Self-management advice, exercise and foot orthoses for plantar heel pain: the TREADON pilot and feasibility randomised trial

Background: Plantar heel pain (PHP) is common and impacts negatively on physical function and quality of life. Initial treatment usually comprises analgesia and self-management advice (SMA), with referral to a physiotherapist or podiatrist recommended only when symptoms persist. Systematic reviews highlight limitations of existing evidence for the effectiveness of exercises and orthoses. The objective of the TREADON pilot and feasibility trial was to inform the design of a future main trial to compare the clinical and cost-effectiveness of self-management advice (SMA), individualised exercises and foot orthoses for PHP. Methods: This was a four-arm randomised feasibility and pilot trial with 12-week follow-up. Adults aged ≥ 18 years with PHP were identified from primary care by general practice consultation, retrospective general practice medical record review or a population survey. Participants were randomised to either (i) SMA, (ii) SMA plus individualised exercises (SMA-exercises), (iii) SMA plus prefabricated foot orthoses (SMA-orthoses) or (iv) SMA plus combined individualised exercises and prefabricated foot orthoses (SMA-combined). Feasibility outcomes were recruitment; retention; intervention adherence, credibility and satisfaction; performance of three potential primary outcome measures (pain numeric rating scale (NRS), Foot Function Index-pain subscale (FFI-pain), Manchester Foot Pain and Disability Index-pain subscale (MFPDI-pain)); and parameters for informing the main trial sample size calculation. Results: Eighty-two participants were recruited. All three identification methods met the target number of participants. Retention at 12 weeks was 67%. All interventions were successfully delivered as per protocol. Adherence (range over 12 weeks 64–100%) and credibility (93%) were highest in the SMA-combined arm. Satisfaction with treatment was higher for the three clinician-supported interventions (SMA 29%, SMA-exercises 72%, SMA-orthoses 71%, SMA-combined 73%). Responsiveness (baseline to 12 weeks) was higher for FFI-pain (standardised response mean 0.96) and pain NRS (1.04) than MFPDI-pain (0.57). Conservative sample size parameter estimates for standard deviation were pain NRS 2.5, FFI-pain 25 and MFPDI-pain 4, and baseline-outcome correlations were 0.5–0.6, 0.4 and < 0.3, respectively. Conclusions: We demonstrated the feasibility of conducting a future main randomised clinical trial comparing the clinical and cost-effectiveness of SMA, exercises and/or foot orthoses for PHP. Trial registration number: ISRCTN 12160508. Prospectively registered 5^th July 2016.