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

Load carriage influences intact limb knee loading estimate associated with osteoarthritis in individuals with transtibial amputation

BACKGROUND

Load carriage can exacerbate the elevated intact limb knee loading in individuals with transtibial amputation, potentially contributing to osteoarthritis. Prosthetic foot mechanical properties like push-off power have the potential to reduce this elevated knee loading. This study investigated how load carriage position and prosthetic foot type affect intact limb knee loading measures for these individuals.

METHODS

Twelve participants with unilateral transtibial amputation were recruited. Intact limb external knee adduction and flexion moments were analyzed, with prosthetic push-off power and work quantified for effects on first peak knee adduction moment. A linear mixed-effects regression evaluated the effects of load position and prosthetic foot on these metrics.

FINDINGS

Participants exhibited the smallest first peak knee adduction moment and impulse with the intact-side load condition, followed by the back load and front load conditions, with the prosthetic-side load condition having the highest magnitude (20-35 % increase). However, we found no significant differences in these metrics by prosthetic foot. Additionally, load position and prosthetic foot did not significantly affect peak knee flexion moment. Only a negative trend toward correlation (P = 0.089) was observed between first peak knee adduction moment and prosthetic push-off work in the back load condition.

INTERPRETATION

Intact-side load carriage may be more clinically beneficial for mitigating the risk of increased intact limb knee loading. Further, load carriage strategy affects intact limb knee loading more than specific prosthetic foot type. These biomechanical findings can help guide rehabilitative load carriage strategies to minimize the elevated risk of knee osteoarthritis in individuals with transtibial amputation.

Screening and patient selection for bone-anchored limb implantation and rehabilitation: what makes a good candidate?

Osseointegration of a bone-anchored limb (BAL) is an emerging rehabilitation technique that offers significant advantages over traditional socket prostheses. By addressing functional limitations and recurrent cutaneous complications, BAL systems have shown an 82%-90% increase in daily prosthesis use among patients, who also report improvements in functional ability, balance, comfort, and overall quality of life. Despite these benefits, the process of patient selection for BAL remains underdeveloped, with evidence-based guidelines still in their infancy. This article aims to propose a workflow for patient selection and screening in BAL osseointegration, leveraging the current literature, interdisciplinary clinical experience, and established models. A comprehensive evaluation process is suggested that incorporates anatomical, physiological, psychological, and lifestyle factors. These include radiological evaluation, amputation history, prosthetic component assessment, laboratory tests, psychiatric history, cognitive assessments, and considerations of home safety and postoperative care. The evaluation should ideally be conducted by an interdisciplinary team to ensure a balanced consideration of risks and benefits for each candidate. As the understanding of BAL osseointegration advances, it is expected that patient indications will expand and contraindications will be more clearly defined. The proposed workflow aims to standardize patient selection, thereby optimizing surgical outcomes and rehabilitation processes. This approach is essential for maximizing the benefits of BAL systems while ensuring patient safety and improving long-term rehabilitation outcomes.

Pain Management in Staged Osseointegration Procedures: A Retrospective Study and Foundation for Future Optimization

INTRODUCTION

Osseointegration is an innovative procedure to attach an external prosthetic device directly to the skeleton. The technique has been shown to improve physical function and quality of life relative to conventional socket prosthetic devices. While much of the research in osseointegration has focused on functional outcomes, less is known regarding perioperative pain management. The purpose of this study was to describe perioperative and postoperative pain management approaches received by patients undergoing osseointegration procedures at a tertiary medical center.

MATERIALS AND METHODS

This retrospective study was determined to be exempt from Institutional Review Board review by the Walter Reed National Military Medical Center Department of Research Programs. Perioperative and postoperative pain management approaches received by 41 patients who underwent 76 staged osseointegration procedures from 2016 to 2021 at Walter Reed National Military Medical Center were described.

RESULTS

Pain management approaches included perioperative ketamine (51% stage I, 55% stage II), epidurals (76% stage I, 77% stage II) with a median of 3-4 days across stages, peripheral nerve catheters (27% stage I, 16% stage II), and/or single-shot peripheral nerve block (<10% across stages). The median morphine equivalent dose provided during surgery was 65 mg across both stages, with 56% and 54% of patients also requiring opioid medication in the post-anesthesia care unit. In 11 of 76 (15%) procedures, patients required an increase in the rate or concentration of epidural or peripheral nerve catheter infusion. In six (8%) unique recovery periods, patients experienced a dislodged catheter. In 27 of 76 (36%) unique recovery periods, patients experienced a significant increase in postoperative pain requiring acute pain service intervention in the form of catheter adjustment, intravenous pain medications, and/or the addition of intravenous patient-controlled analgesia. Adequate pain control was achieved with minimal epidural or peripheral nerve catheter trouble-shooting and a bolus for 24 patients (89% requiring intervention). Summed 24-hour pain scores (SPI24) did not vary across stages. SPI24 was positively correlated with opioid doses received. Patients with single, relative to multiple, limb amputations had similar SPI24 values (P > .05).

CONCLUSIONS

Variability in pain management requirements calls forth opportunities to optimize osseointegration analgesia care and future research. As osseointegration becomes more accessible, the need for optimizing pain management through patient-centered research becomes more salient.

The significance of frontal plane static alignment in anticipating dynamic knee moment among transtibial prosthesis users: A cross-sectional study

BACKGROUND

In the process of transtibial prosthetic fitting, alignment is the process of positioning the prosthetic foot relative to the residual limb. Changes in frontal plane alignment can impact knee moments during walking, which can either cause or, when aligned properly, prevent injuries. However, clinical evaluation of dynamic knee moments is challenging, limiting prosthetists' insights into dynamic joint loading. Typically, knee joint loading is assessed in static stance using the knee moment arm as a proxy for subsequent dynamic alignment. It remains uncertain if static alignment accurately represents actual dynamics during walking.

RESEARCH QUESTION

Is the frontal knee moment arm in stance predictive for the knee moment arm and external knee adduction moment during gait in transtibial bone-anchored prosthesis users?

METHODS

In this cross-sectional study, twenty-seven unilateral transtibial bone-anchored prosthesis users underwent data acquisition on the M-Gait instrumented treadmill. Static and dynamic measurements were conducted, and knee moment arm and external knee adduction moment were calculated. Pearson's correlation and linear regression analyses were performed to examine relationships between static and dynamic knee moment arms and external knee adduction moments.

RESULTS

The static knee moment arm showed significant associations with dynamic knee moment arm at the ground reaction force peaks (First: r=0.60, r2=35%, p<0.001; Second: r=0.62, r2=38%, p=0.001) and knee adduction moment (First: r=0.42, r2=17%, p=0.030; Second: r=0.59, r2=35%, p=0.001). A 1 mm between-subject difference in static knee moment arm corresponded, on average, with a 0.9% difference in knee adduction moment at the first peak and a 1.5% difference at the second peak of the ground reaction force.

SIGNIFICANCE

While static alignment is important to optimize adduction moments during stance it may only partly mitigate excessive moments during gait. The fair correlation and limited percentage of explained variance underscores the importance of dynamic alignment in optimizing the body's dynamic load during walking.

Predicting Prosthetic Mobility at Discharge From Rehabilitation Following Major Amputation in Vascular Surgery

OBJECTIVE

This study aimed to construct a decision aid to estimate the likelihood of independence with a prosthesis following rehabilitation for limb loss secondary to advanced ischaemia (acute or chronic limb threatening ischaemia) or diabetic foot disease (DFD). A secondary aim was to determine whether prosthetic independence is a surrogate marker of long term survival.

METHODS

A retrospective cohort study of a prospectively maintained database of unilateral amputations due to ischaemia or DFD entering rehabilitation between 2007 and 2020 was performed. Predictors of independent prosthetic mobility (IPM) were used in construction of the IPM prediction model, which underwent bootstrap internal and criterion validation through correlation with predictors of other measures of function: Timed Up and Go (TUG) and two minute walk test. Kaplan-Meier and Cox regression analyses were performed to address the secondary aim.

RESULTS

Of the 771 patients included, only 49.9% of amputees achieved IPM. Independent negative predictors of IPM were age > 75 years, female sex, higher amputation level, active malignancy, cerebrovascular disease, end stage renal disease, and cognitive impairment. The model yielded high discrimination (C statistic 0.778), and internal validation was demonstrated with bootstrapping (C statistic 0.778), confirming no over optimism. There was a strong correlation between IPM, TUG, and two minute distance and their predictors, confirming strong criterion validity. The IPM group had a median survival of 93.7 (80.7, 105) months, whereas the non-IPM group fared worse with a median survival of 56.6 (48.5, 66.7) months (p < .001).

CONCLUSION

An internally validated decision aid for estimating the likelihood of independence with a prosthesis after major amputation was constructed. A strong association between female sex and poorer prosthetic mobility was observed. Prosthetic function was shown to be a surrogate marker of long term survival. Future research will involve external validation studies to confirm the generalisability of the decision aid in clinical practice.

Beyond exercise. Can application of manual therapy before exercise benefit a low functioning person with limb loss? A case study

BACKGROUND

Most people with lower-limb loss (PLL) have musculoskeletal conditions and range-of-motion and muscle performance impairments. Such impairments limit potential for functional movement but can be reduced with manual therapy. Manual therapy, however, is rarely used for PLL. This case demonstrated how integrating manual therapy, exercise, and functional training led to lasting benefits for one low functioning PLL.

CASE DESCRIPTION

A 54-year-old woman more than 1 year after transtibial amputation due to peripheral artery disease presented with multiple comorbidities and yellow flags. Her function remained limited to the Medicare K-1 household walking level with slow gait speed <0.25 m/s. Treatment included four weekly sessions each beginning with manual therapy, followed by exercise and functional training.

OUTCOMES

After 1 month, performance-based strength, balance, walking speed, and physical activity increased. She advanced to the K-2 limited community walking level and maintained her functional level without further treatment after 3 months.

DISCUSSION

Improvements maintained without treatment expanded upon research that lacked follow-up and excluded K-1 level walkers. Marked improvement after only four sessions was noteworthy since exercise protocols require ≥4 sessions.

CONCLUSION

Manual therapy followed by exercise and functional training may optimize movement potential and contribute to improving strength, balance, gait, and physical activity among PLL.

Bone density changes after five or more years of unilateral lower extremity osseointegration: Observational cohort study

Context

Rehabilitation following lower extremity amputation presents multiple challenges, many related to the traditional prosthesis (TP) socket. Without skeletal loading, bone density also rapidly decreases. Transcutaneous osseointegration for amputees (TOFA) surgically implants a metal prosthesis attachment directly into the residual bone, facilitating direct skeletal loading. Quality of life and mobility are consistently reported to be significantly superior with TOFA than TP.

Objective

To investigate how femoral neck bone mineral density (BMD, g/cm²) changes for unilateral transfemoral and transtibial amputees at least five years following single-stage press-fit osseointegration.

Methods

Registry review was performed of five transfemoral and four transtibial unilateral amputees who had dual x-ray absorptiometry (DXA) performed preoperatively and after at least five years. The average BMD was compared using Student's t-test (significance p < .05). First, all nine Amputated versus Intact limbs. Second, the five patients with local disuse osteoporosis (ipsilateral femoral neck T-score < -2.5) versus the four whose T-score was greater than -2.5.

Results

The average Amputated Limb BMD was significantly less than the Intact Limb, both Before Osseointegration (0.658 ± 0.150 vs 0.929 ± 0.089, p < .001) and After Osseointegration (0.720 ± 0.096 vs 0.853 ± 0.116, p = .018). The Intact Limb BMD decreased significantly during the study period (0.929 ± 0.089 to 0.853 ± 0.116, p = .020), while the Amputated Limb BMD increased a not statistically significant amount (0.658 ± 0.150 to 0.720 ± 0.096, p = .347). By coincidence, all transfemoral amputees had local disuse osteoporosis (BMD 0.545 ± 0.066), and all transtibial patients did not (BMD 0.800 ± 0.081, p = .003). The local disuse osteoporosis cohort eventually had a greater average BMD (not statistically significant) than the cohort without local disuse osteoporosis (0.739 ± 0.100 vs 0.697 ± 0.101, p = .556).

Conclusions

Single-stage press-fit TOFA may facilitate significant BMD improvement to unilateral lower extremity amputees with local disuse osteoporosis.

Group Lifestyle Balance Adapted for Individuals With Impaired Mobility: Outcomes for 6-Month RCT and Combined Groups at 12 Months

INTRODUCTION

This study examines the feasibility and effectiveness of an intensive lifestyle intervention adapted for people with impaired mobility.

STUDY DESIGN

This was a randomized, wait-list controlled trial. The experimental group immediately received the 12-month weight loss program; the wait-list control group received it after a 6-month delay. Between-group comparisons were conducted for the 6-month RCT study design. Repeated measures were conducted for both groups combined after receiving the 12-month intervention. Data were collected August 2015-February 2017 and analyzed in 2017.

SETTING/PARTICIPANTS

A community-based sample received 23, group-based sessions via a mix of telephone and in-person sessions in a hospital-based setting. Participants with impaired mobility (n=66) were middle-aged (49.80 [SD=11.37] years), mostly White (66.7%), female (66.7%), and most commonly had spinal cord injury (47.0%).

INTERVENTION

The 12-month intervention delivered 23 group-based sessions that promoted weight loss through reducing caloric intake and increasing physical activity.

MAIN OUTCOME MEASURES

Primary outcomes were effectiveness measured as change in weight and time spent in moderate physical activity. Feasibility was assessed in 12-month combined group analyses, measured as retention, attendance, and dietary self-monitoring.

RESULTS

The 6-month RCT results showed that the immediate and delayed groups differed significantly (p<0.05) in weight (-1.66 [SD=4.42] kg loss vs 0.05 [SD=4.15] kg gain) and moderate physical activity (52.93 [SD=90.74] minutes/week increase vs -14.22 [SD=96.02] minutes/week decrease), accounting for baseline weight, time with disability, and age of onset. The 12-month results with groups combined demonstrated 74.2% retention and 77.7% core session attendance. Self-monitoring was higher in the delayed group (77.3%), who used a smartphone app, than the immediate group (47.3%), who mostly used paper trackers. Participants achieved significant 12-month weight loss of 3.31 (SD=10.13) kg (d=0.33) in mixed modeling analyses with groups combined yet did not significantly increase moderate physical activity.

CONCLUSIONS

Group Lifestyle Balance Adapted for Individuals with Impaired Mobility is a feasible, effective approach to teach healthy lifestyle skills to individuals with mobility impairment, yielding modest weight loss and enhanced self-efficacy.

TRIAL REGISTRATION

This study is registered at www.clinicaltrials.gov NCT03307187.

Relevance of medical comorbidities for functional mobility in people with limb loss: retrospective explanatory models for a clinical walking measure and a patient-reported functional outcome

OBJECTIVES

Various modifiable and non-modifiable factors affect functional mobility, but subjective patient-reported and objective performance-based measures are rarely combined in explanatory analyses of functional mobility in people with limb loss. This study determined separate explanatory models for patient-reported function using the Prosthetic Evaluation Questionnaire Mobility Subscale (PEQ-MS), and performance-based 2-Minute Walk Test (2MWT).

DESIGN

Retrospective cross-sectional observational analysis.

SETTING

Wellness-walking program.

PARTICIPANTS

Three hundred five volunteers with lower limb loss participated. Sixty nine percent were men, mean age 56 (15) years. Fifty two percent had vascular amputation causes, 42% had surgical levels above the knee, and 82% had medical comorbidities. Walking levels included limited-household (21%), limited-community (30%), and independent-community (49%). Outcome measures included patient-reported PEQ-MS, Activities-specific Balance Confidence (ABC) and Houghton scales; and performance-based balance and walking.

MAIN OUTCOMES

Separate PEQ-MS and 2MWT multiple regression models fit using backward deletion.

RESULTS

Modifiable (balance ability, ABC, Houghton score; P<0.05) and non-modifiable factors (sex, amputation cause, surgical level; P<0.05) explained the variance in 2MWT (adjusted R²=0.685). Patient-reported and performance-based modifiable factors (Houghton score, 2MWT; P<0.001) explained PEQ-MS variance (adjusted R²=0.660). Integumentary (P=0.022) and cardiopulmonary (P<0.001) comorbidities explained an additional 4% of PEQ-MS variance, while surgical level was insignificant.

CONCLUSIONS

Both modifiable and non-modifiable factors explained prosthetic functional mobility. Performance-based walking was explained by modifiable factors including balance ability and confidence, prosthesis and walking aid use. Patient-reported function was also explained by prosthesis and walking aid use, walking speed and medical comorbidities. Modifiable factors for objective and subjective prosthetic mobility may provide a clinical roadmap for rehabilitation.

Factors associated with committed participation in a wellness-walking program for people with lower limb loss: A prospective cohort study

BACKGROUND:

Wellness activities can benefit health, yet committed adherence is challenging.

OBJECTIVES:

Identify factors associated with committed participation in an amputee wellness-walking program and determine benefits of committed participation.

STUDY DESIGN:

Prospective longitudinal cohort.

METHODS:

Two former Paralympians led the wellness-walking sessions. Participants provided medical history and self-reported balance confidence and prosthetic functional measures. Physiotherapy professionals/paraprofessionals assessed balance and gait. Committed participants-those attending three sessions within 3 years-were compared to one-time-only participants using Fisher's exact and independent t-tests. First and third sessions for committed participants were compared with t-tests. A bootstrapped multivariable logistic regression model was developed using significant univariate predictors.

RESULTS:

A total of 305 volunteers averaged 55.7 ± 15.2 years, including 68.4% men, 78.4% White race; 51.8% with dysvascular amputations, 40.5% with ⩾1 prosthetic knee; and 49.1% independent community walkers. Committed participants were initially similar to one-time-only participants ( p > 0.05) except for fewer years since amputation ( p = 0.007), better balance ability ( p = 0.001), and greater likelihood of dieting ( p = 0.030). The final model-balance ability (odds ratio = 2.4), dieting (odds ratio = 3.3), and years since amputation (odds ratio = 0.94)-identified 88.0% of committed participants ( p = 0.007). Balance confidence and functional improvements after three sessions were not significant ( p > 0.07).

CONCLUSION:

Committed participants were more likely to diet, have better balance ability, and have more recent amputations than one-time-only participants.

CLINICAL RELEVANCE

Knowing which characteristics identify people most likely to become committed participants-such as people with recent amputations, an interest in dieting, and better balance ability-may help health practitioners from different professions promote consistent participation in wellness activities that may benefit self-reported function.