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PubMed1997

Double-limb support and step-length asymmetry in below-knee amputees.

The sequence of gait events and symmetry of kinematic parameters between both lower limbs are compromised in below-knee amputees. In the present study the periods of double-limb support and the step length in below-knee amputees were investigated. The symmetry of the two periods of double-limb support occurring in each stride was obviously abnormal (ratio: 0.74) among temporal and distance parameters. The time of double-limb support (0.211 +/- 0.05 seconds) measured from heel-strike of the amputated leg until toe-off of the normal leg was significantly longer (p = 0.011) when compared with the contralateral leg (0.173 +/- 0.04 seconds). The step length of the normal leg (0.709 +/- 0.07 m) was significantly (p = 0.045) shorter than that of the amputated leg (0.752 +/- 0.08 m). Most of these differences between measured kinematic parameters can be explained by the limited ability of the prosthesis ankle-foot component to reproduce the normal functions of both foot and ankle.

Adult↗

PubMed1986

Function after lower limb amputation.

Functional ability and social dependence were investigated by personal interview of 107 lower limb amputees surviving 1-5 years postoperatively. Among eight independent variables studied by multiple regression analysis, increased age was associated unfavorably with physical ability and social dependence. Independence from social provisions preoperatively showed favorable relationships with functional capacity and postoperative dependence. Above-knee or bilateral amputation and postoperative pain were associated with reduced functional ability, but not with social dependence. No significant association was found with cause of operation or sex of the amputees. The importance of proper prosthetic fitting and pain control is emphasized.

Activities of Daily Living↗

PubMed1986

Management of the upper-limb-deficient child with a powered prosthetic device.

A long-term survey of a large number of children fitted with an electrically powered upper-limb prosthesis seems not to have been reported in the literature. Children with upper-limb deficiencies (congenital or traumatic) were fitted with an electrically powered upper-limb prosthesis in Ontario during the 18-year period of 1965-1983. Seventy-eight patients responded to a questionnaire or were interviewed by telephone. The dropout rate in children with a below-elbow amputation was similar to that reported in below-elbow child amputees wearing a conventional body-powered prosthesis (10% vs. 13%). The acceptance rate in children with above-elbow amputations was higher in those wearing an electrically powered prosthesis than in those using the conventional prosthesis, testifying for improved prosthetic function in the former group.

Amputation, Traumatic↗

PubMed1994

Lower limb amputation: striking the balance.

During a 5-year period, 210 patients (125 male: aged 43-96 years, median 76 years) had 228 primary amputations for peripheral arterial disease. Level selection was by clinical criteria, and there were 148 below-knee (BK, 65%), 72 above-knee (AK, 32%) and eight Gritti-Stokes (GS, 3%). Revision was needed in 43 (19%). The 30-day mortality was 14%. There were 69 patients who had previously undergone bypass grafting (< 30 days in 36; 30 days-1 year 20; > 1 year 13). In these there were 57% BK and 43% AK with a revision rate of 13%--no worse than in patients who had not had attempted limb salvage. Decisions about rehabilitation were made by a team of doctors, nurses and therapists. The 69 patients fitted with prosthetic limbs between 1987 and 1990 were followed up for eventual mobility (minimum 6 months). Of these patients, 81% used their prosthesis at least around the house, but only 16% achieved near normal mobility. This series fails to support the claim that failed arterial bypass surgery prejudices amputation level or healing. Despite attempts to achieve a high rate of below-knee amputation and good rehabilitation, the revision rate remains high and really good prosthesis usage remains low in these elderly patients.

Adult↗

PubMed1995

Syme ankle disarticulation in peripheral vascular disease and diabetic foot infection: the one-stage versus two-stage procedure.

A prospective randomized trial compared performing a Syme ankle disarticulation using a one-stage versus Wagner's two-stage technique. Surgery was performed at two University Medical Centers where patients underwent amputation surgery for gangrene or nonsalvageable diabetic foot infection. Those undergoing surgery subsequent to trauma or congenital anomaly were eliminated. Initially, 21 patients were randomized into one-stage and two-stage surgery. The randomization was stopped for ethical reasons when the results of both procedures appeared to be similar. The next 22 consecutive patients underwent 23 Syme ankle disarticulations in one-stage surgery. Selection of amputation level was based on clinical examination, transcutaneous oximetry as a measure of vascular inflow, serum albumin as a measure of tissue nutrition, and total lymphocyte count as a measure of immunocompetence. As a total group, 31 of 44 amputations progressed to amputation wound healing and prosthetic limb fitting. In the randomized group, 9 of 13 one-stage and 5 of 8 two-stage surgeries healed. In the subsequent consecutive group, 17 of 23 healed. In all, 26 of 36 one-stage and 5 of 8 two-stage surgeries healed successfully. We concluded from this study that Syme ankle disarticulation may be performed as safely in one stage as in two stages in properly selected patients and, therefore, recommend the one-stage Syme ankle disarticulation in those patients suitable for this level amputation.

Adult↗

PubMed2000

Finite element analysis of bone stress and strain around a distal osseointegrated implant for prosthetic limb attachment.

Direct skeletal attachment techniques have recently been identified as an alternative method for percutaneous attachment of prosthetic limbs. Osseointegrated implants for prosthetic attachments are subjected to a complex load condition. This finite element study investigates the effect of varying geometries of the implant on the stress and strain distribution in the area of the bone/implant interface. Simplified three-dimensional axisymmetric models of the femur and seven implants with different core diameters, external diameters, implant lengths and thread pitches were derived. The resulting stress and strain distributions were compared. The significance of each implant geometry was identified for improving implant design in the light of benefit to the bone/implant osseointegration and the bone remodelling of the femur.

Artificial Limbs↗

PubMed1982

A Japanese lower limb prosthesis with a fore-joint foot and turntable.

Amputees wearing conventional prostheses have often found difficulty when conforming with the conventions of Japanese social life, since the prosthesis is not well adapted to walking in bare feet or sitting cross-legged. The authors described a modified prosthesis with a spring-loaded rotation mechanism that can be initiated unobtrusively and a modified foot piece in which the ankle motion is transmitted via a lever arm to a joint placed more anteriorly than usual. Nearly 250 patients have been fitted with the prosthesis and 40 have undergone laboratory gait analysis. The results indicate a walking cycle and foot pressure pattern more closely resembling the normal, than that obtained by other prosthetic systems.

Adolescent↗

PubMed1995

Functional outcomes in a lower limb amputee population.

This paper reports an evaluation of 132 patients seen at the Nova Scotia Rehabilitation Centre amputee programme during a 24-month period, carried out to evaluate the programme's effectiveness. In addition to a review of charts, a questionnaire was used (85% return rate) to help determine functional outcomes. The patient profile revealed a 3.4:1 male-to-female ratio and an average age of 64.8 +/- 13.0 years. The average overall training time was 44.0 +/- 26.5 days. Of the respondents, 65.5% wore their prosthesis at least 9 hours/day, 11.5% wore it at least 4 hours/day, and only 16.1% were no longer using their prosthesis. The programme's effectiveness appears to compare well with that of others reported in the literature.

Adult↗

PubMed1993

Comprehensive analysis of dynamic elastic response feet: Seattle Ankle/Lite Foot versus SACH foot.

This study evaluated biomechanical and metabolic performance differences between two prosthetic foot designs in light of their mechanical properties. Ten unilateral below-knee amputee subjects, at least 1 year after amputation, capable of walking and running, were studied. Differences in heel and forefoot compliance explained differences in gait events and alignment. Increased efficiency of pushoff in the Seattle Ankle/Lite Foot exists as evidenced by the decrease loading on the opposite limb during double support and a less shortened step length on the sound side compared to the SACH foot. The natural frequency of oscillation for the prosthetic feet was determined to be too high to provide energy storage and release synchronized with kinematic requirements because neither metabolic cost savings nor differences in metabolic efficiency were found. Comfortable walking speed and the nadir of metabolic rate and efficiency are not different. Via accelerometer measurement, it was found that the more compliant and lossy SACH foot heel was less likely to transmit high frequency vibration.

Adult↗

PubMed1991

Biomechanical analysis of the influence of prosthetic feet on below-knee amputee walking.

Although energy storing prosthetic feet have achieved widespread clinical acceptance, the effect of these components on the biomechanics of below-knee amputee gait is poorly understood. The purpose of this study was to determine the biomechanical adaptations used by the below-knee amputee while wearing a conventional prosthetic foot and to assess the influence of energy storing prosthetic feet on these adaptations. Mechanical power outputs of the lower extremity in five normal and five below-knee amputee subjects using the SACH, Seattle and Flex feet were studied. Ground reaction forces and kinematic data were collected at a walking speed of 1.5 m/s and were used to determine the muscular power outputs of the lower extremity during stance. Consistent patterns of muscular power output at the hip and knee of the residual limb occur. While wearing the SACH foot, negligible energy generation occurs at the prosthetic foot during pushoff. A decrease in energy absorption at the knee during the first half of stance and an increase in energy generation by the hip extensors were the major adaptations noted in the proximal muscle groups. Compared to the SACH foot, the energy storing feet demonstrated increased energy generation during pushoff. Despite the improvements in the performance of the energy storing prosthetic feet, no significant differences were found in the pattern or magnitude of knee and hip power outputs compared to the SACH foot.

Adult↗

PubMed1999

Save that arm: a study of problems in the remaining arm of unilateral upper limb amputees.

A study has been made by questionnaire, personal examination and telephone interview of unilateral upper limb amputees seen at the Prince Henry Hospital, Australia between 1994 and 1997. There were 60 questionnaires posted. Replies were received from 46. Problems were noted in the remaining arm of 23 (50%). The respondents' problems not only consisted of overuse symptoms, but also of an exacerbation of pre-existing arthritis and injury due to trauma to the remaining arm during the accident. Case histories are given in 3 typical cases. Treating professionals are warned about the hazards that one arm amputations present to the remaining arm.

Activities of Daily Living↗

PubMed1994

Clinical evaluation of the modular electromechanical lock actuator for above-elbow prostheses: a preliminary report.

The Modular Electromechanical Lock Actuator (MELA) is the result of research and development (R&D) conducted under the direction of Dudley S. Childress, PhD, at the Northwestern University Prosthetics Research Laboratory (NUPRL), Chicago, Illinois. NUPRL, based upon their experience with prostheses for persons with high-level, upper-limb amputations, developed MELA to provide users with more efficient, versatile control and operation of their existing, cable-operated, positive-locking elbow and wrist components. The design of MELA has advanced to the point where it has the potential to improve the functionality and effectiveness of existing, body-powered or manually positioned above-elbow prostheses. This R&D effort has resulted in a pre-market model that is now ready for the national field evaluation part of the technology transfer process coordinated through the VA Rehabilitation Research and Development Service, Technology Transfer Section.

Activities of Daily Living↗

PubMed1993

Prosthetic profile of people with lower extremity amputation: conception and design of a follow-up questionnaire.

A questionnaire, the Prosthetic Profile of the Amputee (PPA), is described both in terms of its conceptualization and design. The objectives of the questionnaire (mail and telephone versions) were to evaluate and to determine the factors potentially related to prosthetic use by a person with a lower extremity amputation after discharge from rehabilitation. The PRECEDE theoretical model (Predisposing Reinforcing and Enabling Causes in Educational Diagnosis and Evaluation) was adapted to the present study and served as a guide for the conceptual basis of the instrument. A multidisciplinary group of 13 experts and another group of eight persons with lower limb amputation were involved in the identification, classification, and priority rating of the factors related to prosthetic use. The design of the questionnaire was structured according to Dillman's Total Design Method. To ensure the content validity of the instrument, the pertinence of each question with regard to the questionnaire's objectives was assessed by the group of experts. Pretesting of the questionnaire was then conducted with a random sample of 26 people with lower extremity amputations. The preliminary version of the instrument has already demonstrated the potential for clinical and research use.

Activities of Daily Living↗

PubMed1995

Volumetric determinations with CAD/CAM in prosthetics and orthotics: errors of measurement.

During the next decade CAD/CAM technique will probably become routine in prosthetics and orthotics, not only as a complement to manual techniques, but also introducing new possibilities. However, even complex and sophisticated techniques have errors of measurement that must be considered. Such errors are of two principal kinds: systematic errors and random errors. In this study we have evaluated the Swedish CAPOD system with respect to volumetric determinations. We used two types of reference objects for volume determinations: cylinders and amputation residual limb models. Three different sizes were examined of each type of object. Volume measurements with CAPOD were compared with volumes obtained by water immersion or mathematical calculation (cylinders only). We found a constant, linear systematic error of +2.5%. Such an error can easily be corrected for. The random error, represented by the coefficient of variation, was 0.5%, which means that there is a theoretical possibility to detect volume changes exceeding 1%. We consider the precision sufficient for clinical practice in prosthetics and orthotics. Biological variations due to soft tissue deformation must be added on top of these errors. Such deformations were not evaluated in this study.

Artificial Limbs↗

PubMed1998

[Rehabilitation program for children and adolescents with limb defects or amputations of the lower extremity].

In rehabilitation of children and adolescents with lower limb deficiencies it is very important that the medical team taking care of the patient works out a treatment plan. Responsible cooperation with the parents is of utmost importance, the focus of all efforts is, of course, the handicapped child. The aims of rehabilitation are illustrated by examples demonstrating the course of successful rehabilitation of children and adolescents with damaged limbs. Equally, the psychological situation of the parents and child is taken into consideration. Children with limb deficiencies or amputation of the lower extremities should be enabled to stand and walk according to their state of development, because standing and walking in particular are among the most important preconditions for the best possible integration. Provision with a prosthesis, orthosis and orthoprosthesis is therefore indispensable for rehabilitation. While a prosthesis replaces parts of an extremity, an orthosis stabilizes the existing extremity. Orthoprostheses compensate longitudinal malformations, have a supporting effect, allow growth to be controlled, and compensate for shortening. Just as important as these technical aids is early medical treatment. The sooner the treatment starts, the better the results.

Adolescent↗

PubMed2006

Stump ulcers and continued prosthetic limb use.

Stump ulcers are common problems in amputees. Temporary discontinuation of prosthetic limb use is frequently employed to facilitate healing. Inevitably, this limits activity and may, for instance, prevent an amputee from going to work. A survey of clinical practice was carried out based on the premise that controlled continued prosthetic limb use in patients with stump ulcers will not adversely affect the ulcer nor prevent healing. The survey would also form a basis for developing future guidelines in the management of stump ulcers. All consecutive patients attending the Chapel Allerton Hospital prosthetic clinic between January 2003 and May 2004 with stump ulcers were recruited into the study. Primary outcome measures were changes in the surface area of the ulcers and in clinical photographs taken on 2 occasions 6 weeks apart. Some 102 patients with a mean age 60 years (range 18 - 88 years) were recruited. Eight patients who were established prosthetic limb users did not complete the study and were excluded from the analysis. Of the patients 52 were newly referred patients with delayed surgical wound healing while 42 were established prosthetic limb users for at least 1 year. Continued prosthetic limb was associated with a significant reduction in ulcer size (p < 0.05). Mean sizes of the ulcers at first and second observations were 3.30 cm2 (range 0.06 - 81) and 0.70 cm2 (range 0.00 - 13.00) respectively. The ulcers improved in 83 cases while two were unchanged. Deterioration was observed in nine cases. The current clinical practice is to allow most of the patients to commence or continue prosthetic limb wearing despite the presence of stump ulceration. This observational study found that, despite prosthetic use, 60 (64%) cases healed completely within the six-week study period and 23 (25%) ulcers reduced in size. The ulcers were unchanged in 2% of the cases. Deterioration was observed in nine (9%) cases. This survey suggests that the current practice of allowing patients to use their prostheses is safe. A clinical trial is now needed to establish whether this practice alters healing rate or has any other disadvantages for new or established amputees.

Adolescent↗

PubMed1991

Failure of centralization of the fibula for congenital longitudinal deficiency of the tibia.

Between 1962 and 1983, fourteen patients (twenty knees) had centralization of the fibula for congenital longitudinal deficiency: tibial, complete. Eleven of the twenty index procedures were performed on patients who were one year old or less. A progressive flexion deformity of the knee developed after all twenty index procedures. Twenty-six secondary procedures were needed, including disarticulation at the knee, posterior release, extension osteotomy, femorofibular arthrodesis, and biceps-to-quadriceps transfer, and one patient had a second attempt at centralization of the fibula. The duration of follow-up after the initial centralization of the fibula ranged from four years to twenty-two years and seven months (average, twelve years and four months). Seven patients (eight limbs) in whom the index procedure resulted in failure had a satisfactory result after disarticulation at the knee. The patients who did not have secondary disarticulation at the knee are also considered to have had a failed index procedure because they had a flexion deformity at the latest follow-up. Attempts to reconstruct the knee joint by centralization of the fibula are not warranted for patients who have congenital longitudinal deficiency: tibial, complete. Early disarticulation at the knee and fitting with a prosthesis, with close follow-up, is the treatment of choice.

Amputation, Surgical↗

PubMed1995

The prediction of metabolic energy expenditure during gait from mechanical energy of the limb: a preliminary study.

Measurements of metabolic energy consumption and free-walking velocity were recorded for four persons with trans-femoral amputation with variations of prosthesis mass and mass distribution. Hot-film anemometers, rate gyroscopes, and a force platform were used to measure prosthetic limb segment velocities and ground reaction forces. Metabolic energy consumption for the nine configurations of mass and mass distribution averaged 1.177 cal/kg/m with a standard deviation of +/- 0.052 cal/kg/m. Two measures of mechanical work of the amputated extremity, one based on power developed across joints (W1) and the other based on changes in energy of the body segments (W2), were computed to be 0.162 +/- 0.014 and 0.175 +/- 0.025 cal/kg/m, respectively. A linear regression model led to rejections of both W1 and W2 as predictors of metabolic energy expenditure of the amputee at a significance level of 0.05.

Aged↗