Clinical Outcomes with the Intrepid Dynamic Exoskeletal Orthosis: A Retrospective Analysis

Influence of custom dynamic orthoses on tibiotalar joint reaction force and contact stress: A cadaveric study

Post-traumatic osteoarthritis (PTOA) often develops following tibial pilon fractures. Evidence suggesting PTOA development is driven by elevated articular contact stress from residual malreduction has led surgeons to strive for precise articular reduction, typically at the cost of extended operative time. Post-operative bracing using carbon fiber custom dynamic orthoses (CDOs) offers another means to decrease tibiotalar joint reaction force (JRF) and contact stress. The purpose of this cadaveric study was to measure how CDO stiffness influences ankle JRF and contact stress over the stance phase of gait. A servohydraulic load frame was used to test five cadaver ankles, with axial loading (240-330 N) and pneumatic actuation of the Achilles tendon (50-436 N) serving to quasi-statically model multiple points in the stance phase of gait. Three CDO rotational stiffness conditions were tested: (1) No CDO-0 Nm/deg, (2) low stiffness CDO-1.8 Nm/deg, and (3) moderate stiffness CDO-2.3 Nm/deg. JRF and contact stresses were measured using a piezoresistive pressure sensor inserted into the tibiotalar joint. An insole plantar pressure sensor placed between the cadaveric foot and CDO footplate measured limb/device interactions via the plantar center of pressure (COP). As limb loading progressed through stance, the plantar COP progressed from hindfoot to forefoot, as it would in normal gait. Both CDOs demonstrated decreases in JRF, reaching as high as 32% for the low CDO and 26% for the moderate CDO, with associated decreases in contact stress. This suggests that post-operative bracing could lessen PTOA risk after pilon fractures.

Changes in functional outcomes in people with high-energy ankle trauma after the use of the ReAktiv Posterior Dynamic Element™ orthosis and a rehabilitation program: A case series

The aim of this study was to examine lower-limb function in 2 patients that received a ReAktiv Posterior Dynamic Element™ (PDE) orthosis and 6-week rehabilitation program after a high-energy trauma injury to the lower limb. Lower-limb function was assessed using the lower extremity functional score, walking performance through the 2-minute walk test, and dynamic mobility and balance through the single-leg balance, timed stair ascent, and the 4-square step test. A 6-week physiotherapy-led rehabilitation program was also implemented. Data showed improvements in lower extremity function, walking performance, mobility, and balance measures after 8 weeks of wearing the ReAktiv PDE™ orthosis and completion of the rehabilitation program. The ReAktiv PDE™ orthosis combined with a lower-limb rehabilitation program shows potential as a treatment option to improve lower-limb function and walking performance and return sufferers of high-energy trauma injury to functional levels seen in healthy cohorts.

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.

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.

Lower Extremity Assistive Devices (LEADs): A Contemporary Literature Review

Lower extremity ambulatory assistive devices (LEADs) are important augments that provide mobility and stability when weightbearing is restricted in the setting of injury, surgery, or balance disorders. In order to optimize patient safety and function when prescribing these devices, it is essential for the orthopaedic surgeon to have a firm understanding of their specific indications, proper fitting, energy demand, biomechanical advantages, and potential complications. Comprehension of normal gait cadence, identification of the functional deficit present and knowledge of available options will assist in safely prescribing the proper device. Over the last decade, newer alternatives to traditional LEADs (canes, crutches, walkers) have become available, including the rolling knee scooter and hands-free single crutch. These have been developed to improve mobility and independence; however, it is necessary to appreciate their limitations when prescribing them to patients. This review will provide an update on normal and pathologic gait biomechanics as well as the most common types of LEADs currently available to the orthopaedic surgeon, their indications, important considerations, proper fitting, associated energy expenditure, and complications.

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.

Development and initial validation of the Orthotic Patient-Reported Outcomes-Mobility (OPRO-M): An item bank for evaluating mobility of people who use lower-limb orthoses

Lower limb orthoses (LLOs) are externally-applied leg braces that are designed to improve or maintain mobility in people with a variety of health conditions that affect lower limb function. Clinicians and researchers are therefore often motivated to measure LLO users' mobility to select or assess the effectiveness of these devices. Patient-reported outcome measures (PROMs) can provide insights into important aspects of a LLO user's mobility for these purposes. However, few PROMs are available to measure mobility of LLO users. Those few that exist have issues that may limit their clinical or scientific utility. The objective of this study was to create a population-specific item bank for measuring mobility of LLO users. Previously-developed candidate items were administered in a cross-sectional study to a large national sample of LLO users. Responses from study participants (n = 1036) were calibrated to a graded response statistical model using Item Response Theory methods. A set of 39 items was found to be unidimensional, locally independent, and function without bias due to characteristics unrelated to mobility. The set of final calibrated items, termed the Orthotic Patient-Reported Outcomes-Mobility (OPRO-M) item bank, was evaluated for initial evidence of convergent, divergent, and known groups construct validity. OPRO-M was strongly correlated with existing PROMs designed to measure aspects of physical function. Conversely, OPRO-M was weakly correlated with PROMs that measured unrelated constructs, like sleep disturbance and depression. OPRO-M also showed an ability to differentiate groups with expected mobility differences. Two fixed-length short forms were created from the OPRO-M item bank. Items on the short forms were selected based on statistical and clinical criteria. Collectively, results from this study indicate that OPRO-M can effectively measure mobility of LLO users, and OPRO-M short forms can now be recommended for use in routine clinical practice and research studies.

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.

Development of a candidate item bank for measuring mobility of lower limb orthosis users

BACKGROUND

Orthoses are often prescribed to improve mobility of people with chronic health conditions that affect lower limb function. Patient-reported survey instruments can be used to measure aspects of mobility that cannot be easily assessed in clinical or research settings. A population-specific item bank could be designed to measure aspects of mobility that are most important to lower limb orthosis users and used to evaluate the effects of orthoses.

OBJECTIVE

To develop items for a new survey instrument to measure mobility of lower limb orthosis users.

DESIGN

Survey items were developed using a qualitative item review process.

SETTING

Focus groups were held by video conferencing. Cognitive interviews were conducted by telephone.

PARTICIPANTS

Focus group and cognitive interview participants were adults with at least 6 months of experience using a lower limb orthosis that extended from the foot to a level above the ankle.

METHODS

Research methods included focus groups with lower limb orthosis users, an item generation and reduction process that involved a stakeholder advisory panel, and cognitive interviews with target respondents.

RESULTS

A total of 1180 extant items were identified in a literature review. Focus group participants (n = 29) provided feedback that informed the suitability of a construct definition and conceptual model. An advisory panel contributed to the selection of 118 candidate items for measuring orthotic mobility. Feedback from cognitive interview participants (n = 30) informed removal or revision of problematic items, resulting in a candidate bank of 100 mobility items.

CONCLUSIONS

The rigorous qualitative methods applied here resulted in a large set of candidate items that spanned a range of situations relevant to moving with a lower limb orthosis. Next steps include administration of the candidate items to a large sample of lower limb orthosis users and calibration of the item bank.

Custom Dynamic Orthoses and Physical Therapist Intervention for Bilateral Midfoot Amputation: A Case Report

OBJECTIVE

Partial foot amputation is often associated with decreased mobility and function. Recent advances in custom carbon-fiber dynamic ankle-foot orthoses (CDOs) have improved gait, pain, and function following musculoskeletal trauma and can benefit individuals with partial foot amputation. However, limited information is available related to CDO use outside the military. The purpose of this case report is to describe the course of care and outcomes of a civilian provided with CDOs after bilateral transmetatarsal amputation.

CASE DESCRIPTION

A 72-year-old man had a blood-borne bacterial infection (septicemia) of unknown origin at 68 years of age, developed limb-threatening necrosis of the hands and feet, and received bilateral transmetatarsal amputations with skin grafting. The patient initially used foam toe fillers and cushioned shoes but was functionally limited and experienced recurrent ulceration. He was fitted with bilateral CDOs 39 months after amputation and completed device-specific training with a physical therapist.

RESULTS

After 1 week with the CDOs, ankle range of motion during gait was reduced, but greater than 40% increases were observed in bilateral ankle plantarflexor moments and ankle plantarflexion push-off power compared with the toe fillers. With additional therapist-directed training focused on gait and activity performance, ankle plantarflexor moments and plantarflexion push-off power further increased when compared with results after 1 week of CDO use. The patient reported marked improvement in quality of life with the CDOs due to improved walking ability on level and uneven terrain, marked improvement in confidence, and reduced pain.

CONCLUSION

This case reflects the lessons learned and outcomes of a civilian using bilateral CDOs after bilateral transmetatarsal amputation and with poor skin quality. The results from this case study suggest that carbon-fiber CDOs and focused training by a physical therapist can result in improved gait biomechanics, mobility, and quality of life.