EFFECTS OF INSOLES ADAPTED IN FLIP-FLOP SANDALS FOR PERSISTENT HEEL PAIN: A CONTROLLED AND RANDOMIZED TRIAL
chronic pain, hindfoot, insoles, rehabilitation
Introduction: Persistent heel pain is a common condition in the middle-aged adult population, and is often disabling because it affects the individual's functionality and social aspects. Treatment with insoles is widely investigated, although there is disagreement between the evidence. Because it is a practical and comfortable resource, insoles adapted for flip-flops have recently been investigated in clinical studies with fasciopathies. However, the effects on individuals with persistent heel pain are not yet known. Objective: To evaluate the effects of using insoles adapted for flip-flops in the short and medium term on the intensity of morning pain, pain when walking, foot function and functional walking capacity of individuals with persistent heel pain. Method: Randomized, double-blind, sham-controlled clinical trial registered prospectively in Clinical Trials (NCT04784598). The participants were randomized into two groups: the experimental group (n=40) who used insoles adapted to slippers according to the assessment of the type of foot, and the control group (n=40) who used slippers with sham insoles, that is, flat slippers. All participants were instructed to wear flip-flops daily, for at least four hours a day, for a period of 12 weeks. Assessments were performed at baseline (T0), six (T6), 12 (T12) and 16 (T16) weeks after the intervention. The primary outcome was morning pain intensity according to the Numerical Pain Scale. Secondary outcomes were foot function by the Foot Function Index and functional walking ability by the Six-Minute Walk Test. Analysis of variance with a mixed design was used and the interaction between time and group was considered for all variables. Results: There were no differences between groups for morning pain intensity and when walking throughout the day in short (morning to mean difference [DM] = -0.7 [CI 95% -1.9 to 0.6]; to walking to MD= -0.4 [CI 95% -0.6 to 0.8]) and in the medium term (morning to MD = 0.01 [CI 95% -1.4 to 1.4]; walking to DM = -0.5 [95% CI -1.8 to 0.8]). There was also no difference between groups in the short and medium term for secondary outcomes. No clinically important changes were seen for any of the primary or secondary outcomes. Conclusion: Fitted insoles in slippers were not superior to slippers with sham insoles for pain, function, and functional capacity outcomes in subjects with persistent heel pain.