Quantifying Bone and Skin Movement in the Residual Limb-Socket Interface of Individuals With Transtibial Limb Loss Using Dynamic Stereo X-Ray: Protocol for a Lower Limb Loss Cadaver and Clinical Study.

BACKGROUND: Relative motion between the residual limb and socket in individuals with transtibial limb loss can lead to substantial consequences that limit mobility. Although assessments of the relative motion between the residual limb and socket have been performed, there remains a substantial gap in understanding the complex mechanics of the residual limb-socket interface during dynamic activities that limits the ability to improve socket design. However, dynamic stereo x-ray (DSX) is an advanced imaging technology that can quantify 3D bone movement and skin deformation inside a socket during dynamic activities. OBJECTIVE: This study aims to develop analytical tools using DSX to quantify the dynamic, in vivo kinematics between the residual limb and socket and the mechanism of residual tissue deformation. METHODS: A lower limb cadaver study will first be performed to optimize the placement of an array of radiopaque beads and markers on the socket, liner, and skin to simultaneously assess dynamic tibial movement and residual tissue and liner deformation. Five cadaver limbs will be used in an iterative process to develop an optimal marker setup. Stance phase gait will be simulated during each session to induce bone movement and skin and liner deformation. The number, shape, size, and placement of each marker will be evaluated after each session to refine the marker set. Once an optimal marker setup is identified, 21 participants with transtibial limb loss will be fitted with a socket capable of being suspended via both elevated vacuum and traditional suction. Participants will undergo a 4-week acclimation period and then be tested in the DSX system to track tibial, skin, and liner motion under both suspension techniques during 3 activities: treadmill walking at a self-selected speed, at a walking speed 10% faster, and during a step-down movement. The performance of the 2 suspension techniques will be evaluated by quantifying the 3D bone movement of the residual tibia with respect to the socket and quantifying liner and skin deformation at the socket-residuum interface. RESULTS: This study was funded in October 2021. Cadaver testing began in January 2023. Enrollment began in February 2024. Data collection is expected to conclude in December 2025. The initial dissemination of results is expected in November 2026. CONCLUSIONS: The successful completion of this study will help develop analytical methods for the accurate assessment of residual limb-socket motion. The results will significantly advance the understanding of the complex biomechanical interactions between the residual limb and the socket, which can aid in evidence-based clinical practice and socket prescription guidelines. This critical foundational information can aid in the development of future socket technology that has the potential to reduce secondary comorbidities that result from complications of poor prosthesis load transmission. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/57329.

Utilization and Perception of Peer-Support After Lower Limb Loss in the United States: Potential Benefits on Mobility Outcomes.

OBJECTIVE: To examine participants' experiences with peer-support after lower limb loss (LLL) and the associations between the peer-support experience (perceived benefits and barriers) and mobility outcomes. DESIGN: Quantitative and qualitative descriptive study with a cross-sectional design. SETTING: National survey (distributed to 169 peer-support groups in 44 states in the US). PARTICIPANTS: The survey was completed by 82 individuals with a major lower limb amputation (53% female, 54% over 55 years of age; N=82). MAIN OUTCOME MEASURES: A 32-item survey to examine respondents' experiences in peer-support activities. Prosthetic mobility was measured using the Prosthetic Limb Users Survey of Mobility (PLUS-M). RESULTS: Two out of 3 respondents received some forms of peer-support after amputation. Among them 75% reported peer-support having a positive effect on their outlook on life, and 78% reported that information gained from peer-support was helpful. Companionship, altruistic acts, and gaining information on how to cope with amputation were the top themes of why respondents enjoyed the peer-support experience. Nearly all (94%) respondents would recommend peer-support to other people with LLL. Individuals who received peer-support exhibited a trend of greater mobility (55th vs 36th percentile on PLUS-M; P=.055). CONCLUSION: Individuals with LLL reported generally positive experiences regarding their engagement in peer-support activities. Peer-support groups are viewed as a helpful source for both information and emotional support, potentially benefiting functional and psychological recovery after amputation. Individuals who have received peer-support also exhibited greater mobility.

Hip joint and muscle loading for persons with bilateral transfemoral/through-knee amputations: biomechanical differences between full-length articulated and foreshortened non-articulated prostheses.

BACKGROUND: Currently, there is little available in-depth analysis of the biomechanical effect of different prostheses on the musculoskeletal system function and residual limb internal loading for persons with bilateral transfemoral/through-knee amputations (BTF). Commercially available prostheses for BTF include full-length articulated prostheses (microprocessor-controlled prosthetic knees with dynamic response prosthetic feet) and foreshortened non-articulated stubby prostheses. This study aims to assess and compare the BTF musculoskeletal function and loading during gait with these two types of prostheses. METHODS: Gait data were collected from four male traumatic military BTF and four able-bodied (AB) matched controls using a 10-camera motion capture system with two force plates. BTF completed level-ground walking trials with full-length articulated and foreshortened non-articulated stubby prostheses. Inverse kinematics, inverse dynamics and musculoskeletal modelling simulations were conducted. RESULTS: Full-length articulated prostheses introduced larger stride length (by 0.5 m) and walking speed (by 0.3 m/s) than stubbies. BTF with articulated prostheses showed larger peak hip extension angles (by 10.1°), flexion moment (by 1.0 Nm/kg) and second peak hip contact force (by 3.8 bodyweight) than stubbies. There was no difference in the hip joint loading profile between BTF with stubbies and AB for one gait cycle. Full-length articulated prostheses introduced higher hip flexor muscle force impulse than stubbies. CONCLUSIONS: Compared to stubbies, BTF with full-length articulated prostheses can achieve similar activity levels to persons without limb loss, but this may introduce detrimental muscle and hip joint loading, which may lead to reduced muscular endurance and joint degeneration. This study provides beneficial guidance in making informed decisions for prosthesis choice.

A review of the first wave of lower limb amputees from the Great March of Return in Gaza: Taking stock and preparing for the task ahead.

AIM: Ballistic injuries during the Great March of Return (GMR) protests in Gaza have resulted in young, civilian amputees. This article defines this unique population, their injuries and clinical variables that impacted on amputation. METHOD: A multidisciplinary team (MDT) assessed 103 lower limb amputees (104 stumps). Individualized prescriptions of care were formulated and applied for both stump and prosthesis management. The cohort's health state was assessed at screening by applying the EQ-5D-L5 questionnaire. The EQ-5D-L5 will be repeated on completion of the prescription of care. RESULTS: The population is predominantly young, male, suffering unilateral amputation with an equal ratio of above knee (AKA) to below knee (BKA) amputations. 18% were amputated immediately and 82% with delay. Most amputations occur within 15 days of gunshot wound (GSW). All tissue elements were affected by the severe, ballistic injury. Division, gapping and tissue loss consolidated the decision for amputation rather than limb salvage. Knee zone injury was common, influencing the high numbers AKAs. Primary injury ramified beyond the amputated leg: 38% have contralateral leg injuries. 20% had physiological challenges requiring Intensive care unit (ICU) admissions. Infection was reported in 49% of amputees with 12% reporting acute sepsis. Psychologically, 49% reported severe, or extreme, anxiety and depression. AKAs were associated with greater morbidity: amputees are significantly younger, have more proximal vascular injuries, receive delayed amputations and experience longer time intervals to stump healing. ICU care and contralateral leg injuries were more frequent. One third of amputees used their prostheses', one third did not and one third do not have a prosthesis yet. The limiting factor for repair was supply of materials. 11% of amputees needed no adjustment to stump or prosthesis. Surgical stump revision was recommended in 26% of stumps and prosthetic management in 41%. A further 22%, subject to the success or failure of prescribed prosthetic adjustment, could require stump revision. CONCLUSION: Youth, proximal injury, high numbers of AKA, psychosocial issues and the need for stump and prosthetic support define this group of amputees. Unifying expertise within a National MDT will promote continuity of care necessary for decades to come. The ultimate aim is an evidence-based amputee care system in Gaza, with lower limb specialists promoting best outcomes, judicious allocation of funds and maximising amputee quality of life.

Investigating the Effect of Real-Time Center of Pressure Feedback Training on the Swing Phase of Lower Limb Kinematics in Transfemoral Prostheses With SACH Foot.

Transfemoral amputee often encounters reduced toe clearance resulting in trip-related falls. Swing-phase joint angles have been shown to influence the toe clearance; therefore, training intervention that targets shaping the swing phase joint angles can potentially enhance toe clearance. The focus of this study was to investigate the effect of the shift in the location of the center of pressure (CoP) during heel strike on modulation of the swing-phase joint angles in able-bodied participants (n = 6) and transfemoral amputees (n = 3). We first developed a real-time CoP-based visual feedback system such that participants could shift the CoP during treadmill walking. Next, the kinematic data were collected during two different walking sessions-baseline (without feedback) and feedback (shifting the CoP anteriorly/posteriorly at heel strike to match the target CoP location). Primary swing-phase joint angle adaptations were observed with feedback such that during the midswing phase, posterior CoP shift feedback significantly increases (p < 0.05) the average hip and knee flexion angle by 11.55 deg and 11.86 deg, respectively, in amputees, whereas a significant increase (p < 0.05) in ankle dorsiflexion, hip and knee flexion angle by 3.60 deg, 3.22 deg, and 1.27 deg, respectively, compared to baseline was observed in able-bodied participants. Moreover, an opposite kinematic adaptation was seen during anterior CoP shift feedback. Overall, results confirm a direct correlation between the CoP shift and the modulation in the swing-phase lower limb joint angles.

Quantifying the risk of falls and injuries for amputees beyond annual fall rates-A longitudinal cohort analysis based on person-step exposure over time.

People with lower-limb loss (PLL) have high annual fall and injury rates. People with transtibial amputations have better walking function than those with transfemoral amputations but paradoxically incur more fall-related injuries. Risk exposure, however, has not been previously considered. This study examined whether all-cause fall and injury incidence per person-step exposure over time varied in PLL of different walking abilities. The prospective cohort design, conducted at a major medical center, included five assessments 1-month apart. Walking ability level was categorized by Houghton Scale scores: ≥9 indicating community walking and ≤ 8 indicating limited community-household walking. Accelerometer-measured daily step counts were collected via StepWatch4 monitors. The main outcome measures, self-reported all-cause falls and injuries were assessed using the standard National Health Injury Survey. Generalized estimating equations, using Poisson distributions and log of step count as an offset, determined fall and injury incidence rate ratio [IRR] according to walking ability level. Ten people, aged 33-63 years with amputations of different causes and levels, were assessed monthly over five months. The community walking group (n = 6) had six falls and seven injuries; the limited community walking group (n = 4) had four falls and three injuries. For PLL, limited community walking ability was associated with higher incidence of falls (IRR = 6.10, 95%CI = 1.12-33.33, p = 0.037) and injuries (IRR = 8.56, 95%CI = 1.73-42.40, p = 0.009) when accounting for person-steps. Considering per person-step exposure over time added precision to fall and injury risk assessment that clarified the risks: PLL with limited community walking ability have higher fall and injury risks.

Assessment of the upper limbs maximum power and the locomotion speed in amputee football players

Abstract Aim: The purpose of the study was to assess upper limbs' maximum power and locomotion speed among amputee football (amputee soccer) players. Methods: The 30-s Wingate Anaerobic test and the 20-m sprint test were performed. Anthropometric measurements and body composition (Body mass index (BMI), percentage of body fat (% BF), and lean body mass (LBM)) were examined. Results: BMI significantly differentiated forwards and defenders (p < 0.05). Peak power (PP) and mean power (MP) were related to LBM (p < 0.05), thus defenders reached higher values of PP, in comparison to forwards. % BF and BMI were related to relative mean power (rMP) (p < 0.05). Field position differentiated players in terms of upper limbs' relative peak power (rPP) in favour of forwards (p < 0.05). Age was a significant factor for speed velocity on 10 m and 20 m (p < 0.05). There was no relationship between upper limbs' power and locomotion speed. Conclusion: Body composition, especially % BF may influence on the anaerobic performance of amputee football players.

Knee adduction moment peak and impulse do not change during the first six months of walking with a prosthesis.

BACKGROUND: Individuals with unilateral lower limb loss are at increased risk for developing knee osteoarthritis in their contralateral limb. The mechanisms underlying this phenomenon are unknown, but large or unusual loads on the limb are thought to contribute to osteoarthritis development. Yet, to our knowledge, there have been no longitudinal assessments of knee joint kinetics to assist with identifying the origin or progression of such loads. RESEARCH QUESTION: This study aimed to examine knee joint kinetics of individuals with lower limb loss as a function of time from independent ambulation. METHODS: Eight male Service Members with unilateral lower limb loss (3 transfemoral/5 transtibial) completed gait analyses, walking at self-selected speed and cadence, at 0, 2, and 6 months following initial independent ambulation. RESULTS: Although there was a significant time effect on stride length (p = 0.047), there were no pairwise differences (all p ≥ 0.152). Additionally, there was not a significant effect of time on the peak (p = 0.666), loading rate (p = 0.336), or impulse (p = 0.992) of knee adduction moment (KAM), peak knee flexion moment (KFM) (p = 0.128), or the peak (p = 0.485) or loading rate (p = 0.130) of vertical ground reaction force (VGRF). SIGNIFICANCE: The results of the current study demonstrate that major features of knee joint loading do not change over the first 6 months of independently walking with a prosthesis. The magnitude of these loads are similar to loads observed in individuals with lower limb loss further from injury/initial ambulation, but the present results do not imply that no changes occur after 6 months.

Trunk and pelvic dynamics during transient turns among individuals with unilateral traumatic lower limb amputation.

Prior work has identified alterations in trunk-pelvic dynamics with lower limb amputation (LLA) during in-line walking; however, evaluations of other ambulatory tasks are limited. Turns are ubiquitous in daily life but can be challenging for individuals with LLA, prompting additional or unique proximal compensations when changing direction, which over time may lead to development of low back pain. We hypothesized such proximal kinematic differences between persons with and without LLA would exist in the sagittal and frontal planes. Three-dimensional trunk and pelvic kinematics, translational and rotational momenta, and coordination phase/variability were compared among eight persons with unilateral LLA (4 with transfemoral amputation and 4 with transtibial amputation), and five uninjured controls, who performed 90-degree turns to the left (n = 10) and right (n = 10). Participants self-selected the turn strategy (i.e., step vs. spin) and pivot limb in response to verbal cues regarding when and which direction to turn. Coordination variability and translational angular momenta did not differ between groups in either turn type. During spin turns, frontal rotational angular momenta were larger and frontal trunk-pelvis range of motion was smaller among persons with vs. without LLA. During step turns, pelvis leading transverse coordination was more frequent, frontal trunk rotational angular momentum was smaller, and sagittal pelvis range of motion was larger among persons with vs. without LLA. Altered and task-dependent modulation of trunk-pelvic dynamics among persons with LLA provides additional support for a potential link between repeated exposures to altered trunk-pelvic dynamics with elevated low back pain risk.

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.

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.

A comparison between the suction suspension system and the hypobaric Iceross Seal-In® X5 in transtibial amputees.

BACKGROUND: The two passive vacuum suspension systems currently available in total surface-bearing sockets are the hypobaric Iceross Seal-In(®) and the suction suspension system. OBJECTIVES: The purpose of this study was to compare the effect of the hypobaric Iceross Seal-In(®) liner with that of the suction suspension system for quality of life, pistoning, and prosthesis efficiency in unilateral transtibial amputees. STUDY DESIGN: Single-group repeated measures. METHODS: Ten amputees were enrolled. The pistoning test, used to compare vertical movement of the stump within the socket, and the energy cost of walking test were carried out when the amputees were wearing the suction suspension system and after 2, 5, and 7 weeks of Seal-In® X5 use. The Prosthesis Evaluation Questionnaire and the Houghton Scale Questionnaire of perceived mobility and quality of life with the prosthesis, and the Timed Up&Go Test and the Locomotor Capability Index for functional mobility were also administered at the beginning and end of the study. RESULTS: The hypobaric Iceross Seal-In® X5 led to significant pistoning reduction and improvement on the Houghton Scale Questionnaire and 3 of 9 domains of the Prosthesis Evaluation Questionnaire. No statistical changes were observed in functional mobility or the energy cost of walking tests. CONCLUSION: Replacing the suction suspension system with the hypobaric Iceross Seal-In® X5 improves quality of life in transtibial amputees.