Physical therapy influences chronic pain with the use of specific ingredients of an intervention as well as nonspecific contextual factors such as the setting and therapeutic alliance (TA) between provider and patient. The purpose of this study was to compare the effect of enhanced versus limited TA on pain intensity and muscle pain sensitivity in patients with chronic LBP receiving either active or sham IFC.DesignExperimental controlled study with repeated measures. Participants were separated at random into 4 groups: active limited (AL) (n=30) included the application of active IFC combined with a limited TA, sham limited (SL) (n=29); sham IFC combined with a limited TA, active enhanced (AE) (n=29); active IFC combined with an enhanced TA, and sham enhanced (SE) (n=29); sham IFC combined with an enhanced TA. The study, which was conducted in a clinical laboratory, consisted of 117 participants with chronic low back pain (LBP). A single session of active or sham IFC applied within two separate contexts (enhanced or limited TA) was administered. Pain intensity (PI-NRS) and muscle pain sensitivity (PPT) were measured. Mean differences on the PI-NPR were 18.3 mm (95% CI 14.3 to 20.3), 10.3 mm (95% CI 6.6 to 12.7), 31.4 mm (95% CI 27.2 to 33.3), and 22.2 mm (95% CI 18.9 to 25.0), for the groups AL, SL, AE, and SE respectively. Mean differences on PPTs were 1.2 kg (95% CI 0.7 to 1.6), 0.3 kg (95% CI 0.2 to 0.8), 2.0 kg (95% CI 1.6 to 2.5), and 1.7 kg (95% CI 1.3 to 2.1), for the groups AL, SL, AE, and SE respectively. The study protocol was limited by testing only the immediate effect of the TA.
The study found that the context in which physical therapy interventions are provided has the potential to drastically improve therapeutic effects. The combination of enhanced TA active IFC seams to lead to clinically meaningful improvements in outcomes when treating patients with chronic LBP.