Mechanism of orthotic therapy for the painful cavus foot deformity

The Role of Footwear, Foot Orthosis, and Training-Related Strategies in the Prevention of Bone Stress Injuries: A Systematic Review and Meta-Analysis

Objective

To evaluate the effectiveness of footwear, foot orthoses and training-related strategies to prevent lower extremity bone stress injury (BSI).

Design

Systematic review and meta-analysis.

Data sources

Four bibliographic databases (from inception until November 2021): Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and CINAHL.

Eligibility criteria

Randomised controlled trials (RCTs) that assessed the risk of developing a BSI when using particular footwear, foot orthoses or training-related strategies such as muscle strengthening, stretching, and mechanical loading exercises.

Results

Eleven studies were included in this systematic review. When wearing foot orthoses, the risk ratio of developing a BSI on any lower extremity bone is 0.47 (95% CI 0.26 to 0.87; p = 0.02). When doing pre-exercise dynamic stretching, the risk ratio of suffering a tibial BSI is 1.06 (95% CI 0.67 to 1.68; p = 0.79). No meta-analyses could be performed for footwear or training-related strategies. The quality of evidence for all these results is low considering the high risk of bias in each study, the low number of studies and the low number of cases in each study.

Conclusion

This systematic review reveals the lack of high-quality studies in BSI prevention. Based on studies at high risk of bias, foot orthoses could potentially help prevent BSIs in the military setting. It is still unknown whether footwear and training-related strategies have any benefits. It is crucial to further investigate potential BSI prevention strategies in women and athletes. Research is also needed to assess the influence of running shoes and loading management on BSI incidence.

A Reconfigurable and Adjustable Compliance System for the Measurement of Interface Orthotic Properties

Custom foot orthoses (CFOs) have shown treatment effectiveness by providing improved pressure/load redistribution, skeletal support and comfort level. However, the current design methodologies of CFOs have some problems: (1) the plantar surface is captured without considering the soft tissue impedance, (2) the stiffness of the CFOs is limited to rigid, semi-rigid and soft, which ignores the potential effect of local variation of stiffness on the interface pressure/load distribution and subjective evaluations, and (3) the lack of a human-in-the-loop may lead to multiple design-to-deliver iterations. A new prescription methodology of CFOs is required to satisfy the pressure/load distribution, improve comfort level and decrease iterations.

METHOD

A measurement system which provides INterface with Tunable Ergonomic properties using a Reconfigurable Framework with Adjustable Compliant Elements (INTERFACE system) is developed to implement the Rapid Evaluate and Adjust Device (READ) methodology. The geometry and stiffness of the Medial Longitudinal Arch (MLA) support provided by the INTERFACE system can be adjusted via linear actuators and tunable stiffness mechanisms, based on objective interface pressure/load distribution and subjective feedback evaluations. Validation tests were conducted on 13 subjects to measure the plantar pressure/load distribution and record the subjective feedback in different combinations of geometry and stiffness.

RESULTS

The interface pressure/load distribution and subjective feedback of the support level indicate the efficacy of the adjustable geometry and stiffness. As the stiffness and geometrical height increased, the plantar loadings increased in the MLA region and decreased in the rear foot. Geometrical fitting can be achieved with the reconfigurable MLA support. The integration of locally adjustable stiffness makes it possible to fine tune the plantar pressure/load and provides the subjects with options of orthotic stiffness.

CONCLUSION

The proposed INTERFACE system can be applied to conduct the measurement of the desired orthotic properties which satisfy the interface pressure/load requirement and the subject's comfort.

Dynamic plantar pressure patterns in children and adolescents with Charcot-Marie-Tooth disease

BACKGROUND

The dynamic plantar pressure patterns of children and adolescents with Charcot-Marie-Tooth (CMT) disease and its relationship to musculoskeletal alterations may help to understand the natural history of the disease and improve therapeutic interventions.

RESEARCH QUESTION

The study compared dynamic plantar pressure patterns in children and adolescents with and without CMT. It also tested the associations between isometric muscle strength (IMS), passive range of motion (ROM), foot posture and dynamic plantar pressure patterns in CMT.

METHODS

This cross-sectional study compared children and adolescents (aged 8-18 years) with CMT (n = 40) with a typical group (n = 40). The plantar pressure distribution during gait was recorded, and the contact area (CA), peak pressure (PP), contact time (CT) and pressure-time integral (PTI) in five foot regions (rearfoot, midfoot lateral, midfoot medial, lateral forefoot and medial forefoot) were analysed. The IMS of the dorsiflexors and plantar flexors, passive ROM, and foot posture were also recorded.

RESULTS

PP (medial midfoot and medial forefoot) and PTI (rearfoot, lateral midfoot and medial forefoot) were higher in children with CMT compared with the typical group. The adolescents with CMT presented a less CA (whole foot) and a higher CT (medial midfoot) when compared with typical group. For CMT, in the medial midfoot, plantar flexor IMS associated with PP (β=-11.54, p = 0.01) and PTI (β=-3.38, p = 0.04); supinated foot posture associated with PP (β = 33.89, p = 0.03) and PTI (β = 12.01, p = 0.03).

SIGNIFICANCE

Children with CMT showed clear changes in most of the dynamic plantar pressure variables, while adolescents with CMT showed changes mostly in CA and CT. This information together with the associations established between supinated foot, dorsiflexion ROM and plantar flexions IMS can be useful for guiding rehabilitation professionals in their therapies.

Biomechanical effects of foot orthoses with and without a lateral bar in individuals with cavus feet during comfortable and fast walking

Background/purpose

The biomechanical effects of foot orthoses (FOs) with and without a lateral bar compared to a control condition during walking at different speeds are still unknown. The objective of this study was to compare the biomechanical effects of functional FOs with and without a lateral bar to a control condition during comfortable walking in individuals with cavus feet and determine if their effects change at a fast speed.

Methods

Fifteen individuals with cavus feet (age: 25.3 ± 5.8 yrs) walked under two experimental conditions (FOs with and without a lateral bar) and a control condition (shoes only) at comfortable (CW) and fast (FW) speeds. The outcome measures were ankle and knee angles and gluteus medius, vastus lateralis, gastrocnemius lateralis, gastrocnemius medialis, peroneus longus and tibialis anterior electromyography (EMG) amplitudes during the stance phase of walking and were compared between the FOs and a control condition using one-dimensional statistical parametric mapping.

Results

During CW, both FOs decreased ankle dorsiflexion and increased knee extension angles compared to no FOs. FOs with a lateral bar also decreased peroneus longus EMG amplitudes. During FW, FOs with and without a lateral bar decreased ankle dorsiflexion angles compared to no FOs.

Conclusion

Both types of FOs had different effects on the biomechanics of the lower limb compared to a control condition. The decreased peroneus longus EMG amplitudes during CW in individuals with cavus feet could have important clinical implications in other populations, such as individuals with painful cavus feet. The orthoses only affected the ankle dorsiflexion angles at a fast speed and no EMG amplitude or knee kinematics effects were observed. Further studies assessing the ankle kinematics and kinetics effects of these orthoses are needed to improve our understanding of their mechanism of action and inform future efficacy trials.

Feasibility Study of a Rapid Evaluate and Adjust Device (READ) for Custom Foot Orthoses Prescription

OBJECTIVE

Custom foot orthoses (CFOs) are typically used for the prevention and cure of lower extremity injuries (LEIs). Typically, CFOs are designed and prescribed based on iterative loops including: (1) follow-up loops between the patient and the physician, and (2) design feedback loops between the physician and the fabricator. The current prescription methodology has some deficiencies, i.e. excessive time to satisfactory treatment, and low repeatability in custom fabrication because of missing alignment, soft tissue considerations, and subjective feedback. There are significant opportunities to develop a new CFOs prescription procedure which can improve accuracy prior to the fabrication process by reducing time through minimizing iterations.

METHODS

First, a novel "rapid evaluate and adjust device" (READ) prescription methodology is proposed for CFO design by combining the follow-up loops with design feedback loop. To support the idea of the READ prescription method a novel 3D ergonomic measurement system (3DEMS) is developed. The 3DEMS is designed for the following key targets to: (1) improve the communication between the patient/physician and the fabricator, (2) reduce time to satisfactory treatment, (3) improve repeatability by considering the alignment and the soft tissue deformations, (4) archive digitally with minimal data, (5) reduce the system complexity, and (6) validate with plantar pressure measurements (i.e. Novel Pedar^®). The design process of the 3DEMS involved the following steps: (1) 3D data collection at the desired loading, (2) nested optimization to determine optimal segment design, and (3) system fabrication considering alignment and feedback control.

RESULTS

The results show that the READ prescription method with 3DEMS can be used to recreate the medial longitudinal arch for a range of arch height indices (AHI) by using a minimal number of parameters i.e. 6 parameters, and significant increases in mean peak pressure are observed between optimized and barefoot or flat segments.

CONCLUSION

This study establishes that the proposed READ prescription method with the 3DEMS may be used for CFOs prescription due to better communication between individuals in the follow-up and design loops, less time for satisfactory treatment, improved repeatability, archivable data, and low system complexity.

SIGNIFICANCE

The developed system may be used as measurement systems for CFOs, and in the future the proposed 3DEMS may prove highly important for the measurement of CFOs for flat feet.

Soft tissue release combined with joint-sparing osteotomy for treatment of cavovarus foot deformity in older children: Analysis of 21 cases

BACKGROUND

Cavovarus foot is a common form of foot deformity in children, which is clinically characterized by an abnormal increase of the longitudinal arch of the foot, and it can be simultaneously complicated with forefoot pronation and varus, rearfoot varus, Achilles tendon contracture, or cock-up toe deformity. Muscle force imbalance is the primary cause of such deformity. Many diseases can lead to muscle force imbalance, such as tethered cord syndrome, cerebral palsy, Charcot-Marie-Tooth disease, and trauma. At present, many surgical treatments are available for cavovarus foot. For older children, priority should be given to midfoot osteotomy and fusion. Since complications such as abnormal foot length, foot stiffness, and abnormal gait tend to develop postoperatively, it is important to preserve the joints and correct the deformity as much as possible. Adequate soft tissue release and muscle balance are the keys to correcting the deformity and avoiding its postoperative recurrence.

AIM

To assess the efficacy of soft tissue release combined with joint-sparing osteotomy in the treatment of cavovarus foot deformity in older children.

METHODS

The clinical data of 21 older children with cavovarus foot deformity (28 feet) who were treated surgically at the Ninth Department of Orthopedics of Jizhong Energy Xingtai Mining Group General Hospital from November 2014 to July 2017 were retrospectively analyzed. The patients ranged in age from 10 to 14 years old, with an average age of 12.46 ± 1.20 years. Their main clinical manifestations were deformity, pain, and gait abnormality. The patients underwent magnetic resonance imaging of the lumbar spine, electromyographic examination, weight-bearing anteroposterior and lateral X-rays of the feet, and the Coleman block test. Surgical procedures including metatarsal fascia release, Achilles tendon or medial gastrocnemius lengthening, "V"-shaped osteotomy on the dorsal side of the metatarsal base, opening medial cuneiform wedge osteotomy, closing cuboid osteotomy, anterior transfer of the posterior tibial tendon, peroneus longus-to-brevis transfer, and calcaneal sliding osteotomy to correct hindfoot varus deformity were performed. After surgery, long leg plaster casts were applied, the plaster casts were removed 6 wk later, Kirschner wires were removed, and functional exercise was initiated. The patients began weight-bearing walk 3 mo after surgery. Therapeutic effects were evaluated using the Wicart grading system, and Meary’s angles and Hibbs’ angles were measured based on X-ray images obtained preoperatively and at last follow-up to assess their changes.

RESULTS

The patients were followed for 6 to 32 mo, with an average follow-up period of 17.68 ± 6.290 mo. Bone healing at the osteotomy site was achieved at 3 mo in all cases. According to the Wicart grading system, very good results were achieved in 18 feet, good in 7, and fair in 3, with a very good/good rate of 89.3%. At last follow-up, mean Meary’s angle was 6.36° ± 1.810°, and mean Hibbs’ angle was 160.21° ± 4.167°, both of which were significantly improved compared with preoperative values (24.11° ± 2.948° and 135.86° ± 5.345°, respectively; P < 0.001 for both). No complications such as infection, skin necrosis, or bone nonunion occurred.

CONCLUSION

Soft tissue release combined with joint-sparing osteotomy has appreciated efficacy in the treatment of cavovarus foot deformity in older children.

Hard, soft and off-the-shelf foot orthoses and their effect on the angle of the medial longitudinal arch: A biplane fluoroscopy study

BACKGROUND

Foot orthoses have proven to be effective for conservative management of various pathologies. Pathologies of the lower limb can be caused by abnormal biomechanics such as irregular foot structure and alignment, leading to inadequate support.

OBJECTIVES

To compare biomechanical effects of different foot orthoses on the medial longitudinal arch during dynamic gait using skeletal kinematics.

STUDY DESIGN

This study follows a prospective, cross-sectional study design.

METHODS

The medial longitudinal arch angle was measured for 12 participants among three groups: pes planus, pes cavus and normal arch. Five conditions were compared: three orthotic devices (hard custom foot orthosis, soft custom foot orthosis and off-the-shelf Barefoot Science©), barefoot and shod. An innovative method, markerless fluoroscopic radiostereometric analysis, was used to measure the medial longitudinal arch angle.

RESULTS

Mean medial longitudinal arch angles for both custom foot orthosis conditions were significantly different from the barefoot and shod conditions ( p < 0.05). There was no significant difference between the off-the-shelf device and the barefoot or shod conditions ( p > 0.05). In addition, the differences between hard and soft custom foot orthoses were not statistically significant. All foot types showed a medial longitudinal arch angle decrease with both the hard and soft custom foot orthoses.

CONCLUSION

These results suggest that custom foot orthoses can reduce motion of the medial longitudinal arch for a range of foot types during dynamic gait.

LEVEL OF EVIDENCE

Therapeutic study, Level 2.

CLINICAL RELEVANCE

Custom foot orthoses support and alter the position of the foot during weightbearing. The goal is to eliminate compensation of the foot for a structural deformity or malalignment and redistribute abnormal plantar pressures. By optimizing the position of the foot, the medial longitudinal arch (MLA) will also change and quantifying this change is of interest to clinicians.

Balance impairment in pediatric charcot-marie-tooth disease

INTRODUCTION

Balance impairment contributes to gait dysfunction, falls, and reduced quality of life in adults with Charcot-Marie-Tooth disease (CMT) but has been minimally examined in pediatric CMT.

METHODS

The CMT Pediatric Scale (CMTPedS) was administered to 520 children with CMT. Associations between balance function (Bruininks-Oseretsky Test of Motor Proficiency [BOT-2]) and sensorimotor and gait impairments were investigated.

RESULTS

Daily trips/falls were reported by 42.3% of participants. Balance (BOT-2) varied by CMT subtype, was impaired in 42% of 4-year-olds, and declined with age (P < 0.001). Vibration (P < 0.001), pinprick (P < 0.004), ankle dorsiflexion strength (P < 0.001), and foot alignment (P < 0.004) were associated with BOT-2 balance (adjusted R² = 0.28). The visual dependence of balance increased with age.

DISCUSSION

Balance impairment occurs from a young age in children with CMT. Balance intervention studies are required in pediatric CMT and should consider the degree of sensorimotor impairment, foot malalignment, and visual dependence. Muscle Nerve, 2019.

An Optical-Fiber-Based Smart Textile (Smart Socks) to Manage Biomechanical Risk Factors Associated With Diabetic Foot Amputation

OBJECTIVE

This study aimed to validate a smart-textile based on fiber-optics for simultaneous measurement of plantar temperature, pressure, and joint angles in patients with diabetic peripheral neuropathy (DPN).

METHODS

After in-vitro validation in the laboratory, 33 eligible subjects with DPN were recruited (age: 58 ± 8 years, BMI: 31.5 ± 8 kg/m²) for assessing plantar pressure and temperature during habitual gait-speed in a clinical-setting. All participants were asked to walk at their habitual speed while wearing a pair of sensorized socks made from highly flexible fiber optics (SmartSox). An algorithm was designed to estimate temperature, pressure, and toe range of motion from optical wavelength generated from SmartSox. To validate the device, results from thermal stress response (TSR) using thermography and peak pressure measured by computerized pressure insoles (F-Scan) were used as gold standards.

RESULTS

In laboratory and under controlled conditions, the agreements for parameters of interest were excellent ( r > .98, P = .000), and no noticeable cross-talks between measurements of temperature, angle, and pressure were observed. During clinical data acquisition, a significant correlation was found for pressure profile under different anatomical regions of interest between SmartSox and F-Scan ( r = .67, P < .050) as well as between thermography and SmartSox ( r = .55, P < .050).

CONCLUSION

This study demonstrates the validity of an innovative smart textile for assessing simultaneously the key parameters associated with risk of foot ulcers in patients with DPN. It may empower clinicians to objectively stratify foot risk and provide timely care. Another study is warranted to validate its clinical application in preventing limb threating problems in patients with DPN.

A single-blinded, randomized, parallel group superiority trial investigating the effects of footwear and custom foot orthoses versus footwear alone in individuals with patellofemoral joint osteoarthritis: a phase II pilot trial protocol

BACKGROUND

Patellofemoral joint osteoarthritis is a common condition, yet information regarding conservative management is lacking. Foot orthoses are an effective intervention for improving pain and function in younger individuals with patellofemoral pain and may be effective in those with patellofemoral osteoarthritis. This pilot study will seek to establish the feasibility of a phase III randomised controlled trial to investigate whether foot orthoses worn in prescribed motion controlled footwear are superior to prescribed motion control footwear alone in the management of patellofemoral osteoarthritis.

METHODS/DESIGN

This phase II pilot clinical trial is designed as a randomized, single-blind, parallel group, two arm, superiority trial. The trial will recruit 44 participants from Queensland and Tasmania, Australia. Volunteers aged 40 years and over must have clinical symptoms and radiographic evidence of patellofemoral osteoarthritis to be eligible for inclusion. Those eligible will be randomized to receive either foot orthoses and prescribed motion control shoes, or prescribed motion control shoes alone, to be worn for a period of 4 months. The feasibility of a phase III clinical trial will be evaluated by assessing factors such as recruitment rate, number of eligible participants, participant compliance with the study protocol, adverse events, and drop-out rate. A secondary aim of the study will be to determine completion rates and calculate effect sizes for patient reported outcome measures such as knee-related symptoms, function, quality of life, kinesiophobia, self-efficacy, general and mental health, and physical activity at 2 and 4 months. Primary outcomes will be reported descriptively while effect sizes and 95% confidence intervals will be calculated for the secondary outcome measures. Data will be analysed using an intention-to-treat principle.

DISCUSSION

The results of this pilot trial will help determine the feasibility of a phase III clinical trial investigating whether foot orthoses plus motion control footwear are superior to motion control footwear alone in individuals with patellofemoral osteoarthritis. A Phase III clinical trial will help guide footwear and foot orthoses recommendations in the clinical management of this disorder.

TRIAL REGISTRATION

Retrospectively registered with the Australian New Zealand Clinical Trials Registry: ACTRN12615000002583. Date registered: 07/01/15.

Idiopathic pes cavus in adults is not associated with neurophysiological impairment in the lower limbs

The nerve conduction characteristics of adults with idiopathic pes cavus/hammer toes have not been studied extensively. Among 2048 out-patients (59.5 ± 13.9 years) referring to a laboratory of Neurophysiology in Rome, we recruited 18 patients with idiopathic pes cavus (61.3 ± 12.5 years). Fifty-four age/sex-matched controls were also studied. No nerve conduction differences were observed between patients with and without cavus foot (p > 0.05). The absence of deep tendon reflexes and slight muscle weakness and hypotrophy in the lower limbs were more common in subjects with cavus foot deformity than in controls (p < 0.001). Adult patients with idiopathic pes cavus/hammer toes do not differ from healthy controls from a neurophysiological standpoint, but they could show minor signs of clinical impairment, such as lower limb weakness, hypotrophy and areflexia.

Dynamic plantar loading index detects altered foot function in individuals with rheumatoid arthritis but not changes due to orthotic use

BACKGROUND

Altered foot function is common in individuals with rheumatoid arthritis. Plantar pressure distributions during gait are regularly assessed in this patient group; however, the association between frequently reported magnitude-based pressure variables and clinical outcomes has not been clearly established. Recently, a novel approach to the analysis of plantar pressure distributions throughout stance phase, the dynamic plantar loading index, has been proposed. This study aimed to assess the utility of this index for measuring foot function in individuals with rheumatoid arthritis.

METHODS

Barefoot plantar pressures during gait were measured in 63 patients with rheumatoid arthritis and 51 matched controls. Additionally, 15 individuals with rheumatoid arthritis had in-shoe plantar pressures measured whilst walking in standardized footwear for two conditions: shoes-only; and shoes with prescribed custom foot orthoses. The dynamic plantar loading index was determined for all participants and conditions. Patient and control groups were compared for significant differences as were the shod and orthosis conditions.

FINDINGS

The patient group was found to have a mean index of 0.19, significantly lower than the control group's index of 0.32 (p>0.001, 95% CI [0.054, 0.197]). No significant differences were found between the shoe-only and shoe plus orthosis conditions. The loading index was found to correlate with clinical measures of structural deformity.

INTERPRETATION

The dynamic plantar loading index may be a useful tool for researchers and clinicians looking to objectively assess dynamic foot function in patients with rheumatoid arthritis; however, it may be unresponsive to changes caused by orthotic interventions in this patient group.