Rebecca M. Miro

Differences in knee flexion between the Genium and C-Leg microprocessor knees while walking on level ground and ramps

BACKGROUND Microprocessor knees have improved the gait and functional abilities of persons with transfemoral amputation. The Genium prosthetic knee offers an advanced sensor and control system designed to decrease impairment by: allowing greater stance phase flexion, easing transitions between gait phases, and compensating for changes in terrain. The aim of this study was to determine differences between the knee flexion angle of persons using the Genium knee, the C-Leg knee, and non-amputee controls; and to evaluate the impact the prostheses on gait and level of impairment of the user. METHODS This study used a randomized experimental crossover of persons with transfemoral amputation using the Genium and C-Leg microprocessor knees (n=25), with an observational sample of non-amputee controls (n=5). Gait analysis by 3D motion tracking of subjects ambulating at different speeds on level ground and on 5° and 10° ramps was completed. FINDINGS Use of the Genium resulted in a significant increase in peak knee flexion for swing (5°, p<0.01, d=0.34) and stance (2°, p<0.01, d=0.19) phases relative to C-Leg use. There was a high degree of variability between subjects, and significant differences still remain between the Genium group and the control groups knee flexion angles for most speeds and slopes. INTERPRETATION The Genium knee generally increases flexion in swing and stance, potentially decreasing the level of impairment for persons with transfemoral amputation. This study demonstrates functional differences between the C-Leg and Genium knees to help prosthetists determine if the Genium will provide functional benefits to individual patients.

The Impact of Obesity on Back and Core Muscular Endurance in Firefighters

The purpose of this study was to assess the relationships between obesity and measures of back and core muscular endurance in firefighters. Methods. A cross-sectional study was conducted in career firefighters without low back pain. Obesity measures included body mass index (BMI) and body fat percentage assessed with air displacement plethysmography. Muscular endurance was assessed with the Modified Biering Sorensen (back) and Plank (core) tests. Relationships were explored using t-tests and regression analyses. Results. Of the 83 participants enrolled, 24 (29%) were obese (BMI ≥ 30). Back and core muscular endurance was 27% lower for obese participants. Significant negative correlations were observed for BMI and body fat percentage with back and core endurance (r = −0.42 to −0.52). Stepwise regression models including one obesity measure (BMI, body fat percentage, and fat mass/fat-free mass), along with age and self-reported physical exercise, accounted for 17–19% of the variance in back muscular endurance and 29–37% of the variance in core muscular endurance. Conclusions. Obesity is associated with reduced back and core muscular endurance in firefighters, which may increase the risk of musculoskeletal injuries. Obesity should be considered along with back and core muscular endurance when designing exercise programs for back pain prevention in firefighters.

Ramp descent performance with the C-Leg and interrater reliability of the Hill Assessment Index.

Background: Transfemoral amputees have decreased ability to descend ramps and hills. The Hill Assessment Index quantifies transfemoral amputee ramp performance, but interrater reliability has not been assessed. Objectives: To determine whether C-Leg use improves hill descent gait and evaluate the Hill Assessment Index’s interrater reliability. Methods: Twenty-one transfemoral amputees descended a ramp while timed and video recorded, using their nonmicroprocessor prosthetic knee. Subjects were fitted and accommodated with a C-Leg and retested. Test times were compared, and ramp performances were independently reviewed using the Hill Assessment Index by two raters. Hill Assessment Index scores were compared between knee conditions within raters for performance and between raters to assess the Hill Assessment Index’s interrater reliability. Results: Mean Hill Assessment Index scores were greater for C-Leg compared to nonmicroprocessor prosthetic knee for both raters. C-Leg resulted in faster ramp descent. Strong correlations resulted between raters on Hill Assessment Index scores for nonmicroprocessor prosthetic knee (intraclass correlation coefficient = 0.97) and C-Leg (intraclass correlation coefficient = 0.99). Conclusions: C-Leg improves Hill Assessment Index ramp descent performance and time. In descent quality, C-Leg offers the possibility of eliminating assistive device use and/or improving step length in the absence of an assistive device. C-Leg resulted in 23% gait speed increase during ramp descent. The Hill Assessment Index had very good interrater reliability but should be assessed for intrarater reliability, minimal detectable change, and validity. Clinical relevance Transfemoral amputees have difficulty ambulating on ramps. While the C-Leg has been shown to improve ramp descent, this has not been confirmed, and the Hill Assessment Index has not been studied for reliability. This study confirms that the C-Leg improves ramp descent performance and the Hill Assessment Index’s interrater reliability.

Perceived differences Between the Genium and the c-LeG m icro Processor Prosthetic Knees in Prosthetic-reLated function and QuaLity of Life

Microprocessor knees (MPKs) are a viable option for persons with transfemoral amputation (TFA). Studies have assessed biomechanics and physical function to quantify MPK functional performance. However, it is also essential to assess patient perception as part of evidence-based practice using valid and reliable measures. The Prosthesis Evaluation Questionnaire (PEQ) evaluates prosthetic-related function and quality of life. The PEQ has been used in MPK literature to compare perceptive response between C-Leg and non-microprocessor-controlled knee mechanisms. The Genium, a new MPK, has not been assessed for differences in perceived function. The purpose of this project was to report perceived differences in prosthetic function and quality of life following accommodation with a Genium compared with a C-Leg. Twenty people with TFA participated in this randomized crossover study. C-Leg users randomized to test first with their own C-Leg or a Genium then crossed over into the other condition for repeated testing. Nonknee prosthetic attributes were held constant. Participants completed the PEQ for each knee condition to compare perceived differences in prosthetic function and quality of life. Genium use resulted in significant improvements (p ≤ 0.05) in the following scales — Perceived Response, Social Burden, Utility, and WellBeing — as well as in individual items related to improved standing comfort, satisfaction with walking ability, and improved gait in tight spaces, hills, and slippery surfaces (p < 0.025). As a result of using the Genium, patients perceive improvements in prosthetic-related quality of life and function. Further, patients perceive improvements in very specific mobility functions related to ambulation on complex settings.

Prosthetic interventions for people with transtibial amputation: Systematic review and meta-analysis of high-quality prospective literature and systematic reviews.

Considering transtibial amputation (TTA) rehabilitation costs and complexity, high-quality literature should inform clinical practice. Systematic reviews (SRs) suggest this is not the case. This articles purpose was to review the highest-quality evidence available to guide clinical practice for TTA regarding five prosthetic intervention areas. Six databases were searched for high-quality SRs and prospective clinical trials (randomized clinical trials [RCTs]). Reviewers screened, sorted, rated (i.e., methodologic quality, bias risk), and extracted article data. Meta-analyses were conducted when possible. Thirty-one references were included (25 RCTs and 6 SRs). Five topical areas emerged (alignment, feet and ankles, interface, postoperative care, pylons). Twenty-three evidence statements were supported by level 2 evidence and eight by level 1 evidence. All RCTs reported randomization and reasonable data presentation. Concealed allocation and blinding were not widely used. Mean attrition was 11%. SRs included no meta-analyses. Functional level was poorly reported. Grouping feet and ankle components by functional classification enabled meta-analyses, though variance was considerable given the small sample sizes. Prosthetic interventions are generally safe for TTAs. High-quality literature enabled formulation of evidence statements to support select clinical practice areas, though quantity was lacking. Thus, numerous topics related to TTA care lack rigorous evidence. Although blinding in prosthetic research requires increased funding and effort, it could greatly improve the methodologic quality of prosthetic research.

EFFECTS OF THE GENIUM KNEE SYSTEM ON FUNCTIONAL LEVEL, STAIR AMBULATION, PERCEPTIVE AND ECONOMIC OUTCOMES IN TRANSFEMORAL AMPUTEES

Compared to non-microprocessor knees, the C-Leg microprocessor knee (MPK) is bioenergentically and economically more efficient and safer for transfemoral amputation (TFA) patients. The Genium MPK has demonstrated improvements in perceived function, knee kinematics, and physical functional performance compared to C-Leg. Clinical and health economic analyses have not been conducted with the Genium knee system. The purpose of this study was to determine if laboratory determined benefits of Genium are detectable using common clinical assessments and if there are economic benefits associated with its use. This study utilized a randomized AB crossover study with 60 d follow-up including cost-effectiveness analysis. Twenty TFA patients tested with both knees in mobility and preference measures. Incremental cost-effectiveness ratios (ICER) were calculated based on performance measures. Stair Assessment Index scores improved with Genium. Mean stair completion times and descent stepping rate were not different between knees. Stair ascent stepping rate for C-Leg was greater compared with Genium (p = 0.04). Genium use decreased Four square step test completion time and increased functional level and step activity (p ≤ 0.05). Further, Genium use improved (p ≤ 0.05) function and safety in three out of five Activities of Daily Living (ADL) survey domains. Finally, more subjects preferred Genium following testing. Functional measures were used to calculate ICERs. ICER values for Genium fall within established likely-to-accept value ranges. Compared with C-Leg, Genium use improved stair walking performance, multi-directional stepping, functional level, and perceived function. In this group of community ambulators with TFA, Genium was preferred, and, while more costly, it may be worth funding due to significant improvements in functional performance with ADLs.

Delivery of cosmetic covers to persons with transtibial and transfemoral amputations in an outpatient prosthetic practice

Background: Limb loss negatively impacts body image to the extent that functional activity and societal participation are affected. Scientific literature is lacking on the subject of cosmetic covering for prostheses and the rate of cosmetic cover utilization by cover type, gender, amputation level, and type of healthcare reimbursement. Objectives: To describe the delivery of cosmetic covers in lower limb prostheses in a sample of people with lower extremity amputation. Study design: Cross-sectional design Methods: Patient records from an outpatient practice were reviewed for people who received a transtibial or transfemoral prosthesis within a selected 2-year period. Results: A total of 294 records were reviewed. Regardless of the amputation level, females were significantly (p ≤ 0.05) more likely to receive a cover. Type of insurance did not affect whether or not a cover was used, but Medicare reimbursed more pull-up skin covers. Conclusion: There were differences regarding cosmetic cover delivery based on gender, and Medicare reimbursed for more pull-up skin covers at the transtibial level than other reimbursors did. This analysis was conducted in a warm, tropical geographic region of the United States. Results may differ in other parts of the world based on many factors including climate and local views of body image and disability. Clinical relevance Cosmetic covering rates are clinically relevant because they provide insight into which gender is utilizing more cosmetic covers. Furthermore, it can be determined which type of covers are being utilized with greater frequency and which insurance type is providing more coverage for them.

Economic Evaluations of Interventions For Transtibial Amputees: A Scoping Review of Comparative Studies

Transtibial amputation (TTA) is life-altering emotionally, functionally, and economically. The economic impact to all stakeholders is largely unknown, as is the cost-effectiveness of prosthetic intervention. This scoping reports purpose was to determine if there is sufficient evidence to conduct a formal systematic review or meta-analysis in any particular prosthetic intervention area and to determine if any evidence statements could be synthesized relative to economic evaluation of interventions provided to patients with TTA. The scoping review revealed six articles representing three topical areas of transtibial care: Care Models, Prosthetic Treatment, and Prosthetic Sockets. All six articles were cost-identification or cost-consequence design and included a total of 704 subjects. Presently, it can be concluded with moderate confidence that specific weight-bearing and total-contact sockets for transtibial amputees are functionally and economically equivalent in the short term when costs, delivery time, and all stakeholder perspectives are considered. Long-term socket outcomes are relatively unexplored. Further primary research is needed beyond this to determine cost-effectiveness for other areas of transtibial prosthetic care although clinical outcomes are somewhat established through systematic review and meta-analysis in other areas of care. Conversely, evaluation of narrative economic reports relative to transtibial care may be sufficient to warrant further analysis. Guidance from the profession may also be useful in devising a strategy for how to assure economic analyses are a routine element of future prosthetic science.

Correlations between residual limb length and joint moments during sitting and standing movements in transfemoral amputees

Background and aim: Longer residual limb lengths provide an increased lever arm. Longer residual limbs may produce increased joint moments; the two may be correlated. These correlations have not been evaluated in transfemoral amputees during transitional movements. Correlations between residual limb length and involved side joint moment could contribute to justification supporting maximal residual limb length preservation. This study investigated possible correlations between hip or knee moment and residual limb length. Technique: Hip and knee joint moments were determined while 21 transfemoral amputees performed sitting and standing movements and then evaluated for correlation with residual limb length. Discussion: Residual limb length was not correlated with either knee or involved side hip moments during sit to stand or stand to sit. Conversely, weak inverse correlations (p < 0.05) existed between sound hip moment magnitude and residual limb length. These correlations suggest that in community ambulating transfemoral amputees, longer residual limb length could decrease sound hip kinetic burden during transitional movement. Beyond correlations between residual limb length and sound hip transitional movement kinetics, there are other considerations in determining residual limb length during amputation. Clinical relevance This study examines relationships between lower limb joint moments and residual limb length related to sit-to-stand and stand-to-sit activities. The results have implications for amputation surgery and rehabilitation.

Predictors of success on the American Board for Certification's prosthetics certification examination.

Background: Many factors can potentially impact pass or fail performance of a certification examination. While studies regarding predictors of success have been conducted in other professions, no such studies have been conducted in prosthetics and orthotics. Objectives: Determine whether there are significant differences in prosthetics certification examination success or failure based on gender, Carnegie ranking of the institution from where the candidate received the degree, and whether the candidate is extending credential from orthotics to include prosthetics. Study design: Retrospective study. Methods: Data of candidates who completed prosthetics residency in 2011 and 2012 were evaluated for relationships with the dependent variables. Results: Only credential extension showed a statistically significant relationship with written multiple choice (p = 0.000), written simulation (p = 0.006), and clinical patient management examinations (p = 0.005) as well as with success or failure in obtaining prosthetics certification (p < 0.001). Conclusions: Currently available data for analysis regarding predictors of success are limited. Collection of additional variables (i.e. pre-requisite grade point average) in the future will permit analysis of more robust information. Presently available data reveal that candidates seeking to extend credential are more successful in obtaining certified prosthetist status compared with those testing for the first time. Clinical relevance Understanding factors contributing to attaining licensure is important as the prosthetic/orthotic practitioner population ages. This is the first study to investigate this dimension of prosthetics and orthotics training, which upholds professional standards and protects patients. It helps the profession develop best educational and clinical practices in managing patients who utilize prosthetic technologies.