Using Clinical Balance Tests to Assess Fall Risk among Established Unilateral Lower Limb Prosthesis Users: Cutoff Scores and Associated Validity Indices

Vision Is Not Required to Elicit Balance Improvements From Beam Walking Practice

BACKGROUND

Beam walking is a highly studied assessment of walking balance. Recent research has demonstrated that brief intermittent visual rotations and occlusions can increase the efficacy of beam walking practice on subsequent beam walking without visual perturbations. We sought to examine the influence of full vision removal during practice walking on a treadmill-mounted balance beam. Although visual disruptions improved performance of this task, we hypothesized that removing visual feedback completely would lead to less balance improvements than with normal vision due to the specificity of practice.

METHODS

Twenty healthy young adults trained to walk at a fixed speed on a treadmill-mounted balance beam for 30 min, either with, or without, normal vision. We compared their balance pre-, during, and posttraining by calculating their step-offs per minute and the percentage change in step-offs per minute.

RESULTS

Balance improved in both groups after training, with no significant difference in percentage change in step-offs between the normal vision and the no vision participants. On average, the no vision participants had twice as many step-offs per minute as the normal vision group during training.

CONCLUSION

Although previous experiments show that intermittent visual perturbations led to large enhancements of the effectiveness of beam walking training, completely removing visual feedback did not alter training effectiveness compared with normal vision training. It is likely a result of sensory reweighting in the absence of vision, where a greater weight was placed on proprioceptive, cutaneous, and vestibular inputs.

Validating a fear-of-falling-related activity avoidance scale in lower limb prosthesis users

BACKGROUND

Limited available data suggest that fear of falling (FoF) may be common among lower limb prosthesis users (LLPUs) and associated with negative rehabilitation outcomes. The impact of FoF on outcomes may be exacerbated when fear leads to self-imposed declines in activity. There is a need to identify the validity of fear-of-falling-related activity avoidance scales in LLPUs.

OBJECTIVE

To evaluate the convergent, discriminant, and known-group construct validity of the modified Survey of Activities and FoF in the Elderly (mSAFE) for LLPUs. Secondarily, we sought to determine if the mSAFE scale could be reduced without losing information regarding construct validity.

DESIGN

Online survey.

SETTING

Not applicable.

PARTICIPANTS

Fifty-nine persons with unilateral or bilateral amputation at the transtibial or transfemoral level, with ≥6 months experience using a definitive prosthesis for activities other than transfers.

INTERVENTION

Participants completed an online survey that consisted of the mSAFE and questions to assess FoF (yes/no), fear-of-falling-related activity avoidance (yes/no), as well as previously validated scales capturing related and unrelated constructs. T-tests were used to compare mSAFE score between yes/no respondents for known-group construct validity. Correlations between mSAFE and previously validated surveys assessed convergent and discriminant validity. Analyses were repeated on a reduced number of mSAFE items following a redundancy analysis.

MAIN OUTCOME MEASURES

Not applicable.

RESULTS

Significant correlation coefficients of |0.440-0.825| were found for convergent validity with evidence of known-group construct validity (p < .021 for all comparisons). There was evidence for discriminant validity, with non-significant associations for two-of-three correlations. Results from validity analyses for a shortened 6-item mSAFE were similar to that for the full scale.

CONCLUSION

This study provided initial evidence regarding validity of the mSAFE as a measure to assess fear-of-falling-related activity avoidance in LLPUs. A 6-item scale may be appropriate if the full scale would be taxing or time-consuming.

Investigation of the validity and reliability of the 3-meter backward walk test in high functional level adults with lower limb amputation

BACKGROUND

Backward walk training has an important place in the rehabilitation programs of lower extremity amputees.

OBJECTIVE

This study aimed to investigate the test-retest validity and reliability of the 3-meter backward walk test (3MBWT), minimal detectable change, and the cutoff time in high functional level adults with lower limb amputations (LLAs). Adults with LLA (n = 30) and healthy adults (n = 29) were included in the study.

STUDY DESIGN

This is a randomized cross-sectional study.

METHODS

The Modified Fall Efficacy Score, Rivermead Mobility Index, and Timed Up and Go test with the 3MBWT were used to evaluate the concurrent validity of the test. The second evaluation (retest) was performed by the same physiotherapist 1 week following the first evaluation (test). The validity was assessed by correlating the 3MBWT times with the scores of other measures and by comparing the 3MBWT times between adults with LLA and healthy adults.

RESULTS

Test-retest reliability of the 3MBWT was excellent. The intraclass correlation coefficient for the 3MBWT was 0.950. The standard error of measurement and minimal detectable change values were 0.38 and 0.53, respectively. A moderate correlation was found between the 3MBWT, Modified Fall Efficacy Score, Timed Up and Go test, and Rivermead Mobility Index ( p < 0.001). Significant differences in the 3MBWT times were found between adults with LLA and healthy controls ( p < 0.001). The cutoff time of 3.11 s discriminates healthy adults from high functional level adults with LLA.

CONCLUSIONS

The 3MBWT was determined to be valid, reliable, and easy-to-apply tool in high functional level adults with LLA. This assessment is a useful and practical measurement for dynamic balance in high functional level adults with LLA.

Falls perceived as significant by lower limb prosthesis users are generally associated with fall consequences rather than circumstances

PURPOSE

To determine if falls perceived as significant by lower limb prosthesis (LLP) users were associated with fall circumstances and/or consequences.

MATERIALS AND METHODS

The circumstances and consequences of LLP users' most significant fall in the past 12-months were collected using the Lower Limb Prosthesis User Fall Event Survey. Participants rated fall significance from 0 (not significant) to 10 (extremely significant), which was then dichotomized into "low" and "high". Binary logistic regression was used to assess associations between fall significance and fall circumstances and consequences.

RESULTS

Ninety-eight participants were included in the analysis. Five fall consequences were associated with greater significance: major injury (OR = 26.7, 95% CI: 1.6-459.6, p = 0.024), need to seek medical treatment (OR = 19.0, 95% CI: 1.1-329.8, p = 0.043), or allied-health treatment (OR = 18.2, 95% CI: 2.3-142.4, p = 0.006), decreased balance confidence (OR = 10.9, 95% CI: 2.4-49.3, p = 0.002), and increased fear of falling (OR = 7.5, 95% CI: 2.4-23.8, p = 0.001), compared to two fall circumstances: impact to the arm (OR = 5.0, 95% CI: 2.0-12.1, p = 0.001), and impact to the face, head, or neck (OR = 9.7, 95% CI: 1.2-77.4, p = 0.032).

CONCLUSIONS

Significant falls were generally more associated with fall consequence than fall circumstances.

Association of Race, Ethnicity, and Gender to Disparities in Functional Recovery and Social Health After Major Lower Limb Amputation: A Cross-sectional Pilot Study

OBJECTIVE

To assess if evidence of disparities exists in functional recovery and social health post-lower limb amputation.

DESIGN

Race-ethnicity, gender, and income-based group comparisons of functioning and social health in a convenience sample of lower limb prosthetic users.

SETTING

Prosthetic clinics in 4 states.

PARTICIPANTS

A geographically diverse cohort of 56 English and Spanish speaking community-dwelling individuals with dysvascular lower limb amputation, between 18-80 years old.

INTERVENTIONS

None.

MAIN OUTCOMES MEASURES

Primary outcomes included 2 physical performance measures, the Timed Up and Go test and 2-minute walk test, and thirdly, the Prosthetic Limb Users Survey of Mobility. The PROMIS Ability to Participate in Social Roles and Activities survey measured social health.

RESULTS

Of the study participants, 45% identified as persons of color, and 39% were women (mean ± SD age, 61.6 (9.8) years). People identifying as non-Hispanic White men exhibited better physical performance than men of color, White women, and women of color by -7.86 (95% CI, -16.26 to 0.53, P=.07), -10.34 (95% CI, -19.23 to -1.45, P=.02), and -11.63 (95% CI, -21.61 to -1.66, P=.02) seconds, respectively, on the TUG, and by 22.6 (95% CI, -2.31 to 47.50, P=.09), 38.92 (95% CI, 12.53 to 65.30, P<.01), 47.53 (95% CI, 17.93 to 77.13, P<.01) meters, respectively, on the 2-minute walk test. Income level explained 14% and 11% of the variance in perceived mobility and social health measures, respectively.

CONCLUSIONS

Study results suggest that sociodemographic factors of race-ethnicity, gender, and income level are associated with functioning and social health post-lower limb amputation. The clinical effect of this new knowledge lies in what it offers to health care practitioners who treat this patient population, in recognizing potential barriers to optimal recovery and quality of life. More work is required to assess lived experiences after amputation and provide better understanding of amputation-related health disparities.

Quantitative methods used to evaluate balance, postural control, and the fear of falling in lower limb prosthesis users: A systematic review

Problems with balance, postural control, and fear of falling are highly prevalent in lower limb prosthesis users, with much research conducted to understand these issues. The variety of tools used to assess these concepts presents a challenge when interpreting research outcomes. This systematic review aimed to provide a synthesis of quantifiable methods used in the evaluation of balance, postural control, and fear of falling in lower limb prosthesis users with an amputation level at or proximal to the ankle joint. A systematic search was conducted in CINAHL, Medline, AMED, Cochrane, AgeLine, Scopus, Web of Science, Proquest, PsycINFO, PsycArticles, and PubPsych databases followed by additional manual searching via reference lists in the reviewed articles databases. Included articles used quantitative measure of balance or postural control as one of the dependent variables, lower limb prosthesis users as a sample group, and were published in a peer-reviewed journal in English. Relevant assessment questions were created by the investigators to rate the assessment methods used in the individual studies. Descriptive and summary statistics are used to synthesize the results. The search yielded (n = 187) articles assessing balance or postural control (n = 5487 persons in total) and (n = 66) articles assessing fear of falling or balance confidence (n = 7325 persons in total). The most used test to measure balance was the Berg Balance Scale and the most used test to measure fear of falling was the Activities-specific Balance Confidence scale. A large number of studies did not present if the chosen methods were valid and reliable for the lower limb prosthesis users. Among study limitations, small sample size was common.

Prevalence of physical health comorbidities and long-term functional outcomes among community-reintegrated veterans following lower limb amputation in Sri Lanka

INTRODUCTION

Lower limb amputation (LLA) poses significant health challenges, including physical health comorbidities (PHCs) and functional limitations. Military veterans, who typically undergo traumatic LLA at a young age, endure these challenges for an extended period. Understanding the extent of these challenges is vital to designing tailored and feasible postamputation care for them. In this study, we evaluated the prevalence of PHCs and long-term functional outcomes among community-reintegrated veterans following LLA in Sri Lanka.

METHODS

A comparative cross-sectional study was conducted in five districts in Sri Lanka. Prevalence of PHCs and functional outcomes were compared between community-reintegrated veterans with war-related traumatic LLA and a matched able-bodied cohort. Data on PHCs were collected from participants' medical records and through a self-administered questionnaire. Timed-Up-and-Go (TUG) and 2 min walk test (2MWT) were used to compare functional outcomes between the groups. Veterans' functional level was identified using the K-level classification.

RESULTS

Veterans were active prosthetic users who had undergone LLA >10 years ago. Sixty-six (77.6%) veterans reported experiencing phantom limb pain. A significantly higher prevalence of diabetes mellitus (34.2%), hypertension (22.4%), knee osteoarthritis (18.8%), knee pain (20%) and back pain (69.4%) was observed among veterans compared with the able-bodied group (p<0.05). Veterans demonstrated significantly lower levels of functional mobility (2MWT: mean (SD): 113.6 (14.8); increased risk of falling (TUG): mean (SD): 10.6 (1.8)) compared with able-bodied individuals (150.8 (11.9) and 7.2 (0.9), respectively, p<0.001). The majority of the veterans belonged to the K3 functional level (71.8%).

CONCLUSIONS

The higher prevalence of PHCs and impaired functional outcomes underscores the multifaceted health challenges faced by veterans with LLA living in low-resource community settings with limited access to rehabilitation. These findings provide insights into the unique rehabilitation needs of individuals with similar backgrounds, informing the design and implementation of tailored rehabilitation interventions.

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.

Clinimetrics of performance-based functional outcome measures for vascular amputees: A systematic review

BACKGROUND

Objective physical performance-based outcome measures (PerBOMs) are essential tools for the holistic management of people who have had an amputation due to vascular disease. These people are often non-ambulatory, however it is currently unclear which PerBOMs are high quality and appropriate for those who are either ambulatory or non-ambulatory.

RESEARCH QUESTION

Which PerBOMs have appropriate clinimetric properties to be recommended for those who have had amputations due to vascular disease ('vascular amputee')?

DATA SOURCES

MEDLINE, CINAHL, EMBASE, EMCARE, the Cochrane Library, Cochrane Central Register of Controlled Trials (CENTRAL) and Scopus databases were searched for the terms: "physical performance" or "function", "clinimetric properties", "reliability", "validity", "amputee" and "peripheral vascular disease" or "diabetes".

REVIEW METHODS

A systematic review of PerBOMs for vascular amputees was performed following COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) methodology and PRISMA guidelines. The quality of studies and individual PerBOMs was assessed using COSMIN risk of bias and good measurement properties. Overall PerBOM quality was evaluated with a modified GRADE rating. Key clinimetric properties evaluated were reliability, validity, predictive validity and responsiveness.

RESULTS

A total of 15,259 records were screened. Forty-eight studies (2650 participants) were included: 7 exclusively included vascular amputees only, 35 investigated validity, 20 studied predictive validity, 23 investigated reliability or internal consistency and 7 assessed responsiveness. Meta-analysis was neither possible nor appropriate for this systematic review in accordance with COSMIN guidelines, due to heterogeneity of the data. Thirty-four different PerBOMs were identified of which only 4 are suitable for non-ambulatory vascular amputees. The Amputee Mobility Predictor no Prosthesis (AMPnoPro) and Transfemoral Fitting Predictor (TFP) predict prosthesis use only. PerBOMs available for assessing physical performance are the One-Leg Balance Test (OLBT) and Basic Amputee Mobility Score (BAMS).

CONCLUSION

At present, few PerBOMs can be recommended for vascular amputees. Only 4 are available for non-ambulatory individuals: AMPnoPro, TFP, OLBT and BAMS.

A single-subject comparison of functional outcomes between lower limb salvage vs. transtibial amputation through sequential participation in a fall-prevention program

PURPOSE

Prior research has noted similar functional and subjective outcomes between individuals with delayed amputation vs. limb salvage; however, these reports are generally retrospective in nature. Here, we prospectively compare functional and subjective outcomes from an individual with limb salvage to a delayed transtibial amputation using a single-subject design with sequential participation in a fall-prevention program.

MATERIALS AND METHODS

The subject participated in a fall-prevention rehabilitation training program, once before undergoing a delayed transtibial amputation and again after. As part of the fall-prevention program, the participant completed pretraining and post-training assessments which quantified trunk control by 1) trunk flexion and flexion velocity after trip-inducing perturbations on a treadmill and 2) trunk sway parameters during unstable sitting. In addition, the four square step test was administered, and patient-reported outcomes, including pain, prosthetic/orthotic comfort, and walking/running endurance, were collected.

RESULTS

In general, the participant demonstrated improved trunk control after amputation, as evidenced by decreases in trunk flexion and flexion velocity after perturbation and sway parameters during unstable sitting. In addition, four square step test times were shorter with amputation vs. limb salvage; the participant also reported reduced pain and greater comfort with amputation (vs. limb salvage).

CONCLUSIONS

Although just a single participant, within-subject comparisons provide quantitative evidence that, for some individuals, delayed/late (transtibial) amputation after prolonged limb salvage may be beneficial in reducing pain and restoring function.

Common fall-risk indicators are not associated with fall prevalence in a high-functioning military population with lower limb trauma

BACKGROUND

Persons with lower limb trauma are at high risk for falls. Although there is a wide range of measures used to assess stability and fall-risk that include performance measures, temporal-spatial gait parameters, and nonlinear dynamic stability calculations, these measures are typically derived from fall-prone populations, such as older adults. Thus, it is unclear if these commonly used fall-risk indicators are effective at evaluating fall-risk in a younger, higher-functioning population of Service members with lower limb trauma.

METHODS

Twenty-one Service members with lower limb trauma completed a battery of fall-risk assessments that included performance measures (e.g., four-square-step-test), and gait parameters (e.g., step width, step length, step time) and dynamic stability measures (e.g., local divergence exponents) during 10 min of treadmill walking. Participants also reported the number of stumbles and falls over the previous 4 weeks. Negative Binomial and Quasibinomial Regressions were used to evaluate the strength of associations between fall-risk indicators and self-reported falls.

FINDING

Participants reported on average stumbling 6(4) times and falling 2(3) times in the previous 4 weeks. At least one fall was reported by 62% of the participants. None of the fall-risk indicators were significantly associated with fall prevalence in this population of Service members with lower limb trauma (p > 0.1).

INTERPRETATION

Despite the high number of reported falls in this young active population, none of the fall-risk indicators investigated effectively captured and quantified the fall-risk. Further research is needed to identify appropriate fall-risk assessments for young, high-functioning individuals with lower limb trauma.

Using theoretical frameworks to examine fall history and associated prosthetic mobility in people with nondysvascular lower limb amputation

BACKGROUND

Over a million people live with lower limb amputation (LLA) in the United States, and many of them will experience a fall in the next year. The aim of this study was to use existing theoretical frameworks in an attempt to organize the complex interactions of reported fall history and prosthetic mobility in community-ambulating people with LLA.

METHODS

Self-reported fall rate and fall circumstances were recorded in a cross-section of people with unilateral LLA due to nondysvascular causes. Self-report and performance-based standardized outcome measures assessed prosthetic mobility and balance confidence. All variables were considered and appropriately placed within a proposed International Classification of Functioning, Disability, and Health framework while using a fall-type classification framework to classify fall circumstances.

RESULTS

Information from 69 participants was analyzed. The reported fall rate was at 46%, with those with transfemoral amputation reporting significantly more falls than those with transtibial amputation ( P = 0.001). Tripping over an object was the most common cause (62.5%), and fallers reported significantly lower perceived prosthetic mobility than nonfallers ( P = 0.001). Despite reporting high levels of balance confidence, results indicate that all groups of fallers and nonfallers are at increased fall risk according to performance-based prosthetic mobility score cutoffs.

CONCLUSIONS

Community-dwelling people with nondysvascular LLA are at increased fall risk. Classifying fall-related variables using theoretical frameworks provides a means to structure more informative fall risk surveys for people with LLA in an attempt to identify those at greater risk for falling and its potential detrimental effects.

Artificial referred sensation in upper and lower limb prosthesis users: a systematic review

Objective.Electrical stimulation can induce sensation in the phantom limb of individuals with amputation. It is difficult to generalize existing findings as there are many approaches to delivering stimulation and to assessing the characteristics and benefits of sensation. Therefore, the goal of this systematic review was to explore the stimulation parameters that effectively elicited referred sensation, the qualities of elicited sensation, and how the utility of referred sensation was assessed.Approach.We searched PubMed, Web of Science, and Engineering Village through January of 2022 to identify relevant papers. We included papers which electrically induced referred sensation in individuals with limb loss and excluded papers that did not contain stimulation parameters or outcome measures pertaining to stimulation. We extracted information on participant demographics, stimulation approaches, and participant outcomes.Main results.After applying exclusion criteria, 49 papers were included covering nine stimulation methods. Amplitude was the most commonly adjusted parameter (n= 25), followed by frequency (n= 22), and pulse width (n= 15). Of the 63 reports of sensation quality, most reported feelings of pressure (n= 52), paresthesia (n= 48), or vibration (n= 40) while less than half (n= 29) reported a sense of position or movement. Most papers evaluated the functional benefits of sensation (n= 33) using force matching or object identification tasks, while fewer papers quantified subjective measures (n= 16) such as pain or embodiment. Only 15 studies (36%) observed percept intensity, quality, or location over multiple sessions.Significance.Most studies that measured functional performance demonstrated some benefit to providing participants with sensory feedback. However, few studies could experimentally manipulate sensation location or quality. Direct comparisons between studies were limited by variability in methodologies and outcome measures. As such, we offer recommendations to aid in more standardized reporting for future research.

Disparities in functional recovery after dysvascular lower limb amputation are associated with employment status and self-efficacy

PURPOSE

Employment status is considered a determinant of health, yet returning to work is frequently a challenge after lower limb amputation. No studies have documented if working after lower limb amputation is associated with functional recovery. The study's purpose was to examine the influence of full-time employment on functioning after lower limb amputation.

METHODS

Multisite, cross-sectional study of 49 people with dysvascular lower limb amputation. Outcomes of interest included performance-based measures, the Component Timed-Up-and-Go test, the 2-min walk test, and self-reported measures of prosthetic mobility and activity participation.

RESULTS

Average participant age was 62.1 ± 9.7 years, 39% were female and 45% were persons of color. Results indicated that 80% of participants were not employed full-time. Accounting for age, people lacking full-time employment exhibited significantly poorer outcomes of mobility and activity participation. Per regression analyses, primary contributors to better prosthetic mobility were working full-time (R² ranging from 0.06 to 0.24) and greater self-efficacy (R² ranging from 0.32 to 0.75).

CONCLUSIONS

This study offers novel evidence of associations between employment and performance-based mobility outcomes after dysvascular lower limb amputation. Further research is required to determine cause-effect directionalities. These results provide the foundation for future patient-centered research into how work affects outcomes after lower limb amputation. IMPLICATIONS FOR REHABILITATIONLower limb amputation can pose barriers to employment and activity participation, potentially affecting the quality of life.This study found that the majority of people living with lower limb amputation due to dysvascular causes were not employed full-time and were exhibiting poorer prosthetic outcomes.Healthcare practitioners should consider the modifiable variable of employment when evaluating factors that may affect prosthetic mobility.The modifiable variable of self-efficacy should be assessed by healthcare professionals when evaluating factors that may affect prosthetic mobility.

Recalled Number of Falls in the Past Year-Combined With Perceived Mobility-Predicts the Incidence of Future Falls in Unilateral Lower Limb Prosthesis Users

OBJECTIVE

Falls are a frequent and costly concern for lower limb prosthesis (LLP) users. At present, there are no models that clinicians can use to predict the incidence of future falls in LLP users. Assessing who is at risk for falls, therefore, remains a challenge. The purpose of this study was to test whether easily accessible clinical attributes and measurements predict the incidence of future falls in LLP users.

METHODS

In this prospective observational study, a secondary analysis of data from 60 LLP users was conducted. LLP users reported the number of falls that they recalled over the past year before prospectively reporting falls over a 6-month observation period via monthly telephone calls. Additional candidate predictor variables were recorded at baseline. Negative binomial regression was used to develop a model intended to predict the incidence of future falls.

RESULTS

The final model, which included the number of recalled falls (incidence rate ratio = 1.13; 95% CI = 1.01 to 1.28) and Prosthetic Limb Users Survey of Mobility T-scores (incidence rate ratio = 0.949; 95% CI = 0.90 to 1.01), was significantly better than a null model at predicting the number of falls over the next 6 months (χ22 = 9.76) and fit the observed prospective fall count data (χ256 = 54.78).

CONCLUSION

The number of recalled falls and Prosthetic Limb Users Survey of Mobility T-scores predicted the incidence of falls over the next 6 months in established, unilateral LLP users. The success and simplicity of the final model suggests that it may serve as a screening tool for clinicians to use for assessing risk of falls. Additional research to validate the proposed model in an independent sample of LLP users is needed.

IMPACT

Owing to its simplicity, the final model may serve as a suitable screening measure for clinicians to ascertain an initial evaluation of fall risk in established unilateral LLP users. Analyzing falls data as counts rather than as a categorical variable may be an important methodological consideration for falls prevention research.

Using a microprocessor knee (C-Leg) with appropriate foot transitioned individuals with dysvascular transfemoral amputations to higher performance levels: a longitudinal randomized clinical trial

Background

Individuals with transfemoral amputations who are considered to be limited community ambulators are classified as Medicare functional classification (MFCL) level K2. These individuals are usually prescribed a non-microprocessor controlled knee (NMPK) with an appropriate foot for simple walking functions. However, existing research suggests that these individuals can benefit from using a microprocessor controlled knee (MPK) and appropriate foot for their ambulation, but cannot obtain one due to insurance policy restrictions. With a steady increase in older adults with amputations due to vascular conditions, it is critical to evaluate whether advanced prostheses can provide better safety and performance capabilities to maintain and improve quality of life in individuals who are predominantly designated MFCL level K2. To decipher this we conducted a 13 month longitudinal clinical trial to determine the benefits of using a C-Leg and 1M10 foot in individuals at K2 level with transfemoral amputation due to vascular disease. This longitudinal clinical trial incorporated recommendations prescribed by the lower limb prosthesis workgroup to design a study that can add evidence to improve reimbursement policy through clinical outcomes using an MPK in K2 level individuals with transfemoral amputation who were using an NMPK for everyday use.

Methods

Ten individuals (mean age: 63 ± 9 years) with unilateral transfemoral amputation due to vascular conditions designated as MFCL K2 participated in this longitudinal crossover randomized clinical trial. Baseline outcomes were collected with their current prosthesis. Participants were then randomized to one of two groups, either an intervention with the MPK with a standardized 1M10 foot or their predicate NMPK with a standardized 1M10 foot. On completion of the first intervention, participants crossed over to the next group to complete the study. Each intervention lasted for 6 months (3 months of acclimation and 3 months of take-home trial to monitor home use). At the end of each intervention, clinical outcomes and self-reported outcomes were collected to compare with their baseline performance. A generalized linear model ANOVA was used to compare the performance of each intervention with respect to their own baseline.

Results

Statistically significant and clinically meaningful improvements were observed in gait performance, safety, and participant-reported measures when using the MPK C-Leg + 1M10 foot. Most participants were able to achieve higher clinical scores in gait speed, balance, self-reported mobility, and fall safety, while using the MPK + 1M10 combination. The improvement in scores were within range of scores achieved by individuals with K3 functional level as reported in previous studies.

Conclusions

Individuals with transfemoral amputation from dysvascular conditions designated MFCL level K2 benefited from using an MPK + appropriate foot. The inference and evidence from this longitudinal clinical trial will add to the knowledgebase related to reimbursement policy-making.

Trial registration This study is registered on clinical trials.gov with the study title “Functional outcomes in dysvascular transfemoral amputees” and the associated ClinicalTrials.gov Identifier: NCT01537211. The trial was retroactively registered on February 7, 2012 after the first participant was enrolled.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12984-021-00879-3.

Performance-based balance tests, combined with the number of falls recalled in the past year, predicts the incidence of future falls in established unilateral transtibial prosthesis users

BACKGROUND

Falls are common and consequential events for lower limb prosthesis (LLP) users. Currently, there are no models based on prospective falls data that clinicians can use to predict the incidence of future falls in LLP users. Assessing who is at risk for falls, and thus most likely to need and benefit from intervention, remains a challenge.

OBJECTIVE

To determine whether select performance-based balance tests predict future falls in established, unilateral transtibial prosthesis users (TTPU).

DESIGN

Multisite prospective observational study.

SETTING

Research laboratory and prosthetics clinic.

PARTICIPANTS

Forty-five established, unilateral TTPU.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

The number of falls reported over a prospective 6-month period. Timed Up-and-Go (TUG) and Four-Square Step Test (FSST) times, as well as Narrowing Beam Walking Test scores were recorded at baseline, along with the number of falls recalled over the past 12 months and additional potential fall-risk factors.

RESULTS

The final negative binomial regression model, which included TUG (P = .044) and FSST (P = .159) times, as well as the number of recalled falls (P = .009), was significantly better than a null model at predicting the number of falls over the next 6 months (X² [3] = 11.6, P = .009) and fit the observed fall count data (X² [41] = 36.12, P = .20). The final model provided a significant improvement in fit to the prospective fall count data over a model with fall recall alone X² (1) = 4.342, P < .05.

CONCLUSION

No combination of performance-based balance tests alone predicted the incidence of future falls in our sample of established, unilateral TTPU. Rather, a combination of the number of falls recalled over the past 12 months, along with TUG and FSST times, but not NBWT scores, was required to predict the number of "all-cause" falls over the next 6 months. The resulting predictive model may serve as a suitable method for clinicians to predict the incidence of falls in established, unilateral TTPU.

Falls After Dysvascular Transtibial Amputation: A Secondary Analysis of Falling Characteristics and Reduced Physical Performance

INTRODUCTION

Over half of all people with lower limb amputation (LLA) experience at least one fall annually. Furthermore, the majority of LLAs result from dysvascular health complications, contributing to balance deficits. However, fall-related research specific to dysvascular LLA remains limited.

OBJECTIVE

To characterize falls among adults with dysvascular LLA, using an existing Fall-Type Classification Framework and to describe the functional characteristics of participants across the framework categories.

DESIGN

Secondary data analysis from two randomized controlled trials.

SETTING

Outpatient setting.

PARTICIPANTS

People (n = 69) 6 months to 5 years from dysvascular lower extremity amputation, who were ≥50 years of age and independently ambulatory using a prosthesis.

INTERVENTION

None.

OUTCOME

Descriptions of self-reported falls were collected on a weekly basis for 12 weeks, and analyzed using an existing Fall-Type Classification Framework. Fall frequencies, estimated count, and estimated proportions were compared across all framework categories, with 95% confidence intervals. Functional measures (Timed Up and Go, Two Minute Walk, Five Meter Walk, and average step count) were collected, and averages for each participant who experienced a fall were calculated.

RESULTS

Thirty participants (43.5%) reported 42 falls within 12 weeks. A variety of fall types were described. Incidence of falls was highest for intrinsic destabilization sources, from incorrect weight shift patterns during transfer activities.

CONCLUSION

Patients with dysvascular LLAs experience a variety of fall types. The high frequency of intrinsically sourced, incorrect weight-shift falls during transfer activities emphasizes the need to focus rehabilitation efforts on improving postural control in patients with dysvascular LLAs during activities such as reaching, turning, and transferring.

Current and Emerging Trends in the Management of Fall Risk in People with Lower Limb Amputation

Purpose of Review

People living with lower limb amputation are at an increased risk of falling compared with the healthy geriatric population. Factors of increased age and increased number of comorbidities could compound the already increased risk. The purpose of this article is to highlight recent research associated with fall risk in amputees and provide the reader with evidence to help guide clinical interventions.

Recent Findings

Though research on the topic of falls in people with amputation is becoming more common, there is still a dearth of evidence regarding what contributes to increased fall risk and how to address it in this population. There are recent studies that have examined therapy and prosthetic interventions that could mitigate fall risk in people with amputation, yet there is not enough evidence to develop a consensus on the topic. More research is required to determine what contributes to increased fall rates in people with amputation, and what detriments to an amputee's function or psyche may result after incurring a fall.

Summary

Borrowing from what is known about geriatric fall risk and combining the information with novel and existing approaches to fall mitigation in amputees can offer clinicians the opportunity to develop evidence-based programs to address fall risk in their patients with lower limb amputation.

Interrater and Test-Retest Reliability of Performance-Based Clinical Tests Administered to Established Users of Lower Limb Prostheses

OBJECTIVE

A major barrier to reducing falls among users of lower limb prostheses (LLP) has been an absence of statistical indices required for clinicians to select and interpret scores from performance-based clinical tests. The study aimed to derive estimates of reliability, measurement error, and minimal detectable change values in performance-based clinical tests administered to unilateral LLP users.

METHODS

A total of 60 unilateral LLP users were administered the Narrowing Beam Walking Test, Timed ``Up and Go'' (TUG), Four Square Step Test (FSST), and 10-Meter Walk Test on 2 occasions, 3 to 9 days apart. Intraclass correlation coefficients (ICCs) were calculated to assess interrater and test-retest reliability, while standard error of measurement (SEM) and minimal detectable change (MDC90) were derived to establish estimates of measurement error in individual scores or changes in score for each test.

RESULTS

Interrater reliability ICCs (1,1) were high for all tests (ie, ≥0.98). Test-retest ICCs (2,1) varied by test, ranging from .88 for the TUG to .97 for the FSST. SEM and MDC90 varied between .39 and .96 and between .91 seconds and 2.2 seconds for the time-based tests (FSST, TUG, 10-Meter Walk Test). SEM and MDC90 for the Narrowing Beam Walking Test were .07 and .16, respectively.

CONCLUSION

With the exception of the TUG, studied tests had test-retest ICCs (2,1) that exceeded the minimum required threshold to be considered suitable for group- and individual-level applications (ie, ICC ≥ 0.70 and ≥ 0.90, respectively). Future research on individuals with dysvascular and transfemoral amputations or in specific age categories is required.

IMPACT

Along with published validity indices, these reliability, error, and change indices can help clinicians select balance tests suitable for LLP users. They can also help clinicians interpret test scores to make informed, evidence-based clinical decisions.