: Patient reported outcomes do not match physical performance during rehabilitation following an ACL reconstruction, potentially affecting the how the patient views their readiness to return to sport. Also, caution should be used in using only patient reported outcomes in the decision to allow the patient to progress in rehabilitation and return to sport.