Jason T. Kahle

Safety, energy efficiency, and cost efficacy of the C-Leg for transfemoral amputees: A review of the literature

The purpose of this paper was to review the literature through a structured literature review and provide a grade of recommendation for patient safety, gait energy efficiency, and cost effectiveness of the C-Leg microprocessor-controlled prosthetic knee for transfemoral amputees. Medline (Ovid) and CINAHL (EBSCO) data bases were searched to identify potentially pertinent studies within the 1995–2009 time range. Studies were screened and sorted. Pertinent studies were rated for methodologic quality and for risk of bias. Following assessment of methodologic quality and bias risk, the level of evidence and a grade of recommendation was determined for each of three categories: Safety, energy efficiency, and cost effectiveness. A total of 18 articles were determined to be pertinent: seven for safety, eight for energy efficiency, and three for cost effectiveness. Methodologic quality was low with a moderate risk of bias in the safety and energy effectiveness categories. Studies in cost effectiveness received high scores for methodologic quality. Though methodologic quality varied across the selected topics, there was sufficient evidence to suggest increased efficacy of the C-Leg in the areas of safety, energy efficiency and cost when compared with other prosthetic knees for transfemoral amputees.

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.

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.

Transfemoral sockets with vacuum-assisted suspension comparison of hip kinematics, socket position, contact pressure, and preference: Ischial containment versus brimless

The objective of this study was to investigate the effect of brimless compared with ischial ramus containment (IRC) prosthetic sockets when using vacuum-assisted suspension (VAS) on persons with a unilateral transfemoral amputation (TFA). A randomized crossover design with a 2 d accommodation was used. People with unilateral TFA (n = 9 analyzed) were enrolled. Interventions were IRC VAS and brimless VAS sockets. Main outcome measures included coronal hip angle and vertical and lateral socket movement as measured by X-ray, skin pressure measured by Tekscan, and preference measured subjectively. The brimless design was statistically equivalent to IRC in all measured coronal hip angles and vertical and lateral socket displacement. The peak/stance mean pressure in the medial proximal aspect of the socket was 322 mmHg in the IRC compared with 190 mmHg in the brimless condition. Except for medial proximal pressure, no other measures reached statistical significance. All subjects reported the brimless design to be more comfortable than the IRC in short-term preference. Brimless VAS socket design may be a clinically viable choice for people with TFA.

STAIR ASCENT AND RAMP GAIT TRAINING WITH THE GENIUM KNEE

Accepted May 1, 2013. Address correspondence to M. Jason Highsmith, School of Physical Therapy & Rehabilitation Sciences, Morsani College of Medicine, University of South Florida, 12901 Bruce B. Downs Blvd., MDC 077, Tampa, FL 33612-4799, USA. Tel: +1-813-974-3806 (office); Fax: +1-813-974-8915; E-mail: mhighsmi@health.usf.edu Technology and Innovation, Vol. 15, pp. 349–358, 2014 1949-8241/14

A Case Study Using Fluoroscope to Determine the Vital Elements of Transfemoral Interface Design

90.00 + .00 Printed in the USA. All rights reserved. DOI: http://dx.doi.org/10.3727/194982413X13844488879267 Copyright  2014 Cognizant Comm. Corp. E-ISSN 1949-825X www.cognizantcommunication.com

A Method for Training Step-Over-Step Stair Descent Gait With Stance Yielding Prosthetic Knees: A Technical Note

The purpose of this case study was to isolate and examine the key elements in a transfemoral interface and determine their impact on the femur and the pelvis using a dynamic medium. There are many variations and theories on the most functional interface design. This case study attempts to verify the significance of certain elements of the transfemoral interface. This case study utilizes static medium (radiograph) to confirm an ideal fit of the transfemoral prosthesis. Once this is achieved the vital elements are isolated and examined using the dynamic medium of the fluoroscope. It attempts to show the reaction of the femur, ischium, and the pelvis during the stages of gait. In examining the vital elements in a dynamic medium, and determining their importance, we can place more emphasis on those elements and de-emphasize the non-vital elements. This could potentially increase comfort and function.

Predicting Walking Ability Following Lower Limb Amputation: An Updated Systematic Literature Review

ABSTRACT Limited information is available concerning stair descent training for transfemoral amputees using prosthetic knees. Literature describing stair descent training techniques are predominantly available for the step-to-step stair descent method. A thoroughly descriptive technique for training prosthetic knee users to reciprocally descend stairs, using a step-over-step pattern is not available. The purpose of this technical note is to describe a procedure for training stance-yielding prosthetic knee users how to descend stairs using a reciprocal, step-over-step pattern. The technique describes stair setup, safety considerations including hand railing, use of a gait belt, guarding techniques and a one versus two therapist technique. Nineteen subjects were initially trained in this technique, and all subjects demonstrated the ability to reciprocally descend stairs after training. Reciprocal step-over-step stair descent is not appropriate for all transfemoral amputees; however, we recommend considering the supervised, therapeutic application of this technique for all transfemoral amputees using stance yielding prosthetic knees. We suggest that practicing this technique might improve a prosthetic knee users overall functional performance such as their ability to utilize stumble recovery during a missed step, to transition more symmetrically from stand to sit and to utilize knee flexion during the loading response of gait.

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

There is not a clear clinical recommendation for the determination of prosthetic candidacy. Guidelines do not delineate which member(s) of the multidisciplinary team are responsible for prosthetic candidacy decisions and which factors will best predict a positive outcome. Also not clearly addressed is a patient-centered decision-making role. In a previous systematic review (SR), Sansam et al. reported on the prediction of walking ability following lower limb amputation using literature up to 2007. The search strategy was designed from the previous Sansam SR as an update of previously valuable predictive factors of prosthetic candidacy. An electronic literature search was executed from August 8, 2007, to December 31, 2015, using MEDLINE (Pubmed), Embase, The Cumulative Index to Nursing and Allied Health Literature (CINAHL) (Ovid), and Cochrane. A total of 319 studies were identified through the electronic search. Of these, 298 were eliminated, leaving a total of 21 for full evaluation. Conclusions from this updated study are drawn from a total recruited sample (n) of 15,207 subjects. A total of 12,410 subjects completed the respective studies (18% attrition). This updated study increases the size of the original Sansam et al. report by including 137% more subjects for a total of 21,490 between the two articles Etiology, physical fitness, pre-amputation living status, amputation level, age, physical fitness, and comorbidities are included as moderate to strongly supported predictive factors of prosthetic candidacy. These factors are supported in an earlier literature review and should be strongly considered in a complete history and physical examination by a multidisciplinary team. Predictive factors should be part of the patients healthcare record.

Gait Training Interventions for Lower Extremity Amputees: A Systematic Literature Review.

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.