Reliability, Validity, and Responsiveness of Clinical Performance-Based Outcome Measures of Walking for Individuals With Lower Limb Amputations: A Systematic Review

Categorization and recommendations for outcome measures for lower limb absence by an expert panel

BACKGROUND

Understanding the psychometric strengths and limitations of outcome measures for use with people with lower limb absence (LLA) is important for selecting measures suited to evaluating patient outcomes, answering clinical and research questions, and informing health care policy. The aim of this project was to review the current psychometric evidence on outcome measures in people with LLA to determine which measures should be included in a stakeholder consensus process.

METHODS

An expert panel was assembled, and a 3-stage review process was used to categorize outcome measures identified in a systematic literature review into 3 distinct categories (recommended for measures with better than adequate psychometric properties; recommended with qualification; and unable to recommend). Panelists were asked to individually categorize measures based on results of a systematic review of identified measures' psychometric properties. Each measure's final categorization was based on ≥70% agreement by all panelists.

RESULTS

No outcome measure attained the ≥70% consensus threshold needed to achieve a rating of "recommend." Hence, panelists suggested combining "recommend" and "recommend with qualifications" into a single category of "recommend with qualifications." Using this approach, consensus was reached for 59 of 60 measures. Consensus could not be reached on 1 outcome measure (socket comfort score). Thirty-six outcome measures were categorized as "unable to recommend" based on available evidence; however, 23 (12 patient-reported measures and 11 performance-based measures) demonstrated adequate psychometric properties in LLA samples and were thus rated as "recommend with qualification" by the expert panel. The panel of experts were able to recommend 23 measures for inclusion in the subsequent stakeholder review. A key strength of this process was bringing together international researchers with extensive experience in developing and/or using LLA outcome measures who could assist in identifying psychometrically sound measures to include in a subsequent stakeholder consensus process.

CONCLUSION

The above categorizations represent the current state of psychometric evidence on outcome measures for people with LLA and hence may change over time as additional research becomes available. The results will be used to achieve wider consensus from clinicians, health policymakers, health clinic managers, researchers, and end users (i.e., individuals with LLA) on outcome measures for the International Society of Prosthetics and Orthotics lower limb Consensus Outcome Measures for Prosthetic and Amputation ServiceS.

The Moment Criterion of Anthropomorphicity of Prosthetic Feet as a Potential Predictor of Their Functionality for Transtibial Amputees

The purpose of this paper is to discuss a new quantitative mechanical parameter of prosthetic feet called the Index of Anthropomorphicity (IA), which has the potential to be adopted as an objective predictor of their functionality. The objectives are to present the research findings supporting the introduction of IA and unify previous results into a coherent theory. The IA is founded on the moment criterion of the anthropomorphicity of prosthetic feet. The term "anthropomorphicity" is defined for this application. Studies with a small number of human subjects and prostheses have shown that the value of the parameter is positively correlated with patient comfort and with the restoration of certain normal gait characteristics. Confirmatory studies with controlled human trials and mechanical tests with a wider selection of prosthesis types can give prosthesis manufacturers a new criterion to follow in the design process, and prosthetists may use the IA for selecting more suitable prostheses for a patient's comfort and health.

[Objective measurement tools that predict success in the fitting of major unilateral lower limb amputations patients]

The profile of the patient who most frequently suffers lower limb amputations is usually an elderly patient with high comorbidity. Physiatrists need objective tools in the assessment of these patients that predict the results of prosthetic programs to increase patient safety and efficiency of prosthetic rehabilitation programs. Given the need to update scientific knowledge in this field, we have carried out a review of the literature with the aim of defining a proposal for tools that facilitate decision-making in the indication of prosthetic rehabilitation in these patients. A bibliographic search strategy has been carried out using the scientific databases PubMed, Web of Science, Scopus and Cochrane Library. The quality of the selected articles has been assessed according to the tools proposed by CASPe.

Performance-based outcome measures are associated with cadence variability during community ambulation among individuals with a transtibial amputation

BACKGROUND

In the United States, Medicare Functional Classification Level (K-level) guidelines require demonstration of cadence variability to justify higher-level prosthetic componentry prescription; however, clinical assessment of cadence variability is subjective. Currently, no clinical outcome measures are associated with cadence variability during community ambulation.

OBJECTIVES

Evaluate whether physical performance, i.e. 10-meter Walk Test (10mWT)-based walking speeds, L-Test, and Figure-of-8 Walk Test scores, is associated with community-based cadence variability among individuals with a transtibial amputation.

STUDY DESIGN

Cross-sectional.

METHODS

Forty-nine participants, aged 18-85 years, with a unilateral transtibial amputation were included. Linear regression models were conducted to determine whether physical performance was associated with cadence variability (a unitless calculation from FitBit® One^TM minute-by-minute step counts), while controlling for sex, age, and time since amputation (p ⩽ .013).

RESULTS

Beyond covariates, self-selected gait speed explained the greatest amount of variance in cadence variability (19.2%, p < .001). Other outcome measures explained smaller, but significant, amounts of the variance (11.1-17.1%, p = .001-.008). For each 0.1 m/s-increase in self-selected and fast gait speeds, or each 1-s decrease in L-Test and F8WT time, community-based cadence variability increased by 1.76, 1.07, 0.39, and 0.79, respectively (p < .013).

CONCLUSIONS

In clinical settings, faster self-selected gait speed best predicted increased cadence variability during community ambulation.

CLINICAL RELEVANCE

The 10-meter Walk Test may be prioritized during prosthetic evaluations to provide objective self-selected walking speed data, which informs the assessment of cadence variability potential outside of clinical settings.

Observational Gait Assessment Scales in Patients with Walking Disorders: Systematic Review

Objective

To compile and analyze the characteristics and methodological quality of observational gait assessment scales validated to date.

Methods

PubMed, Scopus, the Cochrane Library, Physiotherapy Evidence Database, Web of Science, Cumulative Index to Nursing and Allied Health Literature, Dialnet, Spanish Medical Index, and Nursing, Physiotherapy, and Podiatry databases were searched up to August 2019. The main inclusion criteria were validated tools based on a conceptual framework developed to evaluate gait, validation design studies of observational scales in their entirety, and articles written in English or Spanish. Evaluators extracted descriptive information of the scales and the metric properties of the studies, which were further analyzed with Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) and COnsensus-based Standards for the selection of health Measurement Instruments (COSMIN checklist).

Results

Eighteen articles based on 14 scales were included. The populations were neurological patients (72.22%), musculoskeletal disorders (11.11%), and other areas such as vestibular disorders (11.11%). The most addressed items were orthopedic aids (64.29%); phases of the gait cycle and kinematics of the leg and trunk (57.14% each one); and spatial and temporal parameters (50%). All studies analyzed criterion validity, and five included content or structural validity (27.78%). Fifteen articles considered reliability (83.33%). Regarding the seven-item scale QUADAS-2, five studies obtained six results on “low” risk of bias or “low” concerns regarding applicability. Nine articles obtained at least a “fair” result on COSMIN checklist.

Conclusions

A necessary compilation of the observational gait assessment scales validated to date was conducted. Besides, their characteristics and methodological quality were analyzed. Most scales were applied in neurological signs. The most approached topics were orthopedic aids, phases of the gait cycle, and kinematics of the leg and trunk. The scale that demonstrated a higher methodological quality was Visual Gait Assessment Scale, followed by CHAGS, Salford Gait Tool, and Edinburgh Visual Gait Score.