Foot Orthoses in the Treatment of Painful Hallux Valgus

Condition(s) studied

Investigational drug(s) / intervention(s)

Sham Foot orthoses: Participants will receive bilateral 3D-printed sham foot orthoses manufactured from low-stiffness FilaForm material. The sham orthoses will have an appearance similar to the customized orthoses but will provide negligible mechanical support, thereby maintaining participant blinding.

Podiatric Education: All participants will receive the same evidence-based information and clinical guidance at the start of the trial, and will follow a 5-day familiarization protocol with progressive foot orthoses wear time, starting at 1 hour per day and increasing by 1 hour daily up to 5 hours per day. Following familiarization, participants will be instructed to wear their assigned FOs during all standing activities, targeting a minimum of 5 hours per day, for the 12-week intervention period.

Exercise: Participants will perform at home, unsupervised, the short foot exercise, the hallux flexion exercise and the big toe pull exercise. Exercises will be required to be performed at least four times per week for 12 weeks. As a motivational strategy, participants will be informed that these exercises target muscles known to be weakened in individuals with hallux valgus. They will be instructed to progressively increase the resistance of the rubber band as needed during the 12-week duration of the trial to ensure that the exercises are difficult to complete, without causing pain. Participants will have access to videos and handouts describing the exercises.

Prefabricated foot orthoses: Participants randomized in this group will receive PowerStep Pinnacle Maxx Support prefabricated FOs for both feet. The top cover will be made of a polyester fabric. The structural arch support will consist of a polypropylene shell incorporating a 2° medial post. A dual-layer system composed of a black foam top layer and a black ethylene-vinyl acetate (EVA) base layer will also be included

Customized foot orthoses: Participants randomized in this group will receive custom foot orthoses for both feet. Custom foot orthoses will be 3D printed (Fuse 1+30W, Formlabs, USA) in PA-11 (2.6 mm if the participants' weight (PW) is inferior or equal to 45 kg; 3.2 mm if 45\<PW\<100 kg; 4.0 mm if PW\>100 kg) with a rearfoot post, a full-length 2 mm EVA top cover over a 3 mm Poron top cover. A kinetic wedge in the Poron top cover (isolation under the 1st metatarsophalangeal joint) will also be added.

Study summary

This randomized pilot feasibility trial will evaluate the feasibility of conducting a full-scale randomized controlled trial comparing custom-made, prefabricated, and sham foot orthoses in people with painful hallux valgus. All participants will also receive a standardized program of foot exercises and education. Thirty-six participants will be randomized to one of the three intervention groups and assessed at baseline, 6 weeks, and 12 weeks. The primary outcomes will assess the feasibility of recruitment, retention, treatment adherence, intervention credibility and expectancy, and use of cointerventions. Secondary outcomes will assess foot pain and function, perceived clinical improvement, and health-related quality of life. The findings will inform the design and conduct of a future full-scale randomized controlled trial.

Eligibility

Primary outcome measure(s)

• Recruitment rate — Baseline
  The number of participants recruited per month.
• Conversion rate — Baseline
  The proportion of individuals providing consent to participate from those who met the selection criteria.
• Foot orthoses average wear time — From baseline to end of treatment at 12 weeks
  Average number of hours the FOs are worn per day.
• Adherence to the exercise program — From allocation to end of treatment at 12 weeks
  The average number of days the exercise program was performed weekly.
• Adverse events — From allocation to end of treatment at 12 weeks
  Participants will be asked to report adverse events they encounter, body location and severity. Adverse events will be classified as unrelated, probably related or definitely related to their participation in the trial.
• Credibility and Expectancy of the Intervention questionnaire — Baseline
  The Credibility and Expectancy of the Intervention questionnaire (CEQ) is a widely used, valid, and reliable self-administered questionnaire designed to assess participants' perceptions of the credibility of an intervention and their expectations regarding its potential effectiveness (23). It consists of 6 items divided into two domains: treatment credibility (3 items) and expectancy of improvement (3 items). The credibility subscale evaluates how logical and convincing participants perceive the intervention to be, while the expectancy subscale assesses the degree to which participants believe the intervention will improve their condition. Scores from both subscales will be analyzed to evaluate participants' perceptions of the intervention.

Trial sites (1)

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