Amputee locomotion: lower extremity loading using running-specific prostheses.

Carbon fiber running-specific prostheses (RSPs) have allowed individuals with lower extremity amputation (ILEA) to actively participate in sporting activities including competitive sports. In spite of this positive trait, the RSPs have not been thoroughly evaluated regarding potential injury risks due to abnormal loading during running. Vertical impact peak (VIP) and average loading rate (VALR) of the vertical ground reaction force (vGRF) have been associated with running injuries in able-bodied runners but not for ILEA. The purpose of this study was to investigate vGRF loading in ILEA runners using RSPs across a range of running speeds. Eight ILEA with unilateral transtibial amputations and eight control subjects performed overground running at three speeds (2.5, 3.0, and 3.5m/s). From vGRF, we determined VIP and VALR, which was defined as the change in force divided by the time of the interval between 20 and 80% of the VIP. We observed that VIP and VALR increased in both ILEA and control limbs with an increase in running speed. Further, the VIP and VALR in ILEA intact limbs were significantly greater than ILEA prosthetic limbs and control subject limbs for this range of running speeds. These results suggest that (1) loading variables increase with running speed not only in able-bodied runners, but also in ILEA using RSPs, and (2) the intact limb in ILEA may be exposed to a greater risk of running related injury than the prosthetic limb or able-bodied limbs.

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.

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.

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.

Comparison of the Power Knee and C-Leg during step-up and sit-to-stand tasks.

For U.S. military service members with transfemoral amputations there are different prosthetic knee systems available that function differently. For example the C-Leg(®) (C-Leg, Otto Bock Healthcare, GmbH, Duderstadt, Germany) is a passive microprocessor knee, and the Power Knee™ (PK, Ossur, Reykjavík, Iceland) provides active positive power generation at the knee joint. This study examined both step-up and sit-to-stand tasks performed by service members using C-Leg and PK systems to determine if the addition of positive power generation to a prosthetic knee can improve symmetry and reduce impact to the remaining joints. For both tasks, average peak sagittal knee powers and vertical ground reaction forces (GRFs) were greater for the intact limb versus the amputated limb across PK and C-Leg groups. For the sit-to-stand task, peak knee power of the amputated limb was greater for PK users versus C-Leg users. Vertical GRFs of the intact limb were greater for the C-Leg versus the PK. The performance of the PK relative to the C-Leg during a STS task illustrated few differences between components and no effect on the intact limb.

Assessment of transfemoral amputees using C-Leg and Power Knee for ascending and descending inclines and steps.

Adding active power to a prosthetic knee unit may improve function and reduce the potential for overuse injuries in persons with transfemoral amputation (TFA). Servicemembers who have sustained a TFA are often young and motivated to perform at high functional levels. The goal of this article is to compare the biomechanics of ramp and stair descent and ascent for participants using the C-Leg and the Power Knee (PK). Subjects were asked to ascend and descend an instrumented staircase and 12 degree ramp at their comfortable pace while equipped with retroreflective markers. Temporal-spatial and kinetic data were collected. Knee power generated by the nondisabled limb during stair ascent for subjects wearing the C-Leg was significantly greater than for those wearing the PK. Knee power generated by prosthetic knee units was significantly greater for subjects while wearing the PK. Although the PK reduced the power required from the nondisabled knee during stair climbing, it does not appear to be superior to the C-Leg for other tasks. Adding power to a prosthetic knee may reduce wear on the nondisabled limb; however, there are still limitations that require improvement.

Core temperature changes in service members with and without amputations during the Army 10-Miler.

The purpose of this case study was to assess differences in core temperature between individuals with and without amputations during a 10-mile run. Decreased body surface area and increased energy needs for ambulation may increase heat production and risk of heat injury for individuals with amputations. Two runners, 1 with and 1 without amputation, completed a 10-mile road race. Anthropometrics, body composition, and energy expenditure were collected before the run. Core temperature and activity were measured continually during the event. Maximum core temperature for the runner with amputation was 38.4 degrees C and for the runner without amputation was 37.9 degrees C. Despite the higher temperature, the runner with amputation completed the run at a slower pace than the one without amputation, indicating that higher core body temperatures may be achieved in individuals with amputation at similar workloads. These data suggest that future research is needed to elucidate differences in core temperature in individuals with amputations.

Three-dimensional movements of the sacroiliac joint: a systematic review of the literature and assessment of clinical utility.

The high frequency of static and dynamic palpation methods used during evaluation of SIJ problems in clinical practice demands an understanding of the factual quantity of movement at the SIJ. The objective of this systematic literature review was to synthesize three-dimensional (3-D) motion of the sacroiliac joint (SIJ) during various functional static postures and movements and to determine the clinical utility of movement during examination. A computer-based search was performed by means of OVID, which included Medline (February 1966 to April 2007) and CINAHL (February 1982 to April 2007) using the key words Pelvis, Kinematics, Imaging, Three-dimensional, and Stereophotogrammetric. Articles included in-vivo or in-vitro studies that investigated human SIJs with 3-D analysis. Three-dimensional analyses conducted using mathematical modeling, computerized modeling, and/or skin markers were not included because of concerns of transferability and validity. Studies that failed to report standard error of measurement (SEM) or defined tabulated values for translations or rotations using the Cartesian coordinate system were not considered for this study. Studies included for review were analyzed by the SBC biomechanical checklist to measure the quality of procedural design. Seven manuscripts were eligible for inclusion in this study. Rotation ranged between -1.1 to 2.2 degrees along the X-axis, -0.8 to 4.0 degrees along the Y-axis, and -0.5 to 8.0 degrees along the Z-axis. Translation ranged between -0.3 to 8.0 millimeters (mm) along the X-axis, -0.2 to 7.0 mm along the Y-axis, -0.3 to 6.0 mm along the Z-axis. Motion of the SIJ is limited to minute amounts of rotation and of translation suggesting that clinical methods utilizing palpation for diagnosing SIJ pathology may have limited clinical utility.