Body mass index patterns following dysvascular lower extremity amputation

A scoping review on nutritional intake and nutritional status in people with a major dysvascular lower limb amputation

PURPOSE

To systematically review literature on nutritional intake, nutritional status and nutritional interventions, and to study their association with short- and long-term clinical outcomes in people with a major dysvascular lower limb amputation.

METHODS

PubMed, Ovid, CINAHL, and The Cochrane Library were searched. Studies were included if nutritional intake, nutritional status, or nutritional interventions in people with a major dysvascular lower limb amputation were analyzed.

RESULTS

Of the 3038 unique papers identified, 30 studies were included. Methodological quality was moderate (1 study) or weak (29 studies). Limited information was available on nutritional intake (2 studies) and nutritional interventions (1 study). Nutritional intake and nutritional status were assessed by diverse methods. The percentage of people with a poor nutritional status ranged from 1% to 100%. In some studies, measures of poor nutritional status were associated with adverse short- and long-term clinical outcomes.

CONCLUSIONS

The percentage of people with a poor nutritional status is inconclusive in the major dysvascular lower limb amputation population, because of the heterogeneity of the assessment methods used. Some included studies reported a negative association between poor nutritional status and clinical outcomes. However, these results should be interpreted with caution, because of the limited quality of the studies available. Studies high in methodological quality and high in hierarchy of evidence are needed.IMPLICATIONS FOR REHABILITATIONThe proportion of people with a poor nutritional status in the major dysvascular lower limb amputation population is inconclusive.Poor nutritional status seems to affect clinical outcomes negatively.More uniformity in assessment of malnutrition in the major dysvascular lower limb amputation population is needed.

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.

Estimated glomerular filtration rate based on creatinine, cystatin C, β-trace protein and β2 microglobulin in patients undergoing nontraumatic lower extremity amputation

AIMS

The study's aim is to compare current and new equations for estimating glomerular filtration rate (GFR) based on creatinine, cystatin C, β-trace protein (BTP) and β2 microglobulin (B2M) among patients undergoing major amputation.

METHODS

This is a secondary analysis of data from a prospective cohort study investigating patients undergoing nontraumatic lower extremity amputation. Estimated GFR (eGFR) was calculated using equations based on creatinine (eGFRcre[2009] and eGFRcre[2021]), cystatin C (eGFRcys), the combination of creatinine and cystatin C (eGFRcomb[2012] and eGFRcomb[2021]) or a panel of all 4 filtration markers (eGFRpanel). Primary outcome was changed in eGFR across amputation according to each equation. Two case studies of prior amputation with GFR measured by 99mTc-DTPA clearance are described to illustrate the relative accuracies of each eGFR equation.

RESULTS

Analysis of the primary outcome included 29 patients (median age 75 years, 31% female). Amputation was associated with a significant decrease in creatinine concentration (-0.09 mg/dL, P = 0.004), corresponding to a significant increase in eGFRcre[2009] (+6.1 mL/min, P = 0.006) and eGFRcre[2021] (+6.3 mL/min, P = 0.006). Change across amputation was not significant for cystatin C, BTP, B2M or equations incorporating these markers (all P > 0.05). In both case studies, eGFRcre[2021] yielded the largest positive bias, eGFRcys yielded the largest negative bias and eGFRcomb[2012] and eGFRcomb[2021] yielded the smallest absolute bias.

CONCLUSION

Creatinine-based estimates were substantially higher than cystatin C-based estimates before amputation and significantly increased across amputation. Estimates combining creatinine and cystatin were stable across amputation, while the addition of BTP and B2M is unlikely to be clinically relevant.

Biomechanical risk factors for knee osteoarthritis and lower back pain in lower limb amputees: protocol for a systematic review

INTRODUCTION

There is a limited research exploring biomechanical risk factors for the development of knee osteoarthritis (KOA) and lower back pain (LBP) between lower limb amputee subgroups, (eg, transtibial amputees (TTA) vs transfemoral amputees (TFA), or TTA dysvascular vs TTA traumatic). Previous reviews have focused primarily on studies where symptoms of KOA or LBP are present, however, due to limited study numbers, this hinders their scope and ability to compare between amputee subgroups. Therefore, the aim of this systematic review is to descriptively compare biomechanical risk factors for developing KOA and LBP between lower limb amputee subgroups, irrespective of whether KOA or LBP was present.

METHODS AND ANALYSIS

This review is currently in progress and screening results are presented alongside the protocol to highlight challenges encountered during data extraction. Five electronic databases were searched (Medline-Web of Science, PubMed, CINAHL, Embase and Scopus). Eligible studies were observational or interventional, reporting biomechanical gait outcomes for individual legs in adult lower limb amputees during flat walking, incline/decline walking or stair ascent/descent. Two reviewers screened for eligibility and level of agreement was assessed using Cohen's Kappa. Data extraction is ongoing. Risk of bias will be assessed using a modified Downs and Black method, and outcome measures will be descriptively synthesised.

ETHICS AND DISSEMINATION

There are no ethical considerations for this systematic review. Due to its scope, results are expected to be published in three separate manuscripts: (1) biomechanical risk factors of KOA between TTA and TFA, relative to non-amputees, (2) biomechanical risk factors of LBP between TTA and TFA, relative to non-amputees and (3) biomechanical risk factors of KOA and LBP between TTA with traumatic or dysvascular causes, relative to non-amputees.

PROSPERO REGISTRATION NUMBER

CRD42020158247.

Sex and gender differences in quality of life and related domains for individuals with adult acquired lower-limb amputation: a scoping review

PURPOSE

To understand what is known about sex and gender differences in quality of life (QoL) and related domains for individuals with an adult acquired lower limb amputation (LLA).

METHODS

A computer-assisted literature search of four online databases was completed. Articles were included if they incorporated sex or gender as part of their data analysis with a focus on QoL-related domains. Data were analyzed using descriptive numerical analysis and thematic analysis.

RESULTS

One hundred and eleven articles were included in this review. Women were under-represented across studies, with most of the participants being men. No articles described the inclusion of trans or non-binary persons. Differences by sex or gender were reported by 66 articles. Articles reporting on gender seldom provided descriptions of how gender was defined. Overall, women/females seemed to have worse outcomes in terms of prosthesis-related outcomes, mental health, and return to occupations.

CONCLUSION

Articles included in this review were not clear with how gender was defined. In order for more targeted interventions that account for sex and gender differences, studies need to be more forthcoming about how they use and define gender. Future research should seek to include gender non-conforming participants to identify additional needs.Implications for rehabilitationSex and gender are important constructs that influence outcomes following lower limb amputation.Rehabilitation professionals should consider sex and gender-specific outcomes when tailoring programs to ensure ethical clinical care.

Direct continuous electromyographic control of a powered prosthetic ankle for improved postural control after guided physical training: A case study

Despite the promise of powered lower limb prostheses, existing controllers do not assist many daily activities that require continuous control of prosthetic joints according to human states and environments. The objective of this case study was to investigate the feasibility of direct, continuous electromyographic (dEMG) control of a powered ankle prosthesis, combined with physical therapist-guided training, for improved standing postural control in an individual with transtibial amputation. Specifically, EMG signals of the residual antagonistic muscles (i.e. lateral gastrocnemius and tibialis anterior) were used to proportionally drive pneumatical artificial muscles to move a prosthetic ankle. Clinical-based activities were used in the training and evaluation protocol of the control paradigm. We quantified the EMG signals in the bilateral shank muscles as well as measures of postural control and stability. Compared to the participant's daily passive prosthesis, the dEMG-controlled ankle, combined with the training, yielded improved clinical balance scores and reduced compensation from intact joints. Cross-correlation coefficient of bilateral center of pressure excursions, a metric for quantifying standing postural control, increased to .83(±.07) when using dEMG ankle control (passive device: .39(±.29)). We observed synchronized activation of homologous muscles, rapid improvement in performance on the first day of the training for load transfer tasks, and further improvement in performance across training days (p = .006). This case study showed the feasibility of this dEMG control paradigm of a powered prosthetic ankle to assist postural control. This study lays the foundation for future study to extend these results through the inclusion of more participants and activities.

The association between body mass index and skin problems in persons with a lower limb amputation: an observational study

Background

Obesity is common in persons with a lower limb amputation, an amputation can also lead to further weight gain. Data regarding the prevalence of obesity in the Dutch population with a lower limb amputation are lacking. Furthermore, the impact of obesity on skin problems of the residual limb and the need of prosthetic repairs is unknown. The aim of this study was to determine the prevalence of obesity in Dutch persons with a lower limb amputation and to investigate the relationship between body weight, body mass index and skin problems of the residual limb and the frequency of prosthetic repairs.

Methods

A survey was performed among adults with a unilateral lower limb amputation due to any cause, and who are user of a prosthesis. The survey consisted of measurement of the subjects’ body height and weight, a questionnaire which assessed self-reported skin problems in the previous month and factors potentially associated with these skin problems, and assessment of the frequency of visits to the orthopedic workshop.

Results

In total, 413 persons were enrolled. Of them, 39% (95 % confidence interval 35;44) were overweight and 28% (95% confidence interval 24;33) were obese. A total of 77% (95% confidence interval 73;81) reported one or more skin problems in the past month. Body weight and body mass index were neither associated with the presence of skin problems in general nor with the number of prosthetic repairs. Persons with severe skin problems had a slightly lower body mass index (26.6 kg/m² vs. 28.0 kg/m², p = 0.012). Persons with skin problems were younger than those without (difference in means 6.0 years (95% confidence interval 3.0;8.9)).

Conclusions

Our findings show that obesity is common in the Dutch ambulant population with a lower limb amputation, with a prevalence being higher than in the general Dutch adult population. However, its negative impact on the presence of skin problems and the frequency of prosthetic repairs may be limited.

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.

Patient Reported Outcome Measures for Major Lower Limb Amputation Caused by Peripheral Artery Disease or Diabetes: A Systematic Review

OBJECTIVE

Most major lower limb amputations are related to peripheral artery disease (PAD) or diabetes. Just 40% of patients who undergo major lower limb amputation will use a prosthesis yet measures of surgical success commonly focus on prosthesis use. Patient reported outcome measures (PROMs) are valuable to comprehensively evaluate health related quality of life (HRQL) after surgery. This systematic review aimed to identify and describe PROMs available to assess HRQL in patients after amputation for PAD or diabetes.

METHODS

A search was conducted based on the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) for systematic reviews of PROMs. Ovid MEDLINE, Ovid EMBASE, PsycINFO, CINAHL, and Cochrane CENTRAL were also searched from inception until August 2019. Included were articles describing the development, measurement properties, or evaluation of HRQL via a PROM in adult patients after amputation for PAD or diabetes. Studies of amputation exclusively for trauma or malignancy were excluded. Data were collected on study characteristics, PROM characteristics (generic/disease specific), and properties of amputation specific PROMs.

RESULTS

Of 3 317 abstracts screened, 111 full text articles were assessed for eligibility and 64 included. Fifty-six studies evaluated HRQL, with 23 (46%) of these using an amputation specific PROM to do so. Eleven different amputation specific PROMs were identified, 10 (91%) of which were developed only for prosthesis users. One measure was suitable for use in all patients after amputation. This "Amputee single item mobility measure" includes a single item evaluating mobility. Nine studies reported some psychometric testing of an amputation specific PROM.

CONCLUSION

A well tested, multidimensional PROM applicable to wheelchair and prosthetic users after amputation is lacking and urgently needed for studies in this field. Future work to develop an appropriate measure is required.

Determinants of dietary behaviour in wheelchair users with spinal cord injury or lower limb amputation: Perspectives of rehabilitation professionals and wheelchair users

Objective

This study aims to identify determinants of dietary behaviour in wheelchair users with spinal cord injury or lower limb amputation, from the perspectives of both wheelchair users and rehabilitation professionals. The findings should contribute to the field of health promotion programs for wheelchair users.

Methods

Five focus groups were held with wheelchair users (n = 25), and two with rehabilitation professionals (n = 11). A thematic approach was used for data analysis in which the determinants were categorized using an integrated International Classification of Functioning, Disability and Health and Attitude, Social influence and self-Efficacy model.

Results

Reported personal factors influencing dietary behaviour in wheelchair users were knowledge, boredom, fatigue, stage of life, habits, appetite, self-control, multiple lifestyle problems, intrinsic motivation, goal setting, monitoring, risk perception, positive experiences, suffering, action planning, health condition, function impairments, attitude and self-efficacy. Reported environmental factors influencing dietary behaviour in wheelchair users were unadjusted kitchens, monitoring difficulties, eating out, costs, unfavourable food supply, nutrition education/counselling, access to simple healthy recipes, eating together, cooking for others, and awareness and support of family and friends.

Conclusions

Important modifiable determinants of dietary behaviour in wheelchair users that might be influenced in lifestyle interventions are knowledge, fatigue, habits, self-control, intrinsic motivation, risk perception, attitude and self-efficacy. It is recommended to involve relatives, since they appear to significantly influence dietary behaviour.

Dietary intakes and prevalence of overweight/obesity in male non-dysvascular lower limb amputees

BACKGROUND

Lower limb amputees are at higher risk of cardiovascular disease compared to non-amputees. Dietary intake, a major determinant of cardiovascular disease risk, has not previously been studied in this group.

OBJECTIVE

The aim of this study was to investigate dietary intakes and prevalence of overweight/obesity in adult lower limb amputees.

STUDY DESIGN

A cross-sectional survey was used to investigate the dietary intake and prevalence of overweight/obesity in adults with lower limb amputations living in the United Kingdom.

METHOD

Dietary intakes of male adult lower limb amputees ( n = 46, non-dysvascular) were assessed using food frequency questionnaires and results were compared to dietary reference values in the United Kingdom. Prevalence of overweight/obesity was assessed through body mass index and waist-to-hip ratio and compared to the general population according to the Health Survey for England 2011.

RESULTS

Dietary intake risk factors for cardiovascular disease such as sugars (22.01%), total fat (34.87%), saturated fat (12.72%) and sodium (2660.10 mg/day) were significantly higher ( p < 0.001, p < 0.001, p = 0.043, p < 0.001; p < 0.001; respectively) than the dietary reference values. A high prevalence (82.8%) of overweight/obesity was found with a significantly higher body mass index and waist-to-hip ratio ( p = 0.027; p = 0.001; respectively) compared to the Health Survey for England 2011.

CONCLUSION

High intakes of sugars, dietary fats, sugars and salts, combined with high prevalence of overweight/obesity observed in lower limb amputees are concerning. These findings suggest that greater emphasis on dietary intakes should be considered for rehabilitation programmes.

CLINICAL RELEVANCE

Findings highlight poor dietary habits in lower limb amputees with respect to fat, sugar and salt intake, also high levels of overweight/obesity. Considering greater emphasis on dietary intake and including lifestyle changing interventions in rehabilitation programmes for lower limb amputees may lower the risk of obesity and CVD.

Innovative Use of Thighplasty to Improve Prosthesis Fit and Function in a Transfemoral Amputee

Supplemental Digital Content is available in the text.

Background:

Excess residual limb fat is a common problem that can impair prosthesis control and negatively impact gait. In the general population, thighplasty and liposuction are commonly performed for cosmetic reasons but not specifically to improve function in amputees. The objective of this study was to determine if these procedures could enhance prosthesis fit and function in an overweight above-knee amputee.

Methods:

We evaluated the use of these techniques on a 50-year-old transfemoral amputee who was overweight. The patient underwent presurgical imaging and tests to measure her residual limb tissue distribution, socket-limb interface stiffness, residual femur orientation, lower-extremity function, and prosthesis satisfaction. A medial thighplasty procedure with circumferential liposuction was performed, during which 2,812 g (6.2 lbs.) of subcutaneous fat and skin was removed from her residual limb. Imaging was repeated 5 months postsurgery; functional assessments were repeated 9 months postsurgery.

Results:

The patient demonstrated notable improvements in socket fit and in performing most functional and walking tests. Her comfortable walking speed increased 13.3%, and her scores for the Sit-to-Stand and Four Square Step tests improved over 20%. Femur alignment in her socket changed from 8.13 to 4.14 degrees, and analysis showed a marked increase in the socket-limb interface stiffness.

Conclusions:

This study demonstrates the potential of using a routine plastic surgery procedure to modify the intrinsic properties of the limb and to improve functional outcomes in overweight or obese transfemoral amputees. This technique is a potentially attractive option compared with multiple reiterations of sockets, which can be time-consuming and costly.

Clinical outcome and complications of thoracic and pelvic limb stump and socket prostheses

Objectives: To describe the use, quality of life, compliance, complications, and outcome of animals fitted with stump socket prostheses.

Methods: Medical records of dogs fitted with a stump socket prosthesis were reviewed. Functional outcome, quality of life and complications were retrospectively assessed from an owner questionnaire.

Results: Thirteen stump socket prostheses (12 dogs) were fitted for a variety of reasons including trauma, congenital abnormalities, and neoplasia. Eight dogs had a good outcome overall and four a poor outcome. Quality of life (QOL) remained good or excellent in 10/12 dogs. Nine complications were seen in 7/12 dogs, most were manageable; surgical wound complications (n = 2) and pressures sores (n = 4) were the most frequently encountered. One dog suffered multiple complications. Thoracic and pelvic limb stump socket prostheses had a similar complication rate, however all animals with a poor outcome had a thoracic limb stump socket prosthesis; two were small breed dogs (under 10 kg) and two had bilateral thoracic limb abnormalities.

Clinical significance: Stump socket prostheses are feasible and versatile in animals. In correctly selected cases, good to excellent outcomes are possible. However, complications are frequent but often manageable. Further investigations are required into the risk factors for poor outcomes and prospective studies are required to assess changes in biomechanics, function, and QOL before and after fitting of a stump socket prosthesis. Until further evidence is available, careful consideration should be given before fitting bilateral thoracic limb stump socket prostheses or thoracic limb stump socket prostheses to small breed dogs.

Supplementary Material to this article is available online at https://doi.org/10.3415/VCOT-16-09-0127

Trunk kinetic effort during step ascent and descent in patients with transtibial amputation using angular momentum separation

BACKGROUND

Patients with transtibial amputation adopt trunk movement compensations that alter effort and increase the risk of developing low back pain. However, the effort required to achieve high-demand tasks, such as step ascent and descent, remains unknown.

METHODS

Kinematics were collected during bilateral step ascent and descent tasks from two groups: 1) seven patients with unilateral transtibial amputation and 2) seven healthy control subjects. Trunk kinetic effort was quantified using translational and rotational segmental moments (time rate of change of segmental angular momentum). Peak moments during the loading period were compared across limbs and across groups.

FINDINGS

During step ascent, patients with transtibial amputation generated larger sagittal trunk translational moments when leading with the amputated limb compared to the intact limb (P=0.01). The amputation group also generated larger trunk rotational moments in the frontal and transverse planes when leading with either limb compared to the healthy group (P=0.01, P<0.01, respectively). During step descent, the amputation group generated larger trunk translational and rotational moments in all three planes when leading with the intact limb compared to the healthy group (P<0.017).

INTERPRETATION

This investigation identifies how differing trunk movement compensations, identified using the separation of angular momentum, require higher kinetic effort during stepping tasks in patients with transtibial amputation compared to healthy individuals. Compensations that produce identified increased and asymmetric trunk segmental moments, may increase the risk of the development of low back pain in patients with amputation.

Standard and Amputation-Adjusted Body Mass Index Measures: Comparison and Relevance to Functional Measures, Weight-Related Comorbidities, and Dieting

People with limb loss may misjudge weight-related health when not adjusting body mass index (BMI) for amputation level. This cross-sectional, community-based study compared BMI and amputation-adjusted BMI (A-BMI) and evaluated relationships among BMI categories, function, and dieting. Subjects provided self-reported demographic, functional, and medical/prosthetic data including height and weight and completed performance-based balance and gait measures. A Web-based A-BMI calculator adjusted for amputation levels. Results for 294 subjects from 11 states (68.4% men; 76.5% white; average age, 55.6 [15.1] y) were reported, with vascular (49.7%) and unilateral transtibial (40.8%) amputations as the most common. Body mass index and A-BMI were closely correlated (Pearson r = 0.99), but a BMI of 28.6 (6.7) was less than an A-BMI of 30.3 (6.2) (t test, P < 0.001). Agreement among Centers for Disease Control BMI categories was moderate (κ = 0.48); 39.7% of BMI categories were underestimated without adjusting for amputations. Functional measures did not differ among BMI/A-BMI categories (P > 0.05). A larger than random proportion categorized as overweight by BMI dieted (χ, P < 0.05), and people categorized as overweight by A-BMI did not (38.3% classified as normal BMI). Functional abilities did not differ among BMI categories (Kruskal-Wallis and analysis of variance, P > 0.05). People with limb loss using BMI may underestimate weight-related health; a Web-based A-BMI calculator may help monitor weight to make dieting decisions.

Limitations of body mass index for counseling individuals with unilateral lower extremity amputation

BACKGROUND

Body composition is important for health screening, but appropriate methods for unilateral lower extremity amputees have not been validated.

OBJECTIVES

To compare body mass index adjusted using Amputee Coalition equations (body mass index-Amputee Coalition) to dual-energy X-ray absorptiometry in unilateral lower limb amputees.

STUDY DESIGN

Cross-sectional, experimental.

METHODS

Thirty-eight men and women with lower limb amputations (transfemoral, transtibial, hip disarticulation, Symes) participated. Body mass index (mass/height²) was compared to body mass index corrected for limb loss (body mass index-Amputee Coalition). Accuracy of classification and extrapolation of percent body fat with body mass index was compared to dual-energy X-ray absorptiometry.

RESULTS

Body mass index-Amputee Coalition increased body mass index (by ~ 1.1 kg/m²) but underestimated and mis-classified 60% of obese and overestimated 100% of lean individuals according to dual-energy X-ray absorptiometry. Estimated mean percent body fat (95% confidence interval) from body mass index-Amputee Coalition (28.3% (24.9%, 31.7%)) was similar to dual-energy X-ray absorptiometry percent body fat (29.5% (25.2%, 33.7%)) but both were significantly higher ( p < 0.05) than percent body fat estimated from uncorrected body mass index (23.6% (20.4%, 26.8%)). However, total errors for body mass index and body mass index-Amputee Coalition converted to percent body fat were unacceptably large (standard error of the estimate = 6.8%, 6.2% body fat) and the discrepancy between both methods and dual-energy X-ray absorptiometry was inversely related ( r = -0.59 and r = -0.66, p < 0.05) to the individual's level of body fatness.

CONCLUSIONS

Body mass index (despite correction) underestimates health risk for obese patients and overestimates lean, muscular individuals with lower limb amputation. Clinical relevance Clinical recommendations for an ideal body mass based on body mass index-Amputee Coalition should not be relied upon in lower extremity amputees. This is of particular concern for obese lower extremity amputees whose health risk might be significantly underestimated based on body mass index despite a "correction" formula for limb loss.

The development and validation of the AMPREDICT model for predicting mobility outcome after dysvascular lower extremity amputation

OBJECTIVE

The objective of this study was the development of AMPREDICT-Mobility, a tool to predict the probability of independence in either basic or advanced (iBASIC or iADVANCED) mobility 1 year after dysvascular major lower extremity amputation.

METHODS

Two prospective cohort studies during consecutive 4-year periods (2005-2009 and 2010-2014) were conducted at seven medical centers. Multiple demographic and biopsychosocial predictors were collected in the periamputation period among individuals undergoing their first major amputation because of complications of peripheral arterial disease or diabetes. The primary outcomes were iBASIC and iADVANCED mobility, as measured by the Locomotor Capabilities Index. Combined data from both studies were used for model development and internal validation. Backwards stepwise logistic regression was used to develop the final prediction models. The discrimination and calibration of each model were assessed. Internal validity of each model was assessed with bootstrap sampling.

RESULTS

Twelve-month follow-up was reached by 157 of 200 (79%) participants. Among these, 54 (34%) did not achieve iBASIC mobility, 103 (66%) achieved at least iBASIC mobility, and 51 (32%) also achieved iADVANCED mobility. Predictive factors associated with reduced odds of achieving iBASIC mobility were increasing age, chronic obstructive pulmonary disease, dialysis, diabetes, prior history of treatment for depression or anxiety, and very poor to fair self-rated health. Those who were white, were married, and had at least a high-school degree had a higher probability of achieving iBASIC mobility. The odds of achieving iBASIC mobility increased with increasing body mass index up to 30 kg/m² and decreased with increasing body mass index thereafter. The prediction model of iADVANCED mobility included the same predictors with the exception of diabetes, chronic obstructive pulmonary disease, and education level. Both models showed strong discrimination with C statistics of 0.85 and 0.82, respectively. The mean difference in predicted probabilities for those who did and did not achieve iBASIC and iADVANCED mobility was 33% and 29%, respectively. Tests for calibration and observed vs predicted plots suggested good fit for both models; however, the precision of the estimates of the predicted probabilities was modest. Internal validation through bootstrapping demonstrated some overoptimism of the original model development, with the optimism-adjusted C statistic for iBASIC and iADVANCED mobility being 0.74 and 0.71, respectively, and the discrimination slope 19% and 16%, respectively.

CONCLUSIONS

AMPREDICT-Mobility is a user-friendly prediction tool that can inform the patient undergoing a dysvascular amputation and the patient's provider about the probability of independence in either basic or advanced mobility at each major lower extremity amputation level.

Lower-limb amputation and body weight changes in men

Little is known about the relationship between lower-limb amputation (LLA) and subsequent changes in body weight. We conducted a retrospective cohort study using clinical and administrative databases to identify and follow weight changes in 759 males with amputation (partial foot amputation [PFA], n = 396; transtibial amputation [TTA], n = 267; and transfemoral amputation [TFA], n = 96) and 3,790 nondisabled persons frequency-matched (5:1) on age, body mass index, diabetes, and calendar year from eight Department of Veterans Affairs medical care facilities in the Pacific Northwest. We estimated and compared longitudinal percent weight change from baseline during up to 39 mo of follow-up in participants with and without amputation. Weight gain in the 2 yr after amputation was significantly more in men with an amputation than without, and in men with a TTA or TFA (8%-9% increase) than in men with a PFA (3%-6% increase). Generally, percent weight gain peaked at 2 yr and was followed by some weight loss in the third year. These findings indicate that LLA is often followed by clinically important weight gain. Future studies are needed to better understand the reasons for weight gain and to identify intervention strategies to prevent excess weight gain and the deleterious consequences that may ensue.

Sound limb loading in individuals with unilateral transfemoral amputation across a range of walking velocities

BACKGROUND

Individuals with unilateral transfemoral amputation demonstrate significantly increased rates of osteoarthritis in their sound knee. This increased risk is likely the result of altered knee mechanical loading and gait compensations resulting from limited function in the prosthetic limb. Altered knee loading as calculated using loading rates and peak external knee adduction moments and impulses have been associated with both the development and progression of knee osteoarthritis in other populations. The purpose of this study was to determine if young individuals with transfemoral amputation demonstrate biomechanical indicators of increased knee osteoarthritis risk.

METHODS

Fourteen young male Service Members with unilateral transfemoral amputation and 14 able-bodied service members underwent biomechanical gait analysis at three standardized walking velocities. A two-way ANOVA (group × speed) with unpaired comparisons with Bonferroni-Holm post-hoc corrections assessed statistical significance and effect sizes (d) were calculated.

FINDINGS

Normalized peak external knee adduction moments and impulses were 25.7% (P < 0.014, d > 0.994) and 27.1% (P < 0.012, d > 1.019) lower, respectively, in individuals with trans-femoral amputation than controls when averaged across speeds, and effect sizes were large. External knee flexor moments were not, however, different between groups and effect sizes were generally small (P > 0.380, d < 0.338). Maximal loading rates were significantly greater in individuals with amputation and effect sizes were large (P < 0.001, d > 1.644).

INTERPRETATION

Individuals with transfemoral amputation did not demonstrate biomechanical risk factors for high medial compartment knee joint loads, but the increased loading rates could place the sound knee at greater risk for cartilage or other tissue damage, even if not localized to the medial compartment.

Biomechanical risk factors for knee osteoarthritis when using passive and powered ankle-foot prostheses

BACKGROUND

Gait compensations following transtibial amputation negatively affect sound limb loading and increase the risk of knee osteoarthritis. Push-off assistance provided by new powered prostheses may decrease the demands on the sound limb. However, their effects in a young population in the early stages of prosthetic use are still unknown. The purpose of this study was to compare limb loading between 1. passive and powered ankle-foot prostheses, 2. sound and amputated limbs, and 3. individuals with amputations in the relatively early stages of prosthetic use and controls.

METHODS

Ten young, active individuals with unilateral transtibial amputation and 10 controls underwent biomechanical gait analysis at three speeds. The peak external knee flexor and adductor moments, adductor moment's angular impulse, peak vertical ground reaction force and loading rate were calculated. Repeated measures ANOVAs compared between limbs, prostheses, and groups.

FINDINGS

The powered prosthesis did not decrease the sound limb's peak adduction moment or its impulse, but did decrease the external flexor moment, peak vertical force and loading rate as speed increased. The powered prosthesis decreased the loading rate from controls. The sound limb did not display a significantly greater risk for knee osteoarthritis than the intact limb or than controls in either device.

INTERPRETATION

In the early stages of prosthetic use, young individuals with transtibial amputation display few biomechanical risk factors for knee osteoarthritis development. However, a powered ankle-foot prosthesis still offers some benefits and may be used prophylactically to mitigate potential increases of these variables with continued prosthetic use over time.

Weight loss intention, dietary behaviors, and barriers to dietary change in veterans with lower extremity amputations

BACKGROUND

Obesity is thought to be highly prevalent in persons with lower extremity amputations (LEAs) and can impair physical and social functioning.

OBJECTIVE

The aim of this study was to determine the prevalence of weight loss intention, weight loss strategies, dietary patterns, and barriers to making dietary changes, and their associations with body mass index (BMI, kg/m(2)), amputation characteristics, health status, and socioeconomic factors.

METHODS

We conducted a cross-sectional study (n = 150) using data from a self-administered questionnaire.

RESULTS

43% of participants were obese and 48% were trying to lose weight; 83% of those trying to lose weight reported trying to "eat differently", but only 7% were following a comprehensive weight loss program involving dietary changes, physical activity, and behavioral counseling. 21% of participants reported ≥ 6 barriers to changing their eating habits (e.g., habit, too little money, stress/depression). Obesity was associated with younger age, lower physical health scores, hypertension, arthritis, and diabetes. Compared to those not trying to lose weight, a greater proportion of those trying to lose weight had a BMI ≥ 35 kg/m(2), age <55 years, higher physical and mental health scores, and more frequent consumption of vegetables, beans, chicken, and fish.

CONCLUSIONS

Though over half of overweight and obese individuals with LEA were trying to lose weight, few reported following a comprehensive program to lose weight, which may indicate an unmet need for services for this group. To be effective, these programs will need to address the complex physical and mental health challenges that many of these individuals face.