Baum, B. S., Schultz, M. P., Tian, A., Shefter, B., Wolf, E. J., Kwon, H. J., & Shim, J. K. (2013). Amputee locomotion: determining the inertial properties of running-specific prostheses. Archives of physical medicine and rehabilitation, 94(9), 1776-1783.

Running-specific prostheses have allowed individuals with lower extremity amputation to actively participate in sporting activities that include running and other high-impact sports.  Therefore, it is important that running specific prostheses be thoroughly evaluated to assure that potential injury risks are attenuated during high-impact activities.   An initial basic-science effort undertaken to assess device stiffness, a potential variable of devices that may affect impact loading, noted that inertial properties differed slightly across stiffness categories of various running-specific prosthetic devices.  

Hobara, H., Baum, B. S., Kwon, H. J., Linberg, A., Wolf, E. J., Miller, R. H., & Shim, J. K. (2014). Amputee locomotion: lower extremity loading using running-specific prostheses. Gait & posture, 39(1), 386-390.

This study revealed that loading variables increased with running speed not only in able-bodied runners, but also in amputees using running-specific prostheses, and that the intact limb in individuals with unilateral amputation may be exposed to a greater risk of running related injury than the prosthetic limb or able-bodied limbs.  These data will be applied to clinical studies designed to optimize rehabilitation and prosthetic prescription for individuals who choose to continue running activities. 

Linberg AA, Roach KE, Campbell SM, Stoneman PD, Gomez-Orozco O, Gailey RS. Comparison of Six-Minute Walk Test performance between non-amputee active duty Soldiers and Service Members with traumatic lower limb loss. (2013). J Rehabil Res Dev (50)7. 931-940.

The opportunity for wounded service members to return to high-level activity and return to duty has improved with advances in surgery, rehabilitation, and prosthetic technology.   High-levels of patient function, however, have exceeded available clinical assessment tools.  As a solution, an assessment tool called the Comprehensive High-Level Activity Mobility Predictor (CHAMP) was developed through a VA/DoD collaboration.  Use of the CHAMP as a functional outcomes assessment tool has been successfully implemented into clinical care at amputee care sites within the DoD and VA.

During FY13 a series of papers was published to establish appropriate normative data, reliability, and validity of the CHAMP.  Reference ranges were established for United States service members with and without various levels of limb loss. 

Raya MA, Gailey RS, Gaunaurd IA, Jayne DM, Linberg AA, Campbell SM, Gagne E, Manrique P, Muller D, Tucker C. A Comparison of Three Agility Tests in Male Service Members: the Edgren Side-Step Test, T-Test and Illinois Agility Test (2013). J Rehabil Res Dev. 50(7). 951-960.

This study established the reliability of three agility tests in male Service members: the Edgren Side-Step Test, T-Test and Illinois Agility Test. Establishing the reliability of these measures provides the clinician with a clinical tool that assesses uniplanar, biplanar, and multiplanar movements, thus creating a comprehensive assessment of agility.

Gailey RS, Raya MA, Gaunaurd IA, Linberg AA, Campbell SM, Jayne DM, Roach KE, Scoville CR. The development and reliability testing of the Comprehensive High-level Activity Mobility Predictor (CHAMP) in Service Members with traumatic lower limb loss.(2013) J Rehabil Res Dev (50)7. 905-918.

This study established the reliability of the CHAMP as an instrument for use in young, athletic Service members with traumatic lower limb amputation to measure changes in high-level mobility occurring throughout the rehabilitation process.  The CHAMP was validated as a high-level mobility outcome measure to evaluate functional mobility with a prosthesis for lower limb amputees.

Scoville CR, Gailey RS, Raya MA, Gaunaurd IA, Linberg AA, Stoneman PD, Roach KE, Campbell SM. Construct validity of the Comprehensive High-level Activity Mobility Predictor (CHAMP) for Service Members with traumatic lower limb loss. (2013) J Rehabil Res Dev. (50)7. 919-930.

Further validity testing revealed that the CHAMP was able to discriminate between individuals with and without limb loss, as well as differing levels of limb loss.  Finally, researchers observed that CHAMP scores were significantly related to rehabilitation factors such as lower-limb strength and dynamic balance, and could be used as a tool to compare outcomes when using high-performance prosthetic feet.  

Gaunaurd IA, Roach KE, Raya MA, Linberg AA, Campbell SM, Hooper RS, Scoville CR, Gailey RS. Factors Related to High Level Mobility in Service Members with Traumatic Lower Limb Loss. (2013) J Rehabil Res Dev. (50)7. 969-984.

Further validity testing revealed that the CHAMP was able to discriminate between individuals with and without limb loss, as well as differing levels of limb loss.  Finally, researchers observed that CHAMP scores were significantly related to rehabilitation factors such as lower-limb strength and dynamic balance, and could be used as a tool to compare outcomes when using high-performance prosthetic feet.  

Sessoms PH, Wyatt M, Grabiner M, Collins JD, Kingsbury T, Thesing N, Kaufman K. Method for evoking a trip response using a treadmill based perturbation during locomotion. (2013). Journal of Biomechanics. (47)1. 277–280.

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.  In this study 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.

Darter BJ, Rodriguez KM, Wilken JM.  Test–retest reliability and minimum detectable change using the K4b2: Oxygen consumption, gait efficiency, and heart rate for healthy adults during submaximal walking. Research Quarterly for Exercise and Sport. 2013, 84(2): 223-231.

Advanced prosthetic technologies can improve endurance by decreasing the amount of work required to perform activities of daily living.  Energy consumption is difficult to measure, however, outside a laboratory setting.  Our laboratory tested efficacy of a new modern portable device, the K4b2, to assess energy consumption, gait efficiency and heart rate.  The study concluded that this portable device is reliable for collecting physiological parameters that relate to endurance across a range of walking speeds. This method can now be successfully used to determine changes in walking performance when assessing effectiveness of prosthetic devices or novel rehabilitation interventions in a population of patients with amputation.

Darter BJ, Wilken JM.  Energetic consequences of using a prosthesis with adaptive ankle motion during slope walking in persons with a transtibial amputation. (2013). Prosthet Orthot Int. (38) 1. 5-11.

Navigating slopes when using prosthetic devices has traditionally been a challenge for patients following amputation.   The PROPRIO prosthetic ankle device was developed to adapt to user motion, and to adjust for walking on slopes while minimizing gait deviations.  A laboratory-based study revealed that use of the PROPRIO ankle device improved energy expenditure and walking difficulty when descending slopes compared to patients’ current ankle device, however there were no differences between using an activated or deactivated PROPRIO device.   These results suggest that the PROPRIO design may pose a biomechanical advantage when negotiating downward slopes.

Gates DH, Scott SJ, Wilken JM, Dingwell JB. Frontal plane dynamic margins of stability in individuals with and without transtibial amputation walking on a loose rock surface. Gait Posture. 2013, 38(4): 570-5.

Uneven walking surfaces can pose challenges to balance in individuals with lower extremity amputation, increasing risk for falls.  In particular, losing balance in a side-to-side direction may pose a higher fall risk than losing balance to the front or back. Biomechanical measurements taken in Individuals with transtibial amputation walking over rocky, uneven terrain exhibited greater lateral stability than able-bodied control subjects when walking on a rock surface, an unexpected observation.

Gates DH, Aldridge J, Wilken JM. Kinematic comparison of walking on uneven ground using powered and unpowered prostheses. (2013). Clin Biomech. 28(4): 467-472.

Greater lateral stability observed in transtibial amputees walking over rocky, uneven terrain versus able-bodied controls appeared to be related to adoption of a wider-based gait that afforded increased stability.  A follow-on study determined that using a powered ankle prosthesis did not improve stability when walking on rocky terrain, though patients did choose to walk at a faster pace.

Wolf, E. J., Everding, V. Q., Linberg, A. A., Czerniecki, J. M., & Gambel, J. M. (2013). Assessment of the Power Knee and C-leg during step-up and sit-to-stand tasks. Gait and Posture, 38(3). 397-402. doi: 10.1016/j.gaitpost.2013.01.007

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 study examining clinically relevant differences among users of the C-leg, a passive microprocessor knee, and the Power Knee, a prosthetic device that provides positive power generation at the knee joint, revealed no differences in the devices with respect to decreasing impact on the intact limb during functional sit-to-stand or step-up task.

Werner, K. M., Linberg, A. A., & Wolf, E. J. (2013). Reliability of digital fluoroscopic video for assessing axial and mediolateral movement of the femur during weight-bearing in individuals with transfemoral amputations. Journal of Prosthetics and Orthotics, 25(2), 64-67. doi: 10.1097/JPO.0b013e31828adc1f

Changes in residual limb volume can affect socket fit, posing a significant challenge for patients with amputation.  Digital fluoroscopic video, a noninvasive tool to dynamically measure motion of the residual limb within the socket, was determined to be a safe and accurate method to measure the position of the femur within the prosthetic socket.  Successful use of this videofluroscopy imaging technique has led to further study to assess the efficacy of suction socket technologies to reduce movement of the residual limb within the socket.