Plantar Fasciitis
Conditions
Keywords
plantar fasciitis, Plantar heel pain, Custom-made insole, Ethylene-vinyl acetate, Thermoplastic polyurethane, Three-dimensional printing, Pedobarography, Surface electromyography, Gastrocnemius muscle activation
Brief summary
This randomized active-comparator clinical trial compared changes over 12 weeks between customized computer numerical control (CNC)-milled ethylene-vinyl acetate (EVA) and fused deposition modelling (FDM) 3D-printed thermoplastic polyurethane (TPU) insoles with plantar fasciitis. The primary outcome was bilateral gastrocnemius medialis and lateralis muscle activation recorded using surface electromyography during a standardized 10-meter walking task. Secondary outcomes included static plantar loading, pain, foot-related function, and user satisfaction. Because both groups received custom-made insoles as active interventions, the trial was designed to compare the two orthosis types rather than to determine the absolute efficacy of insoles.
Detailed description
Plantar fasciitis is a common cause of plantar heel pain that may limit weight-bearing activities and reduce foot-related function. Custom-made insoles are frequently used in conservative management; however, direct evidence comparing orthoses produced using different materials and manufacturing methods remains limited. This study was designed as an exploratory, parallel-group, randomized active-comparator trial. Forty-one participants with plantar fasciitis were randomly allocated to receive either a custom-made ethylene-vinyl acetate (EVA) insole manufactured using computer numerical control (CNC) milling or a custom-made thermoplastic polyurethane (TPU) insole manufactured using fused deposition modelling (FDM) three-dimensional printing. Participants were assessed at baseline and after 12 weeks of orthosis use. The primary objective was to compare the effects of the two orthosis types on static plantar loading characteristics and gastrocnemius muscle activation. Static plantar loading was evaluated using pedobarography. Surface electromyography was used to record the activity of the bilateral gastrocnemius medialis and lateralis muscles during a standardized 10-metre walking task. Electromyographic measurements were normalized to maximum voluntary contraction recordings obtained during standardized plantar-flexion and dorsiflexion tasks. The 10-metre walk was used as the standardized task during which electromyographic data were collected and was not evaluated as a walking-performance outcome. Secondary assessments included pain intensity, pressure pain threshold, foot-related function and participant satisfaction with the assigned orthosis. Pain intensity was evaluated under different symptom-provoking conditions, including first-step morning pain, pain during palpation and pain associated with prolonged standing. Because both groups received custom-made insole as active interventions and the study did not include a sham, usual-care or untreated control group, the trial was designed to compare the two orthosis types rather than to determine the absolute efficacy of insoles. Accordingly, the findings were intended to describe between-group differences between CNC-milled EVA and FDM 3D-printed TPU insoles over the 12-week follow-up period.
Interventions
DEVICECustom-Made CNC-Milled EVA Insole
A custom-made insole was individually manufactured from ethylene-vinyl acetate (EVA) using computer numerical control (CNC) milling. Participants used the assigned insole for 12 weeks.
DEVICECustom-Made FDM 3D-Printed TPU Insole
A custom-made insole was individually manufactured from thermoplastic polyurethane (TPU) using fused deposition modelling (FDM) three-dimensional printing. Participants used the assigned insole for 12 weeks.
Sponsors
Medipol University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
Participants were randomly assigned in parallel to one of two active intervention groups: a custom-made ethylene-vinyl acetate (EVA) foot orthosis manufactured using computer numerical control (CNC) milling or a custom-made thermoplastic polyurethane (TPU) insole manufactured using fused deposition modelling (FDM) three-dimensional printing. Outcome assessments were scheduled at baseline and at week 12.
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* Aged between 18 and 65 years * Clinical diagnosis of plantar fasciitis by a specialist physician * Clinical indication or prescription for custom-made foot orthoses * Plantar fasciitis symptoms lasting for at least 3 months * Heel pain localized to the plantar-medial calcaneal tubercle * First-step pain in the morning or pain during the first steps after a period of rest * Roles and Maudsley score of 3 or 4 at the baseline assessment * Ability and willingness to provide written informed consent and comply with the study procedures
Exclusion criteria
* Body mass index greater than 30 kg/m² * Presence of a clinically relevant cardiopulmonary, dermatological, neurological or musculoskeletal condition other than plantar fasciitis that could affect walking, plantar loading, pain assessment or participation in the study * History of foot or ankle surgery * Requirement for a walking assistive device during the study assessments * Inability or unwillingness to wear footwear compatible with the assigned foot orthoses * Cognitive or psychiatric condition that could prevent understanding of the study instructions, provision of informed consent or completion of the assessments * Pregnancy
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change From Baseline in Gastrocnemius Muscle Activation During a Standardized 10-Metre Walking Task | Baseline and Week 12 | Surface electromyography was recorded bilaterally from the gastrocnemius medialis and gastrocnemius lateralis muscles during a standardized 10-metre walking task. The processed parameters included maximum EMG envelope amplitude and mean-maximum, minimum-peak and maximum-peak activation values normalized to maximum voluntary contraction (%MVC). MVC recordings were obtained during standardized plantar-flexion and dorsiflexion tasks. Higher %MVC values indicate greater muscle activation relative to MVC. The 10-metre walk was used solely as the standardized task for EMG recording and was not evaluated as a walking-performance outcome. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change From Baseline in Affected Foot Loading Assessed by Static Pedobarography | Baseline and Week 12 | Static pedobarography was performed during quiet standing to quantify plantar load distribution. Rearfoot loading of the affected foot was expressed as a percentage of the total plantar load for that foot, ranging from 0% to 100%, with higher values indicating greater relative rearfoot loading. Affected and unaffected feet were coded before analysis. Because forefoot and rearfoot loading percentages are mathematically complementary, forefoot loading was not treated as a separate independent endpoint. |
| Change From Baseline in Foot-Related Function Assessed by the Foot Function Index | Baseline and Week 12 | Foot-related function was evaluated using the 23-item Foot Function Index, comprising pain, disability and activity-limitation subscales. Subscale and total scores are expressed on a scale from 0 to 100, with higher scores indicating greater pain, disability or activity limitation. |
| Change From Baseline in Pain Intensity Assessed by the Visual Analogue Scale | Baseline and Week 12 | Pain intensity was assessed using a 10-cm Visual Analogue Scale ranging from 0 to 10, where 0 indicates no pain and 10 indicates the worst imaginable pain. First-step morning pain, pain during palpation of the plantar heel and pain associated with prolonged standing were recorded and analyzed as separate pain scores. |
| Change From Baseline in Plantar Heel Pressure Pain Threshold | Baseline and Week 12 | Pressure pain threshold at the plantar heel was measured using a pressure algometer and expressed in kg/cm². Higher values indicate a greater pressure pain threshold and lower pressure sensitivity. |
| Participant Satisfaction With the Assigned Insoles Assessed by Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST-2.0). | Week 12 | Participant satisfaction was assessed at Week 12 using the Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST 2.0). The 12-item instrument comprises eight items evaluating satisfaction with the assistive device and four items evaluating satisfaction with related services. Each item is scored from 1 (not satisfied at all) to 5 (very satisfied). Device, service and total QUEST scores are calculated by averaging the applicable item scores, with higher scores indicating greater satisfaction. Participants also identify the three satisfaction items they consider most important; these responses were summarized descriptively. |
Countries
Turkey (Türkiye)
Outcome results
None listed