Jason Mitchell Wilken

Background: The use of ankle-foot orthoses (AFOs) is a mainstay in the treatment of cavovarus deformity associated with Charcot-Marie-Tooth (CMT) disease, but their ability to reduce cavovarus deformity is poorly characterized. Similarly, associations between AFO design features and degree of deformity reduction are unknown. Weightbearing CT has been used to describe CMT disease–related cavovarus deformity through both two-dimensional (2D) radiographic measures and three-dimensional statistical shape modeling (SSM). However, neither method has been used to evaluate differences in foot posture between standing barefoot and wearing AFOs, nor to examine relationships between AFO footplate design and foot morphology. Questions/purposes: (1) Do 2D radiographic measurements demonstrate a reduction in cavovarus position between standing barefoot and standing with AFOs? (2) Does SSM demonstrate a reduction in cavovarus position between standing barefoot and standing with AFOs? (3) Is there an association between AFO footplate design and degree of reduction in cavovarus position between standing barefoot and standing with AFOs? Methods: This prospective study consisted of adults diagnosed with CMT disease who presented to clinic while wearing bilateral AFOs between December 2023 and April 2025. Individuals with prior surgical correction, comorbid neurologic disorders, or unbraceable rigid foot were excluded. This yielded 20 individuals (10 females, 10 males; mean ± SD age 49 ± 17 years). Bilateral weightbearing CT scans were collected with the patient standing barefoot and while wearing AFOs and shoes. 2D radiographic measures (in °) that have been previously reported in CMT disease, consisting of hindfoot alignment angle, talar tilt angle, axial and sagittal talocalcaneal angle, tibiocalcaneal angle, axial and sagittal Meary angle, calcaneal inclination angle, calcaneal-first metatarsal angle, and first-second intermetatarsal angle, were automatically calculated using mathematical axis definitions. Differences between conditions were analyzed with generalized linear mixed-effect models, and differences > 20% of the normal range were considered clinically meaningful. An SSM of the foot was generated and analyzed with principal component analysis to describe population variation through a series of linear modes. Each mode describes a single spectrum, such as low to high arch or planovalgus to cavovarus foot, and accounts for a portion of population variance. The position of each sample along a mode is given by the shape score, and differences in shape scores between groups were analyzed with generalized linear mixed-effect models. Mean percent differences between limbs > 25% were considered meaningful. Participants used self-selected AFOs, and these were categorized into three classes of foot plate design: flat, custom, and flat with a custom orthotic between the footplate and the foot. Differences in demographics and baseline morphology between the three footplate groups were analyzed. Results: 2D radiographic measurements demonstrated a mean 3.8° increase in sagittal Meary angle and mean 3.3° decrease in calcaneal-first metatarsal angle in the AFO scans relative to barefoot, representing a more cavovarus foot in the AFO condition (p < 0.001). SSM analysis demonstrated a mean 27% increase in overall cavovarus position, mean 54% increase in plantarflexion, and mean 42% increase in midfoot elevation in the AFO, relative to the barefoot condition (p < 0.001). Custom footplate AFOs showed smaller changes in calcaneal-first metatarsal angle and shape score than the flat footplate or flat footplate with orthotic AFOs (p = 0.04). Conclusion: Both methods of analysis demonstrated an increase in the cavovarus position of the foot while wearing AFOs. This supports the ability of weightbearing CT to be used in analysis of deformity reduction in an AFO. Subanalysis by footplate type suggested that customized footplates had a lesser deformity-exacerbating impact on foot posture than orthotics or flat footplates. Clinical Relevance: Demonstrated functional benefits of AFO use in CMT disease may be attributed more to stabilization than deformity correction. Weightbearing CT analysis can demonstrate differences in foot posture within a limb with use of an AFO and may be a beneficial tool in future analysis of the effect of AFO design on foot structure.

Barefoot plantar pressure assessment commonly involves discrete regional sampling from maximum pressure distributions measured over the stance phase of gait. This approach fails to capture spatiotemporal variation in plantar pressures across a spectrum of foot morphologies. Here we introduce a framework for systematically evaluating spatiotemporal plantar pressure distributions. Plantar pressures measured over stance are linearly interpolated into 5%-time instance pressure distributions. The foot progression angle is determined using the maximum pressure distribution and used to rotate each interpolated 5%-time instance pressure distribution. A bounding region capturing the entiret maximum pressure distribution is used to scale each 5% distribution to a standardized 50 x 18 grid using a force preserving approach. Reliability was assessed in individuals with structurally altered (n=10) and healthy (n=10) feet. Intraclass Correlation Coefficients (ICCs) were calculated for foot progression angle, minimum detectable change (MDC) for maximum pressure at each grid location, and a linear mixed effects model with Bland-Altman plots for mean pressures between original and aligned intervals. All ICC values were greater than 0.85 with an MDC of 9.05 ± 10.79 kPa across the entire grid. The linear mixed effect model and Bland-Altman plots demonstrated a significant systematic framework bias of 9.91 ± 2.05 kPa (p<0.001) and 8.58 ± 1.88 kPa (p<0.001) for healthy and structurally altered feet, independent of stance interval, foot size, or foot progression angle. These data suggest the framework can be used to reliably assess plantar pressures across varied foot morphologies, enabling robust comparison of spatial pressure distributions during gait.

Background: Achilles tendinopathy (AT) is a common condition that limits activity participation in both active and sedentary populations. While exercise and education are well-established treatments for AT, information is lacking on the amount of intervention required and the prognostic factors associated with response to noninvasive treatments. Objective: This noninferiority randomized controlled trial will determine the efficacy of a single-visit, physical therapist (PT)–initiated rehabilitation program compared to a multivisit, PT-guided telehealth rehabilitation program for AT and will identify early prognostic factors for individuals who experience the greatest improvement in pain and disability by 4 weeks. Methods: In this single-blind, 2-arm, parallel-group trial, 160 individuals with AT will be randomized to either a single-visit PT-initiated rehabilitation program or a multivisit, PT-guided telehealth rehabilitation program. Primary outcomes will be the numeric rating scale for movement pain and the Victorian Institute of Sport Assessment–Achilles score for disability. Secondary outcomes will include measures of tendon health, measures within the psychosocial health domain, and military readiness. Results: This research was funded in July 2024. Participant enrollment began in August 2025 and is expected to conclude in 2028. As of January 2026, 15 participants have been enrolled at the University of Iowa Hospitals and Clinics, meeting the recruitment goals. Conclusions: The PACE (Progressive Achilles Loading via Clinician e-Support) trial will identify a rehabilitation program focused on education and exercise for AT that expands access to care and will identify factors that predict responses to exercise and education.

Limb trauma can result in decreased mobility, compensatory gait patterns, and pain. Carbon fiber custom dynamic orthoses (CDOs) include a cuff below the knee, posterior strut, and semi-rigid footplate. Custom dynamic orthoses alter foot loading within the footplate, but the effects of cuff design are not well understood. The purpose of this study was to determine the effect of cuff design on foot loading. Five individuals without, and 1 individual with, lower limb injury completed testing without a CDO and with a CDO with 3 different cuff designs. Loadsol insoles (Novel Electronics, St Paul, MN) were placed under the foot in the shoe or in the CDO footplate to measure peak forces and force impulse of the total foot, hindfoot, midfoot, and forefoot. No significant differences were observed with post-hoc paired sample t tests ( p > 0.05). Compared to walking without an orthosis, peak forces decreased in the CDO (11%–16% hindfoot, 20%–36% midfoot, 21%–29% forefoot). Effect sizes were medium to large when comparing with and without a CDO ( d = 0.56–1.97) and small to large when comparing between cuffs ( d = 0.24–2.99). Hindfoot force impulse increased with all cuffs (14%–29%), with medium effect sizes ( d = 0.51–0.78). The patellar tendon bearing cuff with ratcheting closure mechanism generally resulted in the greatest changes in peak forces and force impulse. Study data demonstrate the potential importance of cuff design on foot loading. The largest effects were generally observed with use of a patellar tendon bearing design with ratcheting closure mechanism.

BACKGROUND Achilles tendinopathy is a widespread condition that limits activity participation in active and sedentary populations. While exercise and education are well established treatments for Achilles tendinopathy, information is lacking on the amount of intervention required and prognostic factors for responders to non-invasive treatments. OBJECTIVE This non-inferiority, randomized controlled trial will determine the efficacy of a single-visit, physical therapist initiated rehabilitation program compared to a multi-visit, physical therapist guided rehabilitation program for Achilles tendinopathy, and identify early prognostic factors for individuals who experience the greatest improvement in pain and disability by four weeks. METHODS In this single-blind, two-arm, parallel-group, trial, 160 individuals with Achilles tendinopathy will be randomized to a single visit physical therapist-initiated rehabilitation program or to a multi-visit, physical therapist-guided telehealth rehabilitation program. Primary outcomes will be the numeric rating scale for movement pain and the Victorian Institute of Sport Assessment- Achilles for disability. Secondary outcomes will include measures of tendon health, psychosocial health domain measures, and military participation. RESULTS This research was funded in July 2024. Participant enrollment began August 2025 and is expected to conclude in 2028. As of January 2025, 15 participants have been enrolled at UIHC, meeting recruitment goals. CONCLUSIONS The PACE trial will identify a rehabilitation program focused on education and exercise for Achilles tendinopathy that expands access to care and will identify factors that predict responses to exercise and education. CLINICALTRIAL ClinicalTrials.gov NCT06736795; https://clinicaltrials.gov/study/NCT06736795 and OSF Registries osf.io/sgj47; https://osf.io/sgj47

Background: Ankle-foot orthoses (AFO) design, including geometry and material selection, is tailored to meet specific clinical objectives. Understanding AFO mechanical behavior may provide insight into the effect of design considerations on the functional benefits to AFO users. Mechanical characteristics of AFOs are primarily assessed using strain gauges or computational modeling, both of which have limitations. Objectives: Determine the test-retest reliability of weight-bearing carbon fiber dynamic AFO (CDO) surface strain measurements obtained using digital image correlation (DIC). Study design: Prospective, randomized, cross-sectional reliability study. Methods: CDO displacement and surface strain were measured at three strut locations using DIC while 30 participants deflected the CDO into dorsiflexion at three time points. Test-retest reliability of strain measurements was assessed by intraclass correlation coefficient (ICC), minimum detectable change (MDC), and percentage MDC values. Results: Minimum detectable change and ICC values were between 0.005%‒0.010% and 0.14‒0.76, respectively. Intraclass correlation coefficient were generally higher at more distal strut locations and larger ankle dorsiflexion angles, with a mean ICC across locations of 0.55. Proximal strain was 31%‒59% lower than strain in middle and distal regions, respectively. Lower absolute strain values in the proximal location resulted in higher average relative measurement error (12.2%) compared to the distal and middle locations (4.4% and 6.5%, respectively). Conclusions: Three-dimensional digital image correlation can provide reliable estimates of CDO surface strain, supporting its use for evaluating orthosis mechanical behavior. Better understanding of in vivo strain behavior across the CDO surface may assist with future device design and prescription to improve functional outcomes.

Background: Many individuals with Charcot-Marie-Tooth disease (CMT) use ankle foot orthoses (AFOs) to address balance and functional deficits. Objectives: This study was conducted to further understand how individuals with CMT perceive the effects of AFO use on function. Study design: Cross-sectional online survey. Methods: Individuals with CMT provided free text responses to 3 questions: (Q1) What would you change about your orthosis if you could? (Q2) What activities does your ankle foot orthosis improve? (Q3) What activities does your ankle foot orthosis limit? Two independent reviewers evaluated responses and used an inductive approach to identify primary themes. Percent agreement between reviewers was calculated for each primary theme. Results: A total of 310 individuals participated, and 5 primary themes were identified for each question. Q1 primary themes included ease of use or functionality, compatibility with shoes, durability, appearance, and comfort or fit. Q2 primary themes included walking, standing, balance and stability, physical health, and activities of daily life. Q3 primary themes were related to shoes or clothing, balance or inclines, mobility, long-term use, and general activities. Average percent agreement between reviewers was 63% (17%). Conclusions: Study results align with previously reported data collected using patient-reported outcome surveys. In addition, participants highlighted concerns that are not usually addressed in orthosis-related questionnaires. These data emphasize areas of improvement for orthotic treatment relevant to individuals with CMT and which may help guide future research aiming to improve functional outcomes and compliance with orthotic interventions.