Comparative effect of orthosis design on functional performance

Impact of Traumatic Lower Extremity Injuries Beyond Acute Care: Movement-Based Considerations for Resultant Longer Term Secondary Health Conditions

Significance: Advances in field-based trauma care, surgical techniques, and protective equipment have collectively facilitated the survival of a historically large number of service members (SMs) following combat trauma, although many sustained significant composite tissue injuries to the extremities, including limb loss (LL) and limb salvage (LS). Beyond the acute surgical and rehabilitative efforts that focus primarily on wound care and restoring mobility, traumatic LL and LS are associated with several debilitating longer term secondary health conditions (e.g., low back pain [LBP], osteoarthritis [OA], and cardiovascular disease [CVD]) that can adversely impact physical function and quality of life. Recent Advances: Despite recent advancements in prosthetic and orthotic devices, altered movement and mechanical loading patterns have been identified among persons with LL and salvage, which are purported risk factors for the development of longer term secondary musculoskeletal conditions and may limit functional outcomes and/or concomitantly impact cardiovascular health. Critical Issues: The increased prevalence of and risk for LBP, OA, and CVD among the relatively young cohort of SMs with LL and LS significantly impact physiological and psychological well-being, particularly over the next several decades of their lives. Future Directions: Longitudinal studies are needed to characterize the onset, progression, and recurrence of health conditions secondary to LL and salvage. While not a focus of the current review, detailed characterization of physiological biomarkers throughout the rehabilitation process may provide additional insight into the current understanding of disease processes of the musculoskeletal and cardiovascular systems.

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.

Patient Response to an Integrated Orthotic and Rehabilitation Initiative for Traumatic Injuries: The PRIORITI-MTF Study

Although limb salvage is now possible for many high-energy open fractures and crush injuries to the distal tibia, ankle, hindfoot, and midfoot, orthotic options are limited. The Intrepid Dynamic Exoskeletal Orthosis (IDEO) is a custom, energy-storing carbon fiber orthosis developed for trauma patients undergoing limb salvage. The IDEO differs from other orthoses in that it allows patients with ankle weakness to have more normal ankle biomechanics and increased ankle power. This article describes the design of a study to evaluate the effectiveness of the IDEO when delivered together with a high-intensity, sports medicine-based approach to rehabilitation. It builds on earlier studies by testing the program at military treatment facilities beyond the Brooke Army Medical Center and the Center for the Intrepid where the device was developed. The PRIORITI-MTF study is a multicenter before-after program evaluation where participants at least 1 year out from a traumatic lower extremity injury serve as their own controls. Participants are evaluated before receiving the IDEO, immediately after 4 weeks of physical therapy with the IDEO and at 6 and 12 months after the completion of physical therapy. Primary outcomes include functional performance, measured using well-validated assessments of speed, agility, power, and postural stability and self-reported functioning using the Short Musculoskeletal Function Assessment (SMFA) and the Veterans Health Survey (VR-12). Secondary outcomes include pain, depression, posttraumatic stress, and satisfaction with the IDEO.

A Comparison of Four-Year Health Outcomes following Combat Amputation and Limb Salvage

Little research has described the long-term health outcomes of patients who had combat-related amputations or leg-threatening injuries. We conducted retrospective analysis of Department of Defense and Department of Veterans Affairs health data for lower extremity combat-injured patients with (1) unilateral amputation within 90 days postinjury (early amputation, n = 440), (2) unilateral amputation more than 90 days postinjury (late amputation, n = 78), or (3) leg-threatening injuries without amputation (limb salvage, n = 107). Patient medical records were analyzed for four years postinjury. After adjusting for group differences, early amputation was generally associated with a lower or similar prevalence for adverse physical and psychological diagnoses (e.g., pain, osteoarthritis, posttraumatic stress disorder) versus late amputation and/or limb salvage. By contrast, early amputation was associated with an increased likelihood of osteoporosis during the first year postinjury. The prevalence of posttraumatic stress disorder increased for all patient groups over four years postinjury, particularly in the second year. The different clinical outcomes among combat extremity injured patients treated with early amputation, late amputation, or limb salvage highlight their different healthcare requirements. These findings can inform and optimize the specific treatment pathways that address the physical and psychological healthcare needs of such patients over time.

Limb Salvage With Intrepid Dynamic Exoskeletal Orthosis Versus Transtibial Amputation: A Comparison of Functional Gait Outcomes

OBJECTIVES

To determine if there is a difference in functional gait outcomes between patients with limb injuries treated with either transtibial amputation or limb preservation with the Intrepid Dynamic Exoskeletal Orthosis.

DESIGN

Retrospective prognostic study.

SETTING

Tertiary referral military hospital.

PATIENTS

This study included 10 transtibial amputees and 10 limb preservation patients using the Intrepid Dynamic Exoskeletal Orthosis who were matched by body mass index after excluding for nontraumatic, proximal ipsilateral, contralateral, spine, or traumatic brain injuries. Transtibial amputation patients were also excluded if they did not have a gait study between 6 and 12 months after independent ambulation. Limb preservation were excluded if they did not complete the "Return to Run" program.

INTERVENTIONS

An observational study of functional outcomes using instrumented gait analysis.

OUTCOME MEASURES

Spatiotemporal, kinetic (vertical ground reaction force), unified deformable power, work, and efficiency.

RESULTS

Limb preservation patients walked with a significantly slower cadence (P = 0.036) and spent less time on their affected limb in stance (P = 0.045), and longer in swing (P = 0.019). Amputees had significantly increased maximum positive power in both limbs (P = 0.004 and P = 0.029) and increased maximum negative power on the unaffected limb (P = 0.035). Amputees had significantly increased positive and negative work in the affected limb (P = 0.0009 and P = 0.014) and positive work in the unaffected limb (P = 0.042). There was no significant difference in the kinetic data or efficiency.

CONCLUSIONS

Limb preservation patients spend less time on their affected limb as a percentage of the gait cycle. The unified deformable power demonstrated more dynamic gait in amputees, with peak values closer to normative data.

LEVEL OF EVIDENCE

Therapeutic level III. See Instructions for Authors for a complete description of levels of evidence.

Regenerative and Rehabilitative Medicine: A Necessary Synergy for Functional Recovery from Volumetric Muscle Loss Injury

Volumetric muscle loss (VML) is a complex and heterogeneous problem due to significant traumatic or surgical loss of skeletal muscle tissue. The consequences of VML are substantial functional deficits in joint range of motion and skeletal muscle strength, resulting in life-long dysfunction and disability. Traditional physical medicine and rehabilitation paradigms do not address the magnitude of force loss due to VML and related musculoskeletal comorbidities. Recent advancements in regenerative medicine have set forth encouraging and emerging therapeutic options for VML injuries. There is significant potential that combined rehabilitative and regenerative therapies can restore limb and muscle function following VML injury in a synergistic manner. This review presents the current state of the VML field, spanning clinical and preclinical literature, with particular focus on rehabilitation and regenerative medicine in addition to their synergy. Moving forward, multidisciplinary collaboration between clinical and research fields is encouraged in order to continue to improve the treatment of VML injuries and specifically address the encompassing physiology, pathology, and specific needs of this patient population. This is a work of the US Government and is not subject to copyright protection in the USA. Foreign copyrights may apply. Published by S. Karger AG, Basel.

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.

Comparative Study of Assisted Ambulation and Perceived Exertion With the Wheeled Knee Walker and Axillary Crutches in Healthy Subjects

BACKGROUND

Functional limitations after lower extremity surgery often require the use of an assistive device for ambulation during rehabilitation and recovery. There are no known objective data evaluating the wheeled knee walker as an assistive device for protected ambulation. The purpose of this study was to compare assisted ambulation and perceived exertion with the wheeled knee walker and the axillary crutches in healthy participants.

METHODS

A prospective, randomized crossover study was performed using 24 healthy volunteers. Each participant performed a 6-minute walk test (6MWT) using each assistive device in a crossover manner. Preactivity and postactivity heart rates were recorded. The self-selected walking velocity (SSWV) was calculated and the participant's rating of perceived exertion was recorded using the OMNI Rating of Perceived Exertion (OMNI-RPE). Participant's preference for assistive device was identified.

RESULTS

The 6MWT, SSWV, and the Omni-RPE were evaluated using paired t tests and determined to be statistically significant for the wheeled knee walker compared with axillary crutches. Evaluation of the preactivity and postactivity heart rates demonstrated a statistically significant difference for the wheeled knee walker compared with axillary crutches. The wheeled knee walker was preferred by 88% of participants.

CONCLUSIONS

The wheeled knee walker provided increased assisted ambulation and had a lower rating of perceived exertion than axillary crutches on level surfaces in healthy participants.

LEVEL OF EVIDENCE

Level III, comparative study.

Lower Extremity Limb Salvage: Lessons Learned From 14 Years at War

American survivability during the current conflicts in Iraq and Afghanistan continues to improve, though the rate of extremity injury remains quite high. The decision to proceed with amputation versus limb salvage remains controversial. Exposure to combat wound with severe high-energy lower extremity trauma during the previous 14 years at war has incited important advances in limb salvage technique and rehabilitation.

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.

The influence of passive-dynamic ankle-foot orthosis bending axis location on gait performance in individuals with lower-limb impairments

BACKGROUND

Passive-dynamic ankle-foot orthoses are commonly prescribed to augment impaired ankle muscle function, however their design and prescription are largely qualitative. One design includes a footplate and cuff, and flexible strut connecting the two. During gait, deflection occurs along the strut, with the greatest deflection at a central bending axis. The vertical location of the axis can affect lower extremity biomechanics. The goal of this study was to investigate the influence of bending axis location on gait performance.

METHODS

For thirteen participants with unilateral ankle muscle weakness, an additive manufacturing framework was used to fabricate passive-dynamic ankle-foot orthosis struts with central and off-center bending axes. Participants walked overground while electromyographic, kinetic and kinematic data were collected for three different bending axes: proximal (high), central (middle) and distal (low), and the participants indicated their order of bending axis preference after testing. Gait measures and preference effect sizes were examined during six regions of the gait cycle.

FINDINGS

A few differences between bending axes were observed: in the first double-leg support peak plantarflexion angle, peak dorsiflexion moment and positive hip work, in the early single-leg support peak knee extension moment and positive ankle and knee work, and in the late single-leg support gastrocnemius activity and vertical ground reaction force impulse. In addition, preference was strongly related to various gait measures.

INTERPRETATION

Despite the observed statistical differences, altering bending axis location did not produce large and consistent changes in gait performance. Thus, individual preference and comfort may be more important factors guiding prescription.

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.

A systematic review of questionnaires to assess patient satisfaction with limb orthoses

BACKGROUND

Assessment of patient satisfaction with orthosis is a key point for clinical practice and research, requiring questionnaires with robust psychometric properties.

OBJECTIVES

To identify which validated questionnaires are used to investigate patient satisfaction with orthosis in limb orthotics and to analyse (1) their main fields of clinical application, (2) the orthosis-related features analysed by the questionnaires and (3) the strength of their psychometric properties.

STUDY DESIGN

Systematic review.

METHODS

A literature search using MEDLINE (PubMed), Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Scopus databases for original articles published within the last 20 years was performed.

RESULTS

A total of 106 papers pertaining to various clinical fields were selected. The main features of patient satisfaction with orthosis analysed were as follows: aesthetic, ease in donning and doffing the device, time of orthotic use and comfort.

CONCLUSION

Of the questionnaires used to investigate patient satisfaction with orthosis, only four are adequately validated for this purpose: two for generic orthotic use (Quebec User Evaluation of Satisfaction with assistive Technology 2.0 and Client Satisfaction with Device of Orthotics and Prosthetic Users' Survey) and two for specific application with orthopaedic shoes (Questionnaire for the Usability Evaluation of orthopaedic shoes and Monitor Orthopaedic Shoes). Further development, refinement and validation of outcome measures in this field are warranted.

CLINICAL RELEVANCE

Given the importance of analysing patient satisfaction with orthosis (PSwO), appropriate instruments to assess outcome are needed. This article reviews the currently available instruments and reflects on how future studies could be focused on the development, refinement and validation of outcome measures in this field.

Effects of ankle foot orthoses on body functions and activities in people with floppy paretic ankle muscles: a systematic review

BACKGROUND

People with floppy ankle muscles paresis use ankle foot orthoses to improve their walking ability. Ankle foot orthoses also limit ankle range of motion thereby introducing additional problems. Insight in effects of ankle foot orthoses on body functions and activities in people with floppy paretic ankle muscles aids in clinical decision making and may improve adherence.

METHODS

Studies published before October 27th, 2014, were searched in Pubmed, Embase, Cinahl, and Cochrane Library. Studies evaluating effects of ankle foot orthoses on body functions and/or activities in people with floppy paretic ankle muscles were included. Studies solely focusing on people with spastic paretic ankle muscles were excluded. Study quality was assessed using a custom-made scale. Body functions and activities were defined according to the International Classification of Functioning, Disability and Health.

FINDINGS

Twenty-four studies were included, evaluating 394 participants. Participants were grouped according to paresis type (i) dorsiflexor paresis, (ii) plantar flexor paresis, (iii) both dorsiflexor and plantar flexor paresis. Dorsal, circular, and elastic ankle foot orthoses increased dorsiflexion during swing (by 4-6°, group i). Physical comfort with dorsal ankle foot orthoses was lower than that with circular ankle foot orthoses (groups i and iii). Dorsal ankle foot orthoses increased push-off moment (by 0.2-0.5 Nm/kg), increased walking efficiency, and decreased ankle range of motion (by 12-30°, groups ii and iii).

INTERPRETATION

People with dorsiflexor paresis benefit more from circular and elastic ankle foot orthoses while people with plantar flexor paresis (and dorsiflexor paresis) benefit more from dorsal ankle foot orthoses.

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.

Late amputation may not reduce complications or improve mental health in combat-related, lower extremity limb salvage patients

INTRODUCTION

Following severe lower extremity trauma, patients who undergo limb reconstruction and amputations both endure frequent complications and mental health sequelae. The purpose of this study is to assess the extent to which late amputation following a period of limb salvage impacts the evolution of the clinical variables that can affect the patient's perception of his or her limb: ongoing limb associated complications and mental health conditions.

PATIENTS AND METHODS

A case series of US service members who sustained a late major extremity amputation from September 2001 through July 2011 were analysed. Pre- and post-amputation complications, mental health conditions, and reason(s) for desiring amputation were recorded.

RESULTS

Forty-four amputees with detailed demographic, injury and treatment data were identified. The most common reasons for desiring a late amputation were pain and being dissatisfied with the function of the salvage limb. An average of 3.2 (range 1-10) complications were reported per amputee prior to undergoing late amputation and an average of 1.8 (range 0-5) complications reported afterwards. The most common complication prior to and after late amputation was soft tissue infection (24 (17%) and 9 (22%), respectively). Twenty-nine (64%) late amputees were diagnosed with a mental health condition prior to undergoing their amputation and 27 (61%) late amputees were diagnosed with mental conditions after late amputation. Only three of the 15 patients who did not have a mental health condition documented prior to their late amputation remained free of a documented mental health condition after the amputation.

DISCUSSION

Ongoing complications and mental health conditions can affect how a patient perceives and copes with his or her limb following severe trauma. Patient dissatisfaction following limb reconstruction can influence the decision to undergo a late amputation. Patients with a severe, combat related lower extremity injury that are undergoing limb salvage may not have a reduction in their overall complication rate, a resolution of specific complications or an improvement of their mental health after undergoing late amputation.

CONCLUSION

Surgeons caring for limb salvage patients should counsel appropriately when managing expectations for a patient who desires a late amputation.

Biomechanics of uphill walking using custom ankle-foot orthoses of three different stiffnesses

Ankle-foot orthoses (AFOs) can provide support and improve walking ability in individuals with plantarflexor weakness. Passive-dynamic AFO stiffness can be optimized for over-ground walking, however little research exists for uphill walking, when plantarflexor contributions are key.

PURPOSE

Compare uphill walking biomechanics (1) between dynamic AFO users and able-bodied control subjects. (2) between injured and sound limbs (3) across different AFO stiffnesses.

METHODS

Twelve patients with unilateral limb-salvage and twelve matched, able-bodied controls underwent biomechanical gait analysis when walking up a 10° incline. Three AFO stiffnesses were tested in the patient group: Nominal (clinically prescribed), Compliant (20% less stiff), and Stiff (20% more stiff).

RESULTS AND DISCUSSION

AFO users experienced less ankle motion and power generation, lower knee extensor moments, and greater hip flexion and power generation than controls during uphill walking. Despite these deviations, they walked at equivalent self-selected velocities and stride lengths. Asymmetries were present at the ankle and knee with decreased ankle motion and power, and lower knee extensor moments on the AFO limb. Stiffer AFOs increased knee joint flexion but a 40% range in AFO stiffness had few other effects on gait. Therefore, a wide range of clinically prescribed AFO stiffnesses may adequately assist uphill walking.

Return to duty and disability after combat-related hindfoot injury

OBJECTIVES

To characterize the return-to-duty (RTD) rates and disability outcomes for soldiers who sustained combat-related hindfoot injuries that were treated with either reconstruction or transtibial amputation (TTA).

DESIGN

Retrospective cohort series.

SETTING

Tertiary trauma center.

PATIENTS/PARTICIPANTS

All patients treated for combat-related hindfoot injuries between May 2005 and July 2011.

INTERVENTION

TTA or hindfoot reconstruction/ankle fusion.

MAIN OUTCOME MEASUREMENTS

Age, RTD rate, combined disability, and associated disabling conditions.

RESULTS

One hundred twenty-two patients underwent treatment for combat-related hindfoot injuries. Fifty-seven patients were treated with amputation, and 65 patients were treated with hindfoot reconstruction or ankle fusion. The overall RTD rate was 20%. Amputees had a RTD rate of 12%, which was lower than those who had a fusion or hindfoot repair [26% (P < 0.06)]. The disability ratings of amputees were significantly higher than those patients undergoing either ankle fusion or primary hindfoot repair [75% and 62%, respectively (P < 0.006)].

DISCUSSION

While RTD rates were higher for hindfoot reconstruction or ankle fusion compared with TTA, psychiatric conditions were more common among these patients. Although there were clear differences between both groups, the relationship between true functional outcomes and disability ratings remains unclear and both treatment groups seem to do poorly in terms of returning to active duty.

LEVEL OF EVIDENCE

Therapeutic level III. See instructions for authors for a complete description of levels of evidence.

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.

Selective Laser Sintered Versus Carbon Fiber Passive-Dynamic Ankle-Foot Orthoses: A Comparison of Patient Walking Performance

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

Return to duty after integrated orthotic and rehabilitation initiative

OBJECTIVES

To determine the return to active duty rate of military service members undergoing lower extremity limb salvage while using a novel custom orthosis and specialized rehabilitation compared with those receiving a novel custom orthosis alone.

DESIGN

Retrospective cohort study.

SETTING

Military level I trauma center and tertiary referral center for limb salvage.

PATIENTS/PARTICIPANTS

All active duty service members enrolled in our institution's Return to Run Clinical Pathway were analyzed retrospectively. Service members were enrolled if they sustained injuries with residual disability below the knee. Injuries typically involved substantial motor and/or nerve deficit, and the overwhelming majority was secondary to high-energy injuries.

INTERVENTION

Service members were fitted with a customized orthosis, an Intrepid Dynamic Exoskeletal Orthosis (IDEO), for use during rehabilitation. Service members were divided into 2 groups: those who had participated in the Return to Run Clinical Pathway with an IDEO (group 1) and those who only were fitted with an IDEO only (group 2).

MAIN OUTCOME MEASURE

Return to military active duty rate.

RESULTS

One hundred forty-six service members met the inclusion criteria. Group 1 consisted of 115 service members and group 2 consisted of 31 service members. Of those in group 1, 59 (51.3%) returned to active duty compared with 4 (12.9%) in group 2 (P = 0.0001). Mechanisms of injury were significant factors for return to duty (RTD), and those sustaining explosive mechanisms of injury or gunshot wounds had significantly lower RTD rates across both groups.

CONCLUSIONS

Active duty service members participating in an integrated orthotic and rehabilitation initiative after a lower extremity injury have a higher rate of RTD than previous reports, and it is significantly higher than the orthotic device alone.

Autologous minced muscle grafts: a tissue engineering therapy for the volumetric loss of skeletal muscle

Volumetric muscle loss (VML) results in a large void deficient in the requisite materials for regeneration for which there is no definitive clinical standard of care. Autologous minced muscle grafts (MG), which contain the essential components for muscle regeneration, may embody an ideal tissue engineering therapy for VML. The purpose of this study was to determine if orthotopic transplantation of MG acutely after VML in the tibialis anterior muscle of male Lewis rats promotes functional tissue regeneration. Herein we report that over the first 16 wk postinjury, MG transplantation 1) promotes remarkable regeneration of innervated muscle fibers within the defect area (i.e., de novo muscle fiber regeneration); 2) reduced evidence of chronic injury in the remaining muscle mass compared with nonrepaired muscles following VML (i.e., transplantation attenuated chronically upregulated transforming growth factor-β1 gene expression and the presence of centrally located nuclei in 30% of fibers observed in nonrepaired muscles); and 3) significantly improves net torque production (i.e., ∼55% of the functional deficit in nonrepaired muscles was restored). Additionally, voluntary wheel running was shown to reduce the heightened accumulation of extracellular matrix deposition observed within the regenerated tissue of MG-repaired sedentary rats 8 wk postinjury (collagen 1% area: sedentary vs. runner, ∼41 vs. 30%), which may have been the result of an augmented inflammatory response [i.e., M1 (CCR7) and M2 (CD163) macrophage expression was significantly greater in runner than sedentary MG-repaired muscles 2 wk postinjury]. These findings support further exploration of autologous minced MGs for the treatment of VML.

Challenges in severe lower limb injury rehabilitation

Restoration of lower limb function following severe injury is a challenge. Rehabilitation must take into account psychosocial factors and patient self-efficacy as well as functional goals. The Return to Run clinical pathway, an integrated orthotic and rehabilitation initiative, is an example of goal-oriented rehabilitation with periodic assessment aimed at restoring wounded warriors to high-level performance following severe lower extremity trauma. Objective assessment measures of surgical and rehabilitation interventions are lacking for persons with high-level performance demands, such as those required by service members. Thus, the Military Performance Laboratory at the Center for the Intrepid has established normative data for several physical performance measures, some of which are now routinely used to assess service members with severe lower extremity trauma. Patient expectations of treatment and rehabilitation are high and must be met to avoid poor outcomes attributed to nonanatomic factors.

Management of posttraumatic osteoarthritis with an integrated orthotic and rehabilitation initiative

Posttraumatic osteoarthritis affects approximately 5.6 million Americans annually. Those affected are typically younger and more active than persons with primary osteoarthritis. Arthrodesis is the typical management option for persons with end-stage ankle and subtalar posttraumatic arthritis. Arthroplasty is typically reserved for elderly persons. The functional limitations resulting from any of these strategies make treatment of this young population challenging. Combat wounds frequently lead to severe lower extremity injuries. We present a series of patients with severe posttraumatic osteoarthritis of the ankle and subtalar joint after combat trauma. They were treated at our institution with an integrated orthotic and rehabilitation initiative called the Return To Run clinical pathway. This clinical pathway may serve as an alternative or adjunct to arthrodesis and arthroplasty for young patients with severe posttraumatic osteoarthritis of the ankle and subtalar joint.