Center for the Intrepid

Fort Worth, TX, United States

Center for the Intrepid

Fort Worth, TX, United States
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Blair J.A.,Florida Orthopaedic Institute | Patzkowski J.C.,Center for the Intrepid | Blanck R.V.,Carolinas Medical Center | Owens J.G.,Carolinas Medical Center | Hsu J.R.,Carolinas Medical Center
Journal of Orthopaedic Trauma | Year: 2014

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. © 2013 by Lippincott Williams & Wilkins.


Patzkowski J.C.,San Antonio Military Medical Center | Blanck R.V.,Center for the Intrepid | Owens J.G.,Center for the Intrepid | Wilken J.M.,Center for the Intrepid | And 3 more authors.
Journal of Bone and Joint Surgery - Series A | Year: 2012

Background: High-energy extremity trauma is common in combat. Orthotic options for patients whose lower extremities have been salvaged are limited. A custom energy-storing ankle-foot orthosis, the Intrepid Dynamic Exoskeletal Orthosis (IDEO), was created and used with high-intensity rehabilitation as part of the Return to Run clinical pathway. We hypothesized that the IDEO would improve functional performance compared with a non-custom carbon fiber orthosis (BlueRocker), a posterior leaf spring orthosis, and no brace. Methods: Eighteen subjects with unilateral dorsiflexion and/or plantar flexion weakness were evaluated with six functional tests while they were wearing the IDEO, BlueRocker, posterior leaf spring, or no brace. The brace order was randomized, and five trials were completed for each of the functional measures, which included a four-square step test, a sit-to-stand five times test, tests of self-selected walking velocity over level and rocky terrain, and a timed stair ascent. They also completed one trial of a forty-yard (37-m) dash, filled out a satisfaction questionnaire, and indicated whether they had ever considered an amputation and, if so, whether they still intended to proceed with it. Results: Performance was significantly better with the IDEO with respect to all functional measures compared with all other bracing conditions (p < 0.004), with the exception of the sit-to-stand five times test, in which there was a significant improvement only as compared with the BlueRocker (p = 0.014). The forty-yard dash improved by approximately 35%over the values for the posterior leaf spring and no-brace conditions, and by 28% over the BlueRocker. The BlueRocker demonstrated a significant improvement in the forty-yard dash compared with no brace (p = 0.033), and a significant improvement in self-selected walking velocity on level terrain compared with no brace and the posterior leaf spring orthosis (p < 0.028). However, no significant difference was found among the posterior leaf spring, BlueRocker, and no-brace conditions with respect to any other functional measure. Thirteen patients initially considered amputation, but after completion of the clinical pathway, eight desired limb salvage, two were undecided, and three still desired amputation. Conclusions: Use of the IDEO significantly improves performance on validated tests of agility, power, and speed. The majority of subjects initially considering amputation favored limb salvage after this noninvasive intervention. Level of Evidence: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence. Copyright © 2012 by The Journal of Bone and Joint Surgery Incorporated.


Ferris A.E.,Center for the Intrepid | Aldridge J.M.,Center for the Intrepid | Rabago C.A.,Center for the Intrepid | Wilken J.M.,Center for the Intrepid
Archives of Physical Medicine and Rehabilitation | Year: 2012

Objective: To determine whether a powered ankle-foot prosthesis improves gait mechanics, physical performance, and user satisfaction after traumatic transtibial amputation. Design: Pre-post. Setting: Gait analysis laboratory. Participants: Young individuals with traumatic transtibial amputation (n=11) and matched controls (n=11). Interventions: Wearing an energy-storing and -returning (ESR) foot and a powered ankle-foot prosthesis. Main Outcome Measures: Gait mechanics, physical performance, and user satisfaction. Results: The powered prosthesis ankle range of motion (ROM) was significantly larger (∼30%) than that of the ESR limb. However, both devices demonstrated significantly less ankle ROM than the control and intact limbs. At preswing, the ESR limb generated approximately 40% less peak ankle power than control and intact limbs. In contrast, the powered prosthesis generated significantly greater peak ankle power than control (35%) and ESR (∼125%) limbs, resulting in the powered limb absorbing twice the peak knee power observed in the control and intact limbs. The powered prosthesis limb peak hip power generation was approximately 45% greater at preswing than that of the intact limb. Walking velocity increased with the powered prosthesis compared with the ESR limb and was greater than that of the control group. However, physical performance measures were not significantly different between ESR and powered conditions. User satisfaction scores indicated a preference for the powered prosthesis over the ESR limb. Conclusions: Compensatory strategies during gait with the ESR and powered prosthetic devices were similar to those reported in the literature. However, the addition of ankle power and ROM by the powered prosthesis appeared to increase compensatory strategies at proximal joints. © 2012 American Congress of Rehabilitation Medicine.


Garg K.,U.S. Army | Ward C.L.,U.S. Army | Hurtgen B.J.,U.S. Army | Wilken J.M.,Center for the Intrepid | And 4 more authors.
Journal of Orthopaedic Research | Year: 2015

Open fracture is a common occurrence in civilian and military populations. Though great strides have been made in limb salvage efforts, persistent muscle strength deficits can contribute to a diminished limb function after the bone has healed. Over the past decade, a growing effort to establish therapies directed at de novo muscle regeneration has produced several therapeutic approaches. As this effort progresses and as therapies reach clinical testing, many questions remain regarding the pathophysiology of the volumetric loss of skeletal muscle. The current study demonstrates, in a rat "open fracture" model, that the volumetric loss of skeletal muscle results in persistent functional deficits that are dependent on muscle length and joint angle. Moreover, the injured muscle has an increased stiffness during passive stretch and a reduced functional excursion. A case study of a patient with an open type III tibia fracture resulting in volumetric muscle loss in the anterior and posterior compartment is also presented. Eighteen months after injury and tibia healing, persistent functional deficits are apparent with many of the same qualities demonstrated in the animal model. Muscle architectural adaptations likely underlie the altered intrinsic functional characteristics of the remaining musculature. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. © 2014 Orthopaedic Research Society.


Tucker C.J.,U.S. Army | Wilken J.M.,Center for the Intrepid | Stinner D.J.,U.S. Army | Kirk K.L.,U.S. Army
Journal of Bone and Joint Surgery - Series A | Year: 2012

Background: While there are proponents of both bone-bridging and non-bone-bridging transtibial amputation techniques, there is a lack of evidence describing functional differences between these two techniques. The goal of the present investigation was to objectively compare the techniques of bone-bridging and non-bone-bridging with respect to limb socket displacement during physiologic loading. Methods: Fifteen male subjects with an average age of twenty-seven years (range, twenty-two to thirty-two years) who had undergone a unilateral transtibial amputation secondary to a traumatic wartime injury were prospectively evaluated. Seven patients had undergone a bone-bridging amputation, and eight had undergone a non-bone-bridging amputation. Digital fluoroscopic video was used to measure the vertical displacement of the limb within a total-surface-bearing socket with weight-bearing from 0% to 100% of body weight. Results: There was no difference in limb-socket displacement between amputation techniques with initial loading (12.78 mm for the bone-bridging group, compared with 12.43 mm for the non-bone-bridging group; p = 0.88) or with total loading (p = 0.98). Similarly, there was no difference between suspension mechanisms in limb-socket displacement with initial loading (12.15 mm for patients with pin lock suspension, compared with 12.98 mm for those with suction sleeve suspension; p = 0.72) or with total loading (18.24mmfor patients with pin lock suspension, compared with 21.42mmfor those with suction sleeve suspension, p = 0.21). Conclusions: The current study demonstrated no difference between surgical techniques with respect to bone-socket displacement. These data provide no evidence to support statements that bone-bridging contributes to a more efficient platform in the total-surface-bearing socket. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence. Copyright © 2012 by The Journal of Bone and Joint Surgery, Incorporated.


Gates D.H.,Center for the Intrepid | Scott S.J.,U.S. Army | Wilken J.M.,Center for the Intrepid | Dingwell J.B.,University of Texas at Austin
Gait and Posture | Year: 2013

Uneven walking surfaces pose challenges to balance, especially in individuals with lower extremity amputation. The purpose of this study was to determine if lateral stability of persons with unilateral transtibial amputation (TTA) is compromised when walking on a loose rock surface. Thirteen TTA and 15 healthy controls walked over level ground and over a loose rock surface at four controlled speeds. Dependent measures, including medial-lateral center of mass (COM) motion, step width variability, lateral arm swing velocity, and mean and variability of the minimum margins of stability (MOSmin), were compared between subject groups and across conditions. TTA had greater average MOSmin than Control subjects (p=0.018). TTA exhibited decreased MOSmin on their prosthetic limbs compared to their intact limbs (p=0.036), while Control subjects did not exhibit side to side differences. Both groups increased MOSmin with increasing walking speed (p≤0.001). There was no difference in the average MOSmin between walking surfaces (p=0.724). However, the variability of MOSmin was greater on the rocks compared to level ground. Both subject groups increased step width, step width variability, COM range of motion and peak COM velocity when walking on the rock surface. TTA exhibited greater variability of both step width and MOSmin, which suggests that they made larger step-to-step corrective responses, more often, to achieve the same average result. © 2013 Elsevier B.V.


Gates D.H.,Center for the Intrepid | Wilken J.M.,Center for the Intrepid | Scott S.J.,U.S. Army | Sinitski E.H.,Center for the Intrepid | Dingwell J.B.,University of Texas at Austin
Gait and Posture | Year: 2012

It is important to understand how people adapt their gait when walking in real-world conditions with variable surface characteristics. This study quantified lower-extremity joint kinematics, estimated whole body center of mass height (COM VT), and minimum toe clearance (MTC) while 15 healthy, young subjects walked on level ground (LG) and a destabilizing loose rock surface (RS) at four controlled speeds. There were no significant differences in average step parameters (length, time, or width) between the walking surfaces. However, the variability of these parameters increased twofold on the RS compared to LG. When walking on the RS, subjects contacted the surface with a flatter foot and increased knee and hip flexion, which enabled them to lower COM VT. Subjects exhibited increased hip and knee flexion and ankle dorsiflexion during swing on the RS. These changes contributed to a 3.8 times greater MTC on the RS compared to LG. Peak hip and knee flexion during early stance and swing increased with walking speed, contributing to decreased COM VT and increased MTC. Overall, subjects systematically adapted their movement kinematics to overcome the challenge imposed by the destabilizing loose rock surface. © 2011 Elsevier B.V.


Darter B.J.,Virginia Commonwealth University | Sinitski K.,Center for the Intrepid | Wilken J.M.,Center for the Intrepid
Prosthetics and Orthotics International | Year: 2016

Background: Elevated vacuum suspension systems use a pump to draw air from the socket with the intent of reducing bone-socket motion as compared to passive suction systems. However, it remains unknown if elevated vacuum suspension systems decrease limb displacement uniformly during transitions from unloaded to full-body-weight support. Objectives: To compare limb-socket motion between elevated vacuum and passive suction suspension sockets using a controlled loading paradigm. Study design: Comparative analysis. Methods: Persons with transtibial amputation were assessed while wearing either an elevated vacuum or passive suction suspension socket. Digital video fluoroscopy was used to measure axial bone-socket motion while the limb was loaded in 20% body-weight increments. An analysis of variance model was used to compare between suspension types. Results: Total axial displacement (0%-100% body weight) was significantly lower using the elevated vacuum (vacuum: 1.3 cm, passive suction: 1.8 cm; p < 0.0001). Total displacement decreased primarily due to decreased motion during initial loading (0%-20%; p < 0.0001). Other body-weight intervals were not significantly different between systems. Conclusion: Elevated vacuum suspension reduced axial limb-socket motion by maintaining position of the limb within the socket during unloaded conditions. Elevated vacuum provided no meaningful improvement in limb-socket motion past initial loading. Clinical relevance Excessive bone-socket motion contributes to poor residual limb health. Our results suggest elevated vacuum suspensions can reduce this axial displacement. Visual assessment of the images suggests that this occurs through the reduction or elimination of the air pocket between the liner and socket wall while the limb is unloaded. © International Society for Prosthetics and Orthotics International.


McAndrew P.M.,University of Texas at Austin | Dingwell J.B.,University of Texas at Austin | Wilken J.M.,Center for the Intrepid
Journal of Biomechanics | Year: 2010

Walking on uneven surfaces or while undergoing perturbations has been associated with increased gait variability in both modeling and human studies. Previous gait research involving continuous perturbations has focused on sinusoidal oscillations, which can result in individuals predicting the perturbation and/or entraining to it. Therefore, we examined the effects of continuous, pseudo-random support surface and visual field oscillations on 12 healthy, young participants. Participants walked in a virtual reality environment under no perturbation (NOP), anterior-posterior (AP) walking surface and visual oscillation and mediolateral (ML) walking surface and visual oscillation conditions. Participants exhibited shorter (p0.005), wider (p<0.001) and faster (p<0.001) steps relative to NOP during ML perturbations and shorter (p0.005) and wider (p<0.001) steps during AP perturbations. Step length variability and step width variability both increased relative to NOP during all perturbation conditions (p<0.001) but exhibited greater increases for the ML perturbations (p<0.001). Participants exhibited greater trunk position variability and trunk velocity variability in the ML direction than in the AP direction during ML perturbations relative to NOP (p<0.001). Significantly greater variability in the ML direction indicates that to maintain stability, participants needed to exert greater control in the ML direction. This observation is consistent with prior modeling predictions. The large and consistent responses observed during ML visual and walking surface perturbations suggest potential for application during gait training and patient assessment. © 2010.


Patzkowski J.C.,San Antonio Military Medical Center | Owens J.G.,Center for the Intrepid | Blanck R.V.,Center for the Intrepid | Kirk K.L.,San Antonio Military Medical Center | And 2 more authors.
Journal of Trauma and Acute Care Surgery | Year: 2012

Background: Many wounded warriors experienced high-energy lower-extremity trauma (HELET) that may be limb threatening. Volumetric muscle loss, posttraumatic osteoarthritis, nerve injuries, and pain may severely limit physical function. Several wounded warriors express a strong desire to return to their units and be deployed in their original military occupational specialty. We began the return-to-run (RTR) clinical pathway at our institution 2 years ago to facilitate high-performance goals such as these. It involves an energy storing ankle foot orthosis, the intrepid dynamic exoskeletal orthosis in combination with high-intensity, progression-oriented rehabilitation. We sought to determine the rate of deployment or predeployment training after participation in this noninvasive intervention. Methods: A retrospective analysis of the RTR database was performed to determine the rate of deployment or predeployment training among those service members who began participation in the RTR between November of 2009 and March of 2011. Medical records were reviewed for demographics, injury, surgical data, and major complications. Requests for delayed amputation were recorded, and charts were reviewed to determine if patients eventually elected to proceed with amputation or if they chose to continue with limb salvage. Results: Between November 2009 and March 2011, 87 service members completed the RTR. Of these, 17 (19.5%) have been deployed to combat or are in predeployment training. Sixteen serve in combat arms (nine Special Forces, four infantry/ranger, two combat engineers, and one gunner), and one is a member of the military intelligence community. Fifteen patients sustained their injuries as a result of HELET (four gunshot, five motor vehicle collisions, four explosions, one parachute injury, and one fall from height), one had idiopathic avascular necrosis of the talus, and one had an iatrogenic nerve injury after pelvic surgery. Six of the patients underwent circular external fixation, five received joint fusions (three ankle, two subtalar joint), and nine had major nerve injuries. Four initially desired amputation of their injured limb but have subsequently countermanded their request. Conclusion: Returning to high-level physical function after HELET is challenging. After implementation of the RTR clinical pathway with the intrepid dynamic exoskeletal orthosis, 19.5% of wounded warriors treated with the RTR have been deployed or will be deployed in the coming year. Level of Evidence: Therapeutic study, level V. © 2012 Lippincott Williams & Wilkins.

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