Comparison of á priori alignment techniques for transtibial prostheses in the developing world - pilot study

PURPOSE: The purpose of this study was to evaluate three alignment systems based on two alignment theories that can be utilized in the fabrication of monolimb prostheses that have acceptable alignment. A second goal was to assess the feasibility of technology transfer for providing prosthetic services to remote areas of landmine-affected countries. METHOD: Five prosthetists and five healthy transtibial amputees participated in the study. Each prosthetist was trained and then used each of the three systems to capture alignment measurements for one subject. Three monolimbs identified as X, Y and Z were fabricated for each subject and assessed during clinical static and dynamic gait conditions. Training materials and methods were also evaluated. RESULTS: All three systems captured acceptable alignments fairly well, although the two systems that incorporated weight-bearing into the alignment process had slightly better outcomes. Each system has its own advantages in terms of ease of use, required equipment, and ease of technology transfer. CONCLUSION: All three systems have the potential for application in outreach prosthetic services and warrant continued evaluation. Minor changes need to be incorporated into the alignment systems and procedures to make them easier to use and more effective.     

Comparison of á priori alignment techniques for transtibial prostheses in the developing world-pilot study

Purpose. The purpose of this study was to evaluate three alignment systems based on two alignment theories that can be utilized in the fabrication of monolimb prostheses that have acceptable alignment. A second goal was to assess the feasibility of technology transfer for providing prosthetic services to remote areas of landmine-affected countries.

Method. Five prosthetists and five healthy transtibial amputees participated in the study. Each prosthetist was trained and then used each of the three systems to capture alignment measurements for one subject. Three monolimbs identified as X, Y and Z were fabricated for each subject and assessed during clinical static and dynamic gait conditions. Training materials and methods were also evaluated.

Results. All three systems captured acceptable alignments fairly well, although the two systems that incorporated weight-bearing into the alignment process had slightly better outcomes. Each system has its own advantages in terms of ease of use, required equipment, and ease of technology transfer.

Conclusion. All three systems have the potential for application in outreach prosthetic services and warrant continued evaluation. Minor changes need to be incorporated into the alignment systems and procedures to make them easier to use and more effective.     

Comparison of á priori alignment techniques for transtibial prostheses in the developing world – pilot study

Purpose. The purpose of this study was to evaluate three alignment systems based on two alignment theories that can be utilized in the fabrication of monolimb prostheses that have acceptable alignment. A second goal was to assess the feasibility of technology transfer for providing prosthetic services to remote areas of landmine-affected countries.

Method. Five prosthetists and five healthy transtibial amputees participated in the study. Each prosthetist was trained and then used each of the three systems to capture alignment measurements for one subject. Three monolimbs identified as X, Y and Z were fabricated for each subject and assessed during clinical static and dynamic gait conditions. Training materials and methods were also evaluated.

Results. All three systems captured acceptable alignments fairly well, although the two systems that incorporated weight-bearing into the alignment process had slightly better outcomes. Each system has its own advantages in terms of ease of use, required equipment, and ease of technology transfer.

Conclusion. All three systems have the potential for application in outreach prosthetic services and warrant continued evaluation. Minor changes need to be incorporated into the alignment systems and procedures to make them easier to use and more effective.     

Evaluation of amputees]

INTRODUCTION: Review of the literature about evaluation of amputees. MATERIALS AND METHODS: A search of the Medline and Reedoc databases with the key words lower limb amputee, upper limb amputee, evaluation of lower limb amputee, evaluation of upper limb amputee, survey of lower limb amputee, survey of upper limb and the same words in French for reports on the evaluation of amputees. RESULTS: Evaluations of amputees differ according to the level of amputation (lower or upper limb) and age (adult or child). They concern standing balance, walking (lower limb) and the mono- or bimanual prehensile capacities with or without prostheses in daily living activities and leisure (upper limb) as well as quality of life, personal satisfaction, psychological impact and, in particular, coping strategies. DISCUSSION: For lower-limb amputees, tools to evaluate include scales of deambulation, of which few are valid in French, and global scales (on locomotor capacities, quality of life and satisfaction), which have been recently validated, but only one of them is valid in French. For upper-limb amputees, specific and valid tools are not available for adults; however, for children some functional capacity scales in daily activities have been validated and take into account psychomotor development. None of these tools are valid in French, and their use is scattered and limited to validation studies. CONCLUSION: Only a few tools to evaluate amputees are valid in French for adults, and they concern lower-limb amputees only. Validating some of these tools in French is necessary.     

Significance of non-level walking on transtibial prosthesis fitting with particular reference to the effects of anterior-posterior alignment

Despite the fact that non-level walking is known to be important for prosthesis fitting, its clinical significance has not been investigated. In this study, the acceptable prosthesis alignment ranges of six subjects with transtibial amputation on level and non-level walking were determined and compared. With the aid of a recently developed alignment jig, prosthesis fitting was performed for each subject with varied anterior-posterior (AP) alignments. Conventional assessments and the subjects' comment were used to determine whether the alignment was acceptable or not. The results showed that the acceptable alignment range for non-level walking consistently fell within and was significantly smaller than that for level walking with p<0.05. It was evident that non-level walking is important for better approximation of optimum alignment and should be included in routine prosthesis fitting.     

Sprint kinematics of athletes with lower-limb amputations.

OBJECTIVE: To determine and compare the kinematics of the sound and prosthetic limb in five of the world's best unilateral amputee sprinters. SUBJECTS: Five men, all unilateral lower-limb amputee (one transfemoral, four transtibial) athletes. The individual with transfemoral amputation used a Endolite Hi-activity prosthesis incorporating a CaTech hydraulic swing and stance control unit, a Flex-Foot Modular III, and an ischial containment total contact socket. Those with transtibial amputations used prostheses incorporating a Flex-Foot Modular III and patellar tendon-bearing socket, with silicone sheath liner (Iceross) and lanyard suspension. DESIGN: Case series. Subjects were videotaped sprinting through a performance area. Sagittal plane lower-limb kinematics derived from manual digitization (at 50 Hz) of the video were determined for three sprint trials of the prosthetic and sound limb. Hip, knee, and ankle kinematics of each subject's sound and prosthetic limb were compared to highlight kinematic alterations resulting from the use of individual prostheses. Comparisons were also made with mean data from five able-bodied men who had similar sprinting ability. RESULTS: Sound limb hip and knee kinematics in all subjects with amputation were comparable to those in able-bodied subjects. The prosthetic knee of the transfemoral amputee athlete fully extended early in swing and remained so through stance. In the transtibial amputee athletes, as in able-bodied subjects, a pattern of stance flexion-extension was evident for both limbs. During stance, prosthetic ankle angles of the transtibial amputee subjects were similar to those of the sound side and those of able-bodied subjects. CONCLUSION: Prosthetic limb kinematics in transtibial amputee subjects were similar to those for the sound limb, and individuals achieved an "up-on-the-toes" gait typical of able-bodied sprinting. Kinematics for the prosthetic limb of the transfemoral amputee subject were more typical of those seen for walking. This resulted in a sprinting gait with large kinematic asymmetries between contralateral limbs.     

Causes and correction of abnormal gait patterns due to prosthesis in above-knee amputees

Abnormal gait patterns cause an increase in the energy cost of walking in above-knee amputees. Disturbances of the walking pattern are often caused both by the amputated patient himself and by incorrect prosthetic fitting. The early detection and correction of causative factors is of great importance for successful rehabilitation of these amputees. During the follow-up examinations the prosthesis must be inspected for a correct fitting and individually appropriate knee stabilizing components. Prior to any corrective measures it must be excluded that the artificial limb has been put on incorrectly by the amputee himself.     

Isometric and isokinetic hip abductor strength in persons with above-knee amputations

Recently introduced prosthetic socket designs for the above-knee amputee (AKA) feature a narrow medial-lateral dimension and emphasize maintenance of the residual limb in full physiologic adduction. Quantitative data on the effect of frontal plane limb position on the isometric hip abductor strength of ten otherwise healthy AKAs were obtained in the standing position. Residual limb isometric and isokinetic abductor strength was also measured and compared with that of the intact limb and with that of ten healthy age-, sex-, and height-matched control subjects using an identical technique. The testing hardware consisted of a modified Cybex II Isokinetic Dynamometer with a custom-made pelvis and trunk stabilizing device. Anthropometric measurements were taken. Results showed an essentially linear increase in residual limb abduction strength with progressive adduction from 30 degrees abduction to 16 degrees adduction. The average increase in abduction torque was .97% (range .29 to 1.5) of the peak neutral position strength per degree of change in femur angle when corrected for the effect of gravity. Similar strength increases with adduction of the femur were found for intact and control limbs. Mean residual limb isometric abduction torque measured 30% less than the intact limb value (p = .0018). The difference between the intact and the control limb mean isometric abduction torques was less than 1%. Isokinetic testing was technically more difficult than isometric testing but revealed similar weakness of the residual limb abductors when compared to the intact and control limbs.     

Use and satisfaction with prosthetic limb devices and related services

OBJECTIVES: To examine the use and satisfaction with prosthetic limb devices and satisfaction with prosthetist services in a large and diverse sample of persons with limb loss. DESIGN: Retrospective cohort study. SETTING: General community. PARTICIPANTS: Persons aged 18 to 84 years identified from the Amputee Coalition of America registry as having a major upper- or lower-limb loss due to vascular disease, trauma, or malignancy. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Use and satisfaction with prosthetic limb devices and satisfaction with prosthetists' services, assessed via structured telephone interviews. RESULTS: Most persons (94.5%) surveyed had a prosthesis and used it extensively (71h/wk). Most persons with amputations appeared to be satisfied with the overall performance of their prostheses (75.7%). Nearly one third of them, however, expressed dissatisfaction with their prostheses' comfort. Frequency of prosthesis use and satisfaction with the device were significantly higher among those with shorter timing to first prosthesis fitting, even after controlling for a wide array of respondents' sociodemographic and amputation characteristics. Overall, persons with amputations in our sample had positive assessments of their prosthetists' quality. Less favorable ratings concerned items related to the prosthetists' interpersonal skills. Multivariate analyses showed that men and black persons with amputations were less likely than their female or white counterparts to have favorable perceptions about their prosthetists across all dimensions of provider quality. Persons with fewer years of schooling were also less likely to be satisfied with their prosthetist's interpersonal manner. There were no significant differences in prosthesis use, satisfaction, or assessment of prosthetists' quality based on amputation etiology or amputation level. CONCLUSIONS: Efforts should be directed at minimizing the interval from surgery to first prosthesis fitting and at improving communication between patients and prosthetists, to improve the quality of care provided to the growing numbers of persons with limb loss.     

Outcome of prosthetic management of bilateral lower-limb amputees.

This study was designed to evaluate the outcome in 41 bilateral lower-limb amputees admitted to an inpatient unit for prosthetic rehabilitation. Outcome measures were obtained using a simple activities of daily living score, the Frenchay Activities Index, mobility grading, and assessment of home adaptations. Though excellent success rates were obtained after completion of physiotherapy, the majority of the above-knee amputees had abandoned their prostheses by the time of review. Bilateral below-knee amputees, however, continued to do well regarding their prosthetic mobility, and prosthesis users were more independent in their activities of daily living. We believe that inpatient rehabilitation programmes for bilateral amputees are likely to prove more satisfactory than prolonged outpatient physiotherapy.     

The gait initiation process in unilateral lower-limb amputees when stepping up and stepping down to a new level

BACKGROUND: Unilateral lower-limb amputees lead with their intact limb when stepping up and with their prosthesis when stepping down; the gait initiation process for the different stepping directions has not previously been investigated. METHODS: Ten unilateral amputees (5 transfemoral and 5 transtibial) and 8 able-bodied controls performed single steps up and single steps down to a new level (73 and 219 mm). Duration, a-p and m-l centre of mass and centre of pressure peak displacements and centre of mass peak velocity of the anticipatory postural adjustment and step execution phase were evaluated for each stepping direction by analysing data collected using a Vicon 3D motion analysis system. FINDINGS: There were significant differences (in the phase duration, peak a-p and m-l centre of pressure displacement and peak a-p and m-l centre of mass velocity at heel-off and at foot-contact) between both amputee sub-groups and controls (P<0.05), but not between amputee sub-groups. These group differences were mainly a result of amputees adopting a different gait initiation strategy for each stepping direction. INTERPRETATION: Findings indicate the gait initiation process utilised by lower-limb amputees was dependent on the direction of stepping and more particularly by which limb the amputee led with; this suggests that the balance and postural control of gait initiation is not governed by a fixed motor program, and thus that becoming an amputee will require time and training to develop alternative neuromuscular control and coordination strategies. These findings should be considered when developing training/rehabilitation programs.     

Individual responses to alignment perturbations in socket reaction moments while walking in transtibial prostheses

Background

The alignment of transtibial prostheses has a systematic effect on the mean socket reaction moments in amputees. However, understanding their individual differences in response to alignment perturbations is also important for prosthetists to fully utilize the socket reaction moments for dynamic alignment in each unique patient. The aim of this study was to investigate individual responses to alignment perturbations in transtibial prostheses with solid-ankle-cushion-heel feet.

Methods

A custom instrumented prosthesis alignment component was used to measure the socket reaction moments while walking in 11 amputees with transtibial prostheses under 17 alignment conditions, including 3° and 6° of flexion, extension, abduction, and adduction of the socket, 5 mm and 10 mm of anterior, posterior, lateral, and medial translation of the socket, and an initial baseline alignment. Coronal moments at 30% of stance and maximum sagittal moments were extracted for comparisons from each amputee.

Findings

In the coronal plane, varus moment at 30% of stance was generally reduced by adduction or medial translation of the socket in all the amputees. In the sagittal plane, extension moment was generally increased by posterior translation or flexion of the socket; however, this was not necessarily the case for all the amputees.

Interpretations

Individual responses to alignment perturbations are not always consistent, and prosthetists would need to be aware of this variance when addressing individual socket reaction moments during dynamic alignment in clinical setting.     

Investigation of lower-limb tissue perfusion during loading

An extant tissue indentor used for amputee residual limb tissue indentation studies was modified to include laser Doppler flowmetry (LDF) to enable measurement of tissue perfusion during indentation. This device allows quantitative assessment of the mechanical and physiological response of soft tissues to load, as demonstrated by indentation studies of the lower-limb tissues of young healthy subjects. Potential measures of interest include the relative change in tissue perfusion with load and the time delays associated with the perfusion response during tissue loading and unloading. Such measures may prove useful in future studies of residual limb tissues, improving our understanding of tissue viability risk factors for individuals with lower-limb amputation.     

Evaluating a written emotional disclosure homework intervention for lower-limb amputees

OBJECTIVE: To evaluate the Pennebaker Emotional Disclosure paradigm with lower-limb amputee patients in terms of compliance and efficacy. DESIGN: Repeated measures. SETTING: Home based. PARTICIPANTS: Low compliance, both with the initial mailed request (28%) and the subsequent writing task (48%), resulted in 23 lower-limb amputees who had been fitted with a prosthesis participating. INTERVENTIONS: Patients completed a 15-minute writing task, 6 times, over 2 weeks, with initial baseline and 2-month follow-up assessments. MAIN OUTCOME MEASURES: Cognitive processing, well-being, adjustment to an artificial limb, pain, and prosthetic use. RESULTS: Stronger emotional disclosure was associated with significant reductions in psychologic and physical aspects of amputees' satisfaction with their prosthesis, some of which were mediated by positive changes in affect immediately after the writing tasks. CONCLUSIONS: Our results failed to support previous findings with nonclinical samples; in fact, our results contradicted previous findings. We therefore caution that written emotional disclosure may be contraindicated with lower-limb amputee patients.     

A computer-aided socket design procedure for above-knee prostheses.

A computer-aided socket design procedure (CASD) has been developed whereby an above-knee socket shape can be created based on anthropometric measurements taken from an amputee. The anthroometric measurements are used to select a subset of three reference shapes from a Reference Shape Library stored in the computer in the form of three-dimensional numerical data. Transformation procedures then scale the reference shapes at each cross-sectional level to match the amputee's cross-sectional areas. Blending of the three shapes is determined by tissue mass weighting factors, to yield a single custom socket configuration, known as the "basic socket shape." Subsequent graphical procedures in the CASD system allows further sculpting of the shape in the form of interactive adjustments of the numerical data to reach the socket shape desired by the prosthetist. The resultant shape data can then be transferred to a computer numerically controlled (CNC) milling machine to carve a model of the socket shape.     

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.     

Evaluation and comparison of á priori alignment techniques for transtibial prostheses in the developing world – Field trial in Nicaragua

Purpose. The purpose of this study was to transfer three simplified alignment techniques to prosthetic technicians in a developing country through training materials and a hands-on training workshop, and to subsequently evaluate the efficacy of the alignment systems in producing acceptably aligned monolimb prostheses.

Method. Prosthetists utilized the anatomically-based-alignment (ABA)-standing, ABA-supine and vertical alignment axis (VAA) alignment systems to produce three monolimbs for each of 30 healthy and active transtibial amputees. Prosthetists assessed all three monolimbs for each subject in both static and gait conditions to determine which monolimb had the best alignment and produced the best functional gait. Subjects also selected the monolimb which they believed had the best alignment; subjects utilized each monolimb for a 1-month home assessment.

Results. Twenty-eight subjects completed the study. Eighty-four monolimbs were evaluated by the prosthetists and the subjects. A few monolimbs had minor socket fitting and alignment issues, but none prevented evaluation in the laboratory or during the 1-month home assessment. Only three monolimbs had poor alignment and could not be worn by the subjects.

Conclusions. All three systems captured acceptable alignments, although the two systems that incorporate weight bearing, the ABA-standing and VAA alignment systems, produced slightly better outcomes. The alignment ratings between these two systems were statistically insignificant.     

Modeling and simulation of muscle forces of trans-tibial amputee to study effect of prosthetic alignment

BackgroundThe muscle forces tend to change when any musculoskeletal system is damaged. It is necessary to predict and explain the patterns of muscle forces in the stump of a left trans-tibial amputee during walking, and to study the effects of the prosthetic alignment.MethodsMusculoskeletal modeling and computer simulation were combined to calculate muscle forces in the trans-tibial lower limb during walking. The prosthesis was aligned to be in optimal position for the subject and then changed into +6° and −6° in the sagittal plane relatively. Kinematic data of the stump wearing a prosthesis and ground reaction forces were simultaneously recorded by a gait analysis system and a force platform, respectively. The data were input into a model of the lower trans-tibial extremity with three-dimensional geometry and the corresponding seven muscle forces were predicted by a static optimization.FindingsMuscles performed much more actively in stance than in swing phase. Most muscles appeared very active around both heel-strike and toe-off. Muscle forces predicted were similar to that in temporal distribution at all three alignment conditions but the major muscles such as gluteus maximus, hamstrings, vasti and rectus femoris generated remarkable greater forces in −6° and +6° alignments than the normal condition.InterpretationThe above results showed the muscle forces increasing at the mal-alignment. Because the incorrect alignment could break the relative position of the socket and foot, and that would generate the extra joint moments. As a result, muscle forces increased, and the long-duration fatigue occurs more easily. The finding suggests that the proper prosthetic alignment is very important for the stump muscles normal activities.