²²Eckard, C. S., Pruziner, A. L., & Sanchez, A. D. (2015). Metabolic and Body Composition Changes in First Year Following Traumatic Amputation. Journal of Rehabilitation Research and Development, 52(5), 553

Limited available data on changes in body composition changes following amputation prompted a study to quantify weight, muscle mass, fat mass, and metabolic changes during the first year following traumatic lower extremity amputation in Service members.  Interestingly, while weight increased significantly, fat mass did not significantly increase over the one-year observational period.²²  This observation may reflect the success of the daily rehabilitation regimen undertaken by all patients with amputation within the DoD Advanced Rehabilitation Centers.  Follow-on studies are planned to assess long-term changes in fat mass that might predispose to obesity and other health-related challenges.

²³Shojaei, I., Hendershot, B. D., Wolf, E. J., & Bazrgari, B. (2016). Persons with unilateral transfemoral amputation experience larger spinal loads during level-ground walking compared to able-bodied Individuals. Clinical Biomechanics, 32, 157-163.

Low back pain is estimated to occur in 52-71% of individuals with lower limb loss, substantially higher than that of the general population (6-33%).   Larger loads to the spine are observed following transfemoral amputation that result from changes in how trunk muscles are recruited while walking,²³ which may increase the risk for low back pain over time.   Gait training interventions that decrease loads on the spine during walking and other weight bearing activities may be beneficial in preventing the occurrence of low back pain.

⁵Aldridge Whitehead, J. M., Russell Esposito, E., & Wilken, J. M. (2016). Stair ascent and descent biomechanical adaptations while using a custom ankle-foot orthosis. Journal of Biomechanics, 49(13), 2899-2908. doi:10.1016/j.jbiomech.2016.06.035.

A follow-on study revealed that IDEO users were able to navigate stairs in a step-over-step fashion, similar to individuals without limb trauma.  Restrictions in movement of the AFO at the ankle, however, resulted in compensatory strategies that resulted in users relying more on the hip and knee joints.⁵ This information suggests periodic monitoring to prevent secondary injury at the hip and knee joints.

⁶Ranz, E. C., Russell Esposito, E., Wilken, J. M., & Neptune, R. R. (2016). The influence of passive-dynamic ankle-foot orthosis bending axis on gait performance in individuals with lower-limb impairments. Clinical Biomechanics, 37, 13-21. doi: 10.1016/j.clinbiomech.2016.05.001

Modification to existing orthoses, such as the IDEO, may optimize functional outcomes. With this in mind, a study was conducted to compare functional outcomes of three AFO designs that differed in location of the bending axis of the strut (high, middle, low).  While it was hypothesized that changing the bending axis closer to the ankle joint would create more normal gait through improved ankle motion, the observed differences in gait performance related to bending axis were neither large, nor consistent,⁶ and did not have a clinical benefit on walking mechanics.  Individual preference and comfort may be guiding factors toward orthotic prescription.

⁷Bell, E. M., Pruziner, A. L., Wilken, J. M., & Wolf, E. J. (2016). Performance of conventional and X2 prosthetic knees during slope descent. Clinical Biomechanics, 33, 26-31.

Navigating slopes and uneven terrain when using prosthetic devices has traditionally been a significant challenge for patients, particular those with a transfemoral amputation.  Prosthetic device manufacturers continue to develop new devices that can replicate the function of an intact knee.  The X2 prosthetic knee was specifically developed to give service members the ability to navigate uneven terrain through enhanced device control.  Patients using the X2 to navigate a 10 degree downward slope relied less on handrail assistance, and walked with greater speed and longer stride than when using their accustomed mechanical knee,⁷suggesting a higher degree of confidence when ambulating under these conditions.

⁸Bhatnagar, V., Richard, E., Melcer, T., Walker, J., & Galarneau, M. (2015).  Lower-limb amputation and effect of posttraumatic stress disorder on Department of Veterans Affairs outpatient cost trends. Journal of Rehabilitation and Research Development, 52(7), 827-838.

⁹Scoville, C. R., Pruziner, A. L., & Ritland, B. (2016) Rehabilitation without prosthesis (Chapter 60). Atlas of Amputations and Limb Deficiencies: Surgical, Prosthetic, and Rehabilitation Principles, 4th Edition. American Academy of Orthopaedic Surgeons. 731-737.

One of the goals of the EACE is to provide prosthetic solutions that encourage prosthetic use and improve function for patients with amputation.  Among amputees, prosthetics comprise more than 50% of outpatient cost,⁸ therefore it is important to determine the best prosthetic for a patient based on their specific individual needs.  It is important to recognize, however, that not all patients are candidates for prosthetic use.  A book chapter highlighting lessons learned at the Walter Reed Amputee Clinic presents a variety of reasons for prosthetic abandonment and can include age, prior activity, level or severity of injury, health or psychological status, access to prosthetic resources, or other factors that create barriers to use. ⁹ As such, prosthetic prescription is not a simple task, and the goals for the patient should be paramount in developing a treatment plan that includes patient and family education, peer support, assessment for assistive devices, and training in transfers and activities of daily living in an effort to optimize prosthetic use, quality of life, and prevention of secondary health effects related to inactivity.

¹⁰Raschke, S. U., Orendurff, M. S., Mattie, J. L., Kenyon, D. E., Jones, O. Y., Moe, D., Winder, L., Wong, A. S., Moreno-Hernandez, A., Highsmith, M. J., Sanderson, D. J., & Kobayashi, T. U. (2015). Biomechanical characteristics, patient preference and activity level with different prosthetic feet: A randomized double blind trial with laboratory and community testing. Journal of Biomechanics, 48.146-152. doi:10.1016/j.jbiomech.2014.10.002

Prosthetic devices are often prescribed based on a patient’s ability to perform a specific level of activity.  Individuals with higher activity levels generally receive higher stiffness (and more expensive) carbon fiber energy storing feet thought to enhance performance, while individuals with lower functional levels are provided with more basic “compliant” feet.  A recent randomized and blinded study indicates, however, that individuals at all levels of function preferred a compliant foot over a more high-performance stiff foot.¹⁰ This suggests that the “softer feel” of a foot may be preferable to a higher performance foot when maneuvering during real-world use, especially on slopes, stairs, and uneven terrain.

¹¹Klenow, T. D., Kahle, J. T., & Highsmith, M. J. (2016). The dead spot phenomenon in prosthetic gait: Quantified with an analysis of center of pressure progression and its velocity in the sagittal plane. Clinical Biomechanics, 3856-62. doi:10.1016/j.clinbiomech.2016.08.013

Amputees often note a “flat spot” or “stall” when walking with prosthetic foot devices.  Patient comments indicate it feels as if they have to “climb over” their foot.  This disruption in forward progression is described as a “dead spot” phenomenon (DSP), and can affect a patient’s gait efficiency.  A novel exploratory study developed a laboratory methodology to quantify the DSP in both transtibial and transfemoral amputees utilizing a center of pressure gait analysis.  Researchers observed that this metric permitted comparison of the DSP in various passive prosthetic foot and ankle systems, with a continuous lever foot design exhibiting the most favorable metric results.¹¹  

¹²Highsmith, M. J., Kahle, J. T., Miro, R. M., Orendurff, M. S., Lewandowski, A. L., Orriola, J. J., Sutton, B., & Ertl, J. P. (2016).  Prosthetic interventions for people with transtibial amputation: Systematic review and meta-analysis of high-quality prospective literature and systematic reviews. Journal of Rehabilitation Research & Development, 53(2), 157-183.

One way to address and improve the robustness of existing evidence is through the conduct of meta analyses, which combine results from relevant studies and provide comprehensive summary analyses.  A recent metaanalysis generated evidence related to prosthetic alignment, foot and ankle systems, socket interface, postoperative care, and pylon type. Salient findings are summarized as follows:  1)  malalignment of the prosthetic foot can lead to gait deviations and discomfort that can place more load on the sound side limb, which may contribute to future degenerative change in the intact limb; 2) different prosthetic feet may also differ in how loads are placed on the intact limb, in activities that involve the need for great propulsion (stairs), and that can reduce energy cost and fatigue; 3) gel liners improve suspension, load distribution, and can improve pain and comfort, increasing ambulation independence; 4) VASS (suction socket) interfaces were shown to decrease pistoning of the stump within the socket, and improve postoperative mobility and ulceration; 5) rigid removable dressings were more effective at reducing acute post-amputation edema, accelerating healing time, and reducing infection rates and time to prosthetic fitting than conventional elastic compression; and 6) there were no appreciable clinical differences between the use of rigid and telescoping/teletorsion pylons, however the use of monolimbs with elliptical shank pylons did decrease peak loads on both the prosthetic and sound limbs compared with circular shank monolimbs.¹²

¹⁷Gates, D. H., Smurr-Walters, L. M., Cowley, J. C., Wilken, J. M., & Resnik, L. (2015). Motion requirements for upper limb activities of daily living. American Journal of Occupational Therapy, 70(1). doi: 10.5014/ajot.2016.015487

Using a biomechanical approach, a methodological study first quantified the range of motion required for eight upper-extremity activities of daily living in healthy individuals without arm pathology.¹⁷  This preliminary study set the stage for conduct of future studies that will assess functionality of specific prosthetic limbs. 

¹⁸Carey, S. L., Lura, D. J., & Highsmith, M. J. (2015).  Differences in myoelectric and body-powered upper-limb prostheses: Systematic literature review. Journal of Rehabilitation Research & Development, 52(3), 247-262.

Next, there is the challenge of prescribing the best upper-limb prosthesis for an individual’s particular condition or lifestyle.  It is generally thought that myoelectric devices may be best suited for light-intensity work, while body-powered prostheses have shown advantages in durability, maintenance, and feedback for heavier use.  A systematic review of 31 published studies, however, concluded that there is insufficient evidence to conclude that either system provides a significant general advantage,¹⁸ suggesting that prosthetic selection should be based on a patient’s individual needs and include personal preferences, prosthetic experience, and functional needs.

¹⁹Cowley, J., Resnik, L., Wilken, J., Smurr Walters, L., & Gates, D. (2016). Movement quality of conventional prostheses and the DEKA arm during everyday tasks. Prosthetics and Orthotics International [Epub]. doi: 10.1177/0309364616631348

Another challenge is that conventional devices are not able to restore the function and characteristic movement quality of the upper limb.   A large effort is ongoing to advance technologies that will contribute to greater upper extremity function for the prosthetic user.  The DEKA Gen 3 arm is a novel upper limb prosthesis recently approved by the Food and Drug Administration, and features enhanced ability to perform the complex movements required to increase dexterity and movement quality.  Conventional prosthetic users were trained for one month in use of the DEKA Arm, after which movement quality (speed, smoothness, and wrist trajectory) was assessed using both systems.  The results were equivocal, however, in that some users exhibited decreased movement quality, and another exhibited greater movement quality, when using the DEKA arm compared to a conventional prosthesis.¹⁹  Further work is ongoing to optimize function of the DEKA arm and other available prosthetic devices for the upper extremity.

¹Valerio, I. L., Campbell, P., Sabino, J., Dearth, C. L., & Fleming, M. (2015). The use of urinary bladder matrix in the treatment of trauma and combat casualty wound care. Regenerative medicine, 10(5), 611-622.

Use of a biologic scaffold material derived from urinary bladder matrix (UBM) to aid in reconstruction of traumatic combat wounds is one area of regenerative medicine research with promising results.  Fifty-one clinical cases were performed at WRNMMC in which UBM was utilized to help facilitate stable, definitive wound coverage of traumatic combat injuries. UBM was found to facilitate definitive soft tissue reconstruction in 86% of cases by establishing a neovascularized soft tissue base acceptable for second stage skin grafting and/or flap coverage. ¹

²Dearth, C. L., Keane, T. J., Carruthers, C. A., Reing, J. E., Huleihel, L., Ranallo, C. A., & Badylak, S. F., (2016). The effect of terminal sterilization on the material properties and in vivo remodeling of a porcine dermal biologic scaffold. Acta biomaterialia, 33, 78-87.

Biological scaffolds are regulated by the FDA as medical devices and, as such, require terminal sterilization prior to clinical use.  Currently there is no consensus for the most effective yet minimally destructive sterilization procedure.  A study assessing the effect of several different sterilization procedures on the material properties and the remodeling response of biologic scaffolds observed that increased doses of gamma and electron beam radiation increased degradation of the biological scaffold over time.² Future studies will determine the most appropriate irradiation dose to be used during sterilization procedure to avoid tissue damage.

³Dearth, C. L., Keane, T. J., Scott, J. R., Daly, K. A., & Badylak, S. F. (2015). A rodent model to evaluate the tissue response to a biological scaffold when adjacent to a synthetic material. Tissue Engineering Part A, 21(19-20), 2526-2535.

Little is known about the kinetics of biologic scaffold integration or the host tissue response to the biologic scaffold materials when placed adjacent to synthetic materials often utilized in limb preservation procedures.  Researchers observed that the biologic scaffold at the synthetic material interface produced a thinner collagenous tissue layer than when bordering an organic barrier (abdominal wall).³ These findings provide additional information to surgeons to assist with optimizing the surgical procedure.

⁴Dearth, C. L., Slivka, P. F., Stewart, S. A., Keane, T. J., Tay, J. K., Londono, R., & Badylak, S. F. (2016). Inhibition of COX1/2 alters the host response and reduces ECM scaffold mediated constructive tissue remodeling in a rodent model of skeletal muscle injury. Acta biomaterialia, 31, 50-60.

The ability of biologic scaffold materials to both reinforce the surgical repair of soft tissue and serve as an inductive template to promote a constructive tissue remodeling response has been shown previously to be dependent on a dynamic regulation of the inflammatory process which in turn facilitates scaffold degradation and remodeling. Nonsteroidal anti-inflammatory drugs (NSAIDs), such as Aspirin, have been previously shown to alter this inflammatory response in endogenous healing, but its effect on biomaterial-mediated tissue reconstruction was unknown. A study was conducted in which Aspirin, frequently prescribed to patients with extremity trauma, was shown to inhibit the biologic scaffold-mediated remodeling response by altering mechanisms necessary for optimal regeneration,⁴ suggesting that aspirin and other similar pain medications may not be optimal for these patients.