Return to running and sports participation after limb salvage

Quality of Life, Physical Activity Participation, and Perceptions of Physical Rehabilitation Among Community-Reintegrated Veterans With Lower Limb Amputation in Sri Lanka: Convergent Parallel Mixed Methods Study

BACKGROUND

Lower limb amputation (LLA) impacts physical activity (PA) participation and quality of life (QoL). To minimize the effects of these challenges, LLA survivors need to have opportunities to engage in appropriately tailored rehabilitation throughout their lives. However, in Sri Lanka, where a 3-decade civil war resulted in trauma-related LLA among young male soldiers, access to rehabilitation was limited to the immediate postinjury period. Developing rehabilitation interventions for these veterans requires an understanding of their current health status and rehabilitation perceptions.

OBJECTIVE

This study was conducted to evaluate the QoL and PA participation of veterans with LLA and explore perceptions of factors influencing their PA participation and expectations for a future community-based physical rehabilitation (CBPR) intervention.

METHODS

This mixed methods study combined a comparative cross-sectional quantitative survey with qualitative semistructured interviews in 5 districts of Sri Lanka. QoL and PA participation were assessed among community-reintegrated veterans with LLA (n=85) and compared with a matched able-bodied cohort (control; n=85) using Mann-Whitney U and Chi-square tests. PA was assessed in terms of metabolic equivalent of task (MET) minutes per week and was computed for walking, moderate-intensity, and vigorous-intensity activities. PA was classified as sufficiently active, low, or sedentary. The design of interview questions was guided by the Theoretical Domains Framework and followed a phenomenological approach. Interviews were conducted with 25 veterans and were analyzed thematically, and the perceptions regarding PA participation and CBPR were codified using the Consolidated Framework for Implementation Research (CFIR).

RESULTS

Based on the quantitative survey findings, scores for both physical (P<.001) and psychological (P<.001) well-being and participation in walking (P=.004) and vigorous-intensity activities (P<.001) were significantly lower among veterans than among controls. A "sedentary" classification was made for 43% (34/79) of veterans and 12% (10/82) of controls. Veterans mostly engaged in moderate-intensity PA inside the house (49/79, 62%) and in the yard (30/79, 38%). Qualitative interviews revealed that barriers to PA exist at individual (eg, comorbidity burden), primary care (eg, absence of community rehabilitation services), and policy levels (eg, limited resources) and facilitators exist primarily at societal (eg, inclusive community) and individual levels (eg, preinjury activity baseline and positive attitudes toward exercise). Expectations regarding CBPR included individualized rehabilitation parameters; functional exercises; and involvement of peers, amputee societies, and community health care providers. The nonresponse rate for interviews was 7% (2/27).

CONCLUSIONS

The findings of reduced PA participation, poor QoL, and physical and psychological impairments among relatively young veterans reveal the long-term impacts of living with LLA in the absence of long-term rehabilitation. Policy-level changes need to be implemented along with behavior-change strategies to promote PA participation and minimize physical inactivity-induced health issues. Veterans' perceptions regarding future CBPR programs were positive and centered on holistic, individualized, and peer-led activities.

Fall Prevention Training for Service Members With an Amputation or Limb Salvage Following Lower Extremity Trauma

INTRODUCTION

Recent military conflicts have resulted in a significant number of lower extremity injuries to U.S. service members that result in amputation or limb preservation (LP) procedures. Service members receiving these procedures report a high prevalence and deleterious consequences of falls. Very little research exists to improve balance and reduce falls, especially among young active populations such as service members with LP or limb loss. To address this research gap, we evaluated the success of a fall prevention training program for service members with lower extremity trauma by (1) measuring fall rates, (2) quantifying improvements in trunk control, and (3) determining skill retention at 3 and 6 months after training.

MATERIALS AND METHODS

Forty-five participants (40 males, mean [±SD] age, 34 ± 8 years) with lower extremity trauma (20 with unilateral transtibial amputation, 6 with unilateral transfemoral amputation, 5 with bilateral transtibial amputation, and 14 with unilateral LP procedures) were enrolled. A microprocessor-controlled treadmill was used to produce task-specific postural perturbations which simulated a trip. The training was conducted over a 2-week period and consisted of six 30-minute sessions. The task difficulty was increased as the participant's ability progressed. The effectiveness of the training program was assessed by collecting data before training (baseline; repeated twice), immediately after training (0 month), and at 3 and 6 months post-training. Training effectiveness was quantified by participant-reported falls in the free-living environment before and after training. Perturbation-induced recovery step trunk flexion angle and velocity was also collected.

RESULTS

Participants reported reduced falls and improved balance confidence in the free-living environment following the training. Repeated testing before training revealed that there were no pre-training differences in trunk control. The training program improved trunk control following training, and these skills were retained at 3 and 6 months after training.

CONCLUSION

This study showed that task-specific fall prevention training reduced falls across a cohort of service members with diverse types of amputations and LP procedures following lower extremity trauma. Importantly, the clinical outcome of this effort (i.e., reduced falls and improved balance confidence) can lead to increased participation in occupational, recreational, and social activities and thus improved quality of life.

Highly Aligned Ternary Nanofiber Matrices Loaded with MXene Expedite Regeneration of Volumetric Muscle Loss

Current therapeutic approaches for volumetric muscle loss (VML) face challenges due to limited graft availability and insufficient bioactivities. To overcome these limitations, tissue-engineered scaffolds have emerged as a promising alternative. In this study, we developed aligned ternary nanofibrous matrices comprised of poly(lactide-co-ε-caprolactone) integrated with collagen and Ti3C2Tx MXene nanoparticles (NPs) (PCM matrices), and explored their myogenic potential for skeletal muscle tissue regeneration. The PCM matrices demonstrated favorable physicochemical properties, including structural uniformity, alignment, microporosity, and hydrophilicity. In vitro assays revealed that the PCM matrices promoted cellular behaviors and myogenic differentiation of C2C12 myoblasts. Moreover, in vivo experiments demonstrated enhanced muscle remodeling and recovery in mice treated with PCM matrices following VML injury. Mechanistic insights from next-generation sequencing revealed that MXene NPs facilitated protein and ion availability within PCM matrices, leading to elevated intracellular Ca2+ levels in myoblasts through the activation of inducible nitric oxide synthase (iNOS) and serum/glucocorticoid regulated kinase 1 (SGK1), ultimately promoting myogenic differentiation via the mTOR-AKT pathway. Additionally, upregulated iNOS and increased NO- contributed to myoblast proliferation and fiber fusion, thereby facilitating overall myoblast maturation. These findings underscore the potential of MXene NPs loaded within highly aligned matrices as therapeutic agents to promote skeletal muscle tissue recovery.

Rehabilitation Techniques for Adults Undergoing External Fixation Treatment for Lower Limb Reconstruction: A Systematic Review

Introduction

External fixation devices are commonly used in orthopaedic surgery to manage a range of pathologies. In this patient population, there is currently no consensus on optimal rehabilitation techniques. There exists a large variation in practice, with a limited understanding of how these affect treatment outcomes.

Methods

Following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, a systematic review was conducted of Allied and Complementary Medicine Database (AMED), Cumulative Index to Nursing and Allied Health Literature (CINAHL), MEDLINE, PEDro, and COCHRANE databases, grey literature sources and forward and backward searching of included articles. Studies were selected following rigorous screening with predefined inclusion criteria. Data quality was assessed using validated appraisal tools. Articles were synthesised by rehabilitation type and descriptive analysis was subsequently performed.

Results

From 1,156 articles identified, 18 were eligible for inclusion. The overall quality was low, with clinical commentaries and case studies being the most common study type. Studies were synthesised by rehabilitation type, the most common themes being gait re-education, strengthening, therapy-assisted, active exercises and weight-bearing exercises.

Conclusion

There is a lack of high-quality evidence to support meaningful recommendations and guide rehabilitation practices for this patient cohort. Further research for patients being treated in external fixation, especially related to the potential effects of physical rehabilitation on bone healing, return of strength, mobility and independent function is likely to have transferability within wider orthopaedic populations.

Clinical significance

This systematic review is unable to provide clinical recommendations due to the poor quality of the available literature. However, it is hoped this paper will provide a foundation for further research to improve rehabilitation for patients being treated with external fixation.

How to cite this article

Pawson JR, Church D, Fletcher J, et al. Rehabilitation Techniques for Adults Undergoing External Fixation Treatment for Lower Limb Reconstruction: A Systematic Review. Strategies Trauma Limb Reconstr 2024;19(1):45-55.

Novel Metrics for Assessing Mobility During Ground-Standing Transitions

INTRODUCTION

Transitioning between the ground and standing is a required activity for many professions including skilled trades, law enforcement, and military service. However, available assessments are limited and focus primarily on quality of movement. Thus, we developed two novel assessments of functional mobility specific for ground-to-standing transitions: Stand-Prone-Standx2 (SPS2) and Stand-Kneel-Standx2 (SKS2-L/R) tests. The purpose of this study was to determine the psychometrics of these two new measures in able-bodied (AB) service members and in service members with unilateral lower extremity injury (LEI).

MATERIALS AND METHODS

A total of 57 AB service members and 31 service members with a traumatic unilateral LEI wearing a custom carbon-fiber ankle-foot orthosis participated in this study. In total, 36 AB and 18 LEI participants returned for a second session to assess intersession reliability. Intraclass correlation coefficients were calculated for intersession and inter-rater comparisons (two-way random model for consistency and single measure). Additionally, performance was compared between legs and groups.

RESULTS

The SPS2 and SKS2 assessments demonstrated excellent inter-rater and intersession reliability in both the AB and LEI groups with all intraclass correlation coefficient values greater than 0.8. Further, the tests were responsive to deficits associated with LEI, with the LEI group having significantly longer times on all assessments compared to the AB group.

CONCLUSIONS

The SPS2 and SKS2 performance measures were found to have excellent inter-rater and intersession reliability in both AB participants and participants with LEI. Further, participants with LEI performed significantly slower than the AB participants. Excellent reliability and responsiveness to deficits associated with LEI support the use of the SPS2 and SKS2 to assess mobility in individuals with LEI. Transitions between the ground and standing occur in many occupational and daily tasks. These reliable performance measures that assess ground-to-stand transitions can be applied widely, in many populations beyond highly functioning service members with LEI.

Passive Dynamic Ankle Foot Orthoses Use in Civilian Patients with Arthritic Conditions of the Foot and Ankle

Background

Nonsurgical interventions such as bracing with ankle foot orthoses (AFOs) aim to assist, restore, and redirect weightbearing forces to address difficulty with mobilization. We identified a custom carbon fiber passive dynamic ankle foot orthosis (PDAFO) that was designed to meet the needs of military combat veterans. We sought to evaluate the off-loading properties of one model of PDAFO (ExoSym) in a civilian population.

Methods

Civilian patients 18 years or older were prescribed a PDAFO by a single surgeon. Pedobarographic data were obtained using the Tekscan F-Scan system. With the insole, participants were instructed to walk at a self-selected pace along a 20 m walkway under 3 conditions: (1) insole placed in between the brace and foot (over); (2) insole placed between the brace and insole of the shoe (under); (3) without the brace, the insole was placed in between the foot and insole of the shoe in both limbs (without).For assessment, forefoot and heel areas were evaluated with respect to maximal force, force*time integral (FTI), maximal contact area, maximal contact pressure, pressure*time integral (PTI), center of force (COF) excursion.

Results

Six patients with arthritic foot and ankle conditions completed pedobarographic assessment for analysis. The brace reduced forefoot maximal force and contact pressures by 66% and 49%, respectively (538 ± 236 to 185 ± 130 N [P < .001], and 99 ± 38 to 50 ± 24 P < .002). Additionally, participants were observed to load the forefoot portion of the brace with double the maximum contact pressures compared to the unbraced foot (204 ± 57 to 99 ± 38 kPa, P < .001).

Conclusion

The results of this study showed that the PDAFO unloaded substantial force and pressure experienced by the forefoot. Participants loaded the brace to a greater extent than when going unbraced. ADAFO can provide measurable pressure relief for patients with arthritic conditions.

Level of Evidence

Level IV, case series.

Effect of Boron-Doped Mesoporous Bioactive Glass Nanoparticles on C2C12 Cell Viability and Differentiation: Potential for Muscle Tissue Application

Mesoporous bioactive glasses (MBGs) exhibit a high surface area and a highly ordered mesoporous structure. MBGs have potential for both hard and soft tissue engineering applications. MBGs may be doped with biologically active ions to tailor their biological activity. Boron is being widely studied as a dopant of bioactive glasses. Recently, research has demonstrated the potential of boron-containing bioactive glasses for muscle regeneration. In this study, boron-containing MBGs, 10B-MBG and 18B-MBG nanoparticles, were produced by a microemulsion-assisted sol-gel approach for potential muscle regeneration applications. First, X-ray diffraction (XRD), Fourier transform infrared (FTIR), and energy-dispersive X-ray spectroscopy (EDX) analyses were conducted to study the chemical structure and composition of the nanoparticles. To examine the nanoparticle morphology, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images were analyzed. Both SEM images and particle size distribution determined by dynamic light scattering (DLS) indicated a decrease of the average particle size after boron doping. TEM images indicated a slit-shaped mesoporous structure of nanoparticles for all compositions. The ζ potential was measured, and a negative surface charge was found for all study groups due to the presence of silanol groups. Cytocompatibility and fluorescence microscopy studies were also carried out. The results indicated that low concentrations (0.1 and 1 mg mL^-1) of all MBG nanoparticles led to high viability of C2C12 cells. Fluorescence microscopy images indicated that at lower nanoparticle concentrations (0.1 and 1 mg mL^-1), C2C12 cells appeared to differentiate into myotubes, which was indicated by a spindle-shaped morphology. For 10 mg mL^-1 concentration of nanoparticles, C2C12 cells had a lower aspect ratio (estimated qualitatively by inspection of the images), which implied a lower degree of differentiation. Boron-doped MBG nanoparticles in reduced concentrations are suitable to induce differentiation of C2C12 cells into myotubes, indicating their potential for applications in muscle tissue repair.

A modified passive-dynamic ankle-foot orthosis: can it prevent amputation and arthrodesis in patients with ankle-foot trauma?

INTRODUCTION

High-energy lower extremity trauma (HELET) may cause severe damage within the foot-ankle complex. Occasionally, arthrodesis or amputation are the only remaining options to increase activity levels. The modified passive dynamic ankle-foot orthosis (PDAFO) may prove to be a nonsurgical alternative. This study evaluated the effect of a modified PDAFO with a 6-week training program on pain and performance in patients after HELET.

MATERIALS AND METHODS

A retrospective cohort study was conducted on seventeen patients who considered an arthrodesis or an amputation after HELET. In an attempt to avoid surgery, the modified PDAFO with a 6-week training program was provided. Pain scores was measured with the Numeric Rating Scale and administered at the start of testing, immediately after the two performance tests and at the end of the day of testing. Performance was evaluated with the 6-min walk test (6MWT) and the Comprehensive high-level activity mobility predictor (CHAMP).

RESULTS

A significant pain reduction was achieved after the treatment procedure. At the start of the test days (p = 0.002), after the 6MWT (p = 0.001), after the CHAMP (p < 0.001) and at the end of the day (p < 0.001). In addition, a significant improvement on performance was observed in the 6MWT (p < 0.001) and the CHAMP (p = 0.01). None of the patients considered a surgical intervention anymore.

CONCLUSIONS

Patients after HELET show a decrease in pain and an improvement in performance after a 6-week training program with modified PD-AFO. The results suggest that the modified PDAFO is an effective alternative for a surgical approach.

Inclusion of a Military-specific, Virtual Reality-based Rehabilitation Intervention Improved Measured Function, but Not Perceived Function, in Individuals with Lower Limb Trauma

INTRODUCTION

Lower extremity injury is common in the military and can lead to instability, pain, and decreased function. Military service also places high physical demands on service members (SMs). Standard treatment interventions often fail to align with these unique demands. Thus, the goal of the study was to evaluate the effectiveness of a military-specific virtual reality-based rehabilitation (VR) intervention supplemental to standard care (SC) in improving military performance in SMs with lower extremity injuries.

MATERIALS AND METHODS

As part of an institutional review board-approved randomized control trial, SMs receiving care at an advanced rehabilitation center were randomized to receive either SC or VR in addition to SC (VR+SC). Participants were evaluated before treatment and ∼3 weeks later using a previously developed and validated military-specific assessment. Perceived improvement in physical function was measured using a Global Rating of Change (GROC) questionnaire. A repeated measures ANOVA was used to evaluate the effects of adding VR on the military-specific assessment measures. Linear regression was used to determine the relationship between perceived improvement, measured improvement, and VR volume.

RESULTS

The VR+SC group was able to traverse a greater distance in the assessment following the VR intervention. There was no significant difference in GROC between groups. For the VR+SC group, change in distance completed was not correlated with GROC, but GROC was correlated with VR volume.

CONCLUSION

VR improved the distance that participants were able to traverse in the assessment. However, the VR+SC group demonstrated a disconnect between their perceived functional improvement as measured by the GROC and functional improvement as measured by the change in the distance completed. Rather, the perceived improvement appears to be more correlated with the volume of VR received. The way in which the treatment progression is structured and communicated may influence how patients perceive their change in physical function.

Should I Stay or Should I Go? Identifying Intrinsic and Extrinsic Factors in the Decision to Return to Duty Following Lower Extremity Injury

INTRODUCTION

Rehabilitation research of wounded service members (SMs) commonly focuses on physical ability to return to duty (RTD) as a measure of successful recovery. However, numerous factors or barriers may influence a SM's ability and/or desire to RTD after lower extremity musculoskeletal trauma. SMs themselves as well as the clinical care team that works with them daily, often for years at a time, both offer unique perspectives on the influential factors that weigh into decisions to RTD. The purpose of this study was to identify the intrinsic and extrinsic factors patients and clinicians recognized as influencing the decision to RTD after severe lower extremity trauma.

MATERIALS AND METHODS

Thirty-two SMs with severe lower extremity trauma (amputation and lower limb salvage) and 30 providers with at least 2 years' experience caring for SMs with similar injuries participated separately in either a SM or provider/clinician focus group. Open-ended questions on factors influencing RTD and other rehabilitation success were discussed. Data analysis consisted of qualitative transcription and participatory active sorting, followed by thematic coding and grouping of qualitative data.

RESULTS

Individual (health condition, personal traits, and career consideration), interpersonal (clinician's impact, family influence, and peer influence), health care system (systems of care, transdisciplinary rehabilitation, and innovation availability), and institutional (policy, benefits, and unit/commander) themes emerged amongst SM patients and clinicians. Expected frequently occurring themes common to both groups were the influence of the team and family unit, as well as career trajectory options after a severe injury. An unexpected theme was acknowledgment of and dissatisfaction with the recent dismantling of institutional systems that support wounded SMs. Patients placed less emphasis on severity of injury and greater emphasis on system and policy barriers than did clinicians.

CONCLUSIONS

Characterization and classification of these clinician and SM-identified factors that influence the decision to RTD after severe lower extremity trauma is expected to improve the efficacy of future rehabilitation efforts and clinical practice guidelines by providing the clinical team the knowledge necessary to recognize modifiable barriers to patient success. A better understanding of factors influencing RTD decision-making may support policies for mitigating RTD barriers, better monitoring of the changing landscape of RTD after lower extremity trauma, improving systems of health care, and/or reducing turnover and facilitating force readiness.

Regenerative rehabilitation of catastrophic extremity injury in military conflicts and a review of recent developmental efforts

AIM OF THE REVIEW

This review aims to describe the current state of regenerative rehabilitation of severe military extremity injuries, and promising new therapies on the horizon.

DISCUSSION

The nature of warfare is rapidly shifting with information operations, autonomous weapons, and the threat of full-scale peer adversary conflicts threatening to create contested environments with delayed medical evacuation to definitive care. More destructive weapons will lead to more devastating injuries, creating new challenges for limb repair and restoration. Current paradigms of delayed rehabilitation following initial stabilization, damage control surgery, and prolonged antibiotic therapy will need to shift. Advances in regenerative medicine technologies offer the possibility of treatment along the continuum of care. Regenerative rehabilitation will begin at the point of injury and require a holistic, organ-systems approach.

CONCLUSIONS

Both technological improvements and a rapidly advancing understanding of injury pathophysiology will contribute to improved limb-salvage outcomes, and shift the calculus away from early limb amputation.

3D printed oxidized alginate-gelatin bioink provides guidance for C2C12 muscle precursor cell orientation and differentiation via shear stress during bioprinting

Biofabrication can be a tool to three-dimensionally (3D) print muscle cells embedded inside hydrogel biomaterials, ultimately aiming to mimic the complexity of the native muscle tissue and to create in-vitro muscle analogues for advanced repair therapies and drug testing. However, to 3D print muscle analogues of high cell alignment and synchronous contraction, the effect of biofabrication process parameters on myoblast growth has to be understood. A suitable biomaterial matrix is required to provide 3D printability as well as matrix degradation to create space for cell proliferation, matrix remodelling capacity, and cell differentiation. We demonstrate that by the proper selection of nozzle size and extrusion pressure, the shear stress during extrusion-bioprinting of mouse myoblast cells (C2C12) can achieve cell orientation when using oxidized alginate-gelatin (ADA-GEL) hydrogel bionk. The cells grow in the direction of printing, migrate to the hydrogel surface over time, and differentiate into ordered myotube segments in areas of high cell density. Together, our results show that ADA-GEL hydrogel can be a simple and cost-efficient biodegradable bioink that allows the successful 3D bioprinting and cultivation of C2C12 cells in-vitro to study muscle engineering.

Regenerative Repair of Volumetric Muscle Loss Injury is Sensitive to Age

In this study, the influence of age on effectiveness of regenerative repair for the treatment of volumetric muscle loss (VML) injury was explored. Tibialis anterior (TA) VML injuries were repaired in both 3- and 18-month-old animal models (Fischer 344 rat) using allogeneic decellularized skeletal muscle (DSM) scaffolds supplemented with autologous minced muscle (MM) paste. Within the 3-month animal group, TA peak contractile force was significantly improved (79% of normal) in response to DSM+MM repair. However, within the 18-month animal group, muscle force following repair (57% of normal) was not significantly different from unrepaired VML controls (59% of normal). Within the 3-month animal group, repair with DSM+MM generally reduced scarring at the site of VML repair, whereas scarring and a loss of contractile tissue was notable at the site of repair within the 18-month group. Within 3-month animals, expression of myogenic genes (MyoD, MyoG), extracellular matrix genes (Col I, Col III, TGF-β), and key wound healing genes (TNF-α and IL-1β) were increased. Alternatively, expression was unchanged across all genes examined within the 18-month animal group. The findings suggest that a decline in regenerative capacity and increased fibrosis with age may present an obstacle to regenerative medicine strategies targeting VML injury. Impact Statement This study compared the recovery following volumetric muscle loss (VML) injury repair using a combination of minced muscle paste and decellularized muscle extracellular matrix carrier in both a younger (3 months) and older (18 months) rat population. Currently, VML repair research is being conducted with the young patient population in mind, but our group is the first to look at the effects of age on the efficacy of VML repair. Our findings highlight the importance of considering age-related changes in response to VML when developing repair strategies targeting an elderly patient population.

A novel assessment for Readiness Evaluation during Simulated Dismounted Operations: A reliability study

Objective

To determine the intersession reliability of the Readiness Evaluation during Simulated Dismounted Operations (REDOp), a novel ecologically-based assessment for injured Service Members, provide minimal detectable change values, and normative reference range values. To evaluate the ability to differentiate performance limitations between able-bodied and injured individuals using the REDOp.

Design

Repeated measures design and between group comparison.

Setting

Outpatient rehabilitative care setting.

Participants

Service Members who were able-bodied (n = 32) or sustained a traumatic lower extremity injury (n = 22).

Interventions

During the REDOp, individuals walked over variable terrain as speed and incline progressively increased; they engaged targets; and carried military gear.

Main outcome measures

Endurance measured using total distance traveled; walking stability measured using range of full-body angular momentum; and shooting accuracy, precision, reaction time and acquisition time.

Results

Intersession reliability analyses were conducted on a sub-group of 18 able-bodied Service Members. Interclass correlation coefficient values were calculated for distance traveled (0.91), range of angular momentum about three axes (0.78–0.93), shooting accuracy (0.61), precision (0.47), reaction time (0.21), and acquisition time (0.77). Service Members with lower extremity injury demonstrated significantly less distance traveled with a median distance of 0.89 km compared to 2.73 km for the able-bodied group (p < 0.001). Service Members with lower extremity injury demonstrated significantly less stability in the frontal and sagittal planes than the able-bodied group (p < 0.001). The primary performance limiter was endurance followed by pain for both groups. There was no evidence of ceiling effects.

Conclusions

The REDOp is a highly reliable, military-relevant assessment that can be used to measure performance and identify deficits across the domains of activity tolerance, gait stability, and shooting performance.

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

INTRODUCTION

Severe lower limb injuries have a negative impact on many aspects of an individual's life. One rehabilitative option for patients who have undergone limb salvage is the Intrepid Dynamic Exoskeletal Orthosis (IDEO). The IDEO is a custom-made dynamic response device which is used to restore function for patients with a wide variety of injuries. Clinical outcomes were routinely collected on patients fit with IDEOs at the Center for the Intrepid, Brooke Army Medical Center. The purpose of this retrospective study was to analyze the clinical outcomes collection process and the patient outcomes collected as part of routine clinical care.

METHODS

The Brooke Army Medical Center IRB approved this study and granted waivers of informed consent and HIPAA authorization. Electronic medical records were reviewed over an 18-month period from July 2014 to January 2016. Records were examined to obtain the date of IDEO delivery, date of outcomes form completion, responses on the forms, and to verify diagnosis or injury. Data gathered included wear time, IDEO comfort, pain with and without the IDEO, Lower Extremity Functional Scale scores with and without the IDEO, and global rating of change questions for everyday activities and high impact activities. Wilcoxon signed-ranked tests were used to compare pain and function with vs. without the IDEO.

RESULTS

During the 18-month period, new IDEOs were delivered to 156 unique patients. Outcomes forms were collected as part of routine clinical care from 90 of these 156 patients (58%). An additional nine forms were collected from patients who received their IDEOs prior to July 2014. In all, 99 outcomes forms were collected. Mean follow-up time from IDEO delivery to outcomes form completion was 35 ± 31 days for the original 90 patients. The most common patient diagnoses were fracture, nerve injury, arthritis, and fusion. Responses on the forms indicated that patients were generally comfortable wearing their IDEOs (8.3 ± 1.3 on a 0-10 scale) and wore them most of the day (10.7 ± 3.4 hours per day). Improvement in pain (from 5.2 ± 2.9 to 1.7 ± 1.6 points on a 0-10 scale) and Lower Extremity Functional Scale scores (from 29.7 ± 16.6 to 59.5 ± 13.6 points) with the IDEO were both more than the minimal clinically important difference and were statistically significant (p < 0.001).

CONCLUSION

This descriptive retrospective study demonstrated that it was feasible to collect clinical outcomes data which were relevant for characterizing the effects of IDEO use and enabled quantification of improvements in self-reported function and walking pain with the IDEO. Due to the retrospective nature of this study, limitations include missing data and the lack of any performance measures to complement the self-reported data. Clinical outcomes collection continues as a routine part of clinical care and there remains an ongoing aim to collect information on all patients to obtain an accurate assessment of devices and services and ultimately better serve our patients.

Advanced Functional Bracing in Lower Extremity Trauma: Bracing to Improve Function

There are many bracing options for patients with functional limitations of the lower extremity following trauma. The first question that the provider must ask when evaluating a patient with a foot and ankle functional limitation because of weakness or pain is, "what are the patient's expectations?" One option for the patient who desires to return to a higher level of function is a novel, custom dynamic orthosis (CDO) that, when coupled with an advanced rehabilitation program, has improved outcomes in patients following lower extremity trauma who have plateaued after traditional rehabilitation pathways. Although this CDO and rehabilitation program has demonstrated success following lower extremity trauma in heterogenous patient populations, research is ongoing to identify both ideal referral diagnoses or injury characteristics, and to further optimize outcomes with the use of the CDO.

High-Level Performance After the Return to Run Clinical Pathway in Patients Using the Intrepid Dynamic Exoskeletal Orthosis

BACKGROUND

Severe ankle and foot injuries in the US military can result in high-level functional limitation, lost duty days, and medical discharge.

OBJECTIVE

To assess the effectiveness of the Return to Run Clinical Pathway (RTR) in returning patients with lower extremity fractures who utilized the Intrepid Dynamic Exoskeletal Orthosis (IDEO) to high-level mobility.

METHODS

Thirty servicemembers with lower extremity fractures who utilized the IDEO unilaterally and completed the RTR at Naval Medical Center San Diego were included in this retrospective operational review. The Comprehensive High-level Activity Mobility Predictor (CHAMP) and all subtests were completed prior to and after completion of the RTR as part of routine clinical care. An analysis of covariance (ANCOVA) was used to compare CHAMP scores before and after the RTR.

RESULTS

Significant improvements were found in the T test (mean change, faster by 5.3 seconds; 95% confidence interval: 3.6, 7.1 seconds; P = .03) and total CHAMP score (mean change, 4.2 points; 95% confidence interval: 3.0, 5.3 points; P<.05). No significant changes were noted in the single-legged stance subtest, the Edgren sidestep test, or the Illinois agility test.

CONCLUSION

The RTR led to improvements in high-level, multidirectional mobility in IDEO users with a history of fractures. Applicability of the intervention used in this study requires further validation before widespread use.

LEVEL OF EVIDENCE

Therapy, level 4. J Orthop Sports Phys Ther 2019;49(7):529-535. Epub 13 Feb 2019. doi:10.2519/jospt.2019.8763.

Do Spatiotemporal Gait Parameters Improve After Pilon Fracture in Patients Who Use the Intrepid Dynamic Exoskeletal Orthosis?

BACKGROUND

Pilon fractures are high-energy fractures about the ankle observed commonly in both civilian and military trauma populations. Despite surgical management, outcomes are predictably poorly characterized by functional deficits secondary to pain and stiffness. The Intrepid Dynamic Exoskeletal Orthosis (IDEO) and Return-to-Run clinical pathway were initially designed to treat military service members after complex battlefield lower extremity injuries. The IDEO has been used to treat nonbattlefield injuries, but, to our knowledge, it has not been studied specifically among patients with pilon fractures. By studying the use of the IDEO in this patient population, we hope to learn how it might improve ambulation in the community, relieve pain, and return patients to work to better identify patients who might benefit from its use.

QUESTIONS/PURPOSES

The purpose of this study was to determine whether the IDEO would improve gait parameters including velocity, cadence, stride length, and single-leg stance duration in patients with pilon fractures. Our secondary endpoints of interest were reductions in pain and return to duty.

METHODS

A prospectively collected database of all active-duty IDEO users at a single institution was queried for all patients using the IDEO after a pilon fracture. Patients were included if they were using the IDEO after sustaining a surgically treated pilon fracture and had exhausted all nonoperative therapies. Exclusions were patients with an incomplete gait analysis at the two study time points. Seven patients meeting these criteria were identified. Three-dimensional gait analysis was performed two times: first wearing shoes at a self-selected speed and second after a custom-made IDEO was fabricated for the patient and completion of the Return-to-Run pathway. Patients reported their average pain while ambulating using a numeric rating scale. Gait variables of interest were velocity, cadence, stride length, and single stance time. Return to military service was assessed through the military medical record. To return to duty, a service-specific physical readiness test must be completed.

RESULTS

Median gait velocity improved from 1.1 (interquartile range [IQR], 0.9-1.2) to 1.3 m/s (IQR, 1.2-1.5; p = 0.01). All other variables did not change: cadence 98.4 (IQR, 93.0-107.2) to 104.5 steps/min (IQR, 103.0-109.0; p = 0.13), affected stride length 1.3 (IQR, 1.0-1.4 m) to 1.4 m (IQR, 1.3-1.6 m; p = 0.07), and affected single stance 0.42 (IQR, 0.41-0.47) to 0.43 (IQR, 0.42-0.44; p = 0.80). Pain did not change between time points: 3 (IQR, 2-3) to 2.5 (IQR, 1-3.5; p = 0.90). Three of seven patients returned to duty.

CONCLUSIONS

At self-selected walking speeds, we observed no improvements in gait parameters or pain after application of the IDEO that would likely be considered clinically important, and so the device is unlikely to be worth the cost in this setting. It is possible that for higher demand users such as elite athletes, the IDEO could have a role after severe lower extremity trauma; however, this must be considered speculative until or unless proven in future studies.

LEVEL OF EVIDENCE

Level III, therapeutic study.

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 Achilles Tendon Rupture

Blood flow restriction (BFR) training is a technique shown to be safe and effective at increasing muscular strength and endurance in healthy fitness populations and is under study for its use in postinjury rehabilitation. BFR stimulates muscular strength and hypertrophy gains at much lower loads than traditional methods, allowing patients to begin the rehabilitation process much sooner. We report on 2 patients who incorporated BFR training into their traditional rehabilitation program after Achilles tendon ruptures. Patient 1 was a 29-year-old active duty soldier who sustained a left Achilles tendon rupture while playing competitive football. After operative repair and traditional rehabilitative measures, he was unable to ambulate without assistive devices owing to persistent weakness. The patient subsequently started a 5-week "return to run" program using BFR training. He experienced plantarflexion peak torque improvements of 522% and 108.9% and power gains of 4475% and 211% at 60°/s and 120°/s, respectively. He was able to ambulate without assistive devices at the 5-week follow-up examination. Patient 2 was a 38-year-old male soldier who experienced a complete left Achilles tendon rupture while exercising. After nonoperative treatment with an accelerated rehabilitation program, the patient still experienced significant strength and functional deficits. He was subsequently enrolled in a 6-week course of BFR training. He experienced plantarflexion strength improvements of 55.8% and 47.1% and power gains of 68.8% and 78.7% at 60°/s and 120°/s, respectively. He was able to return to running and sports on completion of 6 weeks of BFR-assisted therapy. Incorporating tourniquet-assisted blood flow restriction with rehabilitation programs can improve strength, endurance, and function after Achilles tendon rupture.

Assessment of Mechanical Characteristics of Ankle-Foot Orthoses

Recent designs of ankle-foot orthoses (AFOs) have been influenced by the increasing demand for higher function from active individuals. The biomechanical function of the individual and device is dependent upon the underlying mechanical characteristics of the AFO. Prior mechanical testing of AFOs has primarily focused on rotational stiffness to provide insight into expected functional outcomes; mechanical characteristics pertaining to energy storage and release have not yet been investigated. A pseudostatic bench testing method is introduced to characterize compressive stiffness, device deflection, and motion of solid-ankle, anterior floor reaction, posterior leaf spring, and the intrepid dynamic exoskeletal orthosis (IDEO) AFOs. Each of these four AFOs, donned over a surrogate limb, were compressively loaded at different joint angles to simulate the foot-shank orientation during various subphases of stance. In addition to force–displacement measurements, deflection of each AFO strut and rotation of proximal and supramalleolar segments were analyzed. Although similar compressive stiffness values were observed for AFOs designed to reduce ankle motion, the corresponding strut deflection profile differed based on the respective fabrication material. For example, strut deflection of carbon-fiber AFOs resembled column buckling. Expanded clinical test protocols to include quantification of AFO deflection and rotation during subject use may provide additional insight into design and material effects on performance and functional outcomes, such as energy storage and release.

Ankle-foot orthosis bending axis influences running mechanics

Passive-dynamic ankle-foot orthoses (AFOs) are commonly prescribed to improve locomotion for people with lower limb musculoskeletal weakness. The clinical prescription and design process are typically qualitative and based on observational assessment and experience. Prior work examining the effect of AFO design characteristics generally excludes higher impact activities such as running, providing clinicians and researchers limited information to guide the development of objective prescription guidelines. The proximal location of the bending axis may directly influence energy storage and return and resulting running mechanics. The purpose of this study was to determine if the location of an AFO's bending axis influences running mechanics. Marker and force data were recorded as 12 participants with lower extremity weakness ran overground while wearing a passive-dynamic AFO with posterior struts manufactured with central (middle) and off-centered (high and low) bending axes. Lower extremity joint angles, moments, powers, and ground reaction forces were calculated and compared between limbs and across bending axis conditions. Bending axis produced relatively small but significant changes. Ankle range of motion increased as the bending axis shifted distally (p<0.003). Peak ankle power absorption was greater in the low axis than high (p=0.013), and peak power generation was greater in the low condition than middle or high conditions (p<0.009). Half of the participants preferred the middle bending axis, four preferred low and two preferred high. Overall, if greater ankle range of motion is tolerated, a low bending axis provides power and propulsive benefits during running, although individual preference and physical ability should also be considered.

Gait biomechanics following lower extremity trauma: Amputation vs. reconstruction

BACKGROUND

Surgical advances have substantially improved outcomes for individuals sustaining traumatic lower extremity injury. Injuries once requiring lower limb amputation are now routinely managed with limb reconstruction surgery. However, comparisons of functional outcomes between the procedures are inconclusive.

PURPOSE

To compare gait biomechanics after lower limb reconstruction and transtibial amputation.

METHODS

Twenty-four individuals with unilateral lower limb reconstruction wearing a custom ankle-foot orthosis (Intrepid Dynamic Exoskeletal Orthosis), 24 with unilateral, transtibial amputation, and 24 able-bodied control subjects underwent gait analysis at a standardized Froude speed based on leg length. Lower extremity joint angles, moments, and powers, and ground reaction forces were analyzed on the affected limb of patients and right limb of able-bodied individuals. ANOVA with Tukeys post-hoc tests determined differences among groups and post-hoc paired t-tests with Bonferroni-Holm corrections determined differences between limbs.

RESULTS

The ankle, knee, and hip exhibited significant kinematic differences between amputated, reconstructed and able-bodied limbs. The reconstruction group exhibited less ankle power and range of motion while the amputee group exhibited lower knee flexor and extensor moments and power generation.

CONCLUSION

Gait deficiencies were more pronounced at the ankle following limb reconstruction with orthosis use and at the knee following transtibial amputation with prosthesis use. Although both groups in the cohorts tested can replicate many key aspects of normative gait mechanics, some deficiencies still persist. These results add to the growing body of literature comparing amputation and limb reconstruction and provide information to inform the patient on functional expectations should either procedure be considered.

Effect of Custom Orthosis and Rehabilitation Program on Outcomes Following Ankle and Subtalar Fusions

BACKGROUND

Fractures of the distal tibia, ankle, and foot sustained through a high-energy mechanism can be extremely debilitating, and ankle and/or subtalar fusion may be indicated if the limb is deemed salvageable. Functional outcomes among this population are often poor. The purposes of this study were to evaluate the effect of an advanced rehabilitation program combined with the use of a custom ankle-foot orthosis for patients with ankle or subtalar fusion on selected physical performance measures and patient-derived outcome measures and to determine if the response to treatment was predicated upon the type of fusion.

METHODS

We conducted a prospective, longitudinal, observational, cohort study composed of 23 active duty Service Members treated for lower extremity trauma. Patients were separated into 2 groups: group 1 was composed of 12 patients who underwent isolated ankle fusion or ankle fusion combined with ipsilateral subtalar fusion, group 2 was composed of 11 patients who underwent subtalar fusion only. Patient-reported outcome (PRO) measures and physical performance measures were recorded at baseline and at the conclusion of the rehabilitation program.

RESULTS

Significant improvements in both groups were seen in each of the 4 physical performance measures. Only group 2 showed significant improvements in all domains of the Veteran's Rand 12-Item Health Survey (VR-12) and Short Musculoskeletal Function Assessment (SMFA) at all points during the course of rehabilitation.

CONCLUSION

Among a subset of patients treated for severe lower extremity trauma with ankle and/or subtalar fusion, an integrated orthotic and rehabilitation initiative improved physical performance and PRO measures over an 8-week course.

LEVEL OF EVIDENCE

Level III, prospective comparative series.

Stair ascent and descent biomechanical adaptations while using a custom ankle-foot orthosis

The ability to navigate stairs step-over-step is an important functional outcome following severe lower leg injury and is difficult for many patients. Ankle-foot orthoses, such as the Intrepid Dynamic Exoskeletal Orthosis (IDEO), are often prescribed to improve function. This study compared stair climbing mechanics between IDEO users and able-bodied control participants. Thirteen IDEO users who sustained severe lower leg injury and 13 controls underwent biomechanical gait analysis. Participants ascended and descended a 16-step instrumented staircase without handrail use at a controlled cadence of 80 steps/min. Peak joint angles, moments, powers, and ground reaction forces, and integrated mechanical work were calculated. Independent t-tests with Bonferroni-Holm corrections were used to compare controls to IDEO and sound limbs. Reduced ankle range of motion on the IDEO limb resulted in compensatory strategies while ascending or descending stairs. During ascent, IDEO users had greater bilateral hip power during pull-up (p<0.007) to compensate for the IDEO limb׳s reduced ankle dorsiflexion (p<0.001) and knee extensor moment (p=0.001) while it was leading, and reduced ankle plantarflexor power while it was trailing (p<0.001). During stair descent, when the IDEO limb had was trailing, it had less ankle dorsiflexion during controlled lowering (p<0.001), resulting in greater vertical ground reaction force (p=0.005) and greater ankle and knee power absorption (p<0.001). Reduced IDEO limb ankle power absorption during weight acceptance (p<0.001) resulted in a large knee extensor moment (p<0.001) on the trailing sound limb to lower the body. Despite gait deviations, IDEO users were able to climb stairs step-over-step unassisted.

Manual physical therapy combined with high-intensity functional rehabilitation for severe lower extremity musculoskeletal injuries: a case series

OBJECTIVES

Severe lower extremity trauma accounts for large healthcare costs and often results in elective amputation and poor long-term outcomes. The purpose of this case series is to describe an orthopedic manual physical therapy (OMPT) approach combined with a return to run (RTR) clinical pathway consisting of high-intensity functional rehabilitation with a custom energy-storing orthosis.

METHODS

Three consecutive male patients, aged 21-23 years, with severe lower extremity musculoskeletal injuries were treated with a combined intervention that included a mean (SD) of 12 (2·1) OMPT sessions and 24 (8·7) functional rehabilitation sessions over a mean of 6 weeks (1·0). Additional training with a custom energy-storing orthosis consisted of a mean of 15 (1·2) additional sessions over 4 weeks. Patient self-report outcome measures and a variety of physical performance tests captured change in function.

RESULTS

Baseline lower extremity functional scale (LEFS) and foot and ankle ability measure activities of daily living subscale (FAAM-ADL) scores indicated severe disability. All patients exceeded the minimal clinically important difference (MCID) in at least one self-report outcome or physical performance test without a brace. Two of three patients exceeded the MCID for at least two physical performance tests after training with and utilizing a custom energy-storing orthosis.

DISCUSSION

Clinically meaningful changes in self-reported function or physical performance were observed in all patients. A multi-modal approach, including manual therapy and functional exercise, may address the entire spectrum of impairments in patients with severe lower extremity trauma, resulting in improvements in both braced and un-braced function.

Biomechanical response to ankle-foot orthosis stiffness during running

BACKGROUND

The Intrepid Dynamic Exoskeletal Orthosis (IDEO) is an ankle-foot orthosis developed to address the high rates of delayed amputation in the military. Its use has enabled many wounded Service Members to run again. During running, stiffness is thought to influence an orthosis' energy storage and return mechanical properties. This study examined the effect of orthosis stiffness on running biomechanics in patients with lower limb impairments who had undergone unilateral limb salvage.

METHODS

Ten patients with lower limb impairments underwent gait analysis at a self-selected running velocity. 1. Nominal (clinically-prescribed), 2. Stiff (20% stiffer than nominal), and 3. Compliant (20% less stiff than nominal) ankle-foot orthosis stiffnesses were tested.

FINDINGS

Ankle joint stiffness was greatest in the stiffest strut and lowest in the compliant strut, however ankle mechanical work remained unchanged. Speed, stride length, cycle time, joint angles, moments, powers, and ground reaction forces were not significantly different among stiffness conditions. Ankle joint kinematics and ankle, knee and hip kinetics were different between limbs. Ankle power, in particular, was lower in the injured limb.

INTERPRETATION

Ankle-foot orthosis stiffness affected ankle joint stiffness but did not influence other biomechanical parameters of running in individuals with unilateral limb salvage. Foot strike asymmetries may have influenced the kinetics of running. Therefore, a range of stiffness may be clinically appropriate when prescribing ankle-foot orthoses for active individuals with limb salvage.

Physical rehabilitation improves muscle function following volumetric muscle loss injury

Background

Given the clinical practice of prescribing physical rehabilitation for the treatment of VML injuries, the present study examined the functional and histomorphological adaptations in the volumetric muscle loss (VML) injured muscle to physical rehabilitation.

Methods

Tibialis anterior muscle VML injury was created in Lewis rats (n = 32), and were randomly assigned to either sedentary (SED) or physical rehabilitation (RUN) group. After 1 week, RUN rats were given unlimited access to voluntary running wheels either 1 or 7 weeks (2 or 8 weeks post-injury). At 2 weeks post-injury, TA muscles were harvested for molecular analyses. At 8 weeks post-injury, the rats underwent in vivo function testing. The explanted tissue was analyzed using histological and immunofluorescence procedures.

Results

The primary findings of the study are that physical rehabilitation in the form of voluntary wheel running promotes ~ 17% improvement in maximal isometric torque, and a ~ 13% increase in weight of the injured muscle, but it did so without significant morphological adaptations (e.g., no hypertrophy and hyperplasia). Wheel running up-regulated metabolic genes (SIRT-1, PGC-1α) only in the uninjured muscles, and a greater deposition of fibrous tissue in the defect area of the injured muscle preceded by an up-regulation of pro-fibrotic genes (Collagen I, TGF-β1). Therefore, it is plausible that the wheel running related functional improvements were due to improved force transmission and not muscle regeneration.

Conclusions

This is the first study to demonstrate improvement in functional performance of non-repaired VML injured muscle with physical rehabilitation in the form of voluntary wheel running. This study provides information for the first time on the basic changes in the VML injured muscle with physical rehabilitation, which may aid in the development of appropriate physical rehabilitation regimen(s).

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.

The influence of ankle-foot orthosis stiffness on walking performance in individuals with lower-limb impairments

BACKGROUND

Passive-dynamic ankle-foot orthoses utilize stiffness to improve gait performance through elastic energy storage and return. However, the influence of ankle-foot orthosis stiffness on gait performance has not been systematically investigated, largely due to the difficulty of manufacturing devices with precisely controlled stiffness levels. Additive manufacturing techniques such as selective laser sintering have been used to successfully manufacture ankle-foot orthoses with controlled stiffness levels. The purpose of this study was to use passive-dynamic ankle-foot orthoses manufactured with selective laser sintering to identify the influence of orthosis stiffness on walking performance in patients with lower-limb neuromuscular and musculoskeletal impairments.

METHODS

Thirteen subjects with unilateral impairments were enrolled in this study. For each subject, one passive-dynamic ankle-foot orthosis with stiffness equivalent to the subject's clinically prescribed carbon fiber orthosis, one 20% more compliant and one 20% more stiff, were manufactured using selective laser sintering. Three-dimensional kinematic and kinetic data and electromyographic data were collected from each subject while they walked overground with each orthosis at their self-selected velocity and a controlled velocity.

FINDINGS

As the orthosis stiffness decreased, ankle range of motion and medial gastrocnemius activity increased while the knee became more extended throughout stance. Minimal changes in other kinematic, kinetic and electromyographic quantities were observed.

INTERPRETATION

Subjects effectively compensated for changes in ankle-foot orthosis stiffness with altered gastrocnemius activity, and the stiffness levels analyzed in this study had a minimal effect on overall walking performance.

Initial injury severity and social factors determine ability to deploy after combat-related amputation

OBJECTIVE

While many recent publications have examined the ability of amputees to return to active duty, it remains largely unknown why few amputees deploy after amputation and many amputees do not. The purpose of this study is to examine what predictor(s) exist for whether or not an amputee will deploy after sustaining a combat-related amputation.

METHODS

All U.S. Service members who sustained major extremity amputations from September 2001 through July 2011 were analysed. Amputation level(s), mechanism of injury, time interval to amputation, age, rank, Physical Evaluation Board (PEB) disposition and ability to deploy after amputation were determined.

RESULTS

Deployment information after amputation was obtained for 953 amputees. There were 47 (5%) amputees who deployed. There were no significant differences amongst service branches for the deployment of amputees (p > 0.2). Amputees who underwent their amputation on the same day of their injury were significantly less likely to deploy after amputation than those who had their amputation on the day of injury (p = .01). Deployed amputees had significantly lower Injury Severity Scores than amputees who did not deploy (15.98 vs 20.87, p < 0.01) and officers were significantly (p < .01) more likely to deploy and the average age of amputees who deployed was significantly higher than those who did not (27.5 vs 25.1, p < .01). Lastly, those amputees who sustained a transtibial amputation were significantly more likely to deploy than all other amputation levels (p < .01). Nine out of 19 (47%) Special Forces amputees were able to deploy.

DISCUSSION

The vast majority of amputees do not able to deploy after undergoing amputation. The main predictors of deploying after sustaining a combat-related amputation appear to be: sustaining a transtibial amputation, being of senior rank or age and being a member of the Special Forces. Many of these factors appear to be non-treatment related and highlight the importance that individual and social factors play in the recovery of severe injuries.

Implantation of in vitro tissue engineered muscle repair constructs and bladder acellular matrices partially restore in vivo skeletal muscle function in a rat model of volumetric muscle loss injury

The frank loss of a large volume of skeletal muscle (i.e., volumetric muscle loss [VML]) can lead to functional debilitation and presents a significant problem to civilian and military medicine. Current clinical treatment for VML involves the use of free muscle flaps and physical rehabilitation; however, neither are effective in promoting regeneration of skeletal muscle to replace the tissue that was lost. Toward this end, skeletal muscle tissue engineering therapies have recently shown great promise in offering an unprecedented treatment option for VML. In the current study, we further extend our recent progress (Machingal et al., 2011, Tissue Eng; Corona et al., 2012, Tissue Eng) in the development of tissue engineered muscle repair (TEMR) constructs (i.e., muscle-derived cells [MDCs] seeded on a bladder acellular matrix (BAM) preconditioned with uniaxial mechanical strain) for the treatment of VML. TEMR constructs were implanted into a VML defect in a tibialis anterior (TA) muscle of Lewis rats and observed up to 12 weeks postinjury. The salient findings of the study were (1) TEMR constructs exhibited a highly variable capacity to restore in vivo function of injured TA muscles, wherein TEMR-positive responders (n=6) promoted an ≈61% improvement, but negative responders (n=7) resulted in no improvement compared to nonrepaired controls, (2) TEMR-positive and -negative responders exhibited differential immune responses that may underlie these variant responses, (3) BAM scaffolds (n=7) without cells promoted an ≈26% functional improvement compared to uninjured muscles, (4) TEMR-positive responders promoted muscle fiber regeneration within the initial defect area, while BAM scaffolds did so only sparingly. These findings indicate that TEMR constructs can improve the in vivo functional capacity of the injured musculature at least, in part, by promoting generation of functional skeletal muscle fibers. In short, the degree of functional recovery observed following TEMR implantation (BAM+MDCs) was 2.3×-fold greater than that observed following implantation of BAM alone. As such, this finding further underscores the potential benefits of including a cellular component in the tissue engineering strategy for VML injury.

Functional rehabilitation with a foot plate modification for circular external fixation

BACKGROUND

Customized foot plates attached to the foot ring of an ankle-spanning circular external fixator present a unique opportunity for patients undergoing complex lower-extremity limb salvage to participate in highly advanced weight-bearing physical therapy. The purpose of this study was to identify the rehabilitation capabilities afforded by this external fixator modification.

METHODS

Surgical logs and radiographs were reviewed to identify all lower-extremity limb salvage patients from February 2008 to December 2010 treated with an ankle-spanning circular external fixator and a customized foot plate treated by the same orthopedic surgeon and enrolled in our institution's Return To Run clinical pathway. Medical records were reviewed to identify a series of exercises that each patient was able to perform.

RESULTS

Eleven patients were identified. All patients were treated by the same physical therapist. All 11 patients were able to bear full weight on their foot plates and perform regular and split squats. Six of 11 patients were able to ambulate unassisted, and 5 patients required a cane. All 11 patients could navigate stairs and use an elliptical and stair-stepping machine. Six of 11 patients could perform single-leg hack squats. Eight of 11 patients were able to perform double-leg shuttle jumps, although only 5 of 11 patients could perform single-leg shuttle jumps. Five of 11 patients were able to perform a single-leg balance. Only 1 patient was able to run on the foot plate.

CONCLUSIONS

Patients undergoing lower-extremity limb salvage with an ankle-spanning circular external fixator and a customized foot plate were able to participate in highly advanced weight-bearing physical therapy exercises during the osseous and soft-tissue healing process.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

A standardized rat model of volumetric muscle loss injury for the development of tissue engineering therapies

Soft tissue injuries involving volumetric muscle loss (VML) are defined as the traumatic or surgical loss of skeletal muscle with resultant functional impairment and represent a challenging clinical problem for both military and civilian medicine. In response, a variety of tissue engineering and regenerative medicine treatments are under preclinical development. A wide variety of animal models are being used, all with critical limitations. The objective of this study was to develop a model of VML that was reproducible and technically uncomplicated to provide a standardized platform for the development of tissue engineering and regenerative medicine solutions to VML repair. A rat model of VML involving excision of ∼20% of the muscle's mass from the superficial portion of the middle third of the tibialis anterior (TA) muscle was developed and was functionally characterized. The contralateral TA muscle served as the uninjured control. Additionally, uninjured age-matched control rats were also tested to determine the effect of VML on the contralateral limb. TA muscles were assessed at 2 and 4 months postinjury. VML muscles weighed 22.7% and 19.5% less than contralateral muscles at 2 and 4 months postinjury, respectively. These differences were accompanied by a reduction in peak isometric tetanic force (Po) of 28.4% and 32.5% at 2 and 4 months. Importantly, Po corrected for differences in body weight and muscle wet weights were similar between contralateral and age-matched control muscles, indicating that VML did not have a significant impact on the contralateral limb. Lastly, repair of the injury with a biological scaffold resulted in rapid vascularization and integration with the wound. The technical simplicity, reliability, and clinical relevance of the VML model developed in this study make it ideal as a standard model for the development of tissue engineering solutions for VML.

Deployment after limb salvage for high-energy lower-extremity trauma

BACKGROUND

Many wounded warriors experienced high-energy lower-extremity trauma (HELET) that may be limb threatening. Volumetric muscle loss, posttraumatic osteoarthritis, nerve injuries, and pain may severely limit physical function. Several wounded warriors express a strong desire to return to their units and be deployed in their original military occupational specialty. We began the return-to-run (RTR) clinical pathway at our institution 2 years ago to facilitate high-performance goals such as these. It involves an energy storing ankle foot orthosis, the intrepid dynamic exoskeletal orthosis in combination with high-intensity, progression-oriented rehabilitation. We sought to determine the rate of deployment or predeployment training after participation in this noninvasive intervention.

METHODS

A retrospective analysis of the RTR database was performed to determine the rate of deployment or predeployment training among those service members who began participation in the RTR between November of 2009 and March of 2011. Medical records were reviewed for demographics, injury, surgical data, and major complications. Requests for delayed amputation were recorded, and charts were reviewed to determine if patients eventually elected to proceed with amputation or if they chose to continue with limb salvage.

RESULTS

Between November 2009 and March 2011, 87 service members completed the RTR. Of these, 17 (19.5%) have been deployed to combat or are in predeployment training. Sixteen serve in combat arms (nine Special Forces, four infantry/ranger, two combat engineers, and one gunner), and one is a member of the military intelligence community. Fifteen patients sustained their injuries as a result of HELET (four gunshot, five motor vehicle collisions, four explosions, one parachute injury, and one fall from height), one had idiopathic avascular necrosis of the talus, and one had an iatrogenic nerve injury after pelvic surgery. Six of the patients underwent circular external fixation, five received joint fusions (three ankle, two subtalar joint), and nine had major nerve injuries. Four initially desired amputation of their injured limb but have subsequently countermanded their request.

CONCLUSION

Returning to high-level physical function after HELET is challenging. After implementation of the RTR clinical pathway with the intrepid dynamic exoskeletal orthosis, 19.5% of wounded warriors treated with the RTR have been deployed or will be deployed in the coming year.