Effects of remote ischemic conditioning on conditioned pain modulation and cardiac autonomic modulation in women with knee osteoarthritis: placebo-controlled randomized clinical trial protocol

Abstract

Abstract Background It is estimated that over 240 million people worldwide have osteoarthritis, which is a major contributor to chronic pain and central changes in pain processing, including endogenous pain modulation. The autonomic nervous system plays a crucial role in the pain regulatory process. One of the main mechanisms of remote ischemic conditioning is neuronal signaling from the preconditioned extremity to the heart. This study aims to analyze the acute effect of remote ischemic conditioning on local pain, conditioned pain modulation and cardiac autonomic control in women with knee osteoarthritis and to see if there is a correlation between them. Methods Randomized, placebo-controlled, double-blind clinical trial. Participants will be divided into: i) remote ischemic conditioning in which an adapted cuff will be positioned in the proximal region of the thigh of the lower limb with the greatest complaint of knee pain and a protocol consisting of four cycles of total ischemia, followed immediately by four cycles of five minutes of vascular reperfusion, totaling 40 minutes, will be performed; ii) placebo remote ischemic conditioning that differs from the previous one in relation to ischemia of 10 mmHg. The main outcomes evaluated will be the conditioned pain modulation in which the test stimulus will be performed through the pressure pain threshold and the conditioning stimulus through the cold pressor test and cardiac autonomic modulation through heart rate variability. Comparisons will be performed using generalized linear mixed models fitted to the data. For correlation, the Pearson or Spearman test will be used depending on the normality of the data. All analyzes will assume a significance level of p < 0.05. Discussion the results of this study are believed to show a new perspective for the interaction between pain processing and cardiovascular systems; in addition to providing the therapist and patient with better conditions to ensure greater cardiovascular safety in the use of the intervention and trigger knowledge of an acute response for future chronic intervention strategies that aim to be used in the clinical environment as another strategy that can help, within the multimodal approach, for the management of knee osteoarthritis. Trial registration number: ClinicalTrials.gov, (NCT05059652). Registered on 27 September 2021; Last Update 19 April 2022.