Background Chronic metatarsalgia (CM) causes significant pain and disability, affecting quality of life. Foot orthoses (FOs) including medially wedged designs with a metatarsal pad decrease excessive plantar pressure under the metatarsal heads, which is a suggested risk factor for developing CM. This FOs model may be effective in diminishing pain and improving function in these individuals. Thus, the objective of this trial will be to compare the effects of medially wedged FOs with a metatarsal pad and sham FOs on pain and foot function in individuals with CM. Methods/design This participant- and assessor-blinded superiority randomized controlled trial (RCT) with two parallel groups will be conducted in Trois-Rivières, Canada. Sixty-four participants with CM will be recruited from the Université du Québec à Trois-Rivières outpatient podiatry clinic and via social media invitations. They will be randomized into intervention (customized FOs) or control (sham FOs) groups and will be evaluated at baseline and after 6 and 12 weeks. The primary outcome will be: (1) mean pain during walking for the most painful foot during the past week. The secondary outcomes will be: (1) Foot Function Index, (2) Global rating of change and (3) the 5-level EQ-5D. Discussion Medially wedged FOs with a metatarsal pad are expected to provide a greater reduction in pain and improvement in foot function compared to sham FOs. This trial will help guide FOs prescription recommendations for managing foot pain in individuals with CM in the future.
Foot musculoskeletal disorders cause significant impairments and disabilities for those affected. Among the various types of foot pain, chronic metatarsalgia (CM) is the most prevalent. Metatarsalgia represents 88% of all causes of foot pain, with a prevalence of 13 to 36% in adults. It is characterized by persistent pain to one or more metatarsophalangeal joints, resulting from harm (whether of mechanical origin or not) to the anatomical structures associated with the joint, including bone, cartilage, capsule and ligaments, tendons, bursae and subcutaneous tissue, and skin. Chronic metatarsalgia significantly reduces the quality of life of those affected, physically, psychologically, and socially. Different treatment modalities are used for CM, such as stretching exercises, footwear modifications, and foot orthoses (FOs). The first-line treatment is conservative, and surgery should be considered only when conservative treatment fails. Nevertheless, there is little high-level evidence (level I) to support the efficacy of conservative treatments for CM. The reduction of the mechanical overload under the metatarsal heads during locomotion is a fundamental aspect of CM treatment, and it strongly correlates with pain reduction. Foot orthoses are commonly used devices to reduce pain and improve function in individuals with musculoskeletal disorders. They reduce forefoot plantar pressure during locomotion in individuals with CM and redistribute plantar pressure more evenly. Metatarsal pads, a common FOs modification, effectively redistribute forefoot plantar pressure and thus reduce pain caused by excessive metatarsal loads. Adding a medial wedge to FOs (inclination in the frontal plane) further reduces forefoot peak pressure in healthy adults. While FOs tested so far are generally effective in managing CM, their effects can be inconsistent across patients, some patients did not find them effective. From a biomechanical standpoint, FOs reduce mechanical overload; however, it is crucial to determine whether they also effectively reduce pain and improve foot function. Randomized controlled trials (RCT) are considered the gold standard for evaluating treatment effectiveness and efficiently translating research findings into clinical practice. This study design will allow us to assess whether, in addition to their biomechanical effects, FOs provide clinical benefits for individuals with CM. All details are here : https://doi.org/10.1371/journal.pone.0340905
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
DOUBLE
Enrollment
64
A podiatrist with 11 years of clinical experience will take the negative foot impressions using a semi-weightbearing method with a foam box for both groups to ensure adequate blinding of participants. Then, the foam boxes of the experimental group will be scanned so that the FOs can be 3D printed. Both groups will receive identical clinical guideline-based information and support at the beginning of the trial. The instructions will be as follows: (1) undertake a familiarization protocol of 14 consecutive full days (2) wear the FOs (customized or sham) at all time when they are standing (targeted minimum of 5 hours per day), (3) avoid positions that cause the metatarsophalangeal joints to dorsiflex (e.g., squatting or tiptoeing), (4) mechanical stress load management according to the tissue stress model, (5) do not walk barefoot and (6) wear shoes with good cushioning in which the FOs will be properly placed.
The customized foot orthoses will be manufactured with a Nylon-11 shell with 6° medially wedged forefoot-rearfoot posts (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), a full-length 3 mm Poron top cover and a metatarsal pad (15 shore A) located 5 mm proximal to the metatarsal heads.
The molded sham FOs will be manufactured from 3 mm ethylene vinyl acetate. They will have an identical top cover material, color and a similar shape than the customized FOs, however, they will provide negligible mechanical support, considering the very low stiffness of their medial arch. The only impact of these FOs on plantar pressure is under the heel. These devices have been used as a sham condition in previous trials and a study has validated them as being credible.
Université du Québec à Trois-Rivières
Trois-Rivières, Quebec, Canada
RECRUITINGMean pain during walking for the most painful foot during the past week
visual analog scale (from 0 to 10, 0 being no pain and 10 pain as bad as it could be).
Time frame: From Baseline to the end of follow-up at 12 weeks
Foot Function Index (FFI)
The FFI is a widely used, valid, and reliable self-administered questionnaire consisting of 23 items grouped into 3 domains: foot pain (9 items), disability (9 items), and activity limitation (5 items) : we used disability (min: 0, max: 90) and activity limitation (min: 0, max: 50) subscales.
Time frame: From Baseline to the end of follow-up at 12 weeks
Global rating of change (GROC)
participants' perception of overall treatment effect will be measured using the self-reported global rating of change scale \[33\]. This outcome will then be dichotomized into the categories of "effective" ("a very great deal better", "a great deal better", "a good deal better" and "moderately better") and "ineffective" ("somewhat better", "a little better", "about the same, hardly any better at all", "no change", "about the same, hardly any worse at all", "a little worse", "somewhat worse", "moderately worse", "a good deal worse", "a great deal worse" and 'a very great deal worse")
Time frame: During the follow-up: 6weeks and 12 weeks
Health-related quality of life (HRQoL)
the 5-level EQ-5D (EQ-5D-5L) will be used \[35\]. The descriptive system comprises five dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Each dimension has 5 levels: no problems, slight problems, moderate problems, severe problems and extreme problems. The participant will be asked to indicate his/her health state by ticking the box next to the most appropriate statement in each of the five dimensions. This decision results in a 1-digit number that expresses the level selected for that dimension. The digits for the five dimensions can be combined into a 5-digit number that describes the patient's health state.
Time frame: From Baseline to the end of follow-up at 12 weeks
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.