Metabolic and body composition changes in first year following traumatic amputation

Risk of Heart Disease in Patients With Amputation: A Nationwide Cohort Study in South Korea

BACKGROUND

Amputation confers disabilities upon patients and is linked to substantial morbidity and death attributed to heart disease. While some studies have focused on traumatic amputees in veterans, few studies have focused on traumatic amputees within the general population. Therefore, the present study aimed to assess the risk of heart disease in patients with traumatic amputation with disability within the general population using a large-scale nationwide population-based cohort.

METHODS AND RESULTS

We used data from the Korean National Health Insurance System. A total of 22 950 participants with amputation were selected with 1:3 age, sex-matched controls between 2010 and 2018. We used Cox proportional hazard models to calculate the risk of myocardial infarction, heart failure, and atrial fibrillation among amputees. Participants with amputation had a higher risk of myocardial infarction (adjusted hazard ratio [aHR], 1.30 [95% CI, 1.14-1.47]), heart failure (aHR, 1.27 [95% CI, 1.17-1.38]), and atrial fibrillation (aHR, 1.17 [95% CI, 1.03-1.33]). The risks of myocardial infarction and heart failure were further increased by the presence of disability (aHR, 1.43 [95% CI, 1.04-1.95]; and aHR, 1.38 [95% CI, 1.13-1.67], respectively).

CONCLUSIONS

We demonstrate an increased risk of myocardial infarction, heart failure, and atrial fibrillation among individuals with amputation, and the risk further increased in those with disabilities. Clinicians should pay attention to the increased risk for heart disease in patients with amputation.

Long-Term Health Outcomes of Limb Salvage Compared with Amputation for Combat-Related Trauma

BACKGROUND

There are little long-term health data, particularly in terms of body composition and development of metabolic syndromes, to help surgeons to guide the decision between limb salvage and amputation in patients with limb-threatening trauma. The purpose of this study was to compare long-term health outcomes after high-energy lower-extremity trauma between patients who underwent attempted flap-based limb salvage or amputation.

METHODS

We performed a retrospective review of servicemembers with a minimum 10-year follow-up who underwent flap-based limb salvage followed by unilateral amputation or continued limb salvage after combat-related, lower-extremity trauma between 2005 and 2011. Patient demographic characteristics, injury characteristics, and health outcomes including body mass index (BMI) and development of metabolic disease (e.g., hyperlipidemia, hypertension, heart disease, and diabetes) were compared between treatment cohorts. Adjusted BMIs were calculated for the amputation cohort to account for lost surface area. We performed multivariable and propensity score analysis to determine the likelihood of developing obesity or metabolic disease.

RESULTS

In this study, 110 patients had available long-term follow-up (mean, 12.2 years) from the time of the injury. Fifty-six patients underwent limb salvage and 54 patients underwent unilateral amputation. There was no difference in preinjury BMI (p = 0.30). After adjusting for limb loss, the amputation cohort had a trend toward higher BMIs at ≥1 years after the injury, a higher rate of obesity, and a greater increase in BMI from baseline after the injury. The development of metabolic comorbidities was common after both amputation (23 [43%] of 54) and limb salvage (27 [48%] of 56). With the numbers available, we were unable to demonstrate a difference in risk for the development of hypertension, hyperlipidemia, diabetes, heart disease, or any comorbidity other than obesity (p > 0.05).

CONCLUSIONS

Amputations may be medically necessary and may decrease pain, improve mobility, and/or expedite return to activity compared with limb salvage after similar injuries. However, limb loss may negatively impact metabolic regulation and may contribute to a higher risk of obesity despite beneficial effects on mobility.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Weight Changes in Young Service Members After Lower Limb Amputation: Insights From Group-Based Trajectory Modeling

INTRODUCTION

Weight gain can contribute to osteoarthritis, cardiovascular disease, low back pain, and poor health-related quality of life. Weight trajectory patterns have been described in older veterans with limb loss; however, there is limited evidence of changes in weight in younger veterans with limb loss.

MATERIALS AND METHODS

Service members with unilateral or bilateral lower limb amputations (LLAs) (and without an upper limb amputation) were included in this retrospective cohort analysis (n = 931). The mean postamputation baseline weight was 78.0 ± 14.1 kg. Bodyweight and sociodemographic data were extracted from clinical encounters within electronic health records. Group-based trajectory modeling assessed weight change patterns 2 years postamputation.

RESULTS

Three weight change trajectory groups were identified: 58% (542 of 931) of the cohort had stable weight, 38% (352 of 931) had weight gain (mean gain = 19.1 kg), and 4% (31 of 931) had weight loss (mean loss = 14.5 kg). Individuals with bilateral amputations were more frequently noted in the weight loss group compared with those with unilateral amputations. Individuals with LLAs because of trauma other than blasts were more frequently found in the stable weight group compared with those with amputations because of disease or a blast. Younger individuals (<20 years old) with amputations were more likely to be in the weight gain group compared with older individuals.

CONCLUSIONS

More than half the cohort maintained a stable weight for two years after amputation, and more than a third experienced weight gain during the same time frame. Knowledge of underlying factors that were associated with weight gain could inform preventative strategies for young individuals with LLAs.

Influence of traumatic lower-limb amputation on physical activity, body composition, and cardiometabolic risks: A descriptive preliminary study

BACKGROUND

Following traumatic lower-limb amputation (LLA), humans are predisposed to numerous unfavorable changes in health, including the development of secondary chronic health conditions such as metabolic disorders and cardiovascular disease.

OBJECTIVE

To determine within and between group differences in cardiometabolic component risks, body composition, and physical activity (PA) in individuals with traumatic unilateral and bilateral LLA, compared to noninjured controls.

DESIGN

Prospective observational cohort study.

SETTING

A military complex trauma rehabilitation center.

PARTICIPANTS

Sixteen males with traumatic LLA (8 unilateral, mean age 30 ± 5 years and 8 bilateral, mean age 29 ± 3 years). Thirteen active age-matched males with no LLA (28 ± 5 years) acted as controls and performed habitual activities of daily living.

INTERVENTION

Participants with LLA attended two 4-week periods of inpatient rehabilitation, separated by two 6-week periods of home-based recovery.

MAIN OUTCOME MEASURES

Venous blood samples were taken prior to and following a 75 g oral glucose load, for determination of biomarkers, including insulin and glucose, at baseline and 20 weeks. Body composition (dual X-ray absorptiometry) was measured at baseline, 10 weeks, and 20 weeks. Daily PA was recorded using a triaxial accelerometer for 7 days during inpatient rehabilitation and while at home. Energy expenditure was estimated using population-specific equations.

RESULTS

Individuals with bilateral LLA demonstrated more unfavorable mean body composition values, lower PA, and increased cardiometabolic health risk compared to controls. Cardiometabolic syndrome was identified in 63% of individuals with bilateral LLA. No statistically significant differences in cardiometabolic component risk factors, body composition, and estimated daily PA were reported between unilateral LLA and control groups (p > .05). While at home, mean PA counts.day^-1 reduced by 17% (p = .018) and 42% (p = .001) in the unilateral and bilateral LLA groups, respectively.

CONCLUSIONS

Despite extensive inpatient rehabilitation, cardiometabolic component risks are elevated in individuals with bilateral LLA but are comparable between unilateral LLA and active noninjured control groups. Innovative strategies that improve/support the long-term PA and cardiometabolic health of severely injured individuals with bilateral LLA are warranted.

Males With Traumatic Lower Limb Loss Differ in Body Fat Distribution Compared to Those Without Limb Loss

OBJECTIVES

The primary objective was to examine body fat composition in males with traumatic lower limb loss and a comparison group without limb loss. A secondary objective was to determine if there are differences in body fat composition by traumatic limb loss level.

RESEARCH METHODS AND PROCEDURES

Cross-sectional analyses of baseline in-person intake data was completed at a large military medical center. Data were collected from 2011 to 2020, and analysis was conducted in 2020. Participants (n = 89) included males who sustained traumatic lower limb loss (n = 50) and an age-matched comparison group without limb loss (n = 39). Mean age of participants was 36.0 ± 13.2 years. Main outcomes measured included age, height, body mass index, weight, body fat mass and percent, android fat mass and percent, gynoid fat mass and percent, and android/gynoid percent fat ratio. Differences between groups were assessed using t-tests or Mann-Whitney U tests. Differences between limb loss levels were assessed using one-way ANOVA or Wilcoxon signed-rank test.

RESULTS

Body fat percent (P = .001), gynoid fat percent (P = .010), android fat mass (P = .01), and percent (P = .02) were higher in the group with limb loss. There were no differences in body fat composition between limb loss levels (P > .05).

CONCLUSION

Males with traumatic lower limb loss had a higher body fat percent compared to those without limb loss. Given higher body fat composition in individuals with limb loss and the relationship between body fat composition and cardiovascular disease risk, including body composition analysis with clinical screening could identify changes and allow for early intervention.

General estimates of the energy cost of walking in people with different levels and causes of lower-limb amputation: a systematic review and meta-analysis

BACKGROUND

Energy cost of walking (ECw) is an important determinant of walking ability in people with a lower-limb amputation. Large variety in estimates of ECw has been reported, likely because of the heterogeneity of this population in terms of level and cause of amputation and walking speed.

OBJECTIVES

To assess (1) differences in ECw between people with and without a lower-limb amputation, and between people with different levels and causes of amputation, and (2) the association between ECw and walking speed.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

We included studies that compared ECw in people with and without a lower-limb amputation. A meta-analysis was done to compare ECw between both groups, and between different levels and causes of amputation. A second analysis investigated the association between self-selected walking speed and ECw in people with an amputation.

RESULTS

Out of 526 identified articles, 25 were included in the meta-analysis and an additional 30 in the walking speed analysis. Overall, people with a lower-limb amputation have significantly higher ECw compared to people without an amputation. People with vascular transfemoral amputations showed the greatest difference (+102%) in ECw. The smallest difference (+12%) was found for people with nonvascular transtibial amputations. Slower self-selected walking speed was associated with substantial increases in ECw.

CONCLUSION

This study provides general estimates on the ECw in people with a lower-limb amputation, quantifying the differences as a function of level and cause of amputation, as well as the relationship with walking speed.

Body composition and bone mineral density in athletes with a physical impairment

Background

The impact of the type and the severity of disability on whole-body and regional body composition (BC), and bone mineral density (BMD) must be considered for dietary advice in athletes with a physical impairment (PI). This study aimed to investigate the impact of the type and the severity of disability on BC, the pattern of distribution of fat mass at the regional level, and BMD in athletes with a PI.

Methods

Forty-two male athletes with spinal cord injury (SCI, n = 24; age = 40.04 ± 9.95 years, Body Mass Index [BMI] = 23.07 ± 4.01 kg/m²) or unilateral lower limb amputation (AMP, n = 18; age = 34.39 ± 9.19 years, BMI = 22.81 ± 2.63 kg/m²) underwent a Dual-Energy X-Ray Absorptiometry scan. Each athlete with a PI was matched by age with an able-bodied athlete (AB, n = 42; age = 37.81 ± 10.31 years, BMI = 23.94 ± 1.8 kg/m²).

Results

One-Way Analysis of Variance showed significant differences between the SCI, AMP and AB groups for percentage fat mass (%FM) (P < 0.001, eta squared = 0.440). Post-hoc analysis with Bonferroni’s correction showed that athletes with SCI had significantly higher %FM vs. the AMP and AB groups (25.45 ± 5.99%, 21.45 ± 4.21% and 16.69 ± 2.56%, respectively; P = 0.008 vs. AMP and P < 0.001 vs. AB). The %FM was also significantly higher in the AMP vs. the AB group (P < 0.001). Whole-body BMD was negatively affected in SCI athletes, with about half of them showing osteopenia or osteoporosis. In fact, the mean BMD and T-score values in the SCI group (1.07 ± 0.09 g/cm² and −1.25 ± 0.85, respectively) were significantly lower in comparison with the AB group (P = 0.001 for both) as well as the AMP group (P = 0.008 for both). The type of disability affected BC and BMD in the trunk, android, gynoid and leg regions in SCI athletes and the impaired leg only in AMP athletes.

Conclusions

In conclusion, the type of disability and, partly, the severity of PI impact on BC and BMD in athletes with a PI. Nutritionists, sports medicine doctors, clinicians, coaches and physical conditioners should consider athletes with SCI or AMP separately. Athletes with a PI would benefit from specific nutrition and training programs taking into account the type of their disability.

Development and validation of bioimpedance prediction equations for fat-free mass in unilateral male amputees

Background

Metabolic disease due to increased fat mass is observed in amputees (APTs), thereby restricting their activity. Systemic health management with periodic body composition (BC) testing is essential for healthy living. Bioelectrical impedance analysis (BIA) is a non-invasive and low-cost method to test BC; however, the APTs are classified as being exempted in the BIA.

Objective

To develop segmental estimated regression equations (sEREs) for determining the fat-free mass (FFM, kg) suitable for APTs and improve the accuracy and validity of the sERE.

Methods

Seventy-five male APTs participated in this cross-sectional study. Multiple regression analysis was performed to develop highly accurate sEREs of BIA based on independent variables derived from anthropometric measurements, dual-energy X-ray absorptiometry (DXA), and BIA parameters. The difference in validity between the predicted DXA and sum of the segmentally-predicted FFM values by sEREs (Sum_sEREs) values was evaluated using bivariate linear regression analysis and the Bland–Altman plot.

Results

The coefficient of determination (R²) and total error (TE) between DXA and Sum_sEREs were 71% and 5.4 (kg) in the cross-validation analysis.

Conclusions

We confirmed the possibility of evaluating the FFM of APTs through the sEREs developed in this study. We also identified several independent variables that should be considered while developing such sEREs. Further studies are required to determine the validity of our sEREs and the most appropriate BIA frequencies for measuring FFM in APTs.

Circumference Method Estimates Percent Body Fat in Male US Service Members with Lower Limb Loss

BACKGROUND

The Department of Defense circumference method (CM) is used to estimate percent body fat (%BF) in evaluation of health, physical fitness, appearance, and military readiness; however, the CM has not been validated in individuals with lower limb loss.

OBJECTIVE

To evaluate the agreement between CM and dual-energy X-ray absorptiometry (DXA) for measuring %BF in individuals with lower limb loss.

DESIGN

This study is part of a larger cross-sectional comparison study, and this analysis was included as a secondary objective. Two methods of measuring %BF included CM and DXA, with DXA as the reference standard for this study.

PARTICIPANTS/SETTING

This study was conducted at Walter Reed Army Medical Center. Data were collected from summer 2010 to summer 2011. One hundred individuals, 50 with and 50 without lower limb loss, were screened for this study; three individuals with limb loss and two without limb loss had incomplete data, and one individual (female, without limb loss) lacked a comparison participant. All participants were recruited from a military medical center, and data were collected in a clinic research laboratory.

MAIN OUTCOME MEASURES

Measurements of %BF were compared between methods for each group.

STATISTICAL ANALYSES PERFORMED

Measurements of %BF were compared using paired t-tests and intraclass correlation coefficient. Agreement and bias were assessed with Bland-Altman analysis. Receiver operating characteristic analysis was used to determine the diagnostic accuracy of the CM to identify participants with %BF levels in the obese category (≥25%).

RESULTS

A statistically significant difference was found between %BF methods in the group with limb loss (1.7%; P = 0.001) and the group without limb loss (1.4%; P = 0.005), with DXA consistently higher than CM. However, the intraclass correlation coefficient estimates for the agreement between %BF by CM and DXA were 0.848 (95% confidence interval [CI]: 0.683-0.922; P < 0.001) and 0.828 (CI: 0.679-0.906; P < 0.001), for the groups with and without limb loss, respectively, suggesting that CM has good to near excellent agreement with DXA for estimating %BF in these groups. Receiver operating characteristic analysis indicated that the area under the curve supported predictive ability to detect obesity-based %BF in males with and without limb loss.

CONCLUSIONS

Although a statistically significant difference was found between methods for individuals with limb loss, there was also good agreement between the methods, suggesting that CM may be a useful tool for estimating %BF in individuals with lower limb loss. The CM may be a useful and field expedient method for assessing %BF in a clinical setting when DXA is not available.

Time to weigh in on obesity and associated comorbidities in combat-wounded amputees

BACKGROUND

The Joint Trauma System database estimates that about 1,200 individuals have sustained a combat-related amputation during the Global War on Terror. Previous retrospective studies have demonstrated that combat-related amputees develop obesity and cardiovascular disease, but the incidence of obesity and associated comorbidities in this population is unknown. The objectives of this study are to determine the prevalence of obesity in the military amputee population and to compare this with the general population.

METHODS

This is a retrospective review of 978 patients who sustained a combat-related amputation from 2003 to 2014. Prevalence of obesity and comorbid conditions were determined. A multivariate logistic regression model was performed to identify risk factors for postamputation obesity. Kaplan-Meier curves were constructed using obesity as the event of interest.

RESULTS

A total of 1,233 charts were reviewed with 978 patients included for analysis. The median age of injury was 24 years. Median follow-up time was 8.7 years, ranging from 0.5 years to 16.9 years. The average Injury Severity Score was 23.3. The average body mass index preinjury was 25.6 kg/m2, and the average most recent corrected body mass index was found to be 31.4 kg/m2. Prevalence of comorbidities was higher in the amputee population. Fifty percent of patients who progressed to obesity did so within 1.3 years.

CONCLUSION

There is a notable prevalence of obesity that develops in the amputee population that is much higher than the general population. We determined that the amputee population is at risk, and these patients should be closely monitored for 1 to 2.5 years following injury. This study provides a targeted period for which monitoring and intervention can be implemented.

LEVEL OF EVIDENCE

Retrospective, basic science, outcomes analysis, level III/IV.

Equation Córdoba: A Simplified Method for Estimation of Body Fat (ECORE-BF)

BACKGROUND

Many methods for measuring body fat have been developed, but applications in clinical settings are limited. For this reason, researchers have tried to identify different formulas for its estimation but most of are hard to incorporate into daily work due to the variability in population and difficulty of use. The aim of this study was to develop and validate a new equation for the simplified estimation of body fat using the Clínica Universidad de Navarra - Body Adiposity Estimator (CUN-BAE) as a reference.

METHODS

This research was conducted in two phases. In the first, the new body fat estimation equation was developed. The developed equation was validated in the second phase. Pearson's linear correlation, raw and adjusted linear regressions, the intraclass correlation coefficient, and Bland-Altman graphs were used.

RESULTS

The variables that best adjusted the body fat percentage were age, sex, and the Napierian logarithm of Body Mass Index (LnBMI), forming the Equation Córdoba for Estimation of Body Fat (ECORE-BF) model. In its validation, the model presented correlation values of 0.994, an intraclass correlation coefficient of 0.960, with the Bland-Altman graph indicating means differences of 1.82 with respect to the estimation with the CUN-BAE. Nevertheless, although the aim was to simplify the CUN-BAE, the main limitation of this study is that a gold standard, such as air displacement plethysmography (ADP) or dual-energy X-ray absorptiometry (DXA), was not used.

CONCLUSIONS

The proposed equation (ECORE-BF) simplified the CUN-BAE and provided a precise method, respecting the principle of parsimony, for the calculation of body fat.

Retrospective study of cardiovascular disease risk factors among a cohort of combat veterans with lower limb amputation

Introduction

Previous studies have shown that veterans with lower limb amputation have a higher risk for cardiovascular disease (CVD) compared with population-based controls. American veterans who have served in Iraq and Afghanistan with lower limb amputation may be at a similarly higher risk.

Patients and methods

The Navel Health Research Center (NHRC) maintains the Expeditionary Medical Encounter Database (EMED) of military personnel who have sustained combat limb amputation or serious limb injury during the conflicts in Iraq and Afghanistan. Department of Veterans Affairs data from 2003 to April 2015 was used to analyze CVD risk factors in this cohort. Veterans with either unilateral (n=442) or bilateral (n=146) lower limb amputation were compared to those with serious lower limb trauma without amputation (n=184). Multivariate regression was used to measure associations between lower limb amputation and CVD risk factors over an average of 8 years of follow-up. Outcomes included mean arterial pressure (MAP), low-density lipoprotein, high-density lipoprotein (HDL), and serum triglycerides (TG).

Results

Compared with the limb injury group, those with unilateral lower limb amputation had significantly lower HDL (p<0.05) and higher TG (p<0.05). Those with bilateral lower limb amputation had significantly higher MAP (p<0.05), lower HDL (p<0.01), and higher TG (p<0.001). The prevalence of metabolic syndrome, defined as type 2 diabetes or a constellation of blood pressure and lipid changes consistent with metabolic syndrome, was 8.7%, 14.9%, and 21.9% for limb injury, unilateral amputation, and bilateral amputation groups, respectively. Veterans with bilateral lower limb amputation had a 2.25-increased odds ratio (95% confidence interval 1.19–5.05) of type 2 diabetes or blood pressure and lipid changes consistent with metabolic syndrome compared to those with limb injury.

Conclusions

Results suggest that veterans with lower limb amputation have a higher risk for metabolic syndrome. Primary care interventions to manage weight, blood pressure, and lipid levels are fundamental in order to reduce cardiac risk in this relatively young cohort.

Daily step count of British military males with bilateral lower limb amputations: A comparison of in-patient rehabilitation with the consecutive leave period between admissions

BACKGROUND:

Reduced function and health in individuals with lower limb amputation is well documented. Step count measurement could facilitate rehabilitation and help monitor functional health outcomes.

OBJECTIVES:

To determine whether mean daily step count changed between in-patient rehabilitation and consecutive leave periods.

STUDY DESIGN:

Observational study.

METHODS:

Nine individuals with bilateral traumatic amputations attending rehabilitation at the Defence Medical Rehabilitation Centre during a 4-month period were invited to participate in the study (two bilateral transfemoral, two bilateral transfemoral/knee disarticulation, two transfemoral/transtibial, one bilateral transfemoral plus transradial, one bilateral transfemoral plus transhumeral and one transfemoral/transtibial/transradial). Prostheses worn by each participant were fitted with an activity monitor (LAM2^TM; PAL Technologies Ltd, Glasgow). Mean daily step count was analysed for each participant following 2 weeks in-patient rehabilitation and consecutive 2 weeks away from rehabilitation.

RESULTS:

Nine participants completed the study (time since injury: 19 ± 7 months, age: 26 ± 6 years). Mean daily step count significantly decreased from 2258 ± 192 during in-patient rehabilitation to 1387 ± 363 at home ( p < 0.01).

CONCLUSION:

The step count decreased when away from rehabilitation, confirming the hypothesis that the mean daily step count would change between in-patient rehabilitation and consecutive leave period.

CLINICAL RELEVANCE

These data provide an indication of the step count achievable by young, military male personnel with bilateral lower limb amputations and highlights differences between intensive in-patient rehabilitation and consecutive leave periods. It is suggested that further investigation and support of clinical monitoring could facilitate rehabilitation tailored to the individual.

Predicting ambulatory energy expenditure in lower limb amputees using multi-sensor methods

Purpose

To assess the validity of a derived algorithm, combining tri-axial accelerometry and heart rate (HR) data, compared to a research-grade multi-sensor physical activity device, for the estimation of ambulatory physical activity energy expenditure (PAEE) in individuals with traumatic lower-limb amputation.

Methods

Twenty-eight participants [unilateral (n = 9), bilateral (n = 10) with lower-limb amputations, and non-injured controls (n = 9)] completed eight activities; rest, ambulating at 5 progressive treadmill velocities (0.48, 0.67, 0.89, 1.12, 1.34m.s^-1) and 2 gradients (3 and 5%) at 0.89m.s^-1. During each task, expired gases were collected for the determination of V˙O2 and subsequent calculation of PAEE. An Actigraph GT3X+ accelerometer was worn on the hip of the shortest residual limb and, a HR monitor and an Actiheart (AHR) device were worn on the chest. Multiple linear regressions were employed to derive population-specific PAEE estimated algorithms using Actigraph GT3X+ outputs and HR signals (GT3X+HR). Mean bias±95% Limits of Agreement (LoA) and error statistics were calculated between criterion PAEE (indirect calorimetry) and PAEE predicted using GT3X+HR and AHR.

Results

Both measurement approaches used to predict PAEE were significantly related (P<0.01) with criterion PAEE. GT3X+HR revealed the strongest association, smallest LoA and least error. Predicted PAEE (GT3X+HR; unilateral; r = 0.92, bilateral; r = 0.93, and control; r = 0.91, and AHR; unilateral; r = 0.86, bilateral; r = 0.81, and control; r = 0.67). Mean±SD percent error across all activities were 18±14%, 15±12% and 15±14% for the GT3X+HR and 45±20%, 39±23% and 34±28% in the AHR model, for unilateral, bilateral and control groups, respectively.

Conclusions

Statistically derived algorithms (GT3X+HR) provide a more valid estimate of PAEE in individuals with traumatic lower-limb amputation, compared to a proprietary group calibration algorithm (AHR). Outputs from AHR displayed considerable random error when tested in a laboratory setting in individuals with lower-limb amputation.

Energy expenditure in people with transtibial amputation walking with crossover and energy storing prosthetic feet: A randomized within-subject study

BACKGROUND

Energy storing feet are unable to reduce the energy required for normal locomotion among people with transtibial amputation. Crossover feet, which incorporate aspects of energy storing and running specific feet, are designed to maximize energy return while providing stability for everyday activities.

RESEARCH QUESTION

Do crossover prosthetic feet reduce the energy expenditure of walking across a range of speeds, when compared with energy storing feet among people with transtibial amputation due to non-dysvascular causes?

METHODS

A randomized within-subject study was conducted with a volunteer sample of twenty-seven adults with unilateral transtibial amputation due to non-dysvascular causes. Participants were fit with two prostheses. One had an energy storing foot (Össur Variflex) and the other a crossover foot (Össur Cheetah Xplore). Other components, including sockets, suspension, and interface were standardized. Energy expenditure was measured with a portable respirometer (Cosmed K4b2) while participants walked on a treadmill at self-selected slow, comfortable, and fast speeds with each prosthesis. Gross oxygen consumption rates (VO₂ ml/min) were compared between foot conditions. Energy storing feet were used as the baseline condition because they are used by most people with a lower limb prosthesis. Analyses were performed to identify people who may benefit from transition to crossover feet.

RESULTS

On average, participants had lower oxygen consumption in the crossover foot condition compared to the energy storing foot condition at each self-selected walking speed, but this difference was not statistically significant. Participants with farther six-minute walk test distances, higher daily step counts, and higher Medicare Functional Classification Levels at baseline were more likely to use less energy in the crossover foot.

SIGNIFICANCE

Crossover feet may be most beneficial for people with higher activity levels and physical fitness. Further research is needed to examine the effect of crossover feet on energy expenditure during high-level activities.