Plantar heel pain, self-management, exercise, orthoses, randomised controlled trial, adaptive design
ALL Metrics
-
Views
Downloads
How to cite this article
Thomas MJ, Hughes G, Cooke K et al. Clinical and cost-effectiveness of individualised exercises and foot orthoses in the treatment of plantar heel pain: protocol for the TREADON randomised multi-arm multi-stage adaptive trial [version 1; peer review: 2 approved, 2 approved with reservations]. NIHR Open Res 2025, 5:42 (https://doi.org/10.3310/nihropenres.13930.1) NOTE: If applicable, it is important to ensure the information in square brackets after the title is included in all citations of this article.
Export Citation
Sciwheel
EndNote
Ref. Manager
Bibtex
ProCite
Sente
Select a format first
▬
✚
Study Protocol
[version 1; peer review: 2 approved, 2 approved with reservations]
Martin J Thomas
https://orcid.org/0000-0002-4951-9925
1,2, Gemma Hughes3, Kendra Cooke https://orcid.org/0009-0001-6876-4192
3, [...] Stephanie Butler-Walley4, Emma Marshall3, Laura Bowyer https://orcid.org/0009-0005-0575-7269
3, Simon Wathall https://orcid.org/0000-0002-7107-5785
3, Jo Smith https://orcid.org/0009-0007-9030-4110
3, Sarah A Lawton3, June Brammar5, Thomas Burnett6, Chris Drake7, Nadine E Foster1,8, Gordon J Hendry9, Melaine A Holden1, Thomas Jaki10,11, Royes Joseph1,3, Anne-Maree Keenan https://orcid.org/0000-0003-0926-0397
7,12, Jesse Kigozi13, Martyn Lewis1,3, Christian D Mallen https://orcid.org/0000-0002-2677-1028
1, Hylton B Menz14, Pavel Mozgunov10, Edward Roddy1,2Martin J Thomas
https://orcid.org/0000-0002-4951-9925
1,2, Gemma Hughes3, [...] Kendra Cooke https://orcid.org/0009-0001-6876-4192
3, Stephanie Butler-Walley4, Emma Marshall3, Laura Bowyer https://orcid.org/0009-0005-0575-7269
3, Simon Wathall https://orcid.org/0000-0002-7107-5785
3, Jo Smith https://orcid.org/0009-0007-9030-4110
3, Sarah A Lawton3, June Brammar5, Thomas Burnett6, Chris Drake7, Nadine E Foster1,8, Gordon J Hendry9, Melaine A Holden1, Thomas Jaki10,11, Royes Joseph1,3, Anne-Maree Keenan https://orcid.org/0000-0003-0926-0397
7,12, Jesse Kigozi13, Martyn Lewis1,3, Christian D Mallen https://orcid.org/0000-0002-2677-1028
1, Hylton B Menz14, Pavel Mozgunov10, Edward Roddy1,2 PUBLISHED 06 May 2025
Author details Author details
1 Centre for Musculoskeletal Health Research, School of Medicine, Keele University, Keele, Staffordshire, UK
2 Midlands Partnership University NHS Foundation Trust, Haywood Hospital, Haywood Academic Rheumatology Centre, Burslem, Staffordshire, UK
3 Keele Clinical Trials Unit, David Weatherall Building, Keele University, Keele, Staffordshire, UK
4 Birmingham Clinical Trials Unit, University of Birmingham, Birmingham, UK
5 Research User Group, School of Medicine, Keele University, Keele, Staffordshire, UK
6 Department of Mathematical Sciences, University of Bath, Bath, UK
7 School of Medicine, University of Leeds, Leeds, UK
8 STARS Education and Research Alliance, Surgical Treatment and Rehabilitation Service (STARS), The University of Queensland and Metro North Health, Brisbane, Queensland, Australia
9 School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, UK
10 MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
11 Faculty of Informatics and Data Science, University of Regensburg, Regensburg, Germany
12 NIHR Leeds Biomedical Research Centre, Leeds, UK
13 Health Economics Unit, University of Birmingham, Birmingham, UK
14 School of Allied Health, Human Services and Sport, La Trobe University, Melbourne, Victoria, Australia
2 Midlands Partnership University NHS Foundation Trust, Haywood Hospital, Haywood Academic Rheumatology Centre, Burslem, Staffordshire, UK
3 Keele Clinical Trials Unit, David Weatherall Building, Keele University, Keele, Staffordshire, UK
4 Birmingham Clinical Trials Unit, University of Birmingham, Birmingham, UK
5 Research User Group, School of Medicine, Keele University, Keele, Staffordshire, UK
6 Department of Mathematical Sciences, University of Bath, Bath, UK
7 School of Medicine, University of Leeds, Leeds, UK
8 STARS Education and Research Alliance, Surgical Treatment and Rehabilitation Service (STARS), The University of Queensland and Metro North Health, Brisbane, Queensland, Australia
9 School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, UK
10 MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
11 Faculty of Informatics and Data Science, University of Regensburg, Regensburg, Germany
12 NIHR Leeds Biomedical Research Centre, Leeds, UK
13 Health Economics Unit, University of Birmingham, Birmingham, UK
14 School of Allied Health, Human Services and Sport, La Trobe University, Melbourne, Victoria, Australia
Martin J Thomas
Roles: Conceptualization, Funding Acquisition, Methodology, Project Administration, Resources, Supervision, Visualization, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Conceptualization, Funding Acquisition, Methodology, Project Administration, Resources, Supervision, Visualization, Writing – Original Draft Preparation, Writing – Review & Editing
Gemma Hughes
Roles: Project Administration, Resources, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Project Administration, Resources, Writing – Original Draft Preparation, Writing – Review & Editing
Kendra Cooke
Roles: Project Administration, Resources, Software, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Project Administration, Resources, Software, Writing – Original Draft Preparation, Writing – Review & Editing
Stephanie Butler-Walley
Roles: Project Administration, Resources, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Project Administration, Resources, Writing – Original Draft Preparation, Writing – Review & Editing
Emma Marshall
Roles: Project Administration, Resources, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Project Administration, Resources, Writing – Original Draft Preparation, Writing – Review & Editing
Laura Bowyer
Roles: Project Administration, Resources, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Project Administration, Resources, Writing – Original Draft Preparation, Writing – Review & Editing
Simon Wathall
Roles: Methodology, Project Administration, Resources, Software, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Methodology, Project Administration, Resources, Software, Writing – Original Draft Preparation, Writing – Review & Editing
Jo Smith
Roles: Project Administration, Resources, Software, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Project Administration, Resources, Software, Writing – Original Draft Preparation, Writing – Review & Editing
Sarah A Lawton
Roles: Methodology, Project Administration, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Methodology, Project Administration, Writing – Original Draft Preparation, Writing – Review & Editing
June Brammar
Roles: Conceptualization, Funding Acquisition, Methodology, Resources, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Conceptualization, Funding Acquisition, Methodology, Resources, Writing – Original Draft Preparation, Writing – Review & Editing
Thomas Burnett
Roles: Conceptualization, Formal Analysis, Investigation, Methodology, Resources, Validation, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Conceptualization, Formal Analysis, Investigation, Methodology, Resources, Validation, Writing – Original Draft Preparation, Writing – Review & Editing
Chris Drake
Roles: Investigation, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Investigation, Writing – Original Draft Preparation, Writing – Review & Editing
Nadine E Foster
Roles: Conceptualization, Funding Acquisition, Methodology, Supervision, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Conceptualization, Funding Acquisition, Methodology, Supervision, Writing – Original Draft Preparation, Writing – Review & Editing
Gordon J Hendry
Roles: Conceptualization, Funding Acquisition, Methodology, Project Administration, Resources, Supervision, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Conceptualization, Funding Acquisition, Methodology, Project Administration, Resources, Supervision, Writing – Original Draft Preparation, Writing – Review & Editing
Melaine A Holden
Roles: Conceptualization, Funding Acquisition, Methodology, Project Administration, Resources, Supervision, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Conceptualization, Funding Acquisition, Methodology, Project Administration, Resources, Supervision, Writing – Original Draft Preparation, Writing – Review & Editing
Thomas Jaki
Roles: Conceptualization, Formal Analysis, Funding Acquisition, Investigation, Methodology, Resources, Supervision, Validation, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Conceptualization, Formal Analysis, Funding Acquisition, Investigation, Methodology, Resources, Supervision, Validation, Writing – Original Draft Preparation, Writing – Review & Editing
Royes Joseph
Roles: Data Curation, Formal Analysis, Investigation, Methodology, Project Administration, Resources, Validation, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Data Curation, Formal Analysis, Investigation, Methodology, Project Administration, Resources, Validation, Writing – Original Draft Preparation, Writing – Review & Editing
Anne-Maree Keenan
Roles: Conceptualization, Funding Acquisition, Methodology, Supervision, Visualization, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Conceptualization, Funding Acquisition, Methodology, Supervision, Visualization, Writing – Original Draft Preparation, Writing – Review & Editing
Jesse Kigozi
Roles: Conceptualization, Formal Analysis, Funding Acquisition, Methodology, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Conceptualization, Formal Analysis, Funding Acquisition, Methodology, Writing – Original Draft Preparation, Writing – Review & Editing
Martyn Lewis
Roles: Conceptualization, Data Curation, Formal Analysis, Funding Acquisition, Investigation, Methodology, Project Administration, Resources, Supervision, Validation, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Conceptualization, Data Curation, Formal Analysis, Funding Acquisition, Investigation, Methodology, Project Administration, Resources, Supervision, Validation, Writing – Original Draft Preparation, Writing – Review & Editing
Christian D Mallen
Roles: Conceptualization, Funding Acquisition, Methodology, Supervision, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Conceptualization, Funding Acquisition, Methodology, Supervision, Writing – Original Draft Preparation, Writing – Review & Editing
Hylton B Menz
Roles: Conceptualization, Funding Acquisition, Methodology, Resources, Supervision, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Conceptualization, Funding Acquisition, Methodology, Resources, Supervision, Writing – Original Draft Preparation, Writing – Review & Editing
Pavel Mozgunov
Roles: Conceptualization, Formal Analysis, Funding Acquisition, Investigation, Methodology, Resources, Validation, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Conceptualization, Formal Analysis, Funding Acquisition, Investigation, Methodology, Resources, Validation, Writing – Original Draft Preparation, Writing – Review & Editing
Edward Roddy
Roles: Conceptualization, Funding Acquisition, Methodology, Project Administration, Resources, Supervision, Visualization, Writing – Original Draft Preparation, Writing – Review & Editing
Roles: Conceptualization, Funding Acquisition, Methodology, Project Administration, Resources, Supervision, Visualization, Writing – Original Draft Preparation, Writing – Review & Editing
OPEN PEER REVIEW
REVIEWER STATUS
Plantar heel pain (PHP) is the most common soft tissue foot condition and impairs mobility, physical function, ability to work, and quality of life. Systematic reviews highlight a need for high-quality randomised controlled trials (RCTs) of exercises and orthoses for PHP.
To determine the clinical and cost-effectiveness of individualised exercises and/or prefabricated foot orthoses plus self-management advice (SMA) compared to SMA alone in adults with PHP.
A multi-centre four-arm two-stage adaptive parallel-group RCT with internal pilot. Up to 696 participants aged ≥18 years with PHP will be identified from general practice, physiotherapy/podiatry referrals and self-referral, and randomised 1:1:1:1 to: (1) SMA (control), (2) SMA plus individualised exercises, (3) SMA plus prefabricated foot orthoses, or (4) SMA plus individualised exercises and prefabricated foot orthoses. Outcomes will be collected by SMS text-message (weekly during weeks 1–12, monthly during months 4–12) and questionnaires at 12 weeks and 6 and 12 months. The primary outcome is change in PHP intensity (0–10 numeric rating scale) between baseline and the average over 6–12 weeks. Interim analysis when 348 participants have completed the primary outcome assessment will inform adaptation, where interventions may be dropped or the trial stopped early (for efficacy or futility). The main between-group comparison for the primary outcome will be undertaken using linear mixed modelling. Secondary outcomes will examine i) short-term pain trajectories over weeks 1–12, ii) pain at 6 and 12 months, and monthly from 3–12 months, iii) first step pain, physical function, global rating of change, pain self-efficacy, illness perceptions, ability to work, and treatment satisfaction at 12 weeks, 6 and 12 months, iv) cost-effectiveness. Patient and public partner involvement is embedded throughout.
The TREADON multi-arm multi-stage RCT will provide new evidence on the clinical and cost-effectiveness of individualised exercises and prefabricated foot orthoses for people with PHP.
ISRCTN 12418153. Registration date 06 December 2022 https://doi.org/10.1186/ISRCTN12418153
To show whether exercises and/or foot orthoses (shoe insoles) provide more pain relief for adults with plantar heel pain than a self-management advice booklet alone, and whether this is good value for money for the NHS.
Pain under the heel (plantar heel pain, PHP) affects 1 in 10 adults. It makes walking and everyday tasks, including work, difficult. Most people who consult general practice are given pain medication and advice, yet symptoms often continue. In our pilot and feasibility trial, exercises and foot orthoses showed promise for improving pain and function, but a larger trial is needed to confirm this.
In this randomised controlled trial, up to 696 adults with PHP will be given a self-management advice booklet and allocated by chance to one of four treatments: exercises, foot orthoses, combined exercises and foot orthoses, or no additional treatment. Participants will be sent weekly text-messages or receive brief phone calls, to collect pain scores for up to 12 weeks and then monthly from 3-12 months, plus questionnaires at 3, 6 and 12 months. Half-way through the trial, only treatments that are reducing pain will continue to be offered and the trial will stop early if one treatment is clearly better.
Patient representatives will support the trial and helped write this summary. Five people with PHP took part in a workshop to help with trial design. For example, they helped decide how often pain should be measured. We will involve people with PHP to assist with our recruitment strategy and help us interpret the findings, develop easily understandable messages and publicise them widely.
We will present findings at healthcare conferences, in medical journals, on relevant websites, through social media, and general practice, physiotherapy and podiatry networks. The results will be provided to participants.
Plantar heel pain, self-management, exercise, orthoses, randomised controlled trial, adaptive design
Corresponding Author(s)
Martin J Thomas (
[email protected])
Grant information: This project is funded by the National Institute for Health and Care Research (NIHR) under its Health Technology Assessment Programme (NIHR131638).
The views expressed in this manuscript are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. NEF is funded through an Australian National Health and Medical Research Council (NHMRC) Investigator Grant (ID: 2018182). TJ and PM received funding from the UK Medical Research Council (MC_UU 00002/14, MC UU 00002/19 and MC UU 00040/03). PM is also funded by the NIHR (Advanced Fellowship, NIHR300576). CDM is funded by the NIHR Applied Research Collaboration West Midlands and the NIHR School for Primary Care Research. The funder and trial sponsor had no role in the trial design, data collection and analysis plans, manuscript preparation or decision to submit for publication.
The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Copyright: © 2025 Thomas MJ et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. How to cite: Thomas MJ, Hughes G, Cooke K et al. Clinical and cost-effectiveness of individualised exercises and foot orthoses in the treatment of plantar heel pain: protocol for the TREADON randomised multi-arm multi-stage adaptive trial [version 1; peer review: 2 approved, 2 approved with reservations]. NIHR Open Res 2025, 5:42 (https://doi.org/10.3310/nihropenres.13930.1) First published: 06 May 2025, 5:42 (https://doi.org/10.3310/nihropenres.13930.1) Latest published: 24 Feb 2026, 5:42 (https://doi.org/10.3310/nihropenres.13930.2) The views expressed in this manuscript are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. NEF is funded through an Australian National Health and Medical Research Council (NHMRC) Investigator Grant (ID: 2018182). TJ and PM received funding from the UK Medical Research Council (MC_UU 00002/14, MC UU 00002/19 and MC UU 00040/03). PM is also funded by the NIHR (Advanced Fellowship, NIHR300576). CDM is funded by the NIHR Applied Research Collaboration West Midlands and the NIHR School for Primary Care Research. The funder and trial sponsor had no role in the trial design, data collection and analysis plans, manuscript preparation or decision to submit for publication.
The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
There is a newer version
of this article available.
of this article available.
Plantar heel pain (PHP) is a term describing several undifferentiated painful conditions affecting the plantar heel. It is now preferred to the label “plantar fasciitis”, which was used commonly in the past1. It is the most prevalent soft tissue foot complaint, affecting 10% of adults, and impairs mobility, foot and physical function, and ability to work, impacting negatively on quality of life2–4. Clinical features include pain under the heel, made worse by weight-bearing, particularly after prolonged rest. Its specific cause is uncertain, although established risk factors include obesity; pronated foot posture; reduced ankle or first metatarsophalangeal joint range of motion; prolonged weight-bearing; and tightness in the gastrocnemius and soleus muscles, plantar fascia, and Achilles tendon2,5. Weakness of the gastrocnemius, soleus, and intrinsic foot muscles has also been implicated6.
PHP is commonly stated to be a benign, self-limiting condition that, for most people, resolves within one year7. However, symptoms can become chronic and persistent: in some studies almost half report persistent symptoms after ten years, leading to impaired quality of life, physical inactivity and weight gain4,8. A National Institute for Health and Care Excellence (NICE) Clinical Knowledge Summary recommends initial treatment with analgesia and advice regarding rest, footwear, heel pads, weight loss and stretching exercises7. Referral to a podiatrist or physiotherapist is advised if mild symptoms persist beyond a few months despite conservative treatment or if symptoms are severe. In the Netherlands and Australia, the most frequent strategies employed by General Practitioners (GPs) to manage PHP are referral to a podiatrist (12–20%), watchful waiting (18–32%), non-steroidal anti-inflammatory drugs (NSAIDs) (20–23%), and advice to wear insoles (16%)9,10. Qualitative studies show that the expectations and needs of people with PHP are often unmet11.
Healthcare professionals commonly use foot orthoses and/or lower limb exercises to treat patients with PHP12. Foot orthoses are insole devices designed to optimise foot loading distribution and adjust medial longitudinal arch function through control of specific foot motion13. They reduce rearfoot pronation in a dose-dependent manner, addressing planus foot posture (flat feet) and excessive foot pronation (eversion) associated with PHP, and increase foot-to-surface contact area, lowering plantar heel pressures and tensile stresses at the calcaneal-plantar fascia junction during loading to provide symptomatic relief from PHP13–17. Exercises, including stretching the Achilles tendon and plantar fascia and strengthening of the intrinsic muscles of the foot and lower limb muscles (e.g. hamstrings, quadriceps and triceps surae), aim to improve movement and restore normal foot loading18–20. Tightness and weakness in the plantar fascia, Achilles tendon and foot muscles are therefore viable therapeutic targets for individualised exercises in the treatment of PHP. However, orthoses and exercises are infrequently used in general practice to treat this common and disabling condition despite many people having persistent problems9,11.
The evidence-base to inform clinical decisions about treatments is limited and often of poor quality21–23. Many published randomised controlled trials (RCTs) are limited by small sample sizes, short-term follow-up and poor methodological quality, and there is a need for larger trials incorporating longer follow-up, more robust methods, and higher reporting standards21–23. Two systematic reviews of foot orthoses compared with sham orthoses for PHP published in 2018 reached different conclusions despite pooling data from the same three trials: one found moderate-quality evidence that foot orthoses are effective at reducing pain in the medium term (7–12 weeks) but had no effect in the short term or on function21, whereas the other found that foot orthoses were ineffective22. This difference has been attributed to the reviews extracting outcome data for different measures of foot pain24. Our previous network meta-analysis found that exercises alone did not reduce pain or improve function in patients with PHP in the short or medium term, but improved function at 12 months compared with placebo/sham interventions, based on only two small RCTs (<50 participants each)23. No treatments commonly used for the management of PHP (including orthoses and exercises) were significantly better than any other for pain and function. Placebo/sham interventions and NSAIDs were the least effective, suggesting that current recommendations for first-line management of PHP with analgesics, NSAIDs and watchful waiting may be suboptimal. We found only one RCT which examined the effectiveness of combining orthoses and exercises25. Prefabricated orthoses plus stretching exercises were more effective than stretching exercises alone although the trial was small (42–51 participants per arm), follow-up was short (8 weeks) and risk of bias was high.
Subsequently, one small RCT (n=95) reported greater improvement in pain with usual podiatry care plus physical therapy than with usual podiatry care alone at one year, but there was no difference in physical function26. A larger RCT (n=185) concluded that referral to a podiatrist for custom-made insoles does not lead to better outcomes compared with usual GP care27. However, usual GP care within the trial was more intensive than in routine practice with 41% of participants receiving biomechanical interventions such as heel cups and 15% corticosteroid injection27,28. Other recent small-to-moderate sized trials have investigated foot orthoses versus corticosteroid injection (n=103)29, exercise versus corticosteroid injection plus exercise (n=180)30, insoles versus sham insoles adapted for flip-flop sandals (n=80)31, and radial extracorporeal shock wave therapy versus sham radial extracorporeal shock wave therapy versus exercise versus advice plus customised foot orthoses (n=200)32.
There is currently no evidence of cost-effectiveness of exercise programmes for PHP, and evidence for orthoses is limited to one study which showed that prefabricated orthoses were similarly effective to customised orthoses but significantly less expensive33. Informed by our successful feasibility and pilot trial, which reported no serious adverse events34, the TReatments of Exercise AnD Orthotics for plaNtar heel pain (TREADON) trial will investigate the clinical and cost-effectiveness of individualised exercises and/or pre-fabricated foot orthoses plus self-management advice (SMA) compared with SMA alone for adults with PHP in primary care over the medium and long term. Such a trial is needed to support clinical decision-making and inform National Health Service (NHS) policy and commissioning pathways for this patient group who experience considerable pain and functional limitation but are often overlooked in terms of treatment options that are available but only accessed by a few9,10.
The full current version of the protocol (Version 3.1, 07 October 2024, at the time of submission) can be viewed on the funder website: https://fundingawards.nihr.ac.uk/award/NIHR131638. Details of previous protocol versions and amendments are presented in Table 1.
The overall aim of the trial is to compare the additional benefit of individualised exercises and/or prefabricated foot orthoses versus a SMA booklet alone to treat adults with PHP in primary care.
Primary objective/research question
In adults with PHP, does a SMA booklet combined with individualised exercises and/or prefabricated foot orthoses lead to greater improvement in pain in the medium term (average pain over 6–12 weeks of follow-up) than a SMA booklet alone?
Secondary objectives
To compare, in adults with PHP:
• The effect of a SMA booklet combined with individualised exercises and/or prefabricated foot orthoses with a SMA booklet alone on;
1. short-term pain trajectories over weeks 1 to 12, including individual weekly comparisons,
2. pain at 6 and 12 months, and monthly from 3 months to month 12,
3. first step pain, physical function, patient global rating of change, pain self-efficacy, illness perceptions, ability to work, and treatment satisfaction at 12 weeks, 6 and 12 months.
• The cost-effectiveness of a SMA booklet combined with individualised exercises and/or prefabricated foot orthoses with a SMA booklet alone.
Outcome measures/endpoints
Informed by the TREADON pilot and feasibility trial, the primary outcome is a pain intensity change score using a 0–10 numeric rating scale (NRS). The end points are defined as:
• Primary end point at 6–12 weeks for clinical effectiveness and at 12 months for cost-effectiveness analysis.
Primary endpoint/outcome
The primary outcome for clinical effectiveness is change in PHP intensity (0–10 NRS) between baseline and the average rating over weeks 6 to 12, collected by weekly Short Message Service (SMS) text-message or brief phone call between weeks 1–12.
Secondary endpoints/outcomes
Secondary outcomes will comprise PHP intensity score (0–10 NRS), first step pain (0–10 NRS), Foot Function Index35, (pain, disability, activity restriction subscales, and overall), patient global rating of change, pain self-efficacy questionnaire36, brief illness perceptions questionnaire37, quality of life (EuroQol 5-Dimension 5-level instrument (EQ5D-5L))38 work loss and presenteeism39, self-reported healthcare use for PHP (NHS and private), self-reported treatment adherence, treatment credibility, satisfaction with care, and adverse events.
Adverse events: Trial-related adverse events (for example skin irritation from orthoses, muscle soreness from exercise) will be captured through case report forms (CRF) completed by TREADON physiotherapists/podiatrists, and direct contact between the Keele Clinical Trials Unit (CTU) and the participant, their TREADON physiotherapist/podiatrist, GP or site Principal Investigator (PI). Participants randomised to the clinician-supported intervention arms will record adverse events in a weekly diary for the 12-week intervention period.
Trial safety reporting procedures will ensure any unexpected serious adverse events which are deemed related to the trial will be reported to the Research Ethics Committee and Sponsor.
All Serious Adverse Events either confirmed or suspected to be related to the trial procedures will be reviewed by the independent Data Monitoring Committee (DMC) and reported to the Trial Steering Committee (TSC). The TSC reports directly to the funder.
Estimand
The primary estimand of interest (corresponding to a treatment policy strategy, as suggested in the International Conference of Harmonisation E9 (R1) addendum on estimands and sensitivity analysis in clinical trials)40 is the mean difference in the change in PHP intensity (0-10 NRS) between the baseline and the average rating over weeks 6 to 12, in eligible and randomised adults with PHP intended to be treated with individualised exercises and/or prefabricated foot orthoses in addition to a SMA booklet compared with SMA booklet alone, regardless of treatment adherence, initiation of other treatment, adverse events, intervention fidelity, or other protocol deviations such as treatment switching and subsequent ineligibility (Estimand 1). Thus, a treatment policy approach (the data will be collected and analysed regardless of whether the intercurrent event occurs) is applied for the intercurrent events (intercurrent events occur after randomisation and affect the interpretation of the trial outcome).
In addition to the primary estimand, an alternative estimand (Estimand 2) targeting a different clinical question of interest — treatment effect in the absence of treatment non-compliance and other protocol violations — will be explored in a supplementary analysis where the treatment non-compliance and other protocol violations will be treated under a hypothetical strategy (any data collected after the intercurrent event, which is affected by the intercurrent event, will be treated as missing).
Full details of Estimands 1 and 2 will be provided in the TREADON trial's Data Analysis Plan.
Trial registration: ISRCTN 12418153. Registration date 06 December 2022 https://doi.org/10.1186/ISRCTN12418153
Patient representatives were involved in our pilot and feasibility trial, informing development of the trial interventions, and will support every stage of the main trial. Our lay co-investigator (JB) helped write the Plain English Summary and is a member of the Trial Management Group. Five people with PHP took part in a workshop to help design the main trial. They recommended inclusion of Participant Identification Method 5 (self-referral from the community), helped us decide how often pain should be measured, and advised on how to optimise adherence to exercise. We will also involve people with PHP to assist with our recruitment strategy and help us to interpret the trial findings, develop easily understandable messages to explain the findings and publicise the findings widely. Two people with PHP will sit on the TSC.
Ethical approval was obtained from West of Scotland Research Ethics Service (reference number: 22/WS/0165) on 22 November 2022. Those who wish to take part in the trial will be asked to sign and date the consent form included in their baseline pack and return to the research team either in electronic-consent online format or in the pre-paid envelope provided to those who opt for paper-based involvement.
Multi-centre, randomised, parallel group, four-arm two-stage adaptive trial, with 6-month internal pilot.
Interventions
The duration of intervention regardless of group allocation will be 12 weeks. Participants will be asked not to use other types of treatments, other than medication that their GP has provided (where relevant), during the intervention period if possible; however, any additional healthcare and self-care use will be recorded in the 12-week follow-up questionnaire, 6-month follow-up questionnaire and 12-month follow-up questionnaire.
SMA booklet (control arm)
Participants randomised to receive SMA only will be mailed a SMA booklet, based on the Versus Arthritis leaflets on plantar fasciitis41 and foot and ankle pain42, supplemented with specific advice and information including a small number of stretching exercises and self-help messages about pain relief, footwear, rest and weight loss, consistent with best practice guidance43. The booklet describes five stretching exercises for the plantar fascia and Achilles tendon to be performed twice per day41, without instructions for individualisation, progression or supervision of exercises (see extended data).
SMA booklet plus individualised exercises (SMA-exercises)
Participants randomised to SMA-exercises will be given the SMA booklet at the initial treatment appointment. The treating physiotherapist or podiatrist will assess foot posture and function to determine the exercise type and dose. At the discretion of the clinician, a more generic lower limb assessment of alignment and function can also be undertaken, enabling strengthening and stretching for hip abductors, quadriceps and hamstrings to be prescribed if deemed to be important as part of the overall PHP treatment. Exercise selection will be informed by the level of clinically-observed muscle tightness, weakness and functional limitation (see Figure 1). Exercise dose will be individualised and progressed, based on assessment findings and informed by current exercise guidelines44. The exercises are drawn from best available evidence5,18–20,45,46 and discussion with clinicians during workshops prior to our pilot and feasibility trial. Exercises include foot-specific stretches/exercises targeting the plantar fascia, intrinsic foot muscles, Achilles tendon, key ankle-related muscle groups such as soleus and gastrocnemius, and other muscle groups in the lower limb identified as targets within the assessment. Participants will be taught how to perform and progress these exercises and given an individualised and detailed exercise sheet (online or paper) describing the regimen and showing photographs of the exercises. The exercise sheets provided will be trial-specific exercises selected by the clinician and comprising photographs and written instruction completed by the clinician (see extended data). Participants will be offered up to 6 treatment sessions (1 initial and up to 5 follow ups) over 12 weeks at the discretion of the treating clinician (face-to-face appointments prioritised if possible, or virtual, telephone, if required).
Exercise programme modification will be based on a subjective and/or objective re-assessment and include either:
1. progression of prescribed exercises if tolerated with minimal pain and discomfort,
2. maintenance if tolerated but some moderate pain and discomfort, or
3. reduction in frequency, duration, intensity or modification of exercise type if not tolerated or adhered to.
The exercise programme will be supervised during each treatment appointment and may be progressed at subsequent treatment appointments according to observed changes in presentation, modelled on successful exercise interventions in our earlier trials47,48. A record of the exercise prescription will be recorded on the Intervention Details CRF for each treatment appointment. Adherence will be encouraged by provision of written individualised exercise sheets (online or paper) and use of a paper-based diary to discuss with the clinician during subsequent treatment appointments. The diary will be collected at 12 weeks.
SMA booklet plus prefabricated foot orthoses (SMA-orthoses)
Participants randomised to SMA-orthoses will be given the SMA booklet at the initial treatment appointment. The treating physiotherapist or podiatrist will assess foot posture using the Foot Posture Index-6 (FPI-6)49 and select the appropriate orthotic device according to the degree of static rearfoot eversion and body weight (see Figure 2 for the foot orthoses and body weight algorithm). These data will be recorded on the CRF by the treating clinician at each appointment. If deemed clinically relevant to PHP, this can include assessment of hip position (anteversion/retroversion) and knee position (genu varus/valgus).
Protocol for prescription of prefabricated foot orthoses
The assessment protocol for the prescription of foot orthoses includes two key components to guide the physiotherapist/podiatrist towards the most appropriate foot orthosis prescription.
1. A main driver in influencing the rearfoot posting component of the foot orthosis prescription will be the rearfoot posture component of the FPI-649. This will be assessed by the physiotherapist/podiatrist when the participant is in a relaxed stance position. The physiotherapist/podiatrist will observe whether the calcaneus is inverted, vertical, everted, or highly everted (see Figure 2).
2. Assessment of body weight will also influence the selection of the appropriate orthotic device (greater body weight resulting in selection of a device with a higher material density).
3. Each foot orthotic device will be fitted according to the size of the participant’s foot using the orthotic device shells of various sizes.
4. Clinicians will select the appropriate first choice device with appropriate rearfoot medial posting dose (see Figure 2) in place and assess the participant for correct size of orthotic device (weight-bearing and non-weight-bearing fit-to-foot).
5. Clinicians will then check the fit of the orthotic device to the shoe (fit-to-shoe).
6. Tolerance will be evaluated by asking the participant if they are happy with the comfort and fit of their orthotic device (tolerance). If the participant is not happy with comfort or fit, the clinician may choose to taper the shell density and/or the dose of rearfoot posting.
7. Foot orthoses should be prescribed for both feet according to the intervention protocol, which is driven by participants' foot posture and bodyweight, regardless of whether the heel pain presentation is unilateral or bilateral.
Foot orthoses choice
In the development of our pilot and feasibility trial34, our patient and clinician advisory group identified desirable characteristics of an orthotic intervention protocol including:
1. an element of patient choice between different devices based on comfort and fit
2. scope for device adjustment/tailoring by the clinician to provide the desirable level of rearfoot posture/functional control for individual symptoms.
As a result, we developed a pragmatic foot orthosis intervention algorithm, which includes the following devices:
Vectorthotic® (firm density shell), (with CE marking; Healthy Step; Ashton-under-Lyme, UK)
Salfordinsole™ Firm (medium to firm density shell), (with CE marking; Salfordinsole Health Care Ltd; Nuneaton, UK)
Salfordinsole Flex (low-medium density shell).
These devices are prefabricated and modifiable with the use of ‘click-in’ or adhesive additions (medial rearfoot posts) which can be used to change the level of pronatory control, as well as patient comfort and therefore potentially influence adherence. A range of shell material densities allows for a more supportive orthotic for participants with a higher bodyweight50. At present, there is little evidence to suggest that one brand/type of foot orthoses is more effective than another for the management of PHP21,51. Participants will be instructed how to fit the device and advised to wear it for one hour per day, gradually increasing by one hour per day up to at least four hours per day, and given a detailed orthosis information sheet. Participants will be offered up to 6 treatment sessions (1 initial and up to 5 follow ups) over 12 weeks at the discretion of the treating clinician (face-to-face appointments prioritised if possible, or virtual, telephone, if required). The orthosis can be altered during subsequent consultations according to participants’ self-reported tolerance or clinical presentation. Adherence will be encouraged by a diary to capture use and facilitate discussion with the clinician. The diary will be collected at week 12. The foot orthosis may be changed or altered during subsequent clinical treatment appointments according to participants’ self-report of tolerance or clinical presentation.
Foot orthoses details