Insoles Adapted in Flip-flop Sandals in People With Heel Pain

Study Overview
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Brief Summary
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Introduction: Persistent hindfoot pains are very common and prevalent complaints in the Brazilian population. One of the treatments recommended for these conditions in the literature is the use of insoles. However, to use this resource it is necessary that the individual wear closed shoes and this is an obstacle to treatment in cities with hot climate. Thinking about an alternative treatment, the customized slippers with the corrective elements of the insoles can be an alternative to increase adherence to this type of treatment. Objective: To compare different types of hindfoot elements in insoles adapted in slippers in individuals with persistent hindfoot pain.

Detailed Description
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Methodology: This is a protocol for a controlled, randomized, blinded clinical trial. Eighty participants with persistent hindfoot pain will be evaluated and randomized into two intervention groups: insoles adapted to flip-flops and flip-flops with sham insole. The evaluations will be carried out at baseline (T0), after six (T6) and twelve weeks (T12) of the use of flip-flops, in addition to the follow-up that will be carried out four weeks after the end of the intervention (T16). The primary outcome will be pain, using the Numerical Pain Scale and the secondary outcomes will be: foot function, using the Foot Function Index questionnaire, functional capacity in walking, using the Six-Minute Walk Test and pain catastrophizing using the Scale. of Pain Catastrophizing. Statistical analysis: Data will be analyzed by T-student, Mann-Whitney and repeated measures ANOVA tests and will be analyzed by intention to treat. Ethics and disclosure: This protocol was approved by the Ethics Committee of UFRN/FACISA (number 4,018,821). The results of the study will be disseminated to participants and submitted to a peer-reviewed journal and scientific meetings.

Official Title
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Effects of Insoles Adapted in Flip-flop Sandals in People With Heel Pain: a Randomized, Double-blind Clinical, Controlled Study

Conditions
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Heel Pain Syndrome, Heel

Intervention / Treatment
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* Other: Insoles adapted in flip-flop sandals


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Individuals of both sexes, aged 18 to 65 years; Persistent heel pain for at least three months based on self-reported criteria: heel pain accompanying the first steps in the morning, after a period of inactivity, and/or during prolonged weight-bearing; Pain intensity between 3 and 8 points, according to the Numerical Rating Scale (NRS) [22]; Individuals who can wear flip-flop sandals for at least four hours per day for 12 weeks. Exclusion Criteria: Clinical diagnosis of neuropathic pain or neurodegenerative disorders, persistent heel pain due to rheumatic conditions, and previous ankle and foot surgeries; Physical therapy treatment in the last three months; Corticosteroid injection into feet in the last six months; inability to answer study-related questionnaires; Individuals scheduled to travel in the next six months.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Group 1- (n=40) The participant allocated to the insoles group adapted to flip-flops and classified as having a neutral foot according to the FPI-6 will receive a flip-flop with a horseshoe-type foot element on both feet to maintain symmetry between the limbs. If the participant is classified with the foot pronated or supinated, only the painful foot will be modified since the symmetry of the limbs will not be modified. Participants with pronated foot will receive the medial wedge as a pedal element; already the participants with supinated foot, the lateral wedge. All elements will be 3mm and produced with EVA Shore 32. • Group 2- The control group (n=40) will receive a slipper with a 2.5mm EVA cover (Shore A 32) identical to the one used by the intervention group, but without corrective par.
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Experimental group<br>Group 1- The intervention group I will receive a customized strip slipper with a 3mm EVA horseshoe piece (Shore A 32). And 2.5mm EVA cover (Shore A 28). | Other: Insoles adapted in flip-flop sandals<br>* participants of both groups individually received a pair of customized flip-flop sandals, with or without foot pieces, covered with smooth synthetic leather<br>|
| Sham Comparator: Sham group<br>Group 2- The control group will receive a slipper with a 2.5mm EVA cover (Shore A 32) identical to the one used by the intervention group, but without corrective par | Other: Insoles adapted in flip-flop sandals<br>* participants of both groups individually received a pair of customized flip-flop sandals, with or without foot pieces, covered with smooth synthetic leather<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Numerical pain intensity scale - NPS | Pain intensity will be evaluated with the 10-point Numerical Pain Rating Scale, where 0 is pain-free and 10 is maximum pain. | baseline, 6 weeks after, 12 weeks after, 16 weeks folow up | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Foot function - FFI | Brazilian version of the Foot Function Index questionnaire.15 This questionnaire aims to evaluate the functionality of the foot and is divided into three subscales, which are pain, difficulty and functional limitation. The outcome of all domains was summed and divided by three to achieve the final result of the questionnairewhich can vary from 0% to 100%, and are proportional to functional impairment of the limb.The higher the percentage, the greater the functional alteration presented by the patient | baseline, 6 weeks after, 12 weeks after, 16 weeks folow up | 
| Change in Functional capacity - 6MWT | For this test, the participant walked at full speed for 6minutes along a 30-m lane, and the total distance was recorded. | baseline and 12 weeks after | 
| Change in Pain Catastrophizing Scale (PCS) | Self-administered questionnaire composed of 13 items in which the individual reports the degree of thought or feeling on a 5-point Likert scale. The instrument has three subscales (hopelessness, magnification, and rumination), and the total score (0 to 52 points) is obtained by summing items. The higher the value, the greater the level of catastrophizing | baseline and 12 weeks after | 
| Expectation for treatment | The scale assesses the expectations of individuals at the beginning of the study regarding treatment received. The question Do you think that with flip-flop sandals you will (1) get very worse, (2) get a little worse, (3) neither improve nor get worse, (4) improve a little, or (5) improve a lot. This scale will be applied only in the first (T0) assessment | baseline | 
| Satisfaction with treatment | The scale will assess perceptions of the individual on the effects of treatment through the following question: After using flip-flop sandals with insoles are you feeling (1) much worse, (2) a little worse, (3) neither better nor worse, (4) a little better, or (5) much better | 16 weeks after |