Ignacio A. Gaunaurd

Comparison of three agility tests with male servicemembers: Edgren Side Step Test, T-Test, and Illinois Agility Test.

Performance-based outcomes such as the T-Test, Edgren Side Step Test (ESST), and Illinois Agility Test (IAT) have been used to assess agility in athletes and nonathletes; however, the reliability and validity of these tests have not been established. The purpose of this study was to establish the reliability and convergent construct validity of the ESST, T-Test, and IAT in young, nondisabled, physically active male servicemembers (SMs). Ninety-seven male Active Duty U.S. Army SMs completed the study. Statistically significant differences were not found between the ESST (p = 0.10), T-Test (p = 0.09), and IAT (p = 0.23) when administered twice within a 24 to 48 h period. These tests were found to have excellent interrater reliability and moderate to good test-retest reliability. A good positive relationship exists between the IAT and T-Test (r = 0.76, p < 0.001) and a moderate negative relationship exists between the ESST and both the T-Test (r = -0.69, p < 0.001) and IAT (r = -0.65, p < 0.001). The results suggest that these tests are valid measures of agility that uniquely assess movement in different planes, thus providing a comprehensive assessment of high-level mobility.

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.

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.

Application of Self-Report and Performance-Based Outcome Measures to Determine Functional Differences between Four Categories of Prosthetic Feet

We examined the application of outcome measures to determine changes in function caused by standardized functional prosthetic gait training and the use of four different prosthetic feet in people with unilateral transtibial limb loss. Two self-report measures (Prosthetic Evaluation Questionnaire-Mobility Scale [PEQ-13] and Locomotor Capabilities Index [LCI]), and three performance-based measures (Amputee Mobility Predictor with a prosthesis [AMPPRO], 6-minute walk test [6MWT] and step activity monitor [SAM]) were used. Ten people with unilateral transtibial limb loss, five with peripheral vascular disease (PVD) and five without PVD, completed testing. Subjects were tested at baseline and after receiving training with their existing prosthesis and with the study socket and four prosthetic feet, i.e., SACH (solid ankle cushion heel), SAFE (stationary attachment flexible endoskeletal), Talux, and Proprio feet, over 8 to 10 weeks. Training was administered between testing sessions. No differences were detected by the PEQ-13, LCI, 6MWT, or SAM following training and after fitting with test feet. The AMPPRO demonstrated differences following training with the existing prosthesis in the PVD group and between selected feet from baseline testing ( p </= 0.05). Significant differences were found between the PVD and the non-PVD groups (p </= 0.05) in the AMPPRO and 6MWT when using the Proprio foot. Self-report measures were unable to detect differences between prosthetic feet.

Development and reliability testing of the Comprehensive High-Level Activity Mobility Predictor (CHAMP) in male servicemembers with traumatic lower-limb loss.

The opportunity for wounded servicemembers (SMs) to return to high-level activity and return to duty has improved with advances in surgery, rehabilitation, and prosthetic technology. As a result, there is now a need for a high-level mobility outcome measure to assess progress toward high-level mobility during and after rehabilitation. The purpose of this study was to develop and determine the reliability of a new outcome measure called the Comprehensive High-Level Activity Mobility Predictor (CHAMP). The CHAMP consists of the Single Limb Stance, Edgren Side Step Test, T-Test, and Illinois Agility Test. CHAMP reliability was determined for SMs with lower-limb loss (LLL) (interrater: n = 118; test-retest: n = 111) and without LLL ( n = 97). A linear system was developed to combine the CHAMP items and produce a composite score that ranges from 0 to 40, with higher scores indicating better performance. Interrater and test-retest intraclass correlation coefficient values for the CHAMP were 1.0 and 0.97, respectively. A CHAMP score equal to or greater than 33 points is within the range for SMs without LLL. The CHAMP was found to be a safe and reliable measure of high-level mobility in SMs with traumatic LLL.

Postural asymmetries in transfemoral amputees.

Background: Postural asymmetries are thought to lead to impairment of body structure and function such as muscle imbalance, gait asymmetry and possible chronic conditions, which result in limitation of mobility and restriction of daily activity for transfemoral amputees (TFAs). Despite the potential clinical impact, postural asymmetries have not been confirmed or quantified in TFAs. Objectives: To identify the presence of postural asymmetries in TFAs utilizing clinical evaluation measures. Study design: An observational cross-sectional study in which participants were evaluated at a single time point without intervention or follow-up. Methods: Forty-seven unilateral TFAs were measured for standing limb length, pelvic innominate inclination (PII), lateral trunk flexion and hip extension. Results: Limb length discrepancy was present in 66% of participants and 57% had a short prosthetic limb. PII was greater than has been reported in the literature, and the shorter the prosthetic lower limb, the greater the PII on the amputated side (r = −0.422, p = 0.004). Limb length discrepancy and decreased lateral trunk flexion accounted for 26% of the variance in amputated side PII. Conclusion: Three postural measurements, namely leg length, pelvic innominate inclination and hip extension, were found to differ between the intact and amputated limb in this study sample. Clinical relevance Clinicians should include postural assessment as part of their routine evaluation of TFAs in an effort to achieve postural symmetry and reduce the risk of chronic conditions associated with impairment of body structure and function.

Use of and confidence in administering outcome measures among clinical prosthetists: Results from a national survey and mixed-methods training program.

Background: Outcome measures can be used in prosthetic practices to evaluate interventions, inform decision making, monitor progress, document outcomes, and justify services. Strategies to enhance prosthetists’ ability to use outcome measures are needed to facilitate their adoption in routine practice. Objective: To assess prosthetists’ use of outcome measures and evaluate the effects of training on their confidence in administering performance-based measures. Study design: Cross-sectional and single-group pretest–posttest survey. Methods: Seventy-nine certified prosthetists (mean of 16.0 years of clinical experience) were surveyed about their experiences with 20 standardized outcome measures. Prosthetists were formally trained by the investigators to administer the Timed Up and Go and Amputee Mobility Predictor. Prosthetists’ confidence in administering the Timed Up and Go and Amputee Mobility Predictor was measured before and after training. Results: The majority of prosthetists (62%) were classified as non-routine outcome measure users. Confidence administering the Timed Up and Go and Amputee Mobility Predictor prior to training was low-to-moderate across the study sample. Training significantly (p < 0.0001) improved prosthetists’ confidence in administering both instruments. Conclusion: Prosthetists in this study reported limited use of and confidence with standardized outcome measures. Interactive training resulted in a statistically significant increase of prosthetists’ confidence in administering the Timed Up and Go and Amputee Mobility Predictor and may facilitate use of outcome measures in clinical practice. Clinical relevance Frequency of outcome measure use in the care of persons with limb loss has not been studied. Study results suggest that prosthetists may not regularly use standardized outcome measures and report limited confidence in administering them. Training enhances confidence and may encourage use of outcome measures in clinical practice.

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

Background: 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. Objective: 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. Design: Randomized repeated-measures trial. Methods: 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. Results: 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. Conclusion: 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. Clinical relevance Findings that gait training can influence symmetry of gait dynamics and that K-Level-2 amputees can achieve greater work symmetry with a K3 foot having a “J-shaped” ankle and heel-to-toe footplate could potentially impact prosthetic care and foot prescription by clinicians and reimbursement guidelines by third-party health-care payers.

Comparison between Microprocessor-Controlled Ankle/foot and Conventional Prosthetic Feet during Stair Negotiation in People with Unilateral Transtibial Amputation

Contrary to stance-phase dorsiflexion of conventional prosthetic feet, the microprocessor-controlled Proprio foot permits swing-phase dorsiflexion on stairs. The purpose of this study was to compare Symmetry in External Work (SEW) between a microprocessor-controlled foot and conventional prosthetic feet in two groups with unilateral transtibial amputation (Medicare Functional Classification Levels K-Level-2 and K-Level-3) during stair ascent and descent. Ten subjects were evaluated while wearing three conventional prosthetic feet- solid ankle cushion heel (SACH), stationary attachment flexible endoskeleton (SAFE), and Talux-and the Proprio foot using a study socket and were given a 10- to 14-day accommodation period with each foot. Ground reaction forces were collected using F-scan sensors during stair ascent and descent. The SEW between the intact and amputated limbs was calculated for each foot. During stair ascent, the Proprio foot resulted in a higher interlimb symmetry than conventional prosthetic feet, with significant differences between the Pro prio and SACH/SAFE feet. The swing-phase dorsiflexion appeared to promote greater interlimb symmetry because it facilitated forward motion of the body, resulting in a heel-to-toe center of pressure trajectory. During stair descent, all feet had low symmetry without significant differences between feet. The movement strategy used when descending stairs, which is to roll over the edge of a step, had a greater influence on symmetry than the dorsiflexion features of prosthetic feet.

Construct validity of Comprehensive High-Level Activity Mobility Predictor (CHAMP) for male servicemembers with traumatic lower-limb loss.

This study examined the convergent construct validity of a new performance-based assessment instrument called the Comprehensive High-Level Activity Mobility Predictor (CHAMP) as a measure of high-level mobility in servicemembers (SMs) with traumatic lower-limb loss (LLL). The study was completed by 118 SMs. Convergent construct validity of the CHAMP was established using the 6-minute walk test (6MWT) as a measure of overall mobility and physical function and the Amputee Mobility Predictor (AMP) as a measure of basic prosthetic mobility. The known group methods construct validity examined disparities in high-level mobility capability among SMs with different levels of LLL. The CHAMP score demonstrated a strong positive relationship between 6MWT distance (r = 0.80, p < 0.001) and AMP score (r = 0.87, p < 0.001), respectively. In addition, the CHAMP can discriminate between different levels of LLL. Study findings support the CHAMP as a valid performance-based assessment instrument of high-level mobility for SMs with traumatic LLL.