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PubMed1988

Acceptability of the NYU Number 1 Child-sized Body-powered Hand. New York University.

The NYU Number 1 Child-sized Body-powered Hand was field tested on 24 children with below-elbow limb deficiency. Identical in size (14.4cm, four-knuckle circumference) and shape to the Systemteknik myoelectric number 1 size hand, this hand offers a new prescription alternative for very young children with upper-limb amputation. The participating children and prosthetic clinic teams reacted very favorably to the hand's appearance, function, and light weight. Maintenance reports during the three-month trial were primarily concerned with glove damage. Overall, the hand was received enthusiastically, and is now in commercial production.

Artificial Limbs↗

PubMed2000

Precision-grip force changes in the anatomical and prosthetic limb during predictable load increases.

This study examined precision-grip force applied to an instrumented test object held aloft while the weight of the object was predictably varied by transporting and placing loads (50, 100, or 200 g) atop the test object. Transport of the loads was performed either by the subject or the experimenter. Grip force was examined in four non-amputee control subjects and in the anatomical and prosthetic hand of a subject with a prosthetic device. As subjects transported the load, anticipatory grip-force changes occurred in the anatomical hands and prosthetic hand, which were scaled in relation to the load. When the experimenter transported the load to the anatomical hands of control subjects or the prosthetic user, anticipatory increases in grip force occurred that also were scaled in relation to load. However, when the experimenter transported the load to the prosthetic hand, anticipatory grip-force adjustments were absent. During the phase in which the load was being assumed by the postural hand, grip forces in the anatomical hands and prosthetic hand were further scaled to load demands. Ability to adapt grip force in the prosthetic hand during this phase suggested that the subject was utilizing sensory information from the residual limb to adjust grip force. Thus, while anticipatory changes precede the process of adaptation to load changes, actual sensory consequences resulting from added weight remain necessary to fully adapt grip force to load demands, even for the prosthetic user.

Adaptation, Physiological↗

PubMed1994

Lower limb amputation following injury: a survey of long-term functional outcome.

Although there have been significant advances in surgical methods of limb preservation and various injury scores produced to predict the outcome after severe lower limb injury, there is common belief amongst surgeons that patients rehabilitate rapidly and well after amputation. There is however little evidence in the literature supporting this view of functional outcome of amputation following injury. A subjective assessment of post-injury lower limb amputees implied that there was a similar functional outcome in above- and below-knee amputations. Furthermore, there was little functional difference between early and delayed amputations, the delayed group being more satisfied with the end result.

Adolescent↗

PubMed1995

Development of a non-linear finite element modelling of the below-knee prosthetic socket interface.

A non-linear finite element model has been established to predict the pressure and shear stress distribution at the limb-socket interface in below-knee amputees with consideration of the skin-liner interface friction and slip. In this model, the limb tissue and socket liner were respectively meshed into 954 and 450 three-dimensional eight-node isoparametric brick elements, based on measurements of an individual's amputated limb surface; the bone was meshed into three-dimensional six-node triangular prism elements, based on radiographic measurements of the individual's residual limb. The socket shell was assumed to be a rigid boundary. An important feature of this model is the use of 450 interface elements (ABAQUS INTER4) which mimic the interface friction condition. The results indicate that a maximum pressure of 226 kPa, shear stress of 53 kPa and less than 4 mm slip exist at the skin-liner interface when the full body weight of 800 N is applied to the limb. The results also show that the coefficient of friction is a very sensitive parameter in determining the interface pressures, shear stresses and slip. With the growth of coefficient of friction, the shear stresses will increase, while the pressure and slip will decrease.

Artificial Limbs↗

PubMed2006

High failure rates when avoiding obstacles during treadmill walking in patients with a transtibial amputation.

OBJECTIVE: To investigate if and to what extent patients with a transtibial amputation are less successful in avoiding unexpected obstacles while walking than healthy adults. DESIGN: Experimental 2-group design. SETTING: Dutch rehabilitation center. PARTICIPANTS: Eleven patients with a transtibial amputation and 14 healthy controls. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Subjects walked on a treadmill at .56m/s. In 2 series of 12 trials each, an obstacle was dropped in front of the prosthetic or the nonprosthetic leg of the amputation group and the left leg of the control group at different phases during the step cycle. It was noted which avoidance strategy was used (a long step strategy [LSS] or a short step strategy [SSS]) and whether the obstacle was avoided successfully or not. These data were expressed as a percentage of the total number of trials completed by each subject. RESULTS: With either leg, the amputation group made significantly more errors than the control subjects (prosthetic leg, 24%+/-17%; nonprosthetic leg, 21%+/-17% vs 2%+/-2% for the control group). Highest failure rates were in the amputation group when time pressure was high, requiring an SSS, especially on the prosthetic side. An LSS under time pressure, however, nearly always resulted in failure for both the prosthetic and nonprosthetic legs. Subjects with the longest time since amputation were most successful in avoiding unexpected obstacles. CONCLUSIONS: Under time pressure, patients with a lower-leg prosthesis perform best when they use their nonprosthetic leg as the lead limb in an SSS. The fact that some subjects with the longest time since amputation made no errors suggests that over many years it is possible to relearn the appropriate avoidance reactions sufficiently fast.

Adult↗

PubMed2000

Equilibrium and movement control strategies in trans-tibial amputees.

This study was aimed at identifying changes in equilibrium and movement control strategies in trans-tibial amputees (TTA) related to both the biomechanical changes and the loss of afferent inflow. The coordinations between equilibrium and movement were studied in traumatical TTA and in controls during transition from bipedal to monopodal stance. TTA failed to perform the task in a high percentage of trials both when the sound and the prosthetic limb were supporting. Significant differences were also found between TTA and controls in the duration of the weight transfer phase, in the length of the initial centre of pressure (CP) displacement and in the electromyographic (EMG) patterns. Despite adaptive posturomotor control strategies, transition from bipedal to monopodal stance remains a difficult task to perform for TTA, both when the supporting limb is the affected one and when the sound one is. The results of this study are discussed with respect to the rehabilitation programme and the prosthesis design for transtibial amputees.

Adult↗

PubMed1975

Associated diagnoses which complicate rehabilitation of the patient with bilateral lower extremity amputations.

Cardiopulmonary problems were the most common limiting factor in the rehabilitation of 42 bilateral lower limb amputees. Diabetes mellitus and local stump problems, most common in below knee amputees, delayed rehabilitation but, subsequently, obtained the highest goals. Thirty of the 42 amputees finally were self sufficient; the average time required was 30 weeks to maximum benefit.

Adult↗

PubMed1982

Volume fluctuations in the residual limbs of lower limb amputees.

This study evaluated residual limb volume fluctuations of new and mature amputees in order to better plan for definitive limb prostheses. A measurement system based on a water displacement technique was used to measure cross-sectional area profiles of lower extremity amputation residual limbs. Reliable data were obtained for 32 of the 49 subjects participating in this study. Residual limb shrinkage cannot be characterized by any single pattern and therefore the date for fitting of a final prosthesis cannot be predicted precisely from regular volume measurements. Every amputee studied demonstrated an increase in body weight. Changes in residual limb volume early postoperatively were dictated by interaction of shrinkage and opposite effect of weight gain . Mature amputation limbs were observed to fluctuate in volume, and these fluctuations tended to correspond to body weight changes. For 3 general patterns of volume change observed early postoperatively, the best estimate of time to fit a final prosthesis appears to be about 150 days postamputation.

Adolescent↗

PubMed2000

Prosthetic foot roll-over shapes with implications for alignment of trans-tibial prostheses.

Roll-over shape is introduced as a significant characteristic of prosthetic feet. The roll-over shapes of the Flexwalk, Quantum, SACH, and SAFE prosthetic feet were determined using three methods; two involving quasi-static loading and one dynamic loading. The results show that foot roll-over shape properties obtained by quasi-static and by dynamic methods are similar. Relationships between foot roll-over shape and the alignment of trans-tibial prostheses are introduced that suggest ways to align trans-tibial prostheses without walking trials and iterations. The relationships may explain what prosthetists attempt to accomplish when they dynamically align a trans-tibial limb. They also explain why prosthetic feet with different mechanical properties usually necessitate different alignments, and may explain why a number of gait studies of trans-tibial amputees do not show major gait differences when walking is executed on various kinds of prosthetic feet.

Amputation, Surgical↗

PubMed1984

Characteristics of the child amputee population.

The characteristics and number of children with limb amputations in North America are not known. In an effort to secure information concerning the nature of the child amputee population (to 21 years of age) in the United States and Canada, a census of patients treated at member clinics of the Association of Children's Prosthetic-Orthotic Clinics (ACPOC) was conducted. It was designed to obtain a rational basis for children's prosthetic design, development, research, and educational activities. Of the 74 ACPOC prosthetic clinics to which the questionnaire was sent, 45 replies were analyzed, representing a total of 4,105 children under treatment at the reporting clinics during 1980, of which 679 cases (17%) were seen for the first time in that year. The results are consistent with prior unpublished censuses. Overall, congenital limb deficiencies outnumbered acquired losses by a ratio of 2:1, but among unilateral cases, more lower-limb amputations were acquired postpartum than congenitally. Eighty percent of all child amputees had had only one limb involved, and 54% of these unilateral cases were left amputees. Males outnumbered females 3:2, and over half of the children currently under treatment at the reporting clinics had been under 6 years of age at the time of first admission.

Adolescent↗

PubMed1991

The use of electric elbows in the rehabilitation of children with upper limb deficiencies.

For those with levels of loss above the elbow, the normal prescription choice is now considered to be the use of an electric elbow combined with a myoelectric hand using a single site three state control. The lightweight VASI unit controlled by a harness mounted switch is mounted in a prosthesis the socket of which is total contact, and allows improved power transfer.

Adolescent↗

PubMedDate not supplied

Mechanical properties of prosthetic limbs: adapting to the patient.

Lower-limb amputees have identified comfort and mobility as the two most important characteristics of a prosthesis. While these in turn depend on a multitude of factors, they are strongly influenced by the biomechanical performance of the prosthesis and the loading it imparts to the residual limb. Recent years have seen improvements in several prosthetic components that are designed to improve patient comfort and mobility. In this paper, we discuss two of these: VSAP and prosthetic foot-ankle systems; specifically, their mechanical properties and impact on amputee gait are presented.

Amputees↗

PubMed1992

Gait analysis in pediatric lower extremity amputees.

Walking function in 56 children with lower extremity amputations was assessed using a questionnaire and gait analysis. Children with prosthetic lower extremities can be very functional in society, often participating in sports. Limitations are proportional to the extent of the missing limbs. As a group, pediatric amputees walk more slowly than their normal peers with a slower cadence and a longer stride length. Pediatric amputees have higher heart rates when walking than normal children, but they seem willing to pay a higher physiologic price for ambulation.

Adolescent↗

PubMed1977

Controlled environment treatment for limb surgery and trauma (a preliminary report).

This paper demonstrates a new approach to postsurgical and post-traumatic wound management in the lower limbs. Our own results of 20 below-knee amputations are documented. A less detailed report is then given of experience with an additional 20 amputees: this second group includes experience not only here at Seattle but at five other centers in the United States. The same method for wound management and for control of edema was employed in all cases. The method, Controlled Environment Treatment (CET), uses filtered air as a dressing medium, with a control console to maintain the pressure, constant or varying, according to a preset program. Temperature and humidity are also controllable, as is gas composition. The limb, together with its controlled environment, is contained with a pliable, transparent, treatment bag, which permits inspection and palpation of the wound site without disturbing the bacteriologically sterile air within the chamber. A special seal reduces air leakage yet avoids constriction of the limb. This CET system was originally developed by the Department of Health and Social Security, Biomechanical Research and Development Unit, Roehampton, England. Subsequent developments are also noted of an improved Mark II CET Unit and of simpler, related, management systems for conditions not requiring sterile environments.

Adult↗

PubMed1983

Evaluation of problems and needs of veteran lower-limb amputees in the San Francisco Bay Area during the period 1977-1980.

From 1977 through 1980, 251 veterans from the San Francisco Bay Area received permanent lower-extremity prostheses at the two local Veterans Administration hospitals. For a survey, 213 of the 251 were contacted and 179 of them (84%) responded to written or telephone questionnaires concerning their prosthetic problems and complaints and their recommendations regarding prosthetic care. Seventy-four percent of the patients were traumatic amputees and 23 percent were dysvascular amputees. Eighty-six percent of the traumatic amputees said they wore their limbs all day, compared with only 51 percent of the dysvascular group. Seventy-one percent of traumatic and 43 percent of dysvascular amputees engaged in some form of recreational activity. There was a high incidence of complaints of pain in the residual limb: 55 percent among the dysvascular group and 44 percent among the traumatic group. Half of the patients had socket problems. Fifty-four of the 178 patients received a physical examination, a prosthetic evaluation, and a gait analysis. Among this group, 59 percent of the below-knee prostheses and 78 percent of the above-knee prostheses had inadequate socket fitting. Improper shaping of socket margins was the most frequently observed deficiency. Moreover, 41 percent of below-knee and 22 percent of above-knee amputees had mechanical skin irritation or skin breakdown in the examined residual limbs. Faulty suspension and alignment in addition to improper socket fit and construction contributed to this problem. Excessive stiffness of SACH foot heel cushions was the most common prosthetic foot problem and contributed to gait abnormalities.

Activities of Daily Living↗

PubMed2003

Amputation for soft-tissue sarcoma.

Soft-tissue sarcomas are a group of rare malignant tumours, many of which arise in the limbs. Most are treated with a combination of wide local excision and radiotherapy, but a small number--including proximal, large, high-grade, or recurrent tumours, or those involving major neurovascular structures--necessitate major amputation including forequarter or hindquarter amputation. These uncommon operations should remain in the surgical armamentarium for carefully selected patients. Those being considered for amputation should be referred to a tertiary sarcoma unit for examination of all other options, such as limb-salvage surgery, tumour downstaging with chemotherapy or radiotherapy (perhaps with subsequent limb-salvage surgery), or novel techniques such as isolated limb perfusion. Only after careful assessment should amputation be carried out. Outcomes after major amputation are highly variable, but such procedures can confer useful palliation to patients with distressing symptoms (pain, bleeding, fungation), long-term disease-free survival with reasonable function in carefully selected patients, and cure in some.

Amputation, Surgical↗

PubMed2003

Is the Rivermead Mobility Index appropriate to measure mobility in lower limb amputees?

PURPOSE: Measurement of lower limb amputee mobility was investigated using the Rivermead Mobility Index (RMI). METHOD: Reliability and reproducibility were assessed in 62 patients. The timed waking test (TWT) was used to investigate concurrent validity. The RMI construct was examined in 200 established amputees. RESULTS: One hundred and forty-four males and 66 females, aged 13-90 were recruited. Intraclass correlation coefficients and kappa statistics showed good reproducibility. Spearman correlation coefficient between the RMI and TWT -0.58 (p<0.000). Psychometric properties of the RMI were tested using item response theory. Hierachical differences in RMI grades were identified in amputees compared with neurologically impaired patients for which the RMI was developed. The RMI construct was not unidimensional, with redundancy of items and local dependency. At the upper end of the scale there were insufficient items measuring high levels of mobility. Finally, differential item functioning showed items behaving differently for patient subgroups. CONCLUSIONS: Although initial impressions suggest the RMI is a useful measure of lower limb amputee mobility, further analysis shows it is not appropriate for all amputees, with a number of limitations of its psychometric properties. Its use is not recommended in this population.

Activities of Daily Living↗

PubMed1997

The cost-effectiveness of limb salvage for bone tumours.

The use of endoprostheses for limb salvage in primary bone tumours is highly specialised. Studies have shown no significant difference in survival, function or quality of life between patients with limb salvage and those with amputation. We have derived a formula for calculating the ongoing costs of limb salvage with an endoprosthesis which is based on actual costs and uses historical data to show the likelihood of further surgery or revision. Comparative data for amputation are also shown. Using current prices, the cost-effectiveness of surgery with an endoprosthesis is clearly demonstrated.

Amputation, Surgical↗