Accuracy of the Region of Limb Stability in Predicting Risk for Lower Limb Injury.

PURPOSE: This study aimed to determine whether a measure of lower limb segment stability derived from body-worn inertial measurement units can predict risk for lower limb musculoskeletal injury in Division I Collegiate Football Players (D1CFP). METHODS: The region of limb stability (ROLS) values were collected in a cohort of D1CFP during preseason. ROLS is a measure of knee joint stability, defined by thigh and shank excursion (cm) in the anterior-posterior and medial-lateral direction during single limb stance. The ROLS symmetry index (SI) (%) is the ratio between lower limb ROLS values where 100% suggests absolute symmetry. RESULTS: One-hundred and four D1CFP participated in this study and were divided into two groups: 1) no previous lower limb injury or no in-season injury (n = 70, "noninjured group") and 2) no previous lower limb injury, but in-season injury requiring surgery (n = 34, "injured group" group). The mean ± SD ROLS SI was 82.86% ± 14.75% and 65.58% ± 16.46% for the noninjured and injured group, respectively. Significant differences in ROLS SI were found between groups (P < 0.001). The ROLS SI demonstrated an area under the curve of 0.8 (P < 0.001; 95% confidence interval = 0.71-0.88) with an SE of 0.04, indicating that the ROLS SI has good predictive accuracy in detecting those healthy D1CFP at risk for lower limb injury resulting in surgery. CONCLUSION: The ROLS SI was found to have good predictive accuracy in detecting individuals at risk for injury that were healthy and asymptomatic during preseason testing. Increase in thigh and shank excursions and/or decrease in SI between lower limbs may be a predictor of risk for future injury.

Temporal-Spatial Values During a 180° Step Turn in People with Unilateral Lower Limb Amputation.

BACKGROUND: Daily ambulation with a prosthesis often involves turning to negotiate within the home and community environments, however how people with lower limb loss perform turns is infrequently studied. Administering a common clinical outcome measure to capture turn performance data provides a convenient means of assessing this ubiquitous activity. RESEARCH QUESTION: What temporal-spatial parameters are exhibited by people with unilateral lower limb amputation while performing a 180˚ turn task? METHODS: Forty community-ambulating subjects with unilateral lower limb amputation (20 transtibial amputees, 20 transfemoral amputees) performed the Component Timed-Up-and-Go (cTUG) test turning once in each direction, both toward the intact and toward the prosthetic limb. An instrumented walkway captured temporal-spatial parameters during performance of the 180˚ turn task of the cTUG, while a custom iPad application recorded time and number of steps to perform the turn. Comparisons between turn direction and level of amputation during the cTUG and temporal-spatial results were assessed. RESULTS: People with lower limb amputation spent more time on their intact limb while turning than their prosthetic limb regardless of the position of the intact limb, and those with transfemoral amputation spent significantly more time over the intact limb than those with transtibial amputation. Additionally, subjects with transfemoral amputation performed the turn significantly faster when turning with an inner intact limb. SIGNIFICANCE: Amputees use different movement strategies with altered temporal-spatial characteristics to turn depending on the direction of the turn and the level of amputation. Clinical use of the cTUG could provide evidence supporting prosthetic prescription practice and introduction of novel physical therapy interventions for individuals with lower limb amputation.

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.

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.

Amputee mobility predictor-bilateral: a performance-based measure of mobility for people with bilateral lower-limb loss.

The Amputee Mobility Predictor (AMP) is an outcome measure designed to assess mobility and functional capabilities for people with unilateral lower-limb amputation. No comparable measure exists for those with bilateral lower-limb amputation (BLLA). The purpose of this study was to examine the utility of the AMP-Bilateral (AMP-B) to measure the ability to perform functional tasks related to participation in advanced skill activities in those with BLLA and to determine whether AMP-B scores correlated with 6-minute walk test (6MWT) performance. Twenty-six male servicemembers (SMs) completed the study: 12 with bilateral transtibial amputation (BTTA), 7 with bilateral transfemoral amputation (BTFA), and 7 with combination transtibial and transfemoral amputation (TTA/TFA). Significant differences existed between the AMP-B scores (p < 0.001), AMP scores (p < 0.001), and 6MWT distance (p < 0.05) for SMs with BTTA and TTA/TFA and SMs with BTTA and BTFA but not between those with BTFA and TTA/TFA. Scoring of five AMP items was modified because they necessitate at least one intact knee joint to generate the necessary torque requirements to perform the activity without upper-limb assistance. Minor modifications in scoring of the AMP do not alter total score and allow clinicians to determine the mobility and functional capabilities of SMs with BTFA and TFA/TTA.

Comparison of 6-minute walk test performance between male Active Duty soldiers and servicemembers with and without traumatic lower-limb loss.

The rehabilitation of U.S. military servicemembers (SMs) who have sustained a traumatic loss of one or both lower limbs requires outcome measures that can assess their physical capabilities in comparison with their uninjured colleagues. Describing reference ranges for the 6-minute walk test (6MWT) in both populations will help clinicians develop appropriate goals for rehabilitation and document progress toward those goals. A convenience sample of 118 male U.S. SMs with and 97 without traumatic lower-limb loss participated in this study. All participants completed a 6MWT, and comparisons were made between SMs with and without limb loss and among the levels of limb loss. The SMs without lower-limb loss performed significantly better than all SMs with lower-limb loss. The SMs with transtibial limb loss performed significantly better than those with all other levels of limb loss. Statistically significant and clinically relevant differences were also noted between the other levels of limb loss. No differences were found between different prosthetic components. Reference ranges were established for U.S. SMs with and without various levels of limb loss, and the 6MWT was able to identify functional differences between groups.

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.

Factors related to high-level mobility in male servicemembers with traumatic lower-limb loss.

The purpose of this study was to examine the possible relationship between factors modifiable by rehabilitation interventions (rehabilitation factors), other factors related to lower-limb loss (other factors), and high-level mobility as measured by the Comprehensive High-Level Activity Mobility Predictor (CHAMP) in servicemembers (SMs) with traumatic lower-limb loss. One-hundred eighteen male SMs with either unilateral transtibial amputation (TTA), unilateral transfemoral amputation (TFA), or bilateral lower-limb amputation (BLLA) participated. Stepwise regression analysis was used to develop separate regression models of factors predicting CHAMP score. Regression models containing both rehabilitation factors and other factors explained 81% (TTA), 36% (TFA), and 91% (BLLA) of the variance in CHAMP score. Rehabilitation factors such as lower-limb strength and dynamic balance were found to be significantly related to CHAMP score and can be enhanced with the appropriate intervention. Further, the findings support the importance of salvaging the knee joint and its effect on high-level mobility capabilities. Lastly, the J-shaped energy storage and return feet were found to improve high-level mobility for SMs with TTA. These results could help guide rehabilitation and aid in developing appropriate interventions to assist in maximizing high-level mobility capabilities for SMs with traumatic lower-limb loss.

Impairment variables predicting activity limitation in individuals with lower limb amputation.

The purpose of this study was to determine whether measures of impairment (i.e., muscle strength, balance), personal factors (i.e., comorbidities, demographic information) and amputation specific variables (i.e., time since amputation, cause of amputation, level of amputation) were able to predict performance on the six-minute walk test, a measure of activity limitation, in individuals with lower limb amputation. A total of 72 individuals with lower limb amputation ranging in age from 21-83 were tested for balance, limb muscle strength and function. Medical comorbidities were recorded and activity limitation was measured using the six-minute walk test. Data were analyzed and multivariate relationships were examined using multiple linear regression. Impairment variables of strength, balance, subject demographics, time since amputation, cause of amputation and level of amputation were all significant predictors and explained 72% of the variance in the outcome variable. Strength of the hip extensors was the strongest predictor, accounting for 30.9% of the total variance. Multiple factors impact six minute walk scores in individuals with lower limb amputation. Impairments in hip strength and balance appear to be the two most significant. The findings of this study support the use of the six-minute walk test to underscore impairments of the musculoskeletal system that can affect ambulation ability in the amputee.