Larry J. Mengelkoch

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.

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

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

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.

Metabolic Demands of Rock Climbing in Transfemoral Amputees

This pilot study compared the energy expenditure required to climb an indoor rock wall, in amputees utilizing five prosthetic configurations. Three experienced climbers (1M age 21 yr, 2F ages 30 and 49 yr) with unilateral transfemoral amputation climbed a 9.14 m indoor rock wall, 5.9 Yosemite Decimal Scale rating, using the following prosthetic configurations: 1. no prosthesis; 2. stubby prosthesis-foot forward; 3. stubby prosthesis-foot backward; 4. articulated prosthesis-knee unlocked; 5. articulated prosthesis-knee locked. Subjects climbed three times with each configuration resulting in 15 climbs per subject. Metabolic data was collected using the COSMED K4b(2) system. VO(2) was 15, 18 and 20% greater in the articulated unlocked condition (mean+/-SE: 20.5+/-0.8 ml.kg (-1).min (-1)), and 11, 13 and 15% greater in the articulated locked condition (19.7+/-0.9 ml.kg (-1).min (-1)), compared to the no prosthesis (17.8+/-0.7 ml.kg (-1).min (-1)), stubby backward (17.4+/-0.7 ml.kg (-1).min (-1)) and stubby forward (17.1+/-0.9 ml.kg (-1).min (-1)) conditions. Participants expended 11-20% more energy using the articulated prostheses than with the stubby and no prosthesis conditions. In persons with transfemoral amputation, use of an articulated prosthesis in indoor rock climbing may be a disadvantage in many aspects including competition, training, rehabilitation and satisfaction with the activity.

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.

Comparison of the Metabolic Demands of Dance Performance Using Three Mobility Devices for a Dancer with Spinal Cord Injury and an Able-Bodied Dancer

Mobility devices for dancers with physical mobility impairments have previously been limited to traditional manual or power wheelchairs. The hands-free torso-controlled mobility chair is a unique powered mobility device which allows greater freedom and expression of movement of the trunk and upper extremities. This study compared differences in energy expenditure during a standardized dance activity using three mobility devices: the hands-free torso-controlled mobility chair, a manual sports wheelchair with hand-arm control, and an electric power chair with hand-joystick control. An experienced dancer with C7 incomplete spinal cord injury (SCI) and an experienced able-bodied dancer were recruited for testing. Three measurement trials were obtained for each chair per subject. Oxygen uptake (VO2) and heart rate (HR) were measured continuously during the dance activity. Immediately following the dance activity, subjects rated perceived exertion. Significant differences (p ≤ 0.05) and similar linear patterns in VO2 and HR responses were observed between chairs for both dancers. When the hands-free mobility chair was used, the dance activity required a moderate level of energy expenditure compared to the manual sports chair or electric power chair for both dancers. Higher ratings of perceived exertion were observed in the manual chair compared to the other chairs for the dancer with SCI, but were similar between chairs for the able-bodied dancer. These results suggest that for a dancer with high-level SCI, the hands-free torso-controlled mobility chair may offer improved freedom and expressive movement possibilities and is an energy-efficient mobility device.

Spatiotemporal Parameters and Step Activity of a Specialized Stepping Pattern Used by a Transtibial Amputee During a Denali Mountaineering Expedition

ABSTRACT Specialized mountaineering stepping patterns have not been studied in persons with transtibial amputation (TTA). The purpose of this report was to describe spatiotemporal differences between the specialized French technique and traditional stepping in an individual with TTA and report his step activity during a climbing expedition in Denali, AK, USA. A 51-year-old old man with TTA recorded step count and activities during a summit attempt on Mt. McKinley (Denali). After the climb, the subject traversed a GAITRite walkway simulating French and traditional stepping to compare spatiotemporal differences between stepping patterns. The climber completed 8 days on the trail, with a total step count of 62,421 and average daily count of 10,404. Approximately 27% of the steps were taken using the French technique. Five total events were logged: one dermatologic, three musculoskeletal events, and the culminating event was cardiovascular in nature, where the climber reported overheating and exertion requiring climb cessation and evacuation. For velocity, the French technique was slower than traditional stepping. Stride, step, and double support times were greater in the French technique compared with traditional stepping. Spatially, stride and step lengths were greater in the traditional compared with the French technique. The base of support width was wider in the French than in the traditional stepping. Musculoskeletal rather than dermatologic issues predominated in the event log. Fatigue ultimately concluded the climb, warranting further investigation into balancing component durability and mass in terms of prosthetic foot selection. As altitude increased, the French technique was selected as the preferred stepping strategy. The French technique is ultimately a slower stepping technique favoring stability over mobility.

BIOENERGETIC DIFFERENCES DURING WALKING AND RUNNING IN TRANSFEMORAL AMPUTEE RUNNERS USING ARTICULATING AND NON-ARTICULATING KNEE PROSTHESES.

Transfemoral amputation (TFA) patients require considerably more energy to walk and run than non-amputees. The purpose of this study was to examine potential bioenergetic differences (oxygen uptake (VO2), heart rate (HR), and ratings of perceived exertion (RPE)) for TFA patients utilizing a conventional running prosthesis with an articulating knee mechanism versus a running prosthesis with a non-articulating knee joint. Four trained TFA runners (n = 4) were accommodated to and tested with both conditions. VO2 and HR were significantly lower (p ≤ 0.05) in five of eight fixed walking and running speeds for the prosthesis with an articulating knee mechanism. TFA demonstrated a trend for lower RPE at six of eight walking speeds using the prosthesis with the articulated knee condition. A trend was observed for self-selected walking speed, self-selected running speed, and maximal speed to be faster for TFA subjects using the prosthesis with the articulated knee condition. Finally, all four TFA participants subjectively preferred running with the prosthesis with the articulated knee condition. These findings suggest that, for trained TFA runners, a running prosthesis with an articulating knee prosthesis reduces ambulatory energy costs and enhances subjective perceptive measures compared to using a non-articulating knee prosthesis.

Psychometric Evaluation of the Hill Assessment Index (HAI) and Stair Assessment Index (SAI) In High-functioning Transfemoral Amputees

The hill assessment index (HAI) and stair assessment index (SAI) were developed to objectively evaluate ramp and stair gait. This studys purpose was to determine the validity and reliability of these tests in a sample of persons with unilateral transfemoral amputation (TFA) using microprocessor prosthetic knee systems. All subjects were fit with a microprocessor knee system. After accommodation, subjects performed three trials ascending and descending a 5° ramp and a flight of stairs while being recorded on video. Sensitivity and specificity for the HAI was calculated against degree of asymmetry in step length using Dartfish video analysis software. Reliability was assessed using intraclass correlational coefficients calculated using Spearmans Rho (rs). A priori significance level was set at p ≤ 0.05. Twenty (n = 20) individuals with TFA completed the study protocol. Sensitivity and specificity of the HAI were calculated at 88.0% and 75.0% during ascending conditions and 94.0% and 67.0% during descending conditions, respectively. Significant correlations for the HAI included rs = 0.87 and rs = 0.73 within raters uphill and downhill, respectively. Corresponding coefficients of rs = 0.80 and rs = 0.67 were calculated between raters. For the SAI, significant correlations included rs = 1.00 for both comparisons within raters and in the comparison between raters in the ascending condition. A correlation of rs = 0.89 was calculated for the between-rater comparison in the descending condition. The HAI showed moderate to excellent sensitivity and specificity but good to adequate reliability. The SAI showed excellent to good reliability.

Concurrent Validity of the Continuous Scale-physical Functional Peformance-10 (CS-PFP-10) Test In Transfemoral Amputees

The Continuous Scale-Physical Functional Performance-10 (CS-PFP-10) test consists of 10 standardized daily living tasks that evaluate overall physical functional performance and performance in five individual functional domains: upper body strength (UBS), upper body flexibility (UBF), lower body strength (LBS), balance and coordination (BAL), and endurance (END). This study sought to determine the concurrent validity of the CS-PFP-10 test and its functional domains that involve the lower extremities (LBS, BAL, or END) in comparison to measures that have established validity for use in persons with transfemoral amputation (TFA). Ten TFA patients functioning at K3 or higher (Medicare Functional Classification Level) completed the study. Participants were assessed performing the CS-PFP-10, Amputee Mobility Predictor (AMP), 75 m self-selected walking speed (75 m SSWS) test, timed down stair walking (DN stair time), and the limits of stability (LOS) balance test. Concurrent validity was assessed using correlation analysis. The AMP, 75 m SSWS, LOS, and the DN stair time tests were strongly correlated (r = ± 0.76 to 0.86) with their paired CS-PFP-10 domain score (LBS, BAL, or END) and CS-PFP-10 total score. These findings indicate that the lower limb and balance domains of the CS-PFP-10 are valid measures to assess the physical functional performance of TFA patients.