Skip to main content

Military Health System

EACE Journal Publications: Fiscal Year 2012

Following is a summary of published results in FY12 for several key research initiatives and focused research efforts.

Advanced Rehabilitation Sciences

Return to Running

Can an ankle foot orthosis change hearts and minds?

Patzkowski JC, Blanck RV, Owens JG, Wilken JM, Blair JA, Hsu J. Can an ankle foot orthosis change hearts and minds? Journal of Surgical Orthopaedic Advances, 20(1):8-18, Spring 2011.

A novel “return to run" clinical pathway integrating an advanced bracing solution (the IDEO) with a high-impact rehabilitation regimen was implemented at the Center For the Intrepid (CFI) with significant beneficial results.  A publication of clinical cases treated at the CFI using this protocol suggests that participation in the return to run clinical pathway may prevent amputations by allowing patients with limb reconstruction to participate fully in demanding physical activities.

Comparative effect of orthosis design on functional performance

Patzkowski JC, Blanck RV, Owens JG, Wilken JM, Kirk KL, Wenke JC, Hsu JR. Comparative effect of orthosis design on functional performance. J Bone Joint Surg Am. 2012 Mar 21: 94(6): 507-15.

In a subsequent retrospective study comparing functional outcomes between the IDEO and other clinically-available bracing solution the IDEO significantly outperformed conventional bracing solutions (Blue Rocker and posterior leaf-spring), leading to a concerted effort to make this brace available to all individuals desiring to avoid delayed amputation following combat-related extremity injury. 

The effects of altering initial ground contact in the running gait of an individual with transtibial amputation

Waetjen LF, Park MT, Wilken JM. The effects of altering initial ground contact in the running gait of an individual with transtibial amputation. Prosthet Orthot Int. 2012 Sep;36(3):356-60.

The ability to return to running and other high-impact activities is of high priority to injured military patients, and for amputees this is no exception. Patients with amputation, however, often place additional loads on the non-injured limb that can lead to arthritic change over time. In a published case report use of a forefoot running technique was shown to decrease load to the non-injured limb in an individual with transtibial amputation. This successful clinic intervention served as pilot information for a larger prospective study currently underway to assess the benefits of using a “soft running” technique to decrease joint load in an amputee population.

Core temperature changes in service members with and without amputations during the Army 10-Miler

Andrews AM, Wunderlich BM, Linberg AA. Core temperature changes in service members with and without amputations during the Army 10-Miler. Mil Med. 2011 Jun;176(6):664-8.

Decreased body surface area and increased energy needs during running and other athletic activities may increase heat production and risk of heat injury for individuals with amputations. A study monitoring core body temperature during a 10-mile run found that maximum core temperature in a runner with amputation was 38.4°C, compared to 37.9°C in a runner without amputation, despite the fact that the runner with amputation completed the run at a slower pace. These results suggest that higher core body temperatures may be reached in individuals with amputation even though workloads are similar.

Metabolic Analysis of Service Members with Transtibial Amputations Carrying Military Loads

Schnall BL, Wolf EJ, Bell JC, Gambel J, Bensel CK, Metabolic Analysis of Service Members with Transtibial Amputations Carrying Military Loads, Journal of Rehabilitation Research and Development, 2012, 49(4): 535-544.

Load carriage can pose additional energy demands due to increased body weight and changes in center of mass. Results comparing individuals with and without amputation indicate that metabolic demand during walking under load was 8.5 - 10.4% higher for patients with amputation. These differences are less than previously published data for unloaded walking, however, and may differ based on extent of patient injury.  Further study looking at energy expenditure, stability, and heat dissipation for individuals with amputation are needed to address the complex demands posed when returning an injured individual to full military duty.

Outcome Measures

New guidebook to facilitate VA/DoD collaborations in health care research

Resnik L, Reiber G, Evans RK, Steager P, Barnabe K. New guidebook to facilitate VA/DoD collaborations in health care research. Mil Med, 2011 Oct; 176(10):1085-7.

A guidebook, published both on-line and in Military Medicine, provides guidance for researchers desiring to collaborate with the VA and DoD to address military-relevant health care issues. This will facilitate future DoD/VA efforts to document long-term outcomes across the life span of our patients.

Physical performance assessment in military service members

Wilken JM, Darter BJ, Goffar SL, Ellwein JC, Snell RM, Tomalis EA, Shaffer SW. Physical performance assessment in military service members. J Am Acad Orthop Surg August 2012 ; 20:S39-S41.

In order to assess the short- and long-term outcomes for our patients there is a need to establish an agreed-upon standardized set of outcomes metrics to assess functional outcomes within both clinical and laboratory environments. A recent study established normative data in a military population for six lower extremity clinical performance measures that are easy to perform within a clinical environment. The data from this study provides an appropriate reference population against which to compare functional progress in patients with lower extremity trauma.

Application of a mild traumatic brain injury rehabilitation program in a virtual realty environment: a case study

Rabago CA, Wilken JM. Application of a mild traumatic brain injury rehabilitation program in a virtual realty environment: a case study. Journal of Neurologic Physical Therapy, 2011, 35(4):185-93.

An initiative is also ongoing to develop a comprehensive assessment battery that can be used to assess physical, cognitive, and psychosocial outcomes in individuals with one or more battle-related injuries. A “real world” scenario, developed for use within the CAREN virtual reality environment, was used to assess and treat patients with balance deficit related to traumatic brain injury. Significant improvements in physical and cognitive outcomes were observed after only 6 days of CAREN treatment in a patient who complained of non-resolving symptoms of headache, balance, and dizziness for over 2 months. Shortly after successful treatment, this patient was able to achieve his goal to deploy to Afghanistan. This achievement highlights the possibility that a variety of performance outcomes can be rapidly assessed within the CAREN system, and has led to further efforts to assess a patient’s ability to return to military duty using a virtual reality environment.

Mitigating Falls Risk

Walking variability during continuous pseudo-random oscillations of the support surface and visual field

McAndrew PM, Dingwell JB, Wilken JM. Walking variability during continuous pseudo-random oscillations of the support surface and visual field. J Biomech. 2010 May 28;43(8):1470-5.

Uneven terrain, being bumped while walking in crowds, and visual movement distractions (i.e. passing cars) are all risk factors for loss of balance and subsequent falls. Replicating the movements and conditions that pose risk for falls can allow for training fall-prevention responses during rehabilitation. A series of innovative studies within our virtual environment (CAREN) system have allowed us to study and develop treatment interventions to train these responses within a safe environment. The first study found that, during walking, able-bodied individuals are more destabilized by visual and surface distracters that cause them to fall to the left or right, rather than forward or back. These findings suggest that effective rehabilitation interventions might focus on training patients to respond to side-to-side movements to avoid falls.

Dynamic margins of stability during human walking in visually and mechanically destabilizing environments

McAndrew PM, Wilken JM, Dingwell JB, Dynamic Stability of Human Walking in Visually and Mechanically Destabilizing Environments. J Biomech. 2011 Feb 24;44(4):644-9.

Uneven terrain, being bumped while walking in crowds, and visual movement distractions (i.e. passing cars) are all risk factors for loss of balance and subsequent falls. Replicating the movements and conditions that pose risk for falls can allow for training fall-prevention responses during rehabilitation. A series of innovative studies within our virtual environment (CAREN) system have allowed us to study and develop treatment interventions to train these responses within a safe environment. The first study found that, during walking, able-bodied individuals are more destabilized by visual and surface distracters that cause them to fall to the left or right, rather than forward or back. These findings suggest that effective rehabilitation interventions might focus on training patients to respond to side-to-side movements to avoid falls.

Dynamic margins of stability during human walking in visually and mechanically destabilizing environments

McAndrew PM, Wilken JM, Dingwell JB. Dynamic margins of stability during human walking in visually and mechanically destabilizing environments. J Biomech. 2011 Feb 24;44(4):644-9.

Uneven terrain, being bumped while walking in crowds, and visual movement distractions (i.e. passing cars) are all risk factors for loss of balance and subsequent falls. Replicating the movements and conditions that pose risk for falls can allow for training fall-prevention responses during rehabilitation. A series of innovative studies within our virtual environment (CAREN) system have allowed us to study and develop treatment interventions to train these responses within a safe environment. The first study found that, during walking, able-bodied individuals are more destabilized by visual and surface distracters that cause them to fall to the left or right, rather than forward or back. These findings suggest that effective rehabilitation interventions might focus on training patients to respond to side-to-side movements to avoid falls.

Amplitude effects of medio-lateral mechanical and visual perturbations on gait

Terry K, Sinitski EH, Dingwell JB, Wilken JM. Amplitude effects of medio-lateral mechanical and visual perturbations on gait. J Biomech. 2012 Jul 26;45(11):1979-86.

A follow on study in able-bodied individuals systematically varied the level of side-to-side stability “challenge” using both visual and walking surface movements, and determined the optimal challenge level for use in assessing patient stability within the CAREN system. Data from these studies led to ongoing projects to assess stability and treat individuals with unilateral and bilateral amputations using the CAREN as a virtual reality rehabilitation tool.

Effects of perturbation magnitude on dynamic stability when walking in destabilizing environments

Sinitski EH, Terry K, Wilken JM, Dingwell JB. Effects of perturbation magnitude on dynamic stability when walking in destabilizing environments. J Biomech, May 2012 45 (12): 2084-91.

A follow on study in able-bodied individuals systematically varied the level of side-to-side stability “challenge” using both visual and walking surface movements, and determined the optimal challenge level for use in assessing patient stability within the CAREN system. Data from these studies led to ongoing projects to assess stability and treat individuals with unilateral and bilateral amputations using the CAREN as a virtual reality rehabilitation tool.

Kinematic Strategies when Walking Across a Destabilizing Rock Surface

Gates DH, Wilken JM, Sinitski E, Scott SJ, Dingwell JB, Kinematic Strategies when Walking Across a Destabilizing Rock Surface.  Gait Posture, Jan 2012 35 (1): 36–42.

A second series of studies within a gait laboratory, equipped with uneven terrain pits and instrumented stairs, was designed to assess a patient’s ability to safely walk over destabilizing surface environments.  The first study characterized the response of able-bodied individuals when walking on rocks compared to level ground, observing that individuals bent their limbs to lower their body to gain more stability, and raised their toes more to avoid catching their toe on rocks.

Gait characteristics of individuals with transtibial amputations walking on a destabilizing rock surface

Gates DH, Dingwell JB, Scott S, Sinitski E, Wilken JM.  Gait characteristics of individuals with transtibial amputations walking on a destabilizing rock surface. Gait Posture. 2012 May;36(1):33-9.

A follow-on study in individuals with transtibial amputation, using conventional foot prostheses, achieved stability through the use of similar compensation strategies as able-bodied individuals, but did widen their stance and decrease step length to achieve this stability. This finding supports the effectiveness of our Center’s rehabilitation regimen, in that patients responded nearly identically to uninjured individuals following treatment, even though a conventional prosthetic ankle does not allow for normal movement. Follow-on studies to determine if powered ankle prostheses provide any benefit over conventional foot-ankle prostheses are underway. 

Whole-body angular momentum in Incline and decline walking

Silverman AK, Sinitski EH, Wilken JM, RR Neptune.  Whole-body angular momentum in Incline and decline walking. J Biomech. 2012 Apr 5;45(6):965-71.

We also characterized the able-bodied response when individuals walked on slopes compared to level ground, and observed that people are more cautious when walking on slopes, and use active control at the joints to maintain stability. Follow-on studies will determine if prosthetic devices allow for safe ascent and descent by approximating normal function.

Optimizing Gait Efficiency

Reliability and minimal detectable change values for gait kinematics and kinetics in healthy adults

Wilken JM, Rodriguez KM, Brawner ME, Darter BJ. Reliability and minimal detectable change values for gait kinematics and kinetics in healthy adults. Gait Posture. 2012, 35(2):301-7.

Another area of research focuses on improving patient endurance, and preventing uneven loading of the joints during walking that might lead to arthritic change in the future. Data from able-bodied individuals provided for a standardized set of laboratory-based outcome metrics performed in the gait laboratory, and determined how much a measure must change to indicate “clinical improvement” when assessing walking performance and walking efficiency. This study laid the groundwork for all follow-on studies that will use this marker set, and will contribute to development of the outcomes-based toolbox.

Comparison of walking overground and in a Computer Assisted Rehabilitation Environment (CAREN) in individuals with and without transtibial amputation

Gates DH, Darter BJ, Dingwell JB, Wilken JM.  Comparison of walking overground and in a Computer Assisted Rehabilitation Environment (CAREN) in individuals with and without transtibial amputation.  Accepted, Journal of NeuroEngineering and Rehabilitation, September 2012.

Gait assessments can also be performed in our virtual reality “CAREN” environment. To assure CAREN measurements replicate measurements obtained in the gait laboratory, a study was undertaken which demonstrated that walking within the CAREN environment replicates overground walking within the gait lab environment. This effort provided evidence to support use of the CAREN as a real-life assessment and rehabilitation tool.

Gait Training with Virtual Reality Based Real-Time Feedback: A Case Report on Improving Gait Performance Following Transfemoral Amputation

Darter BJ, Wilken JM. Gait Training with Virtual Reality Based Real-Time Feedback: A Case Report on Improving Gait Performance Following Transfemoral Amputation. Phys Ther. 2011 Sep;91(9):1385-94.

With methods for assessing walking mechanics soundly established, a study was pursued to determine the efficacy of CAREN treatment to improve walking mechanics in a patient with lower extremity amputation.  Following a CAREN treatment designed to provide corrective feedback for his chronic limp clinical researchers observed a 23% improvement in walking efficiency and more normal movement patterns after 3 week of CAREN treatment. Of note, the patient reported significantly decreased low back pain associated with the improvements in gait.

Functional gait analysis before and after delayed combat-related amputation

Schnall BL, Wagner SC, Montgomery JD, Wyatt MP, Potter BK.  Functional gait analysis before and after delayed combat-related amputation. JBJS Case Connector, Vol.2, Issue 1, January 2012

Finally, there are many limb reconstruction patients who, despite multiple limb salvage surgeries, still desire amputation to improve performance deficits related to decreased ankle range of motion and power generation. Gait lab measurements were performed before and after full rehabilitation in a group of patients who chose to undergo an amputation following a failed limb salvage effort. All patients experienced decreased pain and improved function, evidenced by normalized function as assessed in the gait laboratory, and reported improved pain, function, and satisfaction. Documenting long-term outcomes for these patients is an active goal of our research program.

Advanced Prosthetics/Orthotics

Prosthetic Advances

Harvey ZT, Potter BK, Vandersea J, Wolf EJ.  Prosthetic Advances, Journal of Surgical Orthopaedic Advances, Vol. 21(1), pgs 58-64, 2012.

A wide variety of advanced prosthetic technologies are available to our patients. A summary of these currently available prostheses was described in an article by Walter Reed, and describes recent prosthetic innovations such as powered prosthetic joints, advanced microprocessors, osseointegration, innovations in prosthetic hands, and the DARPA arm.

The Role of Lower Extremity Joint Powers in Successful Stair Ambulation

Wilken JM, Sinitski EH, Bagg EA. The Role of Lower Extremity Joint Powers in Successful Stair Ambulation. Gait Posture. 2011 May;34(1):142-4.

Navigating stairs, particular during ascent, has traditionally been a challenge for individuals following amputation. To address this we first studied the contribution of ankle plantar flexion, or "push off", in accelerating the body when going up stairs. These results, conducted in an able-bodied population, provide data from a young, military-aged population against which to assess prosthetic ankle function in young persons with amputation.

Biomechanics of the ankle-foot system during stair ambulation: implications for design of advanced ankle-foot prostheses

Sinitski EH, Hansen A, Wilken JM.  Biomechanics of the ankle-foot system during stair ambulation: implications for design of advanced ankle-foot prostheses.  J Biomechanics, 2012, 45: 588-594.

Patients with unilateral transtibial amputation showed that, with the exception of reduced ankle power, normal biomechanics are achieved during level walking using conventionally-prescribed energy storage and return feet. When going up stairs, however, limitations in both motion and push-off power using conventional prosthetic feet did not allow patients to ascend stairs with normal gait. These results suggest that patients may benefit from advanced ankle prosthetics that provide enhanced motion and power.

Evaluation of a Powered Ankle-Foot Prosthetic System During Walking

Ferris AE, Aldridge JA, Rabago CA, Wilken JM.  Evaluation of a Powered Ankle-Foot Prosthetic System During Walking.  Arch Phys Med Rehabil. 2012 Jun 22.

Two follow-on studies assessed the efficacy of the powered ankle prosthesis, the BIOM®. Results revealed that use of the BIOM® restored normal ankle power and range of motion during both level ground walking and stair ascent in patients with unilateral transtibial amputation. This did not, however, reduce the use of compensatory strategies at proximal joints, as expected.

Stair ascent kinematics and kinetics with a powered lower leg system following transtibial amputation

Aldridge JM, Sturdy JT, Wilken JM. Stair ascent kinematics and kinetics with a powered lower leg system following transtibial amputation. Gait Posture. 2012 Jun;36 (2):291-5.

Two follow-on studies assessed the efficacy of the powered ankle prosthesis, the BIOM®. Results revealed that use of the BIOM® restored normal ankle power and range of motion during both level ground walking and stair ascent in patients with unilateral transtibial amputation. This did not, however, reduce the use of compensatory strategies at proximal joints, as expected.

Assessment of Transfemoral Amputees Using the C-Leg and the Power Knee for Ascending and Descending Inclines and Steps

Wolf EJ, Everding VQ, Linberg AL, Schnall BL, Czerniecki JM, and Gambel JM, Assessment of Transfemoral Amputees Using the C-Leg and the Power Knee for Ascending and Descending Inclines and Steps, Journal of Rehabilitation Research and Development, 2012, 49(6):831-842

Few studies have compared functional outcomes using advanced prosthetic devices, making it difficult to know which device might best be prescribed for a particular patient. A recent effort was undertaken to compare function on stairs and uneven terrain between the microprocessor C-Leg and the Power Knee. Results revealed that use of the Power Knee on stairs reduced reliance on the intact limb, while patients were able to walk up and down slopes and down stairs faster and more symmetrically using the C-leg. These data suggest future research efforts should prioritize comparison of available devices that contribute to more refined prosthetic prescriptions based on a patient’s lifestyle goals.

Medical/Surgical Intervention

The Effect of Arch Height on Kinematic Coupling during walking

Wilken JM, Rao SR, Saltzman CL, Yack HJ. The Effect of Arch Height on Kinematic Coupling during walking. Clin Biomech (Bristol, Avon). 2011 Mar;26(3):318-23.

Complex limb salvage procedures can result in severe restrictions in joint motion, contributing to pain, instability, and poor function. The foot is particularly complex, with a myriad of motions that can be affected through fusion, scarring, and pain. A study describing complex foot anatomy, such as arch height, in able-bodied individuals provides a foundation for assessing the effect of surgical interventions to normalize joint motion following limb salvage procedures.

A New Device for Assessing Ankle Dorsiflexion Motion: Reliability and Validity

Wilken J, Rao S, Estin M, Saltzman CL, Yack HJ. A New Device for Assessing Ankle Dorsiflexion Motion:  Reliability and Validity. J Orthop Sports Phys Ther. 2011 Apr;41(4):274-80.

Ankle joint range of motion is another important aspect of lower extremity function.  The "Iowa Range of Motion" tool (IAROM) was designed by a CFI researcher to rapidly and accurately measure ankle range of motion in a clinic environment.  A paper was recently published showing the IAROM device to be a reliable and valid tool for assessing ankle motion. Use of the tool was implemented within the clinic to assess the clinical effect of surgery and/or rehabilitation on ankle motion following limb salvage procedures.

Functional improvement following ablative fractional laser treatment of a scar contracture

Kwan JM; Wyatt MP; Uebelhoer NS; Pyo J; Shumaker PR. Functional improvement following ablative fractional laser treatment of a scar contracture.  PM&R, Vol.3 986-987, October 2011.

Post-traumatic joint stiffness and contractures are a significant clinical challenge following limb reconstruction.  A novel procedure using ablative fractional laser treatment to reduce scar contracture in a patient with limb trauma significantly increased ankle motion, resulting in improved walking speed, decreased pain, and discontinued need for a brace. This treatment is now being used as a clinical treatment option.

Transfemoral Amputations: The Effect of Residual Limb Length and Orientation on Gait Analysis Outcome Measures

Bell JC, Wolf EJ, Schnall BL, Tis JE, Tis L, Potter BK. Transfemoral Amputations: The Effect of Residual Limb Length and Orientation on Gait Analysis Outcome Measures.  Journal of Bone and Joint Surg Am 2013 Mar 06; 95 (5): 408-414.

Orthopedic surgeons prioritize saving as much of the residual limb as possible during amputation, however  studies are not available that propose an “optimal” residual limb length for maximizing function when using a prosthesis. A laboratory based study concluded that shorter residual limb length was related to increased trunk and pelvic motion and slower walking speed in patients with unilateral transfemoral amputation. Additionally, shorter limbs were more abducted when in static stance. These observations indicate that longer residual limb length may result in more desirable outcomes for patients with transfemoral amputation.

A comparison of limb-socket kinematics of bone bridging and non-bone bridging wartime transtibial amputations

Tucker C, Wilken JM, Stinner D, Kirk K.  A comparison of limb-socket kinematics of bone bridging and non-bone bridging wartime transtibial amputations. J Bone Joint Surg Am. 2012 May 16;94(10):924-30.

An ongoing debate exists as to whether the ERTL bone bridging procedure, which creates a boney bridge between the distal tibia and fibula following amputation, contributes to a more efficient platform in the total-surface-bearing socket. A study designed to address this debate found no differences between ERTL and conventional surgical techniques with respect to bone-socket displacement.

Last Updated: January 28, 2022
Follow us on Instagram Follow us on LinkedIn Follow us on Facebook Follow us on Twitter Follow us on YouTube Sign up on GovDelivery