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.

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.

Do Gait and Functional Parameters Change After Transtibial Amputation Following Attempted Limb Preservation in a Military Population?

BACKGROUND: Surgical attempts at lower limb preservation after trauma may be complicated by pain and gait disturbances, which can impact the activity level of a military service member. It is unclear how later transtibial amputation (TTA) might affect patients who elect this option after attempts at limb preservation. QUESTIONS/PURPOSES: The purposes of the study were to compare preamputation and postamputation (1) the numeric rating scale for pain and pain medication use; (2) self-reported activity level, Four Square Step Test (FSST) results, and assistive device use; and (3) spatiotemporal variables measured with instrumented gait analysis in individuals who elected TTA after multiple attempts at limb preservation. METHODS: Retrospective review revealed 10 patients with unilateral lower extremity injuries who underwent late TTA between 2008 and 2016. All patients had undergone multiple limb preservation attempts and had completed instrumented gait evaluations as part of their routine care before and after TTA. One patient was excluded as a result of short followup. The remaining nine patients (eight men, 29 ± 6 years) averaged five surgeries before amputation. Injuries were from improvised explosive devices (six), motorcycle accidents (two), and one training accident. Strict indications for amputation were pain, difficulties performing activities of daily living, limited physical function, and medication dependence. Data for the aforementioned purposes were collected by gait laboratory staff before and 8 to 17 months after amputation. Time to TTA after initial injury was 5 ± 3 years. At the start of the gait analysis study, pain was assessed at rest, activity level was recorded by patient report, and the FSST was administered. RESULTS: After TTA, there was a decrease in pain scores from 4 ± 2 to 1 ± 1 and patients using narcotics decreased from four to only one patient. Self-reported walking endurance increased from 1 ± 1 mile to 7 ± 8 miles and patients able to run increased from one patient to eight with the ninth having no desire to run but bicycled. Patient FSST times improved from 12 ± 10 seconds to 5 ± 1 seconds. No patients required assistive devices after TTA. There were improvements in velocity (108 ± 16 cm/s to 142 ± 7 cm/s), stride length (129 ± 14 cm to 154 ± 8 cm), cadence (101 ± 9 steps/min to 111 ± 7 steps/min), and step width (16 ± 3 cm to 12 ± 2 cm) between pre- and postassessments. Asymmetric single-limb stance time was measured both pre- and postamputation; this did not worsen with the increase in walking velocity. CONCLUSIONS: The findings of this study show that TTA after attempted limb preservation in a young, motivated group of service members after traumatic injuries can be successful in decreasing pain and narcotic use and can allow for high-level functional activities. Future studies will be needed to compare this cohort with patients who underwent early TTA after traumatic injury. However, we acknowledge that the resources and support structure available for this population are unique and may not be readily available to the general population. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Are Gait Parameters for Through-knee Amputees Different From Matched Transfemoral Amputees?

BACKGROUND: Through-knee amputation is a common amputation level after battlefield injuries during the medical evacuation process. However, there are limited data comparing through-knee amputation with transfemoral amputation as a definitive amputation level in terms of gait parameters. QUESTIONS/PURPOSES: (1) Does through-knee amputation result in improved gait velocity when compared with matched transfemoral amputees? (2) Do through-knee amputees have a faster gait cadence than matched transfemoral amputees? (3) Do through-knee amputees have a different stride length or stride width than matched transfemoral amputees? (4) Does through-knee amputation result in decreased work of ambulation when compared with matched transfemoral amputees? METHODS: Between January 2008 and December 2012, six male active-duty military patients who had undergone unilateral through-knee amputations as a result of trauma underwent gait studies at our institution. Of those, four of six underwent gait analysis after being able to walk for at least 3 months without assistive devices, and this group was studied here. Most through-knee amputees who were not included had elective revisions of their amputations from through-knee to a transfemoral amputation before completing 3-month gait data. Each of the amputees studied was matched to a transfemoral amputee based on height, body mass index, and contralateral amputation level resulting in a case-control study of active-duty military male amputee patients. Inclusion required complete gait data collected while walking at a self-selected pace wearing custom prosthetic devices. The through-knee amputees had a median (range) age of 32 years (23-41 years) and the transfemoral amputees had a median age of 24 years (22-27 years). Three-dimensional gait data were collected and analyzed. A power analysis found that to detect a clinically important difference (set at a change in work of ambulation of 1 J/kgm) with a p value of 0.05 and a ß set to 0.2, a study population of 56 patients per group would be required; that being said, our results on a much smaller population must be considered exploratory. RESULTS: With the numbers available, we found no differences in gait velocity when comparing through-knee (1.18 m/sec) and matched transfemoral amputees (1.20 m/sec, difference of medians = 0.02 m/sec; p = 0.964). Likewise, we found no differences in gait cadence when comparing through-knee with transfemoral amputees (104 versus 106 steps/min, respectively, difference of means 2 steps/min, p = 0.971). There was no difference in stride length or stride width when comparing through-knee (70 cm and 18 cm, respectively) with transfemoral amputees (70 cm and 19 cm, respectively; p = 0.948 and p = 0.440). With the numbers available, we did not identify a difference in the work of ambulation for through-knee amputees when compared with matched transfemoral amputees (8.3 versus 7.5 J/kg, respectively; p = 0.396). CONCLUSIONS: Based on our findings, we are unable to demonstrate any functional advantages of knee disarticulation over transfemoral amputation. Although there are theoretical advantages for maintaining an intact femur during the medical evacuation and serial débridement process, we question the utility of knee disarticulation as a definitive amputation level; however, larger numbers of patients are needed to confirm these results. LEVEL OF EVIDENCE: Level III, therapeutic study.

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.

Measuring Abnormality in High Dimensional Spaces with Applications in Biomechanical Gait Analysis.

Accurately measuring a subject's abnormality using high dimensional data can empower better outcomes research. Utilizing applications in instrumented gait analysis, this article demonstrates how using data that is inherently non-independent to measure overall abnormality may bias results. A methodology is then introduced to address this bias and accurately measure abnormality in high dimensional spaces. While this methodology is in line with previous literature, it differs in two major ways. Advantageously, it can be applied to datasets in which the number of observations is less than the number of features/variables, and it can be abstracted to practically any number of domains or dimensions. Initial results of these methods show that they can detect known, real-world differences in abnormality between subject groups where established measures could not. This methodology is made freely available via the abnormality R package on CRAN.

Performance of an attention-demanding task during treadmill walking shifts the noise qualities of step-to-step variation in step width.

BACKGROUND: The fractal scaling evident in the step-to-step fluctuations of stepping-related time series reflects, to some degree, neuromotor noise. RESEARCH QUESTION: The primary purpose of this study was to determine the extent to which the fractal scaling of step width, step width and step width variability are affected by performance of an attention-demanding task. We hypothesized that the attention-demanding task would shift the structure of the step width time series toward white, uncorrelated noise. METHODS: Subjects performed two 10-min treadmill walking trials, a control trial of undisturbed walking and a trial during which they performed a mental arithmetic/texting task. Motion capture data was converted to step width time series, the fractal scaling of which were determined from their power spectra. RESULTS: Fractal scaling decreased by 22% during the texting condition (p < 0.001) supporting the hypothesized shift toward white uncorrelated noise. Step width and step width variability increased 19% and five percent, respectively (p < 0.001). However, a stepwise discriminant analysis to which all three variables were input revealed that the control and dual task conditions were discriminated only by step width fractal scaling. SIGNIFICANCE: The change of the fractal scaling of step width is consistent with increased cognitive demand and suggests a transition in the characteristics of the signal noise. This may reflect an important advance toward the understanding of the manner in which neuromotor noise contributes to some types of falls. However, further investigation of the repeatability of the results, the sensitivity of the results to progressive increases in cognitive load imposed by attention-demanding tasks, and the extent to which the results can be generalized to the gait of older adults seems warranted.

The Extremity Trauma and Amputation Center of Excellence: Overview of the Research and Surveillance Division.

Congress authorized creation of the Extremity Trauma and Amputation Center of Excellence (EACE) as part of the 2009 National Defense Authorization Act. The legislation mandated the Department of Defense (DoD) and Department of Veterans Affairs (VA) to implement a comprehensive plan and strategy for the mitigation, treatment, and rehabilitation of traumatic extremity injuries and amputation. The EACE also was tasked with conducting clinically relevant research, fostering collaborations, and building partnerships across multidisciplinary international, federal, and academic networks to optimize the quality of life of service members and veterans who have sustained extremity trauma or amputations. To fulfill the mandate to conduct research, the EACE developed a Research and Surveillance Division that complements and collaborates with outstanding DoD, VA, and academic research programs across the globe. The EACE researchers have efforts in four key research focus areas relevant to extremity trauma and amputation: (1) Novel Rehabilitation Interventions, (2) Advanced Prosthetic and Orthotic Technologies, (3) Epidemiology and Surveillance, and (4) Medical and Surgical Innovations. This overview describes the EACE efforts to innovate, discover, and translate knowledge gleaned from collaborative research partnerships into clinical practice and policy.

The Bridging Advanced Developments for Exceptional Rehabilitation (BADER) Consortium: Reaching in Partnership for Optimal Orthopaedic Rehabilitation Outcomes.

The Bridging Advanced Developments for Exceptional Rehabilitation (BADER) Consortium began in September 2011 as a cooperative agreement with the Department of Defense (DoD) Congressionally Directed Medical Research Programs Peer Reviewed Orthopaedic Research Program. A partnership was formed with DoD Military Treatment Facilities (MTFs), U.S. Department of Veterans Affairs (VA) Centers, the National Institutes of Health (NIH), academia, and industry to rapidly conduct innovative, high-impact, and sustainable clinically relevant research. The BADER Consortium has a unique research capacity-building focus that creates infrastructures and strategically connects and supports research teams to conduct multiteam research initiatives primarily led by MTF and VA investigators.BADER relies on strong partnerships with these agencies to strengthen and support orthopaedic rehabilitation research. Its focus is on the rapid forming and execution of projects focused on obtaining optimal functional outcomes for patients with limb loss and limb injuries. The Consortium is based on an NIH research capacity-building model that comprises essential research support components that are anchored by a set of BADER-funded and initiative-launching studies. Through a partnership with the DoD/VA Extremity Trauma and Amputation Center of Excellence, the BADER Consortium's research initiative-launching program has directly supported the identification and establishment of eight BADER-funded clinical studies. BADER's Clinical Research Core (CRC) staff, who are embedded within each of the MTFs, have supported an additional 37 non-BADER Consortium-funded projects. Additional key research support infrastructures that expedite the process for conducting multisite clinical trials include an omnibus Cooperative Research and Development Agreement and the NIH Clinical Trials Database. A 2015 Defense Health Board report highlighted the Consortium's vital role, stating the research capabilities of the DoD Advanced Rehabilitation Centers are significantly enhanced and facilitated by the BADER Consortium.

The Center for Rehabilitation Sciences Research: Advancing the Rehabilitative Care for Service Members With Complex Trauma.

The Center for Rehabilitation Sciences Research (CRSR) was established to advance the rehabilitative care for service members with combat-related injuries, particularly those with orthopedic, cognitive, and neurological complications. The center supports comprehensive research projects to optimize treatment strategies and promote the successful return to duty and community reintegration of injured service members. The center also provides a unique platform for fostering innovative research and incorporating clinical/technical advances in the rehabilitative care for service members. CRSR is composed of four research focus areas: (1) identifying barriers to successful rehabilitation and reintegration, (2) improving pain management strategies to promote full participation in rehabilitation programs, (3) applying novel technologies to advance rehabilitation methods and enhance outcome assessments, and (4) transferring new technology to improve functional capacity, independence, and quality of life. Each of these research focus areas works synergistically to influence the quality of life for injured service members. The purpose of this overview is to highlight the clinical research efforts of CRSR, namely how this organization engages a broad group of interdisciplinary investigators from medicine, biology, engineering, anthropology, and physiology to help solve clinically relevant problems for our service members, veterans, and their families.

A Narrative Review of the Prevalence and Risk Factors Associated With Development of Knee Osteoarthritis After Traumatic Unilateral Lower Limb Amputation.

INTRODUCTION: Young military Service Members with traumatic unilateral lower limb amputations may be at a high risk for developing knee osteoarthritis (OA). There is growing evidence for potential influence and predictive value of nonsystemic risk factors on development and progression of primary knee OA in older adults. Proposed factors include chronic knee pain, obesity, abnormal knee joint mechanics, muscle weakness, previous knee trauma, and altered physical activity level. However, there is limited information available regarding whether such nonsystemic risk factors could also be responsible for the increased risk of knee OA after traumatic, unilateral lower limb amputation in young military Service Members. The purpose of this narrative review is to compile and present evidence regarding prevalence of nonsystemic and potentially modifiable knee OA risk factors in Service Members with traumatic, unilateral lower limb amputation, and to identify potential strategies for intervention. MATERIALS AND METHODS: A comprehensive literature search was performed in July 2015 using structured search terms related to nonsystemic risk factors for knee OA. RESULTS: Current collective evidence does suggest an elevated prevalence of the nonsystemic knee OA risk factors in young military Service Members with unilateral lower limb amputation. In conclusion, the present state of the literature supports that young military Service Members with traumatic unilateral lower limb amputations may be at increased risk for developing knee OA compared to nonamputees. Military Service Members injured at a young age have a long life expectancy, and thus require comprehensive rehabilitation programs to prevent or delay progression of knee OA. Given the lack of strong evidence, further clinical research is needed to determine whether early identification and modification of nonsystemic risk factors for knee OA could optimize long-term function and quality of life in young Service Members after traumatic, unilateral, limb amputations.

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.

Mechanical testing for three-dimensional motion analysis reliability.

The purpose of this study was to use simple mechanical tests to evaluate the reliability of three-dimensional motion analysis systems and biomechanical models. Three different tests were conducted at four motion analysis laboratories where clinical care and research studies are routinely performed. The laboratories had different motion capture systems, different types and number of cameras, different types and numbers of force plates and different biomechanical models. These mechanical tests evaluated the accuracy of the motion capture system, the integration of the force plate and the motion capture system, and the strength of the biomechanical model used to calculate rotational kinematics. Results of motion capture system accuracy tests showed that, for all labs, the error between the measured and calculated distances between markers was less than 2mm and 1° for marker separations which ranged from 24mm to 500mm. Results from the force plate integration tests demonstrated errors in center of pressure calculation of less than 4mm across all labs, despite varied force plate and motion system configurations. Finally, errors across labs for single joint rotations and for combined rotations at the hip and knee were less than 2° at the hip and less than 10° at the knee. These results demonstrate that system accuracy and reliability can be obtained allowing the collection of comparable data across different motion analysis laboratories with varying configurations and equipment. This testing is particularly important when multi-center studies are planned in order to assure data consistency across labs.

Reliability of 3D gait data across multiple laboratories.

The aim of this study was to analyze the repeatability of gait analysis studies performed across multiple trials, sessions, and laboratories. Ten healthy participants (6 male/4 female, mean age of 30, mean BMI of 24kg/m(2)) were assessed in 3 sessions conducted at each of the three Centers of Excellence for Amputee Care within the Department of Defense. For each test session, kinematic and kinetic parameters were collected during five walking trials for each limb. One independent examiner at each site placed markers on the subjects. Biomechanical data were collected at two walking speeds: self-selected and Froude speed. Variability of the gait data was attributed to inter-trial, inter-session, and inter-lab errors for each subject. These error sources were averaged across all ten subjects to obtain a pooled error estimate. The kinematic errors were fairly consistent at the two walking speeds tested. Median inter-lab kinematic errors were <5.0° (median 2.3°) for all joint angle measurements. However, the kinetic error differed significantly between walking speeds. The median inter-lab kinetic error for the self-selected speed was 0.112Nm/kg (ICR 0.091-0.184) with a maximum of 0.226Nm/kg. The errors were greatly reduced when the subjects walked at their Froude speed. The median inter-lab error was 0.048Nm/kg (ICR 0.025-0.078, maximum 0.086). These data demonstrate that it is possible to get reliable data across multiple gait laboratories, particularly when gait speed is standardized across testing sessions. A key similarity between sites was the use of identical anatomical segment definitions for the respective gait models.

Task-specific fall prevention training is effective for warfighters with transtibial amputations.

BACKGROUND: Key factors limiting patients with lower extremity amputations to achieve maximal functional capabilities are falls and fear of falling. A task-specific fall prevention training program has successfully reduced prospectively recorded trip-related falls that occur in the community by the elderly. However, this program has not been tested in amputees. QUESTIONS/PURPOSES: In a cohort of unilateral transtibial amputees, we aimed to assess effectiveness of a falls prevention training program by (1) quantifying improvements in trunk control; (2) measuring responses to a standardized perturbation; and (3) demonstrating retention at 3 and 6 months after training. Second, we collected patient-reported outcomes for balance confidence and falls control. METHODS: Fourteen male military service members (26 ± 3 years) with unilateral transtibial amputations and who had been walking without an assistive device for a median of 10 months (range, 2-106 months) were recruited to participate in this prospective cohort study. The training program used a microprocessor-controlled treadmill designed to deliver task-specific postural perturbations that simulated a trip. The training consisted of six 30-minute sessions delivered over a 2-week period, during which task difficulty, including perturbation magnitude, increased as the patient's ability progressed. Training effectiveness was assessed using a perturbation test in an immersive virtual environment. The key outcome variables were peak trunk flexion and velocity, because trunk kinematics at the recovery step have been shown to be a determinant of fall likelihood. The patient-reported outcomes were also collected using questionnaires. The effectiveness of the rehabilitation program was also assessed by collecting data before perturbation training and comparing the key outcome parameters with those measured immediately after perturbation training (0 months) as well as both 3 and 6 months posttraining. RESULTS: Mean trunk flexion angle and velocity significantly improved after participating in the training program. The prosthetic limb trunk flexion angle improved from pretraining (42°; 95% confidence interval [CI], 38°-47°) to after training (31°; 95% CI, 25°-37°; p < 0.001). Likewise, the trunk flexion velocity improved from pretraining (187°/sec; 95% CI, 166°-209°) to after training (143°/sec; 95% CI, 119°-167°; p < 0.004). The results display a significant side-to-side difference for peak trunk flexion angle (p = 0.01) with perturbations of the prosthetic limb resulting in higher peak angles. Prosthetic limb trips also exhibited significantly greater peak trunk flexion velocity compared with trips of the prosthetic limb (p = 0.005). These changes were maintained up to 6 months after the training. The peak trunk flexion angle of the subjects when the prosthetic limb was perturbed had a mean of 31° (95% CI, 25°-37°) at 0 month, 32° (95% CI, 28°-37°) at 3 months, and 30° (95% CI, 25°-34°) at 6 months. Likewise, the peak trunk flexion velocity for the prosthetic limb was a mean of 143°/sec (95% CI, 118°-167°) at 0 months, 143°/sec (95% CI, 126°-159°) at 3 months, and 132° (95% CI, 115°-149°) at 6 months. The peak trunk flexion angle when the nonprosthetic limb was perturbed had a mean of 22° (95% CI, 18°-24°) at 0 months, a mean of 26° (95% CI, 20°-32°) at 3 months, and a mean of 23° (95% CI, 19°-28°) at 6 months. The peak trunk flexion velocity for the nonprosthetic limb had a mean of 85°/sec (95% CI, 71°-98°) at 0 months, a mean of 96° (95% CI, 68°-124°) at 3 months, and 87°/sec (95% CI, 68°-105°) at 6 months. There were no significant changes in the peak trunk flexion angle (p = 0.16) or peak trunk flexion velocity (p = 0.35) over time after the training ended. The skill retention was present when either the prosthetic or nonprosthetic limb was perturbed. There were side-to-side differences in the trunk flexion angle (p = 0.038) and trunk flexion velocity (p = 0.004). Perturbations of the prosthetic side resulted in larger trunk flexion and higher trunk flexion velocities. Subjects prospectively reported decreased stumbles, semicontrolled falls, and uncontrolled falls. CONCLUSIONS: These results indicate that task-specific fall prevention training is an effective rehabilitation method to reduce falls in persons with lower extremity transtibial amputations.

Do patients with bone bridge amputations have improved gait compared with patients with traditional amputations?

BACKGROUND: Two surgical techniques for performing a transtibial amputation include a traditional approach and a bone bridge approach. To date, there is no conclusive evidence of superiority of either technique in terms of temporal-spatial, kinetic, and mechanical work parameters. QUESTIONS/PURPOSES: We sought to compare instrumented three-dimensional gait parameters and mechanical work measurements of patients who had undergone a traditional or bone bridge amputation at the transtibial level. Residual limb length and its effect on those functional outcomes was a secondary interest irrespective of amputation type. METHODS: This retrospective comparative study included 14 active-duty military men with a mean age of 25 years (range, 20-28 years). Comparisons were made between seven patients with traditional and seven patients with bone bridge amputations at the transtibial level. The patients walked at self-selected and fast paces while three-dimensional gait analysis data were collected and comparisons were made between patients with the two amputation types as well as by length of the residual limb. RESULTS: With the numbers available, we observed no differences between the two surgical groups at either speed for the temporal-spatial parameters or mechanical work metrics. However, the bone bridge group did demonstrate greater rolloff vertical ground reaction force during the fast walking condition with a median 1.02% of body weight compared with 0.94% (p = 0.046), which suggests a more stable platform in terminal stance. When the two groups were combined into one to test the effect of residual limb length, the linear regression resulted in an R(2) value of 0.419 (p = 0.012), in which patients with longer residual limbs had improved F3 force values during self-selected walking. CONCLUSIONS: Overall, limited functional differences were found between the two groups in this small pilot study, so a superior surgical technique could not be determined; whereas our limited sample size prevents a firm conclusion of no difference, our data can be considered hypothesis-generating for future, larger studies. Although some evidence indicated that patients with a bone bridge have improved loading at higher speeds, a regression of all patients walking at self-selected speed indicates that as residual limb length increases, loading increases regardless of amputation type. Thus, our data suggest it is important to preserve residual limb length to allow for improved loading in terminal stance.

Method for evoking a trip-like response using a treadmill-based perturbation during locomotion.

Because trip-related falls account for a significant proportion of falls by patients with amputations and older adults, the ability to repeatedly and reliably simulate a trip or evoke a trip-like response in a laboratory setting has potential utility as a tool to assess trip-related fall risk and as a training tool to reduce fall risk. This paper describes a treadmill-based method for delivering postural perturbations during locomotion to evoke a trip-like response and serve as a surrogate for an overground trip. Subjects walked at a normalized velocity in a Computer Assisted Rehabilitation Environment (CAREN). During single-limb stance, the treadmill belt speed was rapidly changed, thereby requiring the subject to perform a compensatory stepping response to avoid falling. Peak trunk flexion angle and peak trunk flexion velocity during the initial compensatory step following the perturbation were smaller for responses associated with recoveries compared to those associated with falls. These key fall prediction variables were consistent with the outcomes observed for laboratory-induced trips of older adults. This perturbation technique also demonstrated that this method of repeated but randomly delivered perturbations can evoke consistent, within-subject responses.

Integrated musculoskeletal rehabilitation care at a comprehensive combat and complex casualty care program.

OBJECTIVE: The purpose of this study is to describe the musculoskeletal rehabilitation model used to care for combat and severely wounded or ill US military service members at an integrated Comprehensive Combat and Complex Casualty Care center located at Naval Medical Center San Diego. METHODS: Through a collaborative and iterative process, providers from the various services included at the Comprehensive Combat and Complex Casualty Care program developed a description of the integration of services provided at this location. RESULTS: After construction of the facility in 2007, the program has provided services for approximately 2 years. Eighteen different health care providers from 10 different specialties provide integrated musculoskeletal services, which include primary care, physical therapy, occupational therapy, vestibular therapy, gait analysis, prosthetics, recreational therapy, and chiropractic care. At the time of this writing (early 2009), the program had provided musculoskeletal rehabilitation care to approximately 500 patients, 58 with amputations, from the operational theater, Veterans Affairs, other military treatment facilities, and local trauma centers. CONCLUSION: The complex nature of combat wounded and polytrauma patients requires an integrated and interdisciplinary team that is innovative, adaptable, and focused on the needs of the patient. This article presents a description of the model and the experiences of our musculoskeletal rehabilitation team; it is our hope that this article will assist other centers and add to the small but emerging literature on this topic.