Biomechanical and clinical evaluation of a newly designed polycentric knee of transfemoral prosthesis.
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We have designed a new polycentric knee adopting a hydraulic unit and an intelligent mechanism. The biomechanical parameters of this prototype, such as the stance duration, peak knee flexion angle in stance and swing, peak hip flexion angle, and peak hip extension moments were analyzed at three different cadences (88, 96, 104 steps/min) in three amputees, and then compared to those of polycentric hydraulic knees currently in use. The same parameters were also measured for 10 healthy volunteers and subsequently analyzed. In the prototype, almost all the values of the parameters showed no significant variety in individuals at the different cadences. The situation was the same with the healthy volunteers. However, the values of the parameter for the conventional knee varied significantly with the individual at the different cadences. The prototype may be of practical use, contributing to a stable walk even at different cadences. (+info)
Questionnaire for Persons with a Transfemoral Amputation (Q-TFA): initial validity and reliability of a new outcome measure.
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The Questionnaire for Persons with a Transfemoral Amputation (Q-TFA) is a new self-report measure developed for nonelderly transfemoral amputees using a socket- or osseointegrated prosthesis to reflect use, mobility, problems, and global health, each in a separate score (0-100). This paper describes the initial measurement properties of the Q-TFA as completed by 156 persons with a transfemoral amputation using a socket prosthesis (67% male, 92% nonvascular cases, mean age 51 years). Criterion validity was determined by associations between scores of the Q-TFA and the Short-Form 36 (SF-36)-Item Health Survey. Reliability was assessed by retest (n = 48) and by determination of the internal consistency. Correlations between Q-TFA and SF-36-Item Health Survey scales matched hypothesized patterns. Intraclass correlations were between 0.89 and 0.97, and measurement error ranged from 10 to 19 points. Cronbach's alpha revealed good internal consistency, with no values less than 0.7. This study shows that the Q-TFA, applied to persons using a transfemoral socket prosthesis, has adequate initial validity and reliability. (+info)
A customised replacement for polyostotic fibrous dysplasia of the upper femur. A 51-year follow-up.
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We report the case of a 12-year-old boy with polyostotic fibrous dysplasia of the upper femur in whom a massive customised polyethylene prosthesis functioned successfully for more than fifty years. (+info)
Energy expenditure during walking in amputees after disarticulation of the hip. A microprocessor-controlled swing-phase control knee versus a mechanical-controlled stance-phase control knee.
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We have compared the energy expenditure during walking in three patients, aged between 51 and 55 years, with unilateral disarticulation of the hip when using the mechanical-controlled stance-phase control knee (Otto Bock 3R15) and the microprocessor-controlled pneumatic swing-phase control knee (Intelligent Prosthesis, IP). All had an endoskeletal hip disarticulation prosthesis with an Otto Bock 7E7 hip and a single-axis foot. The energy expenditure was measured when walking at speeds of 30, 50, and 70 m/min. Two patients showed a decreased uptake of oxygen (energy expenditure per unit time, ml/kg/min) of between 10.3% and 39.6% when using the IP compared with the Otto Bock 3R15 at the same speeds. One did not show any significant difference in the uptake of oxygen at 30 m/min, but at 50 and 70 m/min, a decrease in uptake of between 10.5% and 11.6% was found when using the IP. The use of the IP decreased the energy expenditure of walking in these patients. (+info)
Late orthopaedic sequelae following meningococcal septicaemia. A multicentre study.
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Between 1990 and 2001, 24 children aged between 15 months and 11 years presented with late orthopaedic sequelae after meningococcal septicaemia. The median time to presentation was 32 months (12 to 119) after the acute phase of the disease. The reasons for referral included angular deformity, limb-length discrepancy, joint contracture and problems with prosthetic fitting. Angular deformity with or without limb-length discrepancy was the most common presentation. Partial growth arrest was the cause of the angular deformity. Multiple growth-plate involvement occurred in 14 children. The lower limbs were affected much more often than the upper. Twenty-three children underwent operations for realignment of the mechanical axis and limb-length equalisation. In 15 patients with angular deformity around the knee the deformity recurred. As a result we recommend performing a realignment procedure with epiphysiodesis of the remaining growth plate when correcting angular deformities. (+info)
Clinical detection and movement recognition of neuro signals.
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Neuro signal has many more advantages than myoelectricity in providing information for prosthesis control, and can be an ideal source for developing new prosthesis. In this work, by implanting intrafascicular electrode clinically in the amputee's upper extremity, collective signals from fascicules of three main nerves (radial nerve, ulnar nerve and medium nerve) were successfully detected with sufficient fidelity and without infection. Initial analysis of features under different actions was performed and movement recognition of detected samples was attempted. Singular value decomposition features (SVD) extracted from wavelet coefficients were used as inputs for neural network classifier to predict amputee's movement intentions. The whole training rate was up to 80.94% and the test rate was 56.87% without over-training. This result gives inspiring prospect that collective signals from fascicules of the three main nerves are feasible sources for controlling prosthesis. Ways for improving accuracy in developing prosthesis controlled by neuro signals are discussed in the end. (+info)
A preliminary investigation into the development of 3-D printing of prosthetic sockets.
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The socket is considered an element of major importance in the makeup of a prosthesis. Each socket is a tailor-made device, designed to fit the unique geometry of the patient's residual limb. The design and manufacture of a prosthetic socket traditionally has been a manual process that relies on the use of plaster of Paris casts to capture the shape of the patient's residual limb and then artisan fabrication techniques to manufacture the socket. Computer-aided design and manufacturing technologies have overcome some of the shortcomings of the traditional process, but the final manufacture of the prosthetic socket is still performed manually. Rapid prototyping (RP), a relatively new class of manufacturing technologies, creates physical models directly from three-dimensional (3-D) computer data. Previous research into the application of RP systems to the manufacture of prosthetic sockets has focused on expensive, high-end technologies that have proven too expensive. This paper investigates the use of a cheaper, low-end RP technology known as 3-D printing. Our investigation was an initial approach to using a technology that is normally associated with producing prototypes quickly, some of which could not be manufactured by alternative means. Under normal circumstances, these printed components are weak and relatively fragile. However, comfortable prosthetic sockets manufactured with 3-D printing have been used in preliminary fittings with patients. (+info)
Residual-limb skin temperature in transtibial sockets.
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The insulated environment of the lower-limb prosthesis can result in elevated residual-limb skin temperatures that may contribute to skin irritation, blistering, and a reduced quality of life. The design and materials of the prosthetic socket, suspension system, and liner can potentially alleviate these conditions, but the thermal load may vary with activity and location within the socket. To characterize the thermal environment at the skin-prosthesis interface, we made temperature measurements on five transtibial amputees at 14 locations on the residual limbs. After the participants donned their prosthesis and rested in the seated position for 15 min, the mean skin temperatures of their residual limbs increased by 0.8 degrees Celcius. Subsequent walking for 10 min resulted in a 1.7 degrees Celsius total increase in mean skin temperature. Thermal contour maps revealed the skin was coolest at the anterior proximal location and warmest across the posterior section, correlating with areas of low and high perfusion. From the results, we determined that residual-limb skin temperature depends on activity and locality. This information may aid in understanding where and why skin problems develop on lower-limb residual limbs and may provide design requirements for new prosthetic socket systems intended to alleviate temperature-related discomfort. (+info)