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Use of force plate data to screen young pigs for osteochondrosis
Abstracts
238
porous-coated. In another model, the implant had bony ingrowth only along the underside of the prosthetic humeral head and the stem was uncoated. Three loading conditions were employed to model various degrees of abduction of the arm. Results indicated that in the normal humerus, the compressive forces are transmitted from the articular surface through cancellous bone to the inferior cortical shell. Contraction of the rotator cuff muscles created tensile stresses in the supero-lateral cancellous bone and the superior cortical shell of the humerus. Results of the implanted humerus indicated that the use ofa prosthesis with bony-ingrowth along the stem would cause stress shielding proximally while the use of implants with porous ingrowth only on the underside of the humeral head replacement produced stress fields more similar to the normal humerus.
QUANTITATION
OF FUJI PRESCALE
FILM PRESSURES
USING
DIGITAL
IMAGE
SCANNING DOUGLAS
R. PEDERSEN, THOMAS D. BROWN and ROBERT J. SINGERMAN(Departments of Orthopaedic Surgery and Biomedical Engineering, University of Iowa, Iowa City, IA 52242, U.S.A.)
A digital image scanning procedure has been developed in order to substantially increase the spatial resolution with which pressure contours can be constructed from Fuji-film stains. An EYECOM II scanner is used to digitize a 640 x 480-pixel Fuji image to eight-bit grey level precision. Histograms prepared from serial Fuji calibration dots (of known, quasi-uniform pressure) demonstrate a substantially broader spectrum of pixel intensities than is apparent to the naked eye. The data demonstrate excellent, but nonlinear, correlation between pressure and mean pixel intensity, and establish that this correlation is virtually independent of the threshold specified for background intensity.
USE OF FORCE
PLATE
DATA TO SCREEN
YOUNG
PIGS FOR OSTEOCHONDROSIS
GERALD J. PIJANOWSKI,RODGER V. ALLHANDS(Department of Veterinary Biosciences and Bioengineering Program, College of Veterinary Medicine, University of Illinois, Urbana, IL 61801, U.S.A.) and STEVEN A. K~NCAID(Department of Anatomy, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, U.S.A.) Osteochondrosis is a nonfatal disease of high morbidity that causes lameness in growing pigs. To date, no effective screening methods are available to detect osteochondrosis before the onset of clinical lameness. The use ofdiscriminant analysis based on the waveform of the vertical component of the ground reaction force proved to be a highly reliable method for screening growing pigs. The implementation of this technique on commercial farms will allow the producer to screen potential breeding stock and eliminate those with osteochondrosis before a substantial economic investment has been made.
TEMPORAL
GAIT ANALYSIS
BY INTER-ANKLE
DISTANCE
MONITORING
M. S. PINZUR, P. DIMONTE-LEVINE,R. SHERMAN,J. TRIMBLEand K. HAAG (Department of Orthopaedics and
Rehabilitation,
Loyola University Medical Center, Maywood, IL60153, U.S.A.)
A new device is presented which is able to provide a temporal recording ofgait as well as a continuous qualitative monitoring of gait events. It can be used with motor point electromyography to perform walking electromyography, an electrogoniometer to record joint position, or other measuring devices to record events relative to phase of gait. The major advantages of this system as compared with available systems are (1) ease of use, (2) decreased patient encumbrance, (3) potential for portability, (4) greatly reduced expense and (5) the potential for digitalking the signal for computer compatability. Preliminary data are comparable to available accepted norms.
SEGMENT
INTERACIION IN TREADMILL RUNNING AT FOUR DIFFERENT SPEEDS C. A. PUTNAM (School of Physical Education, Dalhousie University, Halifax, Nova Scotia, Canada)
Six trained runners were tested at running speeds of 3.0,4.0,5.0 and 6.0 m s - ’ to determine the effect of running speed on the relative roles of the segment interaction and the resultant joint moments in bringing about angular
238
porous-coated. In another model, the implant had bony ingrowth only along the underside of the prosthetic humeral head and the stem was uncoated. Three loading conditions were employed to model various degrees of abduction of the arm. Results indicated that in the normal humerus, the compressive forces are transmitted from the articular surface through cancellous bone to the inferior cortical shell. Contraction of the rotator cuff muscles created tensile stresses in the supero-lateral cancellous bone and the superior cortical shell of the humerus. Results of the implanted humerus indicated that the use ofa prosthesis with bony-ingrowth along the stem would cause stress shielding proximally while the use of implants with porous ingrowth only on the underside of the humeral head replacement produced stress fields more similar to the normal humerus.
QUANTITATION
OF FUJI PRESCALE
FILM PRESSURES
USING
DIGITAL
IMAGE
SCANNING DOUGLAS
R. PEDERSEN, THOMAS D. BROWN and ROBERT J. SINGERMAN(Departments of Orthopaedic Surgery and Biomedical Engineering, University of Iowa, Iowa City, IA 52242, U.S.A.)
A digital image scanning procedure has been developed in order to substantially increase the spatial resolution with which pressure contours can be constructed from Fuji-film stains. An EYECOM II scanner is used to digitize a 640 x 480-pixel Fuji image to eight-bit grey level precision. Histograms prepared from serial Fuji calibration dots (of known, quasi-uniform pressure) demonstrate a substantially broader spectrum of pixel intensities than is apparent to the naked eye. The data demonstrate excellent, but nonlinear, correlation between pressure and mean pixel intensity, and establish that this correlation is virtually independent of the threshold specified for background intensity.
USE OF FORCE
PLATE
DATA TO SCREEN
YOUNG
PIGS FOR OSTEOCHONDROSIS
GERALD J. PIJANOWSKI,RODGER V. ALLHANDS(Department of Veterinary Biosciences and Bioengineering Program, College of Veterinary Medicine, University of Illinois, Urbana, IL 61801, U.S.A.) and STEVEN A. K~NCAID(Department of Anatomy, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, U.S.A.) Osteochondrosis is a nonfatal disease of high morbidity that causes lameness in growing pigs. To date, no effective screening methods are available to detect osteochondrosis before the onset of clinical lameness. The use ofdiscriminant analysis based on the waveform of the vertical component of the ground reaction force proved to be a highly reliable method for screening growing pigs. The implementation of this technique on commercial farms will allow the producer to screen potential breeding stock and eliminate those with osteochondrosis before a substantial economic investment has been made.
TEMPORAL
GAIT ANALYSIS
BY INTER-ANKLE
DISTANCE
MONITORING
M. S. PINZUR, P. DIMONTE-LEVINE,R. SHERMAN,J. TRIMBLEand K. HAAG (Department of Orthopaedics and
Rehabilitation,
Loyola University Medical Center, Maywood, IL60153, U.S.A.)
A new device is presented which is able to provide a temporal recording ofgait as well as a continuous qualitative monitoring of gait events. It can be used with motor point electromyography to perform walking electromyography, an electrogoniometer to record joint position, or other measuring devices to record events relative to phase of gait. The major advantages of this system as compared with available systems are (1) ease of use, (2) decreased patient encumbrance, (3) potential for portability, (4) greatly reduced expense and (5) the potential for digitalking the signal for computer compatability. Preliminary data are comparable to available accepted norms.
SEGMENT
INTERACIION IN TREADMILL RUNNING AT FOUR DIFFERENT SPEEDS C. A. PUTNAM (School of Physical Education, Dalhousie University, Halifax, Nova Scotia, Canada)
Six trained runners were tested at running speeds of 3.0,4.0,5.0 and 6.0 m s - ’ to determine the effect of running speed on the relative roles of the segment interaction and the resultant joint moments in bringing about angular