- Email: [email protected]
The effect of mass on the kinematics of steady state wheelchair propulsion in adults and children with spinal cord injury
Abstracts-International
Society of Biomechanics XIV Congress 1993
825
THE EFFECT OF MASS ON THE KINEMATICS OF STEADY STATE WHEELCHAIR PROPULSION IN ADULTS AND CHILDREN WITH SPINAL CORD INJURY Janet H. Bednarczyk, David J. Sanderson British Columbia Rehabilitation Society, UBC Biomechanics Laboratory, Vancouver, B.C. CANADA A recent trend in wheelchair design has been the reduction in the mass of wheelchairs. The purpose of this study was to examine the effect of mass on the 3D kinematics of wheelchair propulsion. The mass of test chairs (9.3 kg) was manipulated by mass additions (5 and 10 kg) in two, neurologically matched, groups (n=lO) of adults and children with uncomplicated spinal cord injury. The average mass and age of the pediatric group was much smaller than the adult group (37.4 kg and 11.3 years vs 68.5 kg and 33.5 years). The averaged group wheeling velocities were 2.26 m/set (pediatric) and 2.38 m/set (adult) and were significantly different (~~0.05). The two groups spent comparable proportions of the wheeling cycle in propulsion (pediatric = 24.45 %, adult = 24.41 %). An ANCOVA of the angular data, with wheeling velocity as the covariate, showed significant differences for three (elbow, shoulder, and shoulder abduction) of the four angular parameters and nonsignificant groups-by-conditions effects indicating that there were significant differences between ?he two groups but that the group responses to the test conditions were similar. These results, based on a sample of chairs and subjects, indicate that neither the test chairs nor the mass additions had an effect on the angular kinematics, % propulsion or wheeling velocities of two groups of subjects with spinal cord injury in short distance, level wheelchair propulsion.
STABILITY OF THE CONSTRUCTION OF THE ELASTIC EXTERNAL FIXATION OF ILIZAROV SYSTEM USED FOR THE LENGTHENING OF LIMBS R. J.B$dziriski, J.Filipiak, L.Morasiewicz, A.Wall Academy of Wroclaw, Poland Technical University of Wroclaw, Medical From among the external fixation systems being used in clinical practice the system Investigations were started for developed by Ilizarov is of particular interest. including the planned establishing the relationship between the anatomic conditions, and the required spatial configuration of the fixator lengthening value and correction, conditions of the supporting in the course of lengthening the femur bone. The operating elements of the stabiliser were being estimated during the lengthening of the femur bone In order to determine the forces occuring in the supporting pins of (5 patients). In order to estimate and cornpar? were glued on them. gauges the f ixator , strain the stability of the external fixation-femur bone system a physical model was built. and strain of external The fixator was mounted on a fresh femur bone. The displacements by applying speckle (five configurations) and femur bones were investigated f ixators photography and strain gauges method. Test carried out on physical models as well as the clinical investigations indicate a significant effect of the interaction of the soft tissue upon the nature and value of Results of these study may be useful1 in determining the displacements of bone fragments. for particular clinical which of configuration of external fixators may be better application.
FIXATION OF MEDIAL MALLEOLAR FRACTURES WITH REABSORBABLE POLYLACTIC ACID SCREWS G. Bettelli, A. Ferruzzi, M. Messori and G. Gualtieri Istituto Ortopedico Rizzoli, 4th Orthopaedic Division, and Officine Ortopediche Rizzoli, Bologna, Italy. A clinical study of medial malleolar fractures treated by fixation with L-polylactic acid screws was performed after a series of preliminary laboratory tests. The screws have an external diameter of 6.2 mm. Their resistence under torsion is 1.6 N/m. while the resistance under traction is 880 N. Up to June 1992, 10 polylactic acid screws were implanted in 9 patients (2 screws in one patient) with age ranging from 18 to 80 years (average 41). The only selection of the patients was based on the size of the malleolar fragment. The post-operative care was the same usually adopted after conventional fixation. Healing occurred after two months in all the cases. There were no complications, and particularly we never observed the phenomenon of non-septic sinus draining that was reported to occur in about 8% of the patients treated with polyglycolide or lactide-glycolyde rods by Bostman et al. The use of reabsorbable materials for the fixation of fractures would allow to overcome the problems of metal corrosion and the rare cases of allergic reactions to metals, but most important of all, it would abolish the need for a second operation to remove the materials, and inherent complications. The biomechanic features of reabsorbable materials up to now, however, are far inferior to those of conventional materials. The main scope of this clinical trial was to achieve a basic, preliminary experience in the use of reabsorbable systems, in order to become able in the future to develope more complex and stron g reabsorbable devices, capable to substitute the conventional means in a wider range of conditions.
Society of Biomechanics XIV Congress 1993
825
THE EFFECT OF MASS ON THE KINEMATICS OF STEADY STATE WHEELCHAIR PROPULSION IN ADULTS AND CHILDREN WITH SPINAL CORD INJURY Janet H. Bednarczyk, David J. Sanderson British Columbia Rehabilitation Society, UBC Biomechanics Laboratory, Vancouver, B.C. CANADA A recent trend in wheelchair design has been the reduction in the mass of wheelchairs. The purpose of this study was to examine the effect of mass on the 3D kinematics of wheelchair propulsion. The mass of test chairs (9.3 kg) was manipulated by mass additions (5 and 10 kg) in two, neurologically matched, groups (n=lO) of adults and children with uncomplicated spinal cord injury. The average mass and age of the pediatric group was much smaller than the adult group (37.4 kg and 11.3 years vs 68.5 kg and 33.5 years). The averaged group wheeling velocities were 2.26 m/set (pediatric) and 2.38 m/set (adult) and were significantly different (~~0.05). The two groups spent comparable proportions of the wheeling cycle in propulsion (pediatric = 24.45 %, adult = 24.41 %). An ANCOVA of the angular data, with wheeling velocity as the covariate, showed significant differences for three (elbow, shoulder, and shoulder abduction) of the four angular parameters and nonsignificant groups-by-conditions effects indicating that there were significant differences between ?he two groups but that the group responses to the test conditions were similar. These results, based on a sample of chairs and subjects, indicate that neither the test chairs nor the mass additions had an effect on the angular kinematics, % propulsion or wheeling velocities of two groups of subjects with spinal cord injury in short distance, level wheelchair propulsion.
STABILITY OF THE CONSTRUCTION OF THE ELASTIC EXTERNAL FIXATION OF ILIZAROV SYSTEM USED FOR THE LENGTHENING OF LIMBS R. J.B$dziriski, J.Filipiak, L.Morasiewicz, A.Wall Academy of Wroclaw, Poland Technical University of Wroclaw, Medical From among the external fixation systems being used in clinical practice the system Investigations were started for developed by Ilizarov is of particular interest. including the planned establishing the relationship between the anatomic conditions, and the required spatial configuration of the fixator lengthening value and correction, conditions of the supporting in the course of lengthening the femur bone. The operating elements of the stabiliser were being estimated during the lengthening of the femur bone In order to determine the forces occuring in the supporting pins of (5 patients). In order to estimate and cornpar? were glued on them. gauges the f ixator , strain the stability of the external fixation-femur bone system a physical model was built. and strain of external The fixator was mounted on a fresh femur bone. The displacements by applying speckle (five configurations) and femur bones were investigated f ixators photography and strain gauges method. Test carried out on physical models as well as the clinical investigations indicate a significant effect of the interaction of the soft tissue upon the nature and value of Results of these study may be useful1 in determining the displacements of bone fragments. for particular clinical which of configuration of external fixators may be better application.
FIXATION OF MEDIAL MALLEOLAR FRACTURES WITH REABSORBABLE POLYLACTIC ACID SCREWS G. Bettelli, A. Ferruzzi, M. Messori and G. Gualtieri Istituto Ortopedico Rizzoli, 4th Orthopaedic Division, and Officine Ortopediche Rizzoli, Bologna, Italy. A clinical study of medial malleolar fractures treated by fixation with L-polylactic acid screws was performed after a series of preliminary laboratory tests. The screws have an external diameter of 6.2 mm. Their resistence under torsion is 1.6 N/m. while the resistance under traction is 880 N. Up to June 1992, 10 polylactic acid screws were implanted in 9 patients (2 screws in one patient) with age ranging from 18 to 80 years (average 41). The only selection of the patients was based on the size of the malleolar fragment. The post-operative care was the same usually adopted after conventional fixation. Healing occurred after two months in all the cases. There were no complications, and particularly we never observed the phenomenon of non-septic sinus draining that was reported to occur in about 8% of the patients treated with polyglycolide or lactide-glycolyde rods by Bostman et al. The use of reabsorbable materials for the fixation of fractures would allow to overcome the problems of metal corrosion and the rare cases of allergic reactions to metals, but most important of all, it would abolish the need for a second operation to remove the materials, and inherent complications. The biomechanic features of reabsorbable materials up to now, however, are far inferior to those of conventional materials. The main scope of this clinical trial was to achieve a basic, preliminary experience in the use of reabsorbable systems, in order to become able in the future to develope more complex and stron g reabsorbable devices, capable to substitute the conventional means in a wider range of conditions.