Gait adjustments in obstacle crossing, gait initiation and gait termination after a recent lower limb amputation.

OBJECTIVE: To describe the adjustments in gait characteristics of obstacle crossing, gait initiation and gait termination that occur in subjects with a recent lower limb amputation during the rehabilitation process. DESIGN: Prospective and descriptive study. SUBJECTS: Fourteen subjects with a recent transfemoral, knee disarticulation or transtibial amputation. METHODS: Subjects stepped over an obstacle and initiated and terminated gait at four different times during the rehabilitation process. OUTCOME MEASURES: Success rate, gait velocity and lower limb joint angles in obstacle crossing, centre of pressure shift and peak anteroposterior ground reaction force in gait initiation and termination. RESULTS: In obstacle crossing amputees increased success rate, gait velocity and swing knee flexion of the prosthetic limb. Knee flexion in transfemoral and knee disarticulation amputees was not sufficient for safe obstacle crossing, which resulted in a circumduction strategy. In gait initiation and termination amputees increased the anteroposterior ground reaction force and the centre of pressure shift in the mediolateral direction in both tasks. Throughout the rehabilitation process the centre of pressure was shifted anteriorly before single-limb stance on the trailing prosthetic limb in gait initiation, whereas in gait termination the centre of pressure in single-limb stance remained posterior when leading with the prosthetic limb. CONCLUSION: Subjects with a recent amputation develop adjustment strategies to improve obstacle crossing, gait initiation and gait termination. Innovations in prosthetic design or training methods may ease the learning process of these tasks.

Job adjustments, job satisfaction and health experience in upper and lower limb amputees.

OBJECTIVES: To explore job adjustments, job satisfaction, and health experience among employees with an upper limb amputation and to compare the results with those of lower limb amputees and control subjects. METHODS: Amputees were recruited from data files of a large European University Medical Centre and orthopaedic workshops. Controls were matched colleagues of the lower limb amputees. All participants filled out the VAG questionnaire (Vragenlijst Arbeid en Gezondheid), assessing job satisfaction and job adjustments, and the RAND-36. RESULTS: 28 upper limb amputees were compared to 144 lower limb amputees and 144 controls. Job adjustments were necessary in 38% and 28% of upper and lower limb amputees, respectively. All three groups were equally satisfied with their jobs (p = 0.90). Vocational rehabilitation was applied to 26% and 8% of upper and lower limb amputees, respectively. Upper limb amputees rated their general health worse (18 points, 95% CI: 12-25) compared to lower limb amputees, corrected for effects of confounders (age and co-morbidity). CONCLUSIONS: Upper and lower limb amputees have high job satisfaction and a minority need job adjustments. In upper limb amputees, the causes of the worrisome general health experience need further investigation. In upper and lower limb amputees, vocational rehabilitation deserves additional attention.

Controlling propulsive forces in gait initiation in transfemoral amputees.

During prosthetic gait initiation, transfemoral (TF) amputees control the spatial and temporal parameters that modulate the propulsive forces, the positions of the center of pressure (CoP), and the center of mass (CoM). Whether their sound leg or the prosthetic leg is leading, the TF amputees reach the same end velocity. We wondered how the CoM velocity build up is influenced by the differences in propulsive components in the legs and how the trajectory of the CoP differs from the CoP trajectory in able bodied (AB) subjects. Seven TF subjects and eight AB subjects were tested on a force plate and on an 8 m long walkway. On the force plate, they initiated gait two times with their sound leg and two times with their prosthetic leg. Force measurement data were used to calculate the CoM velocity curves in horizontal and vertical directions. Gait initiated on the walkway was used to determine the leg preference. We hypothesized that because of the differences in propulsive components, the motions of the CoP and the CoM have to be different, as ankle muscles are used to help generate horizontal ground reaction force components. Also, due to the absence of an active ankle function in the prosthetic leg, the vertical CoM velocity during gait initiation may be different when leading with the prosthetic leg compared to when leading with the sound leg. The data showed that whether the TF subjects initiated a gait with their prosthetic leg or with their sound leg, their horizontal end velocity was equal. The subjects compensated the loss of propulsive force under the prosthesis with the sound leg, both when the prosthetic leg was leading and when the sound leg was leading. In the vertical CoM velocity, a tendency for differences between the two conditions was found. When initiating gait with the sound leg, the downward vertical CoM velocity at the end of the gait initiation was higher compared to when leading with the prosthetic leg. Our subjects used a gait initiation strategy that depended mainly on the active ankle function of the sound leg; therefore, they changed the relative durations of the gait initiation anticipatory postural adjustment phase and the step execution phase. Both legs were controlled in one single system of gait propulsion. The shape of the CoP trajectories, the applied forces, and the CoM velocity curves are described in this paper.

Control of lateral balance in walking. Experimental findings in normal subjects and above-knee amputees.

In walking the human body is never in balance. Most of the time the trunk is supported by one leg and the centre of mass (CoM) 'falls' to the contralateral side. In dynamical situations the velocity of the CoM should be acknowledged as well in the 'extrapolated centre of mass' (XcoM). Centre of pressure (CoP) position was recorded by a treadmill with built-in force transducers. Lateral CoM and XcoM position were computed by filtering the CoP data. Subjects were six above-knee amputees and six matched healthy controls. They walked at approximately 0.75, 1, and 1.25m/s for 2min. Amputees showed asymmetric gait with shorter stance (60%) at the prosthetic side versus 68% at the non-prosthetic side and a wider stride (13+/-4cm, mean+/-S.D.) compared to controls (9+/-3cm). At foot placement CoP was just lateral to the XcoM. The margin between average CoP and XcoM at foot contact was only 1.6+/-0.7cm in controls, 2.7+/-0.5cm in amputees at the prosthetic side and 1.9+/-0.6cm at the non-prosthetic side. Next to this 'stepping strategy', CoP position was corrected after initial contact by modulating the lateral foot roll-off ('lateral ankle strategy') in non-prosthetic legs up to about 2cm. A simple mechanical model, the inverted pendulum model, can explain that: (1) a less precise foot placement (greater CoP-XcoM margin) results in a wider stride, (2) this effect can be reduced by walking with a higher cadence, and (3) a greater margin at one side, as with a leg prosthesis, should be compensated by a shorter stance duration at the same side to achieve a straight path. This suggests that not in all cases symmetric gait should be an aim of rehabilitation.

Development of an exercise testing protocol for patients with a lower limb amputation: results of a pilot study.

Due to a decrease in physical activity, lower limb amputees experience a decline in physical fitness. This causes problems in walking with a prosthesis because energy expenditure in walking with a prosthesis is much higher than in walking with two sound legs. Exercise training may therefore increase the functional walking ability of these patients. To generate a safe and effective aerobic training program, exercise testing of amputees is recommended. The objectives of this study were to develop a maximal exercise testing protocol for lower limb amputees and to compare two different testing methods: combined arm-leg ergometry and arm ergometry. The protocols were tested in five amputee patients. Combined ergometry elicited a higher oxygen uptake and heart rate than arm ergometry. Electrocardiography during combined ergometry was easier to read. Combined ergometry was judged most comfortable by the amputees. The exercise testing protocol was useful in lower limb amputees to determine their maximal aerobic capacity and their main exercise limitation. Future exercise training programs may be based on this testing protocol. Combined arm-leg ergometry is appropriate for unilateral amputees without significant claudication of the remaining leg. Continuous arm ergometry is suitable for unilateral amputees with significant claudication of the remaining limb or bilateral amputees.

Physical, mental, and social predictors of functional outcome in unilateral lower-limb amputees.

OBJECTIVE: To study the value of physical, mental, and social characteristics as predictors of functional outcome of elderly amputees. DESIGN: Prospective, inception cohort study; comparisons with reference populations. SETTING: Main hospitals, rehabilitation centers, nursing homes, patients' own residence settings in 1 of the 3 northern provinces in the Netherlands. PARTICIPANTS: Forty-six patients older than 60 years, with unilateral transtibial or transfemoral amputation or knee disarticulation because of vascular disease. INTERVENTIONS: Measurement of physical, mental, and social predictors 2 and 6 weeks postamputation. MAIN OUTCOME MEASURES: The Sickness Impact Profile (SIP-68), Groningen Activity Restriction Scale (GARS), Timed up and go (TUG) test, and prosthetic use. RESULTS: A total of 15% of amputees died within the first year after amputation. Seventy percent lived independently at home 1 year postamputation. The functional level of the patients was low, as shown by high scores on the SIP-68 (mean, 23.6), GARS (mean, 41.2), and TUG test (mean, 23.9s). Functionally effective prosthetic use, as measured with the classification of Narang and Pohjolainen, was reached by 49%. For the SIP-68 scores, age, comorbidity, 1-leg balance, and the 15-word test predicted functional outcome in 69% of amputees. For the GARS score, age, 1-leg balance, and the 15-word test predicted functional outcome in 64%. For the TUG test, age and 1-leg balance predicted functional outcome in 42% of amputees. After correction for age, the only significant predictor for prosthetic use was 1-leg balance. CONCLUSIONS: Elderly patients with a leg amputation had a low functional level 1-year postamputation. An important part of functional outcome could be predicted 2 weeks after amputation by age at amputation, 1-leg balance on the unaffected limb, and cognitive impairment. Severe comorbidity probably also played a role. The results may be used in the general policy concerning leg amputees.

Phantom pain and health-related quality of life in lower limb amputees.

Amputation of a limb may affect quality of life. However, little is known concerning health-related quality of life in amputees. The purposes of this study were to describe health-related quality of life in a population of lower limb amputees and to investigate potential determinants, including phantom pain. Data from 437 patients with a lower limb amputation were analyzed in this cross-sectional study. Amputation-related problems were investigated using a questionnaire. Health-related quality of life was investigated using the RAND-36 DLV. Amputees with phantom pain had a poorer health-related quality of life than amputees without phantom pain. In general, the most important amputation-specific determinants of health-related quality of life were "walking distance" and "stump pain."

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.