Clinical Implications of Uninvolved Limb Function After Anterior Cruciate Ligament Reconstruction: Letter to the Editor

Dear Editor: A recently published article by Rohman et al (‘‘Changes in Involved and Uninvolved Limb Function During Rehabilitation After Anterior Cruciate Ligament Reconstruction: Implications for Limb Symmetry Index Measures’’) focuses interest on the effects of anterior cruciate ligament reconstruction (ACLR) rehabilitation on the uninvolved limb. We would respectfully like to share our opinions with the authors of this study. Osteoarthritis (OA) of the knee is a common disorder reported in people older than 45 years. We noticed that the participants in this study were older than 45 years, and we wondered whether the possibility of early-stage OA of the knee may have influenced the current study outcomes. Had any signs or symptoms of OA been considered for selection criteria among the participants? In addition, patient sex plays a significant role in determining the outcomes of functional activities; males have been reported to have poorer proprioception compared with females. Might the observed outcome of the study have differed if the results had been analyzed based on sex? We would also like to request the opinion of the authors regarding the external and internal validity of the study findings, based on patient age and sex, in routine clinical practice. The reliability and validity of clinical tests affect the quality of the clinical measurement. Functional test batteries should undergo reliability testing before they are used in clinical practice. Some of the clinical tests used in the Standard Functional Test (SFT) battery have not been validated and lack reliability. In real practice, is it important to consider all of the tests used in the SFT battery? Perhaps the authors can recommend the tests in their battery that are valid and reliable. Such information may help clinicians to save time by using only effective tests. We agree with the authors that reporting the minimal clinically important change (MCIC) would strengthen the clinical application of the study results, and we would be grateful if they could share their reasons for not reporting the MCIC. In our opinion, the MCIC may help clinicians to better understand the functional performance of patients at 4 and 6 months after ACLR. The Limb Symmetry Index (LSI) and the symmetry ratio are commonly used to evaluate limb asymmetry. Would the study findings have varied if the symmetry ratio had been reported instead of the LSI (ie, are symmetry index and symmetry ratio the same)? If they are not the same, which of them is recommended for evaluating limb asymmetry in clinical practice? Biomechanical changes in the uninjured limb during ACLR rehabilitation are insufficiently studied in the literature. Therefore, there is not enough knowledge of the changes in the uninjured limb to understand limb asymmetry during functional rehabilitation. In this context, we applaud the authors for emphasizing functional performance changes in the uninjured limb during ACLR rehabilitation. This current study has made a significant contribution to the practice of ACLR rehabilitation. We congratulate the authors and editor for publishing this interesting work.