The Comprehensive High-level Activity Mobility Predictor (CHAMP): A Performance-based Assessment Instrument to Quantify High-level Mobility in Service Members with Traumatic Lower Limb Loss

The psychometric properties of a new high-level mobility outcome measure for Service Members (SMs) with traumatic lower limb loss called the Comprehensive High-level Activity Mobility Predictor (CHAMP) was developed in order objectively evaluate functional abilities and measure change in function throughout the rehabilitation process. The CHAMP was administered to a population of SMs with traumatic lower limb loss who were representative of those who have suffered limb loss in recent conflicts. In addition, a population of non-amputee Active Duty soldiers completed the CHAMP and provided normative data for high-level mobility and threshold levels of performance for those SMs with lower limb loss. A simple grading system, absent of floor and ceiling effects, generates a composite score providing a single numeric value representing the physical performance factors of high-level mobility in different plane of motion and under different conditions. The CHAMP was found to be a safe, reliable, valid, and responsive performance-based outcome measure of high-level mobility. It was found to have excellent interrater and test-retest reliability suggesting that it is a stable and repeatable measure of high-level mobility. Convergent construct validity and known group methods were utilized to establish the CHAMP as a valid measure of high-level mobility. Predictive models of CHAMP performance were established utilizing variables representing impairments of body structure and function and contextual factors by level of lower limb amputation. The CHAMP has the potential to be used for lower limb amputees throughout the rehabilitation process and could translate to the non-amputee population for assessment of high-level mobility capabilities

The Comprehensive High-level Activity Mobility Predictor (CHAMP): A Performance-based Assessment Instrument to Quantify High-level Mobility in Service Members with Traumatic Lower Limb Loss

The psychometric properties of a new high-level mobility outcome measure for Service Members (SMs) with traumatic lower limb loss called the Comprehensive High-level Activity Mobility Predictor (CHAMP) was developed in order objectively evaluate functional abilities and measure change in function throughout the rehabilitation process. The CHAMP was administered to a population of SMs with traumatic lower limb loss who were representative of those who have suffered limb loss in recent conflicts. In addition, a population of non-amputee Active Duty soldiers completed the CHAMP and provided normative data for high-level mobility and threshold levels of performance for those SMs with lower limb loss. A simple grading system, absent of floor and ceiling effects, generates a composite score providing a single numeric value representing the physical performance factors of high-level mobility in different plane of motion and under different conditions. The CHAMP was found to be a safe, reliable, valid, and responsive performance-based outcome measure of high-level mobility. It was found to have excellent interrater and test-retest reliability suggesting that it is a stable and repeatable measure of high-level mobility. Convergent construct validity and known group methods were utilized to establish the CHAMP as a valid measure of high-level mobility. Predictive models of CHAMP performance were established utilizing variables representing impairments of body structure and function and contextual factors by level of lower limb amputation. The CHAMP has the potential to be used for lower limb amputees throughout the rehabilitation process and could translate to the non-amputee population for assessment of high-level mobility capabilities.</p

Symmetry in external work (SEW): a novel method of quantifying gait differences between prosthetic feet

Unilateral transtibial amputees (TTAs) show subtle gait variations while using different prosthetic feet. These variations have not been detected consistently with previous experimental measures. We introduce a novel measure called Symmetry in External Work (SEW) for quantifying kinetic gait differences between prosthetic feet. External work is the result of changes in kinetic and potential energy of body center of mass (CoM). SEW is computed by integrating vertical ground reaction forces obtained using F-scan in-sole sensors. Since various prosthetic feet have different designs, we hypothesized that SEW will vary with the type of foot used. This hypothesis was tested with a single unilateral TTA using four prosthetic feet (Proprio, Trias+, Seattle Lite and SACH). The Proprio (mean symmetry 94.5% +/- 1.1%) and the Trias+ (92.1% +/- 2.5%) feet exhibited higher symmetry between the intact and prosthetic limbs, as compared to the Seattle (67.8% +/- 19.3%) and SACH (35.7% +/- 11.1%) feet. There was also a good agreement in vertical CoM excursion between the intact foot and prosthetic feet with heel-toe foot plate designs. Results indicate that SEW measure may be a viable method to detect kinetic differences between prosthetic feet and could have clinical applications because of relatively low cost instrumentation and minimal subject intervention

Analysis of weight distribution strategies in unilateral transtibial amputees during the stand-to-sit activity.

Current methods of quantifying the stand-to-sit activity (StTS) are resource intensive and have not been applied to unilateral transtibial amputees (TTAs). The purpose of this study is to define five phases of arm-rest assisted and unassisted StTS using simple instrumentation and implement this method for assessing TTA movement patterns. Twelve TTAs and 12 age-matched non-amputees performed StTS with and without arm-rest support. Symmetry of weight distribution between lower limbs was calculated for five StTS phases: Descent Initiation; Descent Deceleration; Seat-Contact; Stabilisation and Sitting. TTAs demonstrated an asymmetrical weight distribution pattern and a tendency to transfer weight to the intact limb during the course of the activity. Non-amputees had relatively higher symmetry and did not exhibit substantial weight shifts during the activity. Symmetry indices were similar for assisted and unassisted sitting in both subject groups. These results highlight a need for therapeutic interventions in TTAs for reducing loading asymmetries and associated co-morbidities. Practitioner Summary: This study defines a novel method for quantifying stand-to-sit movements using clinically friendly equipment and is the first to investigate the stand-to-sit activity of unilateral transtibial amputees. The observed differences in inter-limb weight distribution strategies between amputees and non-amputees could provide insights for clinical assessment and intervention

Influence of gait training and prosthetic foot category on external work symmetry during unilateral transtibial amputee gait

Prosthetic foot prescription guidelines lack scientific evidence and are concurrent with an amputee's concurrent with an amputee's Medicare Functional Classification Level (K-Level) and categorization of prosthetic feet. To evaluate the influence of gait training and four categories of prosthetic feet (K1, K2, K3, and microprocessor ankle/foot) on Symmetry in External Work for K-Level-2 and K-Level-3 unilateral transtibial amputees. Randomized repeated-measures trial. Five K-Level-2 and five K-Level-3 subjects were tested in their existing prosthesis during Session 1 and again in Session 2, following 2 weeks of standardized gait training. In Sessions 3-6, subjects were tested using a study socket and one of four randomized test feet. There was an accommodation period of 10-14 days with each foot. Symmetry in External Work for positive and negative work was calculated at each session to determine symmetry of gait dynamics between limbs at self-selected walking speeds. K-Level-2 subjects had significantly higher negative work symmetry with the K3 foot, compared to K1/K2 feet. For both subject groups, gait training had a greater impact on positive work symmetry than test feet. Higher work symmetry is possible for K-Level-2 amputees who are trained to take advantage of K3 prosthetic feet designs. There exists a need for an objective determinant for categorizing and prescribing prosthetic feet

Weight distribution symmetry during the sit-to-stand movement of unilateral transtibial amputees

This study characterises weight distribution symmetry between the intact and amputated limbs of unilateral transtibial amputees during a sit-to-stand movement. A total of 12 amputees and 12 age-matched, non-amputees performed the activity for two conditions - rising with and without chair arm-rest assistance. The sit-to-stand movement was divided into five events: Pre-Ascent; Ascent Initiation; Seat-Off; Deceleration; Standing. Symmetry in ground reaction forces between limbs was calculated at each event together with the rise time. Results indicate that during the course of the movement, amputees increased loading of the intact limb by approximately 27%, resulting in a significant asymmetry at seat-off and deceleration events. Non-amputees loaded the dominant limb more than the non-dominant limb throughout the activity but did not exhibit substantial weight shifts. Weight distribution symmetry was not significantly different between the two rising conditions in either population. Amputees had significantly longer rise times than non-amputees only while rising without arm-rest assistance. Statement of Relevance: Sit-to-stand movements are performed frequently every day. Incorrect movement biomechanics caused by musculoskeletal impairments can lead to reduced functional independence and secondary co-morbidities. This study defines five events of a sit-to-stand cycle and is the first to address asymmetries of transtibial amputees, providing ergonomic insights for clinical assessment and intervention

The development and internal consistency of the comprehensive lower limb amputee socket survey in active lower limb amputees

Prosthetic socket fit is an important element associated with successful ambulation and use of a prosthesis. Prosthetists and rehabilitation clinicians would benefit from an assessment tool that discriminates between and quantifies the multiple determinants that influence the lower limb amputee's performance and satisfaction of a prosthetic socket. To determine the internal consistency of the comprehensive lower limb amputee socket survey, a new self-report measure of prosthetic socket satisfaction that quantifies suspension, stability, comfort, and appearance. Cross-sectional sample of active amputees. Interviews were conducted with prosthetists, physical therapists, and lower limb amputees to identify clinical concerns and common activities influencing socket fit. An expert panel of five clinicians reviewed the items and constructed the original version of the comprehensive lower limb amputee socket survey which was then administered to a convenience sample of 47 active lower limb amputees. Item analysis and Cronbach's alpha were used to determine the final version of the comprehensive lower limb amputee socket survey. Following item raw score-to-total score correlation with Cronbach's alpha for comprehensive lower limb amputee socket survey determinants, internal consistency improved when nine questions were eliminated. The comprehensive lower limb amputee socket survey is a self-report measure of prosthetic socket satisfaction with very good internal consistency. When socket problems occur, the ability to determine the specific cause can reduce modification time, enhance socket fit, and promote patient satisfaction. A standardized multi-dimensional assessment measure of socket satisfaction enables prosthetists to quantify the multiple determinants of socket satisfaction, improve patient communication, and demonstrate the value of socket interventions

Evidence-Based Amputee Rehabilitation: a Systematic Approach to the Restoration of Function in People with Lower Limb Loss

Purpose of Review The purpose of this review is to illustrate how existing outcome measures and clinical models can be applied to outline an evidence-based rehabilitation program for people with lower limb loss (LLL). The use of outcome measures in rehabilitation in addition to providing a numeric value of a person’s rehabilitation status can identify patient-specific functional impairments, activity limitations, establish treatment goals, guide targeted treatment interventions, detect change over time, and classify patients and with some populations develop predictive models. Recent Findings The model for the rehabilitation of people with LLL is based on the Evidence-Based Amputee Rehabilitation program that uses outcome measures to identify patient-specific impairments and limitations, set realistic goals, and track change over time. Summary The standardized use of outcome measures and evidence-based patient care can be used to help guide best practices for post-amputation rehabilitation and prosthetic interventions, and care over the life span for people with LLL