Carbon Fiber-Based Twisted and Coiled Artificial Muscles (TCAMs) for Powered Ankle-Foot Orthoses.

Ankle foot orthoses (AFOs) control the position and motion of the ankle, compensate for weakness, and correct deformities. AFOs can be classified as passive or powered. Powered AFOs overcome the limitations of passive AFOs by adapting their performance to meet a variety of requirements. However, the actuators currently used to power AFOs are typically heavy, bulky, expensive, or limited to laboratory settings. Thus, there is a strong need for lightweight, inexpensive, and flexible actuators for powering AFOs. In this technical brief, carbon fiber/silicone rubber (CF/SR) twisted and coiled artificial muscles (TCAMs) are proposed as novel actuators for powered AFOs. CF/SR TCAMs can lift to 12,600 times their weight with an input power of only 0.025 W cm-1 and are fabricated from inexpensive materials through a low-cost manufacturing process. Additionally, they can provide a specific work of 758 J kg-1 when an input voltage of 1.64 V cm-1 is applied. Mechanical characterization of CF/SR TCAMs in terms of length/tension, tension/velocity, and active-passive length/tension is presented, and results are compared with the performance of skeletal muscles. A gait analysis demonstrates that CF/SR TCAMs can provide the performance required to supplement lower limb musculature and replicate the gait cycle of a healthy subject. Therefore, the preliminary results provided in this brief are a stepping stone for a dynamic AFO powered by CF/SR TCAMs.

Satisfaction with ankle foot orthoses in individuals with Charcot-Marie-Tooth disease.

BACKGROUND: Ankle foot orthoses (AFOs) are commonly prescribed to individuals with Charcot-Marie-Tooth disease (CMT). The aim of this study was to evaluate patient reported satisfaction with orthotic devices and services in individuals with CMT to provide preliminary data for advancing AFO development and improving clinical care. METHODS: The Orthotics and Prosthetics Users Survey was distributed via e-mail through the Inherited Neuropathy Consortium (INC) Contact Registry and includes 11 device-specific questions and 10 service-related questions. Participants were also asked open-ended questions about their experiences with AFOs. RESULTS: Three hundred and fourteen individuals completed the survey. Over one-third of participants provided negative responses, including dislike of AFO appearance, discomfort, abrasions or irritations, and pain. Ratings of orthotic services were generally positive. CONCLUSIONS: Lower scores related to discomfort, abrasions and pain identified areas for AFO improvement. Continued research in these areas will be beneficial to informing and advancing AFO development and improving clinical care.

Muscle Contributions to Balance Control During Amputee and Nonamputee Stair Ascent.

Dynamic balance is controlled by lower-limb muscles and is more difficult to maintain during stair ascent compared to level walking. As a result, individuals with lower-limb amputations often have difficulty ascending stairs and are more susceptible to falls. The purpose of this study was to identify the biomechanical mechanisms used by individuals with and without amputation to control dynamic balance during stair ascent. Three-dimensional muscle-actuated forward dynamics simulations of amputee and nonamputee stair ascent were developed and contributions of individual muscles, the passive prosthesis, and gravity to the time rate of change of angular momentum were determined. The prosthesis replicated the role of nonamputee plantarflexors in the sagittal plane by contributing to forward angular momentum. The prosthesis largely replicated the role of nonamputee plantarflexors in the transverse plane but resulted in a greater change of angular momentum. In the frontal plane, the prosthesis and nonamputee plantarflexors contributed oppositely during the first half of stance while during the second half of stance, the prosthesis contributed to a much smaller extent. This resulted in altered contributions from the intact leg plantarflexors, vastii and hamstrings, and the intact and residual leg hip abductors. Therefore, prosthetic devices with altered contributions to frontal-plane angular momentum could improve balance control during amputee stair ascent and minimize necessary muscle compensations. In addition, targeted training could improve the force production magnitude and timing of muscles that regulate angular momentum to improve balance control.

The effects of ankle stiffness on mechanics and energetics of walking with added loads: a prosthetic emulator study.

BACKGROUND: The human ankle joint has an influential role in the regulation of the mechanics and energetics of gait. The human ankle can modulate its joint 'quasi-stiffness' (ratio of plantarflexion moment to dorsiflexion displacement) in response to various locomotor tasks (e.g., load carriage). However, the direct effect of ankle stiffness on metabolic energy cost during various tasks is not fully understood. The purpose of this study was to determine how net metabolic energy cost was affected by ankle stiffness while walking under different force demands (i.e., with and without additional load). METHODS: Individuals simulated an amputation by using an immobilizer boot with a robotic ankle-foot prosthesis emulator. The prosthetic emulator was controlled to follow five ankle stiffness conditions, based on literature values of human ankle quasi-stiffness. Individuals walked with these five ankle stiffness settings, with and without carrying additional load of approximately 30% of body mass (i.e., ten total trials). RESULTS: Within the range of stiffness we tested, the highest stiffness minimized metabolic cost for both load conditions, including a ~ 3% decrease in metabolic cost for an increase in stiffness of about 0.0480 Nm/deg/kg during normal (no load) walking. Furthermore, the highest stiffness produced the least amount of prosthetic ankle-foot positive work, with a difference of ~ 0.04 J/kg from the highest to lowest stiffness condition. Ipsilateral hip positive work did not significantly change across the no load condition but was minimized at the highest stiffness for the additional load conditions. For the additional load conditions, the hip work followed a similar trend as the metabolic cost, suggesting that reducing positive hip work can lower metabolic cost. CONCLUSION: While ankle stiffness affected the metabolic cost for both load conditions, we found no significant interaction effect between stiffness and load. This may suggest that the importance of the human ankle's ability to change stiffness during different load carrying tasks may not be driven to minimize metabolic cost. A prosthetic design that can modulate ankle stiffness when transitioning from one locomotor task to another could be valuable, but its importance likely involves factors beyond optimizing metabolic cost.

Muscle Function and Coordination of Stair Ascent.

Stair ascent is an activity of daily living and necessary for maintaining independence in community environments. One challenge to improving an individual's ability to ascend stairs is a limited understanding of how lower-limb muscles work in synergy to perform stair ascent. Through dynamic coupling, muscles can perform multiple functions and require contributions from other muscles to perform a task successfully. The purpose of this study was to identify the functional roles of individual muscles during stair ascent and the mechanisms by which muscles work together to perform specific subtasks. A three-dimensional (3D) muscle-actuated simulation of stair ascent was generated to identify individual muscle contributions to the biomechanical subtasks of vertical propulsion, anteroposterior (AP) braking and propulsion, mediolateral control and leg swing. The vasti and plantarflexors were the primary contributors to vertical propulsion during the first and second halves of stance, respectively, while gluteus maximus and hamstrings were the primary contributors to forward propulsion during the first and second halves of stance, respectively. The anterior and posterior components of gluteus medius were the primary contributors to medial control, while vasti and hamstrings were the primary contributors to lateral control during the first and second halves of stance, respectively. To control leg swing, antagonistic muscles spanning the hip, knee, and ankle joints distributed power from the leg to the remaining body segments. These results compliment previous studies analyzing stair ascent and provide further rationale for developing targeted rehabilitation strategies to address patient-specific deficits in stair ascent.

Experimental comparisons of passive and powered ankle-foot orthoses in individuals with limb reconstruction.

BACKGROUND: Ankle-foot orthoses (AFO) are commonly prescribed to provide functional assistance for patients with lower limb injuries or weakness. Their passive mechanical elements can provide some energy return to improve walking ability, but cannot restore plantar flexor push-off. Powered AFOs provide an assistive torque about the ankle to address the limitations of passive devices, but current designs have yet to be implemented on a large scale clinically. PURPOSE: To compare passive AFOs to a new untethered, powered AFO design in a clinical population with lower limb reconstruction. METHODS: A crossover study design, conducted on three individuals with lower limb reconstruction, compared gait mechanics at a standardized speed (based on leg length) in 4 AFO conditions: 1. None (shoes only), 2. Blue Rocker (BR, Allard, USA), 3. Intrepid Dynamic Exoskeletal Orthosis (IDEO), and 4. PowerFoot Orthosis (PFO BionX Medical Technologies, Inc.). The PFO was a custom, battery-powered device whose damping and power were capable to being tuned to meet patient needs. Subjects performed biomechanical gait analysis and metabolic testing at slow, moderate and fast speeds. Dependent variables included total limb power (calculated using a unified deformable segment model), mechanical work, mechanical efficiency, ankle motion, net metabolic cost across three speeds, and performance measures were calculated. Effect sizes (d) were calculated and d > 0.80 denoted a large effect. RESULTS: Net positive work (d > 1.17) and efficiency (d > 1.43) were greatest in the PFO. There were large effects for between limb differences in positive work for all conditions except the PFO (d = 0.75). The PFO normalized efficiency between the affected and unaffected limbs (d = 0.50), whereas efficiency was less on the affected limb for all other conditions (d > 1.69). Metabolic rate was not consistently lowest in any one AFO condition across speeds. Despite some positive results of the PFO, patient preferred their daily use AFO (2 IDEO, 1 BR). All participants indicated that mass and size were concerns with using the PFO. CONCLUSIONS: A novel PFO resulted in more biomimetic mechanical work and efficiency than commercially-available and custom passive AFO models. Although the powered AFO provided some biomechanical benefits, further improvements are warranted to improve patient satisfaction.

Blood Flow Restriction Training After Knee Arthroscopy: A Randomized Controlled Pilot Study.

INTRODUCTION: Quadriceps strength after arthroscopic knee procedures is frequently diminished several years postoperation. Blood flow restriction (BFR) training uses partial venous occlusion while performing submaximal exercise to induce muscle hypertrophy and strength improvements. The purpose of this study was to evaluate BFR as a postoperative therapeutic intervention after knee arthroscopy. METHODS: A randomized controlled pilot study comparing physical therapy with and without BFR after knee arthroscopy was conducted. Patients underwent 12 sessions of supervised physical therapy. Subjects followed the same postoperative protocol with the addition of 3 additional BFR exercises. Outcome measures included thigh girth, physical function measures, Knee Osteoarthritis Outcome Score (KOOS), Veterans RAND 12-Item Health Survey (VR12), and strength testing. Bilateral duplex ultrasonography was used to evaluate for deep venous thrombosis preintervention and postintervention. RESULTS: Seventeen patients completed the study. Significant increases in thigh girth were observed in the BFR group at 6-cm and 16-cm proximal to the patella (P = 0.0111 and 0.0001). All physical outcome measures significantly improved in the BFR group, and the timed stair ascent improvements were greater than conventional therapy (P = 0.0281). The VR-12 and KOOS subscales significantly improved in the BFR group, and greater improvement was seen in VR-12 mental component score (P = 0.0149). The BFR group displayed approximately 2-fold greater improvements in extension and flexion strength compared with conventional therapy (74.59% vs 33.5%, P = 0.034). No adverse events were observed during the study. CONCLUSIONS: This study suggests that BFR is an effective intervention after knee arthroscopy. Further investigation is warranted to elucidate the benefits of this intervention in populations with greater initial impairment.

Range of Motion Requirements for Upper-Limb Activities of Daily Living.

OBJECTIVE: We quantified the range of motion (ROM) required for eight upper-extremity activities of daily living (ADLs) in healthy participants. METHOD: Fifteen right-handed participants completed several bimanual and unilateral basic ADLs while joint kinematics were monitored using a motion capture system. Peak motions of the pelvis, trunk, shoulder, elbow, and wrist were quantified for each task. RESULTS: To complete all activities tested, participants needed a minimum ROM of -65°/0°/105° for humeral plane angle (horizontal abduction-adduction), 0°-108° for humeral elevation, -55°/0°/79° for humeral rotation, 0°-121° for elbow flexion, -53°/0°/13° for forearm rotation, -40°/0°/38° for wrist flexion-extension, and -28°/0°/38° for wrist ulnar-radial deviation. Peak trunk ROM was 23° lean, 32° axial rotation, and 59° flexion-extension. CONCLUSION: Full upper-limb kinematics were calculated for several ADLs. This methodology can be used in future studies as a basis for developing normative databases of upper-extremity motions and evaluating pathology in populations.

Selective laser sintered versus carbon fiber passive-dynamic ankle-foot orthoses: a comparison of patient walking performance.

Selective laser sintering (SLS) is a well-suited additive manufacturing technique for generating subject-specific passive-dynamic ankle-foot orthoses (PD-AFOs). However, the mechanical properties of SLS PD-AFOs may differ from those of commonly prescribed carbon fiber (CF) PD-AFOs. Therefore, the goal of this study was to determine if biomechanical measures during gait differ between CF and stiffness-matched SLS PD-AFOs. Subject-specific SLS PD-AFOs were manufactured for ten subjects with unilateral lower-limb impairments. Minimal differences in gait performance occurred when subjects used the SLS versus CF PD-AFOs. These results support the use of SLS PD-AFOs to study the effects of altering design characteristics on gait performance.

Does a microprocessor-controlled prosthetic knee affect stair ascent strategies in persons with transfemoral amputation?

BACKGROUND: Stair ascent can be difficult for individuals with transfemoral amputation because of the loss of knee function. Most individuals with transfemoral amputation use either a step-to-step (nonreciprocal, advancing one stair at a time) or skip-step strategy (nonreciprocal, advancing two stairs at a time), rather than a step-over-step (reciprocal) strategy, because step-to-step and skip-step allow the leading intact limb to do the majority of work. A new microprocessor-controlled knee (Ottobock X2(®)) uses flexion/extension resistance to allow step-over-step stair ascent. QUESTIONS/PURPOSES: We compared self-selected stair ascent strategies between conventional and X2(®) prosthetic knees, examined between-limb differences, and differentiated stair ascent mechanics between X2(®) users and individuals without amputation. We also determined which factors are associated with differences in knee position during initial contact and swing within X2(®) users. METHODS: Fourteen individuals with transfemoral amputation participated in stair ascent sessions while using conventional and X2(®) knees. Ten individuals without amputation also completed a stair ascent session. Lower-extremity stair ascent joint angles, moment, and powers and ground reaction forces were calculated using inverse dynamics during self-selected strategy and cadence and controlled cadence using a step-over-step strategy. RESULTS: One individual with amputation self-selected a step-over-step strategy while using a conventional knee, while 10 individuals self-selected a step-over-step strategy while using X2(®) knees. Individuals with amputation used greater prosthetic knee flexion during initial contact (32.5°, p = 0.003) and swing (68.2°, p = 0.001) with higher intersubject variability while using X2(®) knees compared to conventional knees (initial contact: 1.6°, swing: 6.2°). The increased prosthetic knee flexion while using X2(®) knees normalized knee kinematics to individuals without amputation during swing (88.4°, p = 0.179) but not during initial contact (65.7°, p = 0.002). Prosthetic knee flexion during initial contact and swing were positively correlated with prosthetic limb hip power during pull-up (r = 0.641, p = 0.046) and push-up/early swing (r = 0.993, p < 0.001), respectively. CONCLUSIONS: Participants with transfemoral amputation were more likely to self-select a step-over-step strategy similar to individuals without amputation while using X2(®) knees than conventional prostheses. Additionally, the increased prosthetic knee flexion used with X2(®) knees placed large power demands on the hip during pull-up and push-up/early swing. A modified strategy that uses less knee flexion can be used to allow step-over-step ascent in individuals with less hip strength.

How does ankle-foot orthosis stiffness affect gait in patients with lower limb salvage?

BACKGROUND: Ankle-foot orthoses (AFOs) are commonly prescribed during rehabilitation after limb salvage. AFO stiffness is selected to help mitigate gait deficiencies. A new custom dynamic AFO, the Intrepid Dynamic Exoskeletal Orthosis (IDEO), is available to injured service members but prescription guidelines are limited. QUESTIONS/PURPOSES: In this study we ask (1) does dynamic AFO stiffness affect gait parameters such as joint angles, moments, and powers; and (2) can a given dynamic AFO stiffness normalize gait mechanics to noninjured control subjects? METHODS: Thirteen patients with lower limb salvage (ankle arthrodesis, neuropathy, foot/ankle reconstruction, etc) after major lower extremity trauma and 13 control subjects who had no lower extremity trauma and wore no orthosis underwent gait analysis at a standardized speed. Patients wore their custom IDEO with posterior struts of three different stiffnesses: nominal (clinically prescribed stiffness), compliant (20% less stiff), and stiff (20% stiffer). Joint angles, moments, powers, and ground reaction forces were compared across the varying stiffnesses of the orthoses tested and between the patient and control groups. RESULTS: An increase in AFO compliance resulted in 20% to 26% less knee flexion relative to the nominal (p = 0.003) and stiff (p = 0.001) conditions, respectively. Ankle range of motion and power generation were, on average, 56% (p < 0.001) and 63% (p < 0.001), respectively, less than controls as a result of the relatively fixed ankle position. CONCLUSIONS: Patients with limb salvage readily adapted to different dynamic AFO stiffnesses and demonstrated few biomechanical differences among conditions during walking. None of the stiffness conditions normalized gait to controls. CLINICAL RELEVANCE: The general lack of differences across a 40% range of strut stiffness suggests that orthotists do not need to invest large amounts of time identifying optimal device stiffness for patients who use dynamic AFOs for low-impact activities such as walking. However, choosing a stiffer strut may more readily translate to higher-impact activities and offer less chance of mechanical failure.

Can an integrated orthotic and rehabilitation program decrease pain and improve function after lower extremity trauma?

BACKGROUND: Patients with severe lower extremity trauma have significant disability 2 years after injury that worsens by 7 years. Up to 15% seek late amputation. Recently, an energy-storing orthosis demonstrated improved function compared with standard orthoses; however, the effect when integrated with rehabilitation over time is unknown. QUESTIONS/PURPOSES: (1) Does an 8-week integrated orthotic and rehabilitation initiative improve physical performance, pain, and outcomes in patients with lower extremity functional deficits or pain? (2) Is the magnitude of recovery different if enrolled more than 2 years after their injury versus earlier? (3) Does participation decrease the number considering late amputation? METHODS: We prospectively evaluated 84 service members (53 less than and 31 > 2 years after injury) who enrolled in the initiative. Fifty-eight sustained fractures, 53 sustained nerve injuries with weakness, and six had arthritis (there was some overlap in the patients with fractures and nerve injuries, which resulted in a total of > 84). They completed 4 weeks of physical therapy without the orthosis followed by 4 weeks with it. Testing was conducted at Weeks 0, 4, and 8. Validated physical performance tests and patient-reported outcome surveys were used as well as questions pertaining to whether patients were considering an amputation. RESULTS: By 8 weeks, patients improved in all physical performance measures and all relevant patient-reported outcomes. Patients less than and greater than 2 years after injury improved similarly. Forty-one of 50 patients initially considering amputation favored limb salvage at the end of 8 weeks. CONCLUSIONS: We found this integrated orthotic and rehabilitation initiative improved physical performance, pain, and patient-reported outcomes in patients with severe, traumatic lower extremity deficits and that these improvements were sustained for > 2 years after injury. Efforts are underway to determine whether the Return to Run clinical pathway with the Intrepid Dynamic Exoskeletal Orthosis (IDEO) can be successfully implemented at additional military centers in patients > 2 years from injury while sustaining similar improvements in patient outcomes. The ability to translate this integrated orthotic and rehabilitation program into the civilian setting is unknown and warrants further investigation.

Effect of crutch and walking-boot use on whole-body angular momentum during gait.

Crutches are the most prescribed ambulatory assistive device and are used for mobility and maintaining weight-bearing restrictions after injury or surgery. However, standard axillary crutches (SACs) can lead to overuse and other injuries and restrict upper limb movement. Hands-free crutches (HFC) do not restrict upper limb movement but their effect on balance control, with or without commonly prescribed walking boots, is poorly understood. The purpose of this study was to compare the effect of crutch type (SACs vs. HFC) and boot use on whole-body angular momentum (RAM), a measure of balance control. Participant's balance confidence, pain, comfort, and device preference were assessed. Seventeen participants were evaluated while walking without a crutch (NONE), with SACs, and with an HFC, and walked with and without a walking boot in each crutch condition. The gait pattern used with SACs resulted in significantly greater limb angular velocity (p < .05), and an 84% increase in RAM (p < .001) as compared to the HFC. There were no differences between the SAC and HFC for balance confidence, pain, or comfort, however most (71.1%) participants preferred the HFCs. These results suggest that individuals can better control angular momentum with the HFCs and thus may be less susceptible to loss of balance.

Foot offloading associated with carbon fiber orthosis use: A pilot study.

BACKGROUND: Traumatic lower limb injuries can result in chronic pain. Orthotic interventions are a leading conservative approach to reduce pain, manage loading, and protect the foot. Robust carbon fiber custom dynamic orthoses (CDOs) designed for military service members have been shown to reduce foot loading. However, the effect of carbon fiber orthosis design, including designs widely used in the civilian sector, on foot loading is unknown. RESEARCH QUESTION: Determine if carbon fiber orthoses alter foot loading during gait. METHODS: Loadsol insoles were used to measure peak forces and force impulse acting on the forefoot, midfoot, hindfoot, and total foot. Nine healthy, able-bodied individuals participated. Force impulse was quantified as cumulative loading throughout stance phase. Participants walked without an orthosis and with three carbon fiber orthoses of differing designs: a Firm stiffness CDO, a Moderate stiffness CDO, and a medial and lateral strut orthosis (MLSO). RESULTS: There were significant main effects of orthosis condition on peak forefoot forces as well as forefoot and hindfoot force impulse. Peak forefoot forces were significantly lower in the Moderate and Firm CDOs compared to no orthosis and MLSO. Compared to walking without an orthosis, forefoot force impulse was significantly lower and hindfoot force impulse was significantly greater in all carbon fiber orthoses. Additionally, hindfoot force impulse in the Firm CDO was significantly higher than in the MLSO and Moderate CDO. SIGNIFICANCE: The three carbon fiber orthosis designs differed regarding foot loading, with more robust orthoses providing greater forefoot offloading. Orthosis-related changes in forefoot loading suggest that carbon fiber orthoses could reduce loading-associated pain during gait. However, increased hindfoot force impulse suggests caution should be used when considering carbon fiber orthoses for individuals at risk of skin breakdown with repetitive loading.

The effect of carbon fiber custom dynamic orthosis use and design on center of pressure progression and perceived smoothness in individuals with lower limb trauma.

BACKGROUND: Carbon-fiber custom dynamic orthoses are used to improve gait and limb function following lower limb trauma in specialty centers. However, the effects of commercially available orthoses on center of pressure progression and patient perception of orthosis smoothness during walking are poorly understood. METHODS: In total, 16 participants with a unilateral lower extremity traumatic injury underwent gait analysis when walking without an orthosis, and while wearing monolithic and modular devices, in a randomized order. Device alignment, stiffness, participant rating of perceived device smoothness, center of pressure velocity, and ankle zero moment crossing were assessed. FINDINGS: The modular device was approximately twice as stiff as the monolithic device. Alignment, smoothness ratings, peak magnitude of center of pressure velocity, and zero moment crossing were not different between study devices. The time to peak center of pressure velocity occurred significantly later for the modular device compared to the monolithic and no orthosis conditions, with large effect sizes observed. INTERPRETATION: Commercially available orthoses commonly used to treat limb trauma affect the timing of center of pressure progression relative to walking without an orthosis. Despite multiple design differences, monolithic and modular orthoses included in this study did not differ with respect to other measures of center of pressure progression. Perceived smoothness ratings were approximately 40% greater with the study orthoses as compared to previous studies in specialty centers, which may be due to a more gradual center of pressure progression, as indicted by lower peak magnitude of center of pressure velocity with both study orthoses.

Current Challenges in Chronic Ankle Instability: Review and Perspective.

Chronic ankle instability (CAI) is common, disabling, and represents a significant socioeconomic burden. Current treatment options are not adequately efficacious. CAI is multifaceted, yet it is commonly addressed in terms of either mechanical instability or functional impairment. Both are inherently linked. Basic research must be conducted to foster reliable translational research encompassing both mechanical and functional aspects. A review was conducted to identify CAI risk factors for inclusion in future studies, and we offer here opinions and perspectives for future research.

Carbon fiber ankle-foot orthoses in impaired populations: A systematic review.

BACKGROUND: Carbon fiber is increasingly being used in ankle-foot orthoses (AFOs). Orthotic devices and carbon fiber-containing devices have been shown to reduce pain and improve function in multiple patient populations. Although the number of publications and interest in carbon fiber AFOs is growing, a systematic evaluation of their effects is lacking. OBJECTIVES: To characterize the effects of carbon fiber AFOs in impaired individuals. STUDY DESIGN: Qualitative systematic review. METHODS: Systematic searches in PubMed, Embase, CINAHL, and Cochrane Library were completed in July 2020. The results were deduplicated, screened, and assessed for quality by independent reviewers. Articles were excluded if they had nonhuman subjects, only healthy subjects, or included active control systems, motors, or other power sources. RESULTS: Seventy-eight articles were included in the qualitative synthesis. Most articles were of low to moderate methodological quality. Five commonly used devices were identified: the Intrepid Dynamic Exoskeletal Orthosis, ToeOff, WalkOn, Neuro Swing, and Chignon. The devices have unique designs and are associated with specific populations. The Intrepid Dynamic Exoskeletal Orthosis was used in individuals with lower-limb trauma, the Neuro Swing and ToeOff in individuals with neurological disorders, the Chignon in individuals with hemiplegia and stroke, and the WalkOn in people with hemiplegia and cerebral palsy. Each device produced favorable outcomes in their respective populations of interest, such as increased walking speed, reduced pain, or improved balance. CONCLUSIONS: The mechanical characteristics and designs of carbon fiber AFOs improve outcomes in the populations in which they are most studied. Future literature should diligently report patient population, device used, and fitting procedures.

Predictors of long-term pain and function in individuals who received a custom dynamic orthosis and device-centric care pathway.

INTRODUCTION: Carbon fiber custom dynamic orthoses (CDOs) have been shown to effectively reduce pain and improve function in military service members with lower-limb impairment, but data are limited for civilians. OBJECTIVES: To evaluate the long-term outcomes of individuals who completed a CDO-centric care pathway in a civilian clinic by comparing baseline pain, mobility, and function with outcomes at long-term follow-up. To identify baseline characteristics and postintervention outcomes predictive of outcomes at long-term follow-up. METHODS: Records of 131 adult patients who received a CDO and CDO-centric training were reviewed. Patient-reported measures of pain and physical function and timed assessment of walking and agility collected during routine clinical care were extracted. These patients were contacted on average 4 (±1) years postintervention to complete a survey including measures of pain and physical function. RESULTS: The 63 participants who responded reported improved or greatly improved function, maximum pain, and typical pain on average, irrespective of age or sex (P < 0.001). Change in function from baseline to long-term follow-up was predicted by short-term change in function (35.1% of the variance; P < 0.001). Change in pain from baseline to long-term follow-up was predicted by baseline typical pain and change in four square step test time (63% of variance; P < 0.001). CONCLUSIONS: Most survey respondents reported positive outcomes. Long-term pain reduction and improved function were predicted by baseline status and by short-term changes associated with receiving a CDO and completing an intensive training program.

Short-term effect of a carbon fiber custom dynamic orthosis and integrated rehabilitation on self-reported physical function, pain, speed, and agility in civilians.

BACKGROUND: Ankle-foot orthoses (AFOs) are widely used to restore mobility and reduce pain in individuals with lower extremity pain and disability. The use of a carbon fiber custom dynamic orthosis (CDO) with integrated physical training and psychosocial intervention has been shown to improve outcomes in a military setting, but civilian data are limited. OBJECTIVES: To use existing clinical data to evaluate the initial effectiveness of an integrated CDO and rehabilitative program and identify baseline characteristics that impact patient response to the intervention. STUDY DESIGN: Retrospective cohort. METHODS: Records of 131 adult patients who received a CDO and device specific training were reviewed. Patient-reported measures of pain and lower extremity function and physical measurements of walking and agility were extracted at baseline and on training completion. RESULTS: A majority of patients reported improved or greatly improved physical function (92%), maximum pain (69%), and typical pain (55%) and experienced improved or greatly improved walking speed (92%) and agility (52%) irrespective of age and sex. Regression models for examining short-term improvement in pain and physical function accounted for 52% (p < 0.001) and 26% (p < 0.001) of the outcome variance, respectively. Improvement in typical pain was influenced by baseline typical and maximum pain, and functional improvement was influenced by sex and baseline physical function. CONCLUSIONS: Most patients (92.4%) reported a positive initial outcome after intervention as measured using patient-reported and objective measures.

Patterns of movement-evoked pain during tendon loading and stretching tasks in Achilles tendinopathy: A secondary analysis of a randomized controlled trial.

BACKGROUND: This study aimed to characterize movement-evoked pain during tendon loading and stretching tasks in individuals with Achilles tendinopathy, and to examine the association between movement-evoked pain with the Achilles tendinopathy type (insertional and midportion), biomechanical, and psychological variables. METHODS: In this laboratory-based, cross-sectional study, 37 individuals with chronic Achilles tendinopathy participated. Movement-evoked pain intensity (Numeric Rating Scale: 0 to 10) and sagittal-plane ankle biomechanics were collected simultaneously during standing, fast walking, single-leg heel raises, and weight-bearing calf stretch. Description of symptoms, including location of Achilles tendon pain and duration of tendon morning stiffness, as well as pain-related psychological measures, including the Tampa Scale of Kinesiophobia were collected. Linear mixed effects models were built around two paradigms of movement-evoked pain (tendon loading and stretching tasks) with each model anchored with pain at rest. FINDINGS: Movement-evoked pain intensity increased as task demand increased in both models. Lower peak dorsiflexion with walking (ß = -0.187, 95% CI: -0.305, -0.069), higher fear of movement (ß = 0.082, 95% CI: 0.018, 0.145), and longer duration of tendon morning stiffness (ß = 0.183, 95% CI: 0.07, 0.296) were associated with greater pain across tendon loading tasks (R2 = 0.47). Lower peak dorsiflexion with walking (ß = -0.27, 95% CI: -0.41, -0.14), higher dorsiflexion with the calf stretch (ß = 0.095, 95% CI: 0.02, 0.16), and insertional Achilles tendinopathy (ß = -0.93, 95% CI: -1.65, -0.21) were associated with higher pain across tendon stretching tasks (R2 = 0.53). INTERPRETATION: In addition to exercise, the ideal management of Achilles tendinopathy may require adjunct treatments to address the multifactorial aspects of movement-evoked pain.