Abstract
We read with interest the article by Veeramachaneni et al. (Global Spine J. 2025;15:2890-2899) evaluating a foot-worn biomechanical intervention compared with traditional physical therapy (TPT) in chronic low back pain (CLBP). 1 While the authors are to be commended for conducting a randomised clinical trial in this challenging patient population, we would like to raise a few concerns that may affect the interpretation of their findings. A key issue is the disparity in compliance between groups, with 77% of patients in the device arm reported as compliant vs only 6% in the TPT arm. This imbalance could itself explain much of the difference in outcomes, given that adherence is strongly correlated with improvement in CLBP, and raises the possibility of performance bias. 2 The lack of blinding further compounds this, since outcomes were primarily subjective and vulnerable to expectation effects. This risk may have been amplified by the fact that participants in the intervention arm received the device at no cost, potentially influencing both motivation and perception of benefit. 3
In addition, the intensity of engagement differed between groups: patients in the device arm underwent personalised calibration and periodic recalibration, while those in the TPT arm followed a standard protocol with less individualisation. Such differences in perceived care may themselves bias results. 4 Although the authors describe the device as altering gait biomechanics and neuromuscular control, the mechanism of action remains abstract. Inclusion of a case example or gait analysis illustration would have enhanced the reader understanding. Moreover, there were significant baseline differences in age and BMI between groups. While the authors state these were adjusted for, the precise statistical methods used to control for these imbalances are not detailed, which limits confidence in the robustness of the findings. Finally, while the trial declared no conflicts of interest, the provision of devices by the manufacturer introduces the possibility of subtle industry influence that should be more explicitly acknowledged.
In summary, this innovative intervention shows promise, but interpretation should be tempered given concerns regarding compliance imbalance, lack of blinding, expectation bias from free device provision, unequal personalisation, limited mechanistic explanation, and incomplete reporting of statistical adjustments. Further independent, blinded, and multicenter trials with transparent methodology are necessary to validate the true clinical value of this device.
