Evolution in prostheses for sprinters with lower-limb amputation]

For about 15 years, technical advances in prosthetic treatment have been the main factor in the increased performance of athletes with lower-limb amputation. For trans-tibial amputation, the prosthesis for sprinting is composed of a gel liner and a socket joined by a locking or virtual vacuum liner. Because of these dynamic properties, the carbon prosthetic foot equipped with tacks ensures outstanding performance. For trans-femoral amputation, a hydraulic swing and a stance control unit are added to the same prosthesis. In comparison with the able-bodied runner, athletes with amputation have smaller loading times in the prosthetic limb and larger ones in the sound limb. The length of the energy-storing prosthetic foot is determined by the "up-on-the-toes" running gait. The sprinting gait with trans-tibial amputation is almost symmetrical. The hip extensor effort is the main compensation of propulsion reduction with lower-limb amputation. With trans-femoral amputation, the lack of knee increases the asymmetry. The total prosthetic knee extension (early in late-swing phase and lasting during total stance phase) compensates with extension of both hips, especially the opposite one. The amputation and sound limb load transfer with lumbar hyperlordosis concern the pelvis, trunk and shoulders. Because of athletes with amputation, research in prosthetic treatment has progressed. The development of orthotics and prostheses for such athletes has benefited non-athletes with amputation.     

A preliminary investigation of pelvic obliquity patterns during gait in persons with transtibial and transfemoral amputation

Differences in pelvic obliquity between small groups of persons with unilateral lower limb amputation and subjects without amputation were analyzed. Kinematic walking data were collected as six males with transtibial amputation and three males with transfemoral amputation walked over a range of speeds. The pelvic obliquity patterns and amplitudes from the groups with amputation were compared to normal data. Results showed that smaller peak-to-peak amplitudes of pelvic obliquity were associated with higher amputation levels. Pelvic drop during early prosthetic-limb stance tended to be smaller than during early sound-limb stance. Most of the subjects with amputation exhibited an obliquity pattern in which the hip on the prosthetic side was raised above the stance-side hip during prosthetic swing phase, indicative of a compensatory action known as hip-hiking. The subjects with transfemoral amputation exhibited this hip-hiking pattern during sound-limb swing phase as well. Results from this study suggest that further investigation is required to determine those limitations of current prosthetic technology that adversely affect pelvic obliquity in the gait of persons with amputation, and to determine if significant benefit can be realized by restoring a normal pattern of pelvic obliquity to the gait of persons with amputation.     

Biomechanical adaptations of transtibial amputee sprinting in athletes using dedicated prostheses

OBJECTIVE: To determine the biomechanical adaptations of the prosthetic and sound limbs in two of the world's best transtibial amputee athletes whilst sprinting. DESIGN: Case study design, repeated measures. BACKGROUND: Using dedicated sprint prostheses transtibial amputees have run the 100 m in a little over 11 s. Lower-limb biomechanics when using such prostheses have not previously been investigated. METHODS: Moments, muscle powers and the mechanical work done at the joints of the prosthetic and sound limbs were calculated as subjects performed repeated maximal sprint trials using a Sprint Flex or Cheetah prosthesis. RESULTS: An increased hip extension moment on the prosthetic limb, with an accompanying increase in the amount of concentric work done, was the most notable adaptation in Subject 1 using either prosthesis. In Subject 2, an increased extension moment at the residual knee, and an accompanying increase in the amount of total work done, was the most notable adaptation using either prosthesis. This later adaptation was also evident in Subject 1 when using his Sprint Flex prosthesis. CONCLUSIONS: Increased hip work on the prosthetic limb has previously been shown to be the major compensatory mechanism that allow transtibial amputees to run. The increased work found at the residual knee, suggests that the two amputee sprinters used an additional compensatory mechanism. RELEVANCE: These findings provide an insight into the biomechanical adaptations that allow a transtibial amputee to attain the speeds achieved when sprinting.     

Kinematics in the Terminal Swing Phase of Unilateral Transfemoral Amputees: Microprocessor-Controlled Versus Swing-Phase Control Prosthetic Knees

Mâaref K, Martinet N, Grumillier C, Ghannouchi S, André JM, Paysant J. Kinematics in the terminal swing phase of unilateral transfemoral amputees: microprocessor-controlled versus swing-phase control prosthetic knees.

Objectives

To analyze the spatiotemporal parameters in the terminal swing phase of the prosthetic limb in unilateral transfemoral amputees (TFAs) compared with a group of asymptomatic subjects, and to identify a latency period (LP) in the TFA between the full extension of the prosthetic knee and the initial ground contact of the ipsilateral foot. To study the correlation between the LP and the duration of the swing phase. To evaluate the influence of the type of knee, the time since amputation, and the amputation level on the latency period.

Design

Three-dimensional gait analysis with an optoelectronic device.

Setting

Gait analysis laboratory of a re-education and functional rehabilitation service.

Participants

TFA (n=29) and able-bodied (n=15) subjects.

Interventions

Not applicable.

Main Outcome Measures

Spatiotemporal and kinematics gait parameters.

Results

The swing phase and the LP of the prosthetic limb, associated with a consequently longer single-limb stance phase in the intact limb, were significantly longer than those measured in the intact limbs of these subjects, as well as those measured on both lower limbs of the able-bodied subjects (P<.05). There is a positive correlation (P<.05; r²=.58 between the LP and the swing phase on the TFA's prosthetic side. The LP measured in the prosthetic limb of TFA with a swing-phase control prosthetic knee is significantly greater than in those using the microprocessor-controlled prosthetic knee (P<.05).

Conclusions

Of negligible duration in able-bodied subjects and in the intact limb of TFA, the LP is significantly greater in the prosthetic limb. It can explain the lengthened swing phase on the prosthetic side of those subjects. The use of a microprocessor-controlled prosthetic knee allows the LP to be reduced. This LP appears to be necessary to insure the stability of the prosthetic knee. We suggest calling this time “confidence time.”     

Does Unilateral Lower Limb Amputation Influence Ankle Joint Torque in the Intact Leg?

ObjectiveTo investigate ankle torque and steadiness in the intact leg of transtibial and transfemoral unilateral amputees.DesignComparative study.SettingMedical rehabilitation centers.ParticipantsFifteen persons with a unilateral transfemoral amputation, 8 persons with a transtibial amputation, and 14 able-bodied male participants volunteered to participate in this study (N=37).InterventionsNot applicable.Main Outcomes MeasuresMaximal isometric torque performed during ankle plantarflexion and dorsiflexion in the intact limb of amputees and in the dominant limb of able-bodied persons. The coefficient of variation (CV) of the plantarflexion torque was calculated over 5 seconds during a submaximal isometric contraction (15%) in order to assess torque steadiness. Furthermore, electromyographic activity (the root mean square amplitude) of the gastrocnemius medialis and tibialis anterior muscles was analyzed.ResultsPlantarflexion maximal torque was significantly higher for the able-bodied group (115±39 Nm) than for the group with a transfemoral amputation (77±34 Nm) (P<.01), and did not differ between able-bodied group and the group with a transtibial amputation (97±26 Nm) (P=.25). Furthermore, the transfemoral amputee group was 29% less steady than the able-bodied group (P=.01). However, there were no significant differences in torque steadiness between the able-bodied group and transtibial amputee group (P=.26) or between transtibial and transfemoral amputee groups (P=.27). The amputation had no significant effect between groups on dorsiflexion maximal torque (P=.10), gastrocnemius medialis electromyography (EMG) (P=.85), tibialis anterior coactivation (P=.95), and coactivation ratio (P=.75).ConclusionThe present study suggests that as the level of amputation progresses from below the knee to above the knee, the effect on the intact ankle is progressively more negative.     

Prosthetic gait of unilateral lower-limb amputees with current and novel prostheses: A pilot study

BackgroundNovel lower-limb prostheses aim to improve the quality of locomotion of individuals with an amputation. This study evaluates the biomechanics of a novel bionic foot during walking.MethodsAble-bodied individuals (n = 7) and individuals with a transfemoral (n = 6) or transtibial amputation (n = 6) were included. Able-bodied individuals conducted one experimental trial, whereas individuals with transtibial and transfemoral amputations conducted a familiarization (with current prosthesis) and two experimental trials using a passive and bionic prosthesis. Each trial consisted of 3 bouts of 2 min of treadmill walking at different speeds. Biomechanical data were gathered using a force platform and motion capture system and analysed using Statistical Parametric Mapping and (non)-parametric tests.FindingsConventional prosthetic feet alter gait patterns and induce locomotion difficulties. While walking at a normal speed with the passive prosthesis, transtibial amputees display reduced maximum heel forces, increased ankle and trunk angular velocities at midstance, and increased knee angle during stance and swing phases on their effected side (P ≤ 0.026). Improved lower-limb kinematics was demonstrated during slow and normal speed walking with the bionic prosthesis; however, dynamic trunk stability was negatively impacted during this condition. The bionic prosthesis did not benefit transfemoral amputees at any walking speed.InterpretationTranstibial amputees can better approximate typical movement patterns at slow and normal walking speeds using the novel bionic prosthesis; however the same benefit was not observed in transfemoral amputees.     

The mechanics of landing when stepping down in unilateral lower-limb amputees

BACKGROUND: The ability to successfully negotiate stairs and steps is an important factor for functional independence. While work has been undertaken to understand the biomechanics of gait in lower-limb amputees, little is known about how amputees negotiate stairs and steps. This study aimed to determine the mechanics of landing in unilateral lower-limb amputees when stepping down to a new level. A secondary aim was to assess the effects of using a shank-mounted shock-absorbing device (Tele-Torsion Pylon) on the mechanics of landing. METHODS: Ten unilateral amputees (five transfemoral and five transtibial) and eight able-bodied controls performed single steps down to a new level (73 and 219 mm). Trials were repeated in amputees with the Tele-Torsion Pylon active and inactive. The mechanics of landing were evaluated by analysing peak limb longitudinal force, maximal limb shortening, lower extremity stiffness, and knee joint angular displacement during the initial contact period, and limb and ankle angle at the instant of ground-contact. Data were collected using a Vicon 3D motion analysis system and two force platforms. FINDINGS: Amputees landed on a straightened and near vertical limb. This limb position was maintained in transfemoral amputees, whereas in transtibial amputees knee flexion occurred. As a result lower extremity stiffness was significantly greater in transfemoral amputees compared to transtibial amputees and able-bodied controls (P<0.001). The Tele-Torsion Pylon had little effect on the mechanics of landing in transtibial amputees, but brought about a reduction in lower extremity stiffness in transfemoral amputees (P<0.05). INTERPRETATION: Amputees used a stepping strategy that ensured the direction of the ground reaction force vector was kept anterior of the knee joint centre. Using a Tele-Torsion Pylon may improve the mechanics of landing during downward stepping in transfemoral amputees.     

单侧小腿截肢患者穿假肢后的步态运动学参数研究

目的 采用计算机辅助康复环境(CAREN)步态评估系统分析单侧小腿截肢患者穿假肢后的步态运动学参数,并分析其产生差异的原因。 方法 选取单侧小腿中段截肢但均装配假肢的受试者9例设为假肢组,同期选择健全受试者11例设为标准组,通过CAREN步态评估系统对2组受试者的步态运动学参数进行收集、处理、分析,并根据分析报告阐明产生差异原因。 结果 假肢组步态时相性指数为(0.88±0.04),其假肢侧的步长、支撑期百分比、髋关节支撑期最大伸展角度、膝关节支撑期最大屈曲角度、踝关节足跟着地背屈角度、踝关节支撑期最大背屈角度、踝关节支撑期最大跖屈角度与健侧比较,差异均有统计学意义(P<0.05）。假肢组假肢侧的步行速度、步态周期、跨步长、支撑期百分比、髋关节足跟落地屈髋角度、髋关节支撑期最大伸展角度、髋关节支撑期最大屈曲角度、膝关节足跟着地屈膝角度、踝关节足跟着地背屈角度、踝关节支撑期最大跖屈角度、踝关节支撑期最大背屈角度与标准组双侧均值比较,差异均有统计学意义(P<0.05）。 结论 单侧小腿截肢者穿戴假肢后步态时相对称性为（0.88±0.04）,假肢侧踝关节运动学参数显著弱于自身健侧,其时空与运动学参数也显著弱于健全人。     

Insights into amputee running. A muscle work analysis.

Five young, active, unilateral below knee amputees wearing the SACH prosthetic foot, and six normal subjects participated in the study. Subjects ran at a controlled velocity of 2.8 m/s +/- 10% over a ground reaction force plate while being filmed with a video camera. Joint moments, power outputs and mechanical work characteristics were then calculated. During stance phase the amputee prosthetic limb exhibited a marked reduction in total work. There was a reduction in the mechanical work at the knee and the prosthetic foot/ankle with a compensatory increase in mechanical work by the hip musculature. The intact stance phase limb mechanical work characteristics were not significantly different from normal. The hip flexors were the only muscle group in the swing phase prosthetic limb with a significant increase in muscle work compared with normal subjects. The intact swing phase limb in contrast exhibited a marked increase in concentric muscle work by the hip flexors and eccentric muscle work by the knee flexors in early swing phase, and an increase in concentric hip extensor and eccentric knee flexor muscle work in late swing phase. The major compensatory patterns, therefore, that allow below knee amputees to run appear to be an increase in stance phase hip muscle work on the prosthetic limb and increased hip and knee muscle work on the intact limb during swing phase.     

Determining asymmetry of roll-over shapes in prosthetic walking

How does the inherent asymmetry of the locomotor system in people with lower-limb amputation affect the ankle-foot roll-over shape of prosthetic walking? In a single-case design, we evaluated the walking patterns of six people with lower-limb amputation (3 transtibial and 3 transfemoral) and three matched nondisabled controls. We analyzed the walking patterns in terms of roll-over characteristics and spatial and temporal factors. We determined the level of asymmetry by roll-over shape comparison (root-mean-square distance) as well as differences in radius of curvature. In addition, we calculated ratios to determine spatial and temporal asymmetries and described different aspects of asymmetry of roll-over shapes. All participants showed some level of asymmetry in roll-over shape, even the nondisabled controls. Furthermore, we found good intralimb reproducibility for the group as a whole. With respect to spatial and temporal factors, the participants with transtibial amputation had a quite symmetrical gait pattern, while the gait in the participants with transfemoral amputation was more asymmetrical. The individual ankle-foot roll-over shapes provide additional insight into the marked individual adjustments occurring during the stance phase of the nondisabled limb. The two methods we present are suitable for determining asymmetry of roll-over shapes; both methods should be used complementarily.     

Gait evaluation of a transfemoral prosthetic simulator

OBJECTIVE: To test a prosthetic simulator developed to allow persons without amputation to walk like a person with a transfemoral (TF) amputation. PATIENTS: Five able-bodied subjects; comparison with data from the literature on persons with TF amputations. SETTING: Motion analysis laboratory. DESIGN: Two 45- to 60-minute gait training sessions before subjects walked along a 10-meter walkway. There were 6 trials: 3 walking with a cane, 3 without a cane. MAIN OBJECTIVE MEASURES: Sagittal plane kinematic and kinetic analysis of ankle, knee, and hip: angular velocity, joint moment, and power. RESULTS: Kinematic and kinetic analyses showed that joint mechanics during walking were similar between the test subjects and comparative results from persons with TF amputations (reported in the literature). Test subjects walked slower and moved their hip and knee joints faster (higher angular velocity values during the terminal swing) than the TF amputee subjects, although these results were not statistically significant (p < .05). These findings were consistent with new prosthetic users who are more tentative during gait training. However, a perfect simulation would show no difference in kinematic results. CONCLUSION: These results support the use of a TF prosthetic simulator to help health care professionals experience the process of fitting the prosthesis from the client's perspective.     

Walking characteristics of runners with a transfemoral or knee-disarticulation prosthesis

BackgroundRunning with prostheses has become a common activity for amputees participating in sports and recreation. However, very few studies have characterized the kinematic and kinetic parameters of walking in individuals with amputation who are runners. Thus, this study attempts to elucidate the kinematics and kinetics of walking in runners with a unilateral transfemoral amputation or knee-disarticulation.MethodsThis study experimentally compares the prosthetic and intact limbs of runners with prostheses as well as compares the findings against the limbs of age-matched able-bodied individuals while walking. Fourteen runners with a unilateral transfemoral amputation or knee-disarticulation were recruited and 14 age-matched able-bodied individuals were prepared using gait database. Spatiotemporal, kinematic, and kinetic parameters of walking were analyzed using a 3-demensional motion capture system.ResultsThe results showed that the peak ankle positive power at pre-swing and peak hip positive power from loading response to mid stance in the intact limb were significantly larger than that in the prosthetic limb. Moreover, to compensate for missing anatomical functions on the prosthetic limb, it appeared that the intact limb of the runners generated larger peak joint power by producing more ankle plantarflexor and hip extensor moments while walking.InterpretationThis study demonstrated that the runners rely on their intact limb while walking. Training of hip extensor muscles of the intact limb may be beneficial for these individuals.     

Inertial sensor-based measures of gait symmetry and repeatability in people with unilateral lower limb amputation

BackgroundPeople with lower limb amputation often walk with asymmetrical gait patterns potentially leading to long-term health problems, ultimately affecting their quality of life. The ability to discreetly detect and quantify the movement of bilateral thighs and shanks using wearable sensor technology can provide additional insight into how a person walks with a lower limb prosthesis. This study investigated segmental symmetry and segmental repeatability of people with unilateral lower limb amputation, examining performance of the prosthetic and intact limbs.MethodsGyroscope signals were recorded from four inertial measurement units worn on bilateral lower limb segments of subjects with unilateral lower limb amputation during the 10-m walk test. Raw angular velocity signals were processed using dynamic time warping and application of algorithms resulting in symmetry measures comparing similarity of prosthetic to intact limb strides, and repeatability measures comparing movement of one limb to its consecutive strides.FindingsBiomechanical differences in performance of the prosthetic and intact limb segments were detected with the segmental symmetry and segmental repeatability measures in 128 subjects. More asymmetries and less consistent movements of the lower limbs were exhibited by subjects with transfemoral amputation versus transtibial amputation (p < .004, Cohen's d = 0.65–1.1).InterpretationSensor-based measures of segmental symmetry and segmental repeatability were found to be reliable in detecting discreet differences in movement of the prosthetic versus intact lower limbs in amputee subjects. These measures provide a convenient tool for enhanced prosthetic gait analysis with the potential to focus rehabilitative and prosthetic interventions.     

Walking and balance in children and adolescents with lower-limb amputation: A review of literature

BackgroundChildren with lower limb loss face gait and balance limitations. Prosthetic rehabilitation is thus aimed at improving functional capacity and mobility throughout the developmental phases of the child amputee. This review of literature was conducted to determine the characteristics of prosthetic gait and balance among children and adolescents with lower-limb amputation or other limb loss.MethodsBoth qualitative and quantitative studies were included in this review and data were organized by amputation etiology, age range and level of amputation.FindingsThe findings indicated that the structural differences between children with lower-limb amputations and typically developing children lead to functional differences. Significant differences with respect to typically developing children were found in spatiotemporal, kinematic, and kinematic parameters and ground-reaction forces. Children with transtibial amputation place significantly larger load on their intact leg compared to the prosthetic leg during balance tasks. In more complex dynamic balance tests, they generally score lower than their typically developing peers.InterpretationThere is limited literature pertaining to improving physical therapy protocols, especially for different age groups, targeting gait and balance enhancements. Understanding gait and balance patterns of children with lower-limb amputation will benefit the design of prosthetic components and mobility rehabilitation protocols that improve long-term outcomes through adulthood.     

Muscle activation patterns during walking from transtibial amputees recorded within the residual limb-prosthetic interface

Powered lower limb prostheses could be more functional if they had access to feedforward control signals from the user’s nervous system. Myoelectric signals are one potential control source. The purpose of this study was to determine if muscle activation signals could be recorded from residual lower limb muscles within the prosthetic socket-limb interface during walking. We recorded surface electromyography from three lower leg muscles (tibilias anterior, gastrocnemius medial head, gastrocnemius lateral head) and four upper leg muscles (vastus lateralis, rectus femoris, biceps femoris, and gluteus medius) of 12 unilateral transtibial amputee subjects and 12 non-amputee subjects during treadmill walking at 0.7, 1.0, 1.3, and 1.6 m/s. Muscle signals were recorded from the amputated leg of amputee subjects and the right leg of control subjects. For amputee subjects, lower leg muscle signals were recorded from within the limb-socket interface and from muscles above the knee. We quantified differences in the muscle activation profile between amputee and control groups during treadmill walking using cross-correlation analyses. We also assessed the step-to-step inter-subject variability of these profiles by calculating variance-to-signal ratios. We found that amputee subjects demonstrated reliable muscle recruitment signals from residual lower leg muscles recorded within the prosthetic socket during walking, which were locked to particular phases of the gait cycle. However, muscle activation profile variability was higher for amputee subjects than for control subjects. Robotic lower limb prostheses could use myoelectric signals recorded from surface electrodes within the socket-limb interface to derive feedforward commands from the amputee’s nervous system.     

Muscle activation patterns during walking from transtibial amputees recorded within the residual limb-prosthetic interface

ABSTRACT: BACKGROUND: Powered lower limb prostheses could be more functional if they had access to feedforward control signals from the user's nervous system. Myoelectric signals are one potential control source. The purpose of this study was to determine if muscle activation signals could be recorded from residual lower limb muscles within the prosthetic socket-limb interface during walking. METHODS: We recorded surface electromyography from three lower leg muscles (tibilias anterior, gastrocnemius medial head, gastrocnemius lateral head) and four upper leg muscles (vastus lateralis, rectus femoris, biceps femoris, and gluteus medius) of 12 unilateral transtibial amputee subjects and 12 non-amputee subjects during treadmill walking at 0.7, 1.0, 1.3, and 1.6 m/s. Muscle signals were recorded from the amputated leg of amputee subjects and the right leg of control subjects. For amputee subjects, lower leg muscle signals were recorded from within the limb-socket interface and from muscles above the knee. We quantified differences in the muscle activation profile between amputee and control groups during treadmill walking using cross-correlation analyses. We also assessed the step-to-step intersubject variability of these profiles by calculating variance-to-signal ratios. RESULTS: We found that amputee subjects demonstrated reliable muscle recruitment signals from residual lower leg muscles recorded within the prosthetic socket during walking, which were locked to particular phases of the gait cycle. However, muscle activation profile variability was higher for amputee subjects than for control subjects. CONCLUSION: Robotic lower limb prostheses could use myoelectric signals recorded from surface electrodes within the socket-limb interface to derive feedforward commands from the amputee's nervous system.     

Biomechanical risk factors for knee osteoarthritis when using passive and powered ankle–foot prostheses

BackgroundGait compensations following transtibial amputation negatively affect sound limb loading and increase the risk of knee osteoarthritis. Push-off assistance provided by new powered prostheses may decrease the demands on the sound limb. However, their effects in a young population in the early stages of prosthetic use are still unknown. The purpose of this study was to compare limb loading between 1. passive and powered ankle–foot prostheses, 2. sound and amputated limbs, and 3. individuals with amputations in the relatively early stages of prosthetic use and controls.MethodsTen young, active individuals with unilateral transtibial amputation and 10 controls underwent biomechanical gait analysis at three speeds. The peak external knee flexor and adductor moments, adductor moment's angular impulse, peak vertical ground reaction force and loading rate were calculated. Repeated measures ANOVAs compared between limbs, prostheses, and groups.FindingsThe powered prosthesis did not decrease the sound limb's peak adduction moment or its impulse, but did decrease the external flexor moment, peak vertical force and loading rate as speed increased. The powered prosthesis decreased the loading rate from controls. The sound limb did not display a significantly greater risk for knee osteoarthritis than the intact limb or than controls in either device.InterpretationIn the early stages of prosthetic use, young individuals with transtibial amputation display few biomechanical risk factors for knee osteoarthritis development. However, a powered ankle–foot prosthesis still offers some benefits and may be used prophylactically to mitigate potential increases of these variables with continued prosthetic use over time.     

A comparative study of conventional and energy-storing prosthetic feet in high-functioning transfemoral amputees

OBJECTIVE: To compare the results of gait analysis, timed walking tests, and socket comfort for transfemoral amputees wearing initially a Multiflex conventional prosthetic foot and then a Vari-Flex energy-storing prosthetic foot. DESIGN: Experimental crossover trial. SETTING: A regional prosthetic and amputee rehabilitation tertiary referral center in a teaching hospital. PARTICIPANTS: Six established unilateral transfemoral prosthetic users. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Gait analysis, a timed walking test, and a Prosthetic Socket Fit Comfort Score for each amputee wearing the Multiflex foot and then repeated wearing the Vari-Flex foot. RESULTS: Wearing the Vari-Flex foot, our subjects walked faster in the gait lab (1.38 +/- 0.13 m/s, P < .001) and took more equal step lengths at fast speed (1.063 +/- 0.05, P < .05). They also had greater peak ankle dorsiflexion at push-off on the prosthetic side (18.3 degrees +/-4.73 degrees, P<.001) and 3 times as much power from the prosthetic ankle at push-off (1.13 +/- 0.22 W/kg, P < .001). There were no significant changes in temporal symmetry or loading of the prosthetic limb, in the timed walking test with each foot, or in the comfort score. CONCLUSIONS: A transfemoral amputee who wears an energy-storing foot can have a more symmetric gait with regard to some measures of spatial symmetry, kinetics, and kinematics than one who wears a conventional foot. However, in this study important aspects such as more symmetric loading and comfort did not differ significantly between the 2 foot types.     

Job satisfaction and health experience of people with a lower-limb amputation in comparison with healthy colleagues

OBJECTIVES: To describe indicators of job dissatisfaction among amputee employees and to compare job satisfaction and health experience of working amputee employees with that of control subjects. DESIGN: A cross-sectional study, mailed questionnaire. SETTING: Patients were recruited by the orthopedic workshops of the Netherlands. PARTICIPANTS: One hundred forty-four patients who had an acquired unilateral major amputation of the lower limb at least 2 years before, were aged 18 to 60 years (mean age, 43y), and were living and working in the Netherlands. One hundred forty-four control subjects matched for age, gender, and type of job. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Statistical analysis of responses to a questionnaire regarding patient characteristics and amputation-related factors, amputee patients' opinions about their work and the social atmosphere at work, and their general health (RAND 36-Item Health Survey [RAND-36]). RESULTS: People with an amputation had greater job satisfaction (70%) than did the able-bodied control group (54%). The wish for (better) modifications in the workplace and the presence of comorbidity were significantly related to job dissatisfaction in people with limb loss. Amputee employees were less often hindered by the failures of others and by fluctuations in temperature. People with limb loss showed a worse physical health experience than controls on the RAND-36. CONCLUSIONS: The vocational satisfaction of people with limb loss may be improved by better workplace modifications, depending on the functional capabilities of the person and the functional demands of the job; improvement may also be achieved by vocational rehabilitation programs, especially for those with an amputation in combination with other morbidity. Despite experiencing more health problems, the amputee group expressed greater job satisfaction than the able-bodied group, reflecting a great appreciation of job reintegration by people with a lower-limb amputation.