Abstract
Dear Editor,
Thank you for bringing to our attentions a letter regarding our article, “Clinical Outcomes of a New Foot-Worn Non-Invasive Biomechanical Intervention Compared to Traditional Physical Therapy in Patients With Chronic Low Back Pain. A Randomized Clinical Trial,” published in the Global Spine Journal. We appreciate the authors who found interest in our study and dedicated the time to provide insightful feedback.
We agree with some of the observations made by the correspondents. Regarding the disparity in compliance between groups, we acknowledge that this is a concern, but full compliance was attendance at all traditional physical therapy sessions. More than 50% of the participants had partial to complete adherence, which may be consistent with what actual clinical patients often achieve. This may reflect the experience in real-world settings, where compliance with traditional physical therapy is often low, and this is an inherent challenge in the management of chronic low back pain. Moreover, a Cochrane review suggested that higher exercise adherence is associated with larger improvements in clinical outcomes, although overall differences are small compared with lower adherence. 1 We agree that future studies should explore strategies to improve compliance across all treatment arms.
The readers raise concerns about additional sources of potential bias such as blinding, baseline differences, providing the device at no cost, etc. All are valid concerns that could have affected the outcomes. We did this study attempting to limit some of the bias effects of cost interfering with eligibility by providing the devices for no cost in order to allow all participants to enter the trial, similar to other trials for other interventions. We agree that future trials should aim to address the other concerns and control for potential source of bias. Additionally, this treatment was provided in our facility for insured patients with knee osteoarthritis and low back pain between 2015-2022 and a study looking at those outcomes found that this home-based biomechanical intervention leads to clinical improvements and high patient satisfaction, ultimately offering a non-surgical alternative to patients.2,3
With regard to the biomechanical basis for the intervention, it is important to note that earlier studies have employed three-dimensional motion analysis to assess the impact of similar center of pressure (COP)-shifting devices on lower limb biomechanics.4-8 These studies provided valuable insights into the kinematic and kinetic changes occurring at the ankle, knee, and hip joints in response to COP manipulation. The current study builds upon this foundation by extending the analysis to the lumbopelvic region, providing a more comprehensive understanding of the device’s effect on the entire kinetic chain. Now that a positive clinical effect was found (ie, reduction in pain), consideration of radiographic and other three-dimensional analysis in future studies may allow us to better understand the pathomechanics of the intervention.
We believe that the promising results of our study, which is the first randomized controlled trial of this biomechanical intervention for patient with chronic low back pain, provide evidence of the positive clinical effect of this intervention. Further studies are clearly warranted, including confirmatory ones on the examined intervention in our trial. We appreciate your suggestions and will carefully consider them as we plan future research.
Thank you again for your thoughtful comments and your contribution to the ongoing discussion of this important topic.
