Progressive Collapsing Foot Deformity
Conditions
Keywords
Foot orthoses, Gait biomechanics, Conservative treatment, Foot Function, Randomized Controlled Trial
Brief summary
Background Progressive collapsing foot deformity (PCFD) is a painful musculoskeletal disorder leading to a progressively developing flat foot, which affects mobility and function and negatively impairs quality of life. Foot orthoses (FOs) are often prescribed to attenuate pain and improve function in patients with PCFD. However, no study has yet investigated the impact of adding FOs, whether custom (CFOs) or prefabricated (PFOs), to the usual treatment for PCFD. Thus, the primary objective of this trial will be to compare three different non-surgical interventions combining foot exercises and education with either CFOs, PFOs or sham FOs (SFOs). Methods/Design This participant-blinded multicentric superiority randomized controlled trial with three parallel groups will be conducted at the Université du Québec à Trois Rivières (UQTR) and the Center for Interdisciplinary Research in Rehabilitation and Social Integration (Cirris) in Canada. One hundred and ninety-eight participants with PCFD will be recruited via referral from physiotherapy and podiatry clinics and targeted advertising on social media. Participants will be randomized to receive CFOs, PFOs or SFOs. All groups will also receive a foot and ankle exercises program and education about their condition. They will be evaluated at four time points: baseline, 12 weeks, 24 weeks and 52 weeks. The primary outcome will be the subcategories of pain from the Foot Function Index (FFI) questionnaire. The secondary outcomes will be: foot pain and limitations (other categories of FFI, mean and maximal pain during walking for the most painful foot during the past week), self-assessed clinical progress (Global Rating Of Change), health-related quality of life (5-Level EQ-5D), gait biomechanics, fear avoidance (Fear avoidance Scale), supination resistance and ankle and hip endurance and force. Discussion This trial first aims to determine whether FOs treatment is effective, and second, whether one of the three FO interventions is more effective than the others. This trial will help guide FOs prescription recommendations for managing foot pain, function, and biomechanical outcomes in individuals with PCFD in the future.
Detailed description
Progressive collapsing foot deformity (PCFD) was historically described under the terminology posterior tibial tendon dysfunction (PTTD), later expanded through the adult acquired flatfoot deformity (AAFD) framework, before being reclassified in 2020 as PCFD to better reflect its progressive, multiplanar nature. Beyond pain, PCFD carries substantial functional and social consequences: patients report marked difficulty with activities such as climbing stairs, walking fast, or running, along with challenges finding comfortable or fashionable footwear, all of which negatively affect quality of life. These functional limitations are caused by specific gait alterations, including increased forefoot abduction, greater hindfoot eversion and internal rotation, reduced ankle inversion and dorsiflexion, and a medial shift in plantar pressure during walking. Foot orthoses (FOs) are thought to counteract these alterations: a systematic review found that most studies report improvements in kinetics, and kinematics following FO use. These biomechanical effects have supported the widespread clinical use of FOs as part of first-line conservative management for PCFD. However, whether these biomechanical improvements translate into a clinical benefit specifically attributable to FOs remains unclear. In all prior RCTs reporting pain and functional improvements with FOs in this population, orthoses were provided as part of a broader multimodal program that also included education and exercise therapy, meaning the additional contribution of FOs alone has never been isolated. Furthermore, no RCT has directly compared custom CFOs and PFOs in individuals with PCFD. A recent retrospective cohort analysis reported meaningful pain reduction and functional improvement with CFOs, but the absence of a control group limits the extent to which this improvement can be attributed to the orthotic intervention itself rather than to natural symptom evolution. By comparing CFOs, PFOs, and SFOs against a common background of standardized education and exercise, this randomized controlled trial design will allow us to determine whether, beyond their known biomechanical effects, FOs provide an additional clinical benefit for individuals with PCFD, and whether this benefit differs according to orthosis design.
Interventions
Individually customized bilateral 3D-printed foot orthoses will be designed from each participant's foot morphology and manufactured at UQTR using a Nylon-11 shell, with shell thickness individualized according to body mass and sex. Orthoses will incorporate a rearfoot-forefoot post (neutral, 3°, or 6° medial inclination, determined by supination resistance) and a medial heel skive (0 or 6 mm, determined by subtalar joint axis position) to provide individualized mechanical support. Participants will wear the orthoses during weight-bearing activities for 24 weeks.
OTHERExercise
Participants will complete a progressive home-based strengthening program targeting the tibialis posterior, tibialis anterior, and triceps surae muscles. The program will consist of six progressive levels prescribed by a podiatrist according to the participant's baseline clinical presentation. Exercise sessions will last approximately 30 minutes and will be performed at least four times per week for 12 weeks. Progression to the next level will occur after successful completion of four sets of 20 repetitions at the current level.
OTHERPodiatric Education
All participants will receive the same evidence-based information and clinical guidance at the start of the trial, and will follow a 7-day familiarization protocol with progressive FO 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 24-week intervention period. FO-wearing instructions, the exercise program, and study information will be available at any time on the study website : "projetpied.com".
OTHERSham 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. Participants will wear the orthoses during weight-bearing activities for 24 weeks.
A pair of commercially available PFOs (Powerstep Pinnacle Maxx support, United States of America), in the proper size, will be provided to each participant. 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 (Figure 2). An additional 1 mm black vinyl surface layer will be manually added to the PFOs to keep participants blinded to the condition they are allocated to.
Sponsors
Université du Québec à Trois-Rivières
Canadian Institutes of Health Research (CIHR)
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
* Present with PCFD according to Myerson et al. (M. S. Myerson et al., 2020) classification * Report medial ankle or foot pain lasting six weeks or more with a pain score of ≥ 3 out of 10 on a Visual Analogue Scale (VAS) and pain to the posterior tibial tendon * Are aged 18 to 70 years, * Can walk without assistive devices (e.g., cane, walker), * Are willing to wear shoes that accommodate their FOs daily, * Are willing to minimize the use of other interventions (e.g., pain medications, physical therapy) during the trial period. * Obtain a positive result on the single and/or double heel rise test (important pain during the test or inability to perform the test).
Exclusion criteria
* Are classified as having Stage II rigid deformities according to Myerson classification, * Have a history of musculoskeletal surgery to the foot and ankle, * Present cognitive impairment, * Are currently pregnant or breastfeeding, * Have worn FOs within the past year.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Foot pain | From baseline to the end of follow-up at 52 weeks | Foot Function Index pain subscale (FFI) , compose of 9 items, scored from 0 to 100, 0 being no pain and 100 representing maximum pain and dysfunction |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Mean and maximal pain during walking for the most painful foot during the past week | From baseline to the end of follow-up at 52 weeks | Visual Analog Scale (VAS) (from 0 to 10; 0 being no pain and 10 worst pain imaginable). |
| Disability and activity limitation | From Baseline to the end of follow-up at 52 weeks | The disability and activity limitation subscales of the Foot Function Index, each ranging from 0 to 100, will be used, with higher scores indicating greater disability or activity limitation. |
| Global rating of change (GROC) | From 12 weeks to the end of follow-up at 52 weeks | participants' perception of overall treatment effect will be measured using the self-reported global rating of change scale. 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") |
| Health-related quality of life | From baseline to the end of follow-up at 52 weeks | the 5-level EQ-5D (EQ-5D-5L) will be used. 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. |
| Fear-Avoidance Components Scale (FACS) | From Baseline to the end of follow-up at 52 weeks | The FACS will assess pain-related fear and avoidance. It includes two main dimensions: fear of pain and avoidance of physical activities due to that fear. Each dimension is rated on a scale from 0 to 5 (0 = "strongly disagree", 5 = "strongly agree"). The total score reflects the overall level of fear-avoidance. |
| Muscle strength | At delivery of FOs and at 24 weeks | Hip and foot muscle strength will be measured using a handheld dynamometer. Hip strength, will be assessed in a side-lying position for the hip abductor strength and lying on the stomach for the extension. Ankle plantarflexion and dorsiflexion strength, will be measured. Participants will perform three trials of maximal force, each maintained for 4 to 5 seconds, with 15 seconds of rest between trials. |
| Endurance | At delivery of FOs and at 24 weeks | Isometric hip muscle endurance will be assessed at 10° of abduction and extension, with time to failure recorded. Ankle plantar flexor endurance will be evaluated using the bilateral heel-rise test, in which participants perform as many heel raises as possible at a self-selected rapid pace. |
| Supination resistance test | At delivery of FOs and at 24 weeks | This test will be measured with the Keystone device (Interpod, Australia) using a validated method. The test will be performed 3 consecutive times on each foot. |
| Gait biomechanics | At delivery of FOs and at 24 weeks | Kinematic and kinetic data will be collected using two motion capture systems, an OptiTrack system (Natural Point, Corvallis, OR, USA) at UQTR and a Vicon system (Peak, UK) at Cirris, both operating at a sampling rate of 200 Hz, synchronized with AMTI force plates (Watertown, MA, USA) sampled at 1000 Hz. The modified Oxford Foot Model will be used. Participants will perform five gait trials, with and without FOs. Forefoot-hindfoot and ankle angles and moments will be calculated. |
Countries
Canada
Contacts
CONTACTLéa Tessiot
PRINCIPAL_INVESTIGATORTessiot Léa
Université du Québec à Trois-Rivières
Outcome results
None listed