Return to Sport After ACL Reconstruction: Strength and Functionality Testing

Background: Functionality testing following anterior cruciate ligament (ACL) reconstruction can benefit clinicians and patients in determining readiness for return to sport. While a component of a multifactorial decision, inability to perform well on these tests predicts increased risk of reinjury. As of 2013, only 41% of orthopaedic surgeons report using strength or functionality testing in evaluating patients for return to sport (RTS). Indications: In the intermediate to late stages of their rehabilitation program, patients may undergo these tests to determine readiness and safety to return to sport. Technique Description: The tests described in this video include the single and triple hop for distance, triple crossover hop, single and double vertical leg jump tasks, drop jump landing task, and isokinetic and isometric strength testing. Results: Clinicians who incorporate these tests into patient rehabilitation programs may reduce patient risk of ACL reinjury by 75% to 84%. The limb symmetry index (LSI) is a reliable calculated measure for these tests, with a strong reliability for the hop tests. The limb symmetry index can be calculated for each test and represents the ratio of measured performance of the involved, or post-ACL reconstruction, leg when compared against the uninvolved leg. The commonly used limb symmetry index threshold for passing each hop test is 90%. Patients who score 90% or greater on each of these tests are less likely to experience knee reinjury. Discussion/Conclusion: The ability of knee strength and functionality tests in determining RTS following ACL reconstruction has been highlighted as a tool in potentially reducing risk of knee reinjury. Other isometric and isokinetic testing can be used in addition to the described functionality tests but may not be possible in certain practices due to equipment and funding limitations. Usage of these strength and functionality tests, in conjunction with clinician evaluation, may lead to more optimal outcomes for patients and lower rates of reinjury. Psychological assessment may aid in evaluating patient readiness for return to sport. Importantly, further sport-specific testing is still recommended and will optimize patient outcomes.

Lower limb symmetry index (LLSI) pre- and post-reconstruction of the ACL: a controlled study

Background: The anterior cruciate ligament (ACL) lesion causes a deficit in joint stability and mobility, trophism and muscular strength, generating asymmetries between the lower limbs. Objective: To verify the effect of a physiotherapeutic protocol on the Lower Limb Symmetry Index (LLSI) and the correlation between strength and EMGs, pre and post reconstruction of the ACL. Methods: Twenty subjects (10 ACLrg + 10 CONTg) were evaluated regarding isometric force and electrical activity of knee extensors, knee flexors and hip abductors. Results: A significant increase (P<0.01) in knee extension and flexion strength and hip abduction strength were observed both for the affected limb and non-affected limb. Regarding the LLSI, a significant increase was observed for knee extension and hip abduction movements in the pre- and post-treatment comparison, and between ACLrg X CONTg (P<0.01) for the knee extension movement in the pre-reconstruction phase of the ACL. A very strong correlation (r=0.945; P<0.01) was also observed between the LLSI strength X EMGs during knee extension, pre- and post-reconstruction surgery. Conclusions: Six months after reconstruction of the ACL, there was an increase in strength and EMG activity of the knee flexor, knee extensor and hip abductor muscles, leveling the LLSI between ACLrg and the CONTg, however, with a significant correlation between the two variables (strength X EMGs) for only one of the three movements (knee extension).