Concurrent meniscal injury in dogs with cranial cruciate ligament tears ranges from 10-70%, and these injuries can increase the risk of developing osteoarthritis. Studies regarding joint space width on knee radiographs in people have indicated correlations between joint space width and meniscal injuries. The aim of this study was to determine if there was correlation between stifle joint space width on three different radiographic projections and meniscal injuries identified at surgery in dogs. Four blinded observers measured the radiographic joint space width three times, and the measurements were compared to surgical findings. Intraclass correlation coefficients for inter- and intraobserver variability ranged from moderate to excellent. There was significance between dogs with a meniscal tear and the corresponding joint space width on standard TPLO lateral radiographic projections. Joint space narrowing is seen with meniscal tears in dogs, and radiography may be a noninvasive way to identify meniscal tears prior to surgery.

No description available.

Cheung Chi-Kin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 53-60). / Text in English; abstracts in English and Chinese. / Cheung Chi-Kin. / Acknowledgement --- p.i / Abstract --- p.ii / Table of Contents --- p.v / List of Figures --- p.viii / List of Tables --- p.ix / Introduction --- p.1 / Statement of Problem --- p.3 / Research Questions --- p.4 / Significance of the Study --- p.4 / Theoretical contribution --- p.4 / Practical contribution --- p.5 / Review of Literature --- p.6 / Physiological Studies regarding Load Carriage --- p.6 / Energy expenditure --- p.7 / Heart rate --- p.7 / Comparison between physiological studies and biomechanical studies regarding load carrying --- p.8 / Motor Control during Load Carrying --- p.10 / Gait Pattern --- p.11 / Gait pattern under load carrying --- p.11 / Walking velocity --- p.13 / Treadmill vs. overground walking --- p.13 / Trunk Posture --- p.15 / Electromyographic Activity --- p.16 / EMG and muscle force --- p.17 / EMG and fatigue --- p.18 / EMG during load carrying --- p.19 / Load Carrying Studies in Children --- p.21 / Methodology --- p.24 / Design --- p.24 / Subject --- p.24 / Instrumentation --- p.25 / Motion analysis --- p.25 / Electromyography --- p.25 / Heart rate measurement --- p.26 / School bag --- p.26 / Experimental Set-up --- p.27 / Procedures --- p.27 / Data Reduction --- p.29 / Gait parameters --- p.29 / Trunk posture --- p.31 / Electromyographic analysis --- p.32 / Heart rate --- p.34 / Data Analysis --- p.34 / Results --- p.35 / Gait Pattern --- p.35 / Trunk Posture --- p.36 / Electromyographic Activity --- p.37 / Channel 1 --- p.37 / Channel 2 --- p.37 / Channel 3 --- p.38 / Heart Rate --- p.38 / Summary --- p.39 / Discussion --- p.40 / Gait Pattern during Load Carriage --- p.40 / Stride parameters --- p.40 / Temporal parameters --- p.42 / Trunk Posture --- p.43 / Electromyographic Activity --- p.44 / Erector spinea --- p.45 / Upper trapezius --- p.45 / Risk factor from EMG measurement --- p.47 / Heart Rate --- p.47 / Maximum Permissible Backpack Weight for Children --- p.48 / Limitations of the Study --- p.49 / Further Direction --- p.50 / Conclusion --- p.52 / References --- p.53 / Appendix / Appendix A - Subject Information & Consent form --- p.61 / Appendix B - Experiment Set-up --- p.66 / Appendix C - Measurement of Skinfold --- p.67 / Appendix D - Standardized Isometric Maximum Voluntary Contraction --- p.68 / Appendix D - Figures and Tables --- p.69

It has been suggested that simulating physiological loading of the knee during magnetic resonance imaging (MRI) is a promising technique for assessing soft and hard tissues in the knee joint. We have developed a novel MRI-compatible lower limb loading and positioning device to assess knee biomechanics in a physiologically relevant environment using MRI. The objectives of this study were (1) to evaluate inter- and intra-examiner reliability for using our custom-built loading system to maintain a desired load magnitude and direction during each loading trial and over repeated subject visits and (2) to determine the effect of the applied load on motion of the subject's knee over the duration of a loading trial. The pneumatic-controlled loading system was tested on ten subjects at a compression load of 50% of the subject's bodyweight. Two examiners separately positioned and loaded each subject for three loading trials per visit, repeated for three visits. The primary outcome measure was the magnitude of the primary axial load (proximal/distal force) applied to the subject's foot over a loading trial. Secondary outcome measures included average magnitude of medial/lateral and anterior/posterior forces as well as valgus/varus, flexion/extension, and external/internal moments applied to the subject's foot during a loading trial. Location of center of loading at the foot was also recorded. Primary axial load was found to be maintained to within 44-47% of subject bodyweight. Following load-application, the subject's knee exhibited movement throughout the duration of each loading trial. We found that 61.0% of proximal/distal knee displacement occurred within the first 2 minutes following loading. Between minutes 4 and 12, knee positioning was maintained to within 0.92 mm in the medial/lateral direction and 1.24 mm in the proximal/distal direction. We conclude that our loading device can apply controllable and reproducible loading over repeated trials as well as limit subject motion throughout each trial.

We developed a novel approach that requires subjects to produce and finely tune ground reaction forces (GRFs) while standing. Using this method we were able to identify specific contributions of individual muscles and how these contributions change with the effects of age. One of the aims of this investigation was to determine whether electromyographic data in our findings was due to random muscle activation or representative of a neuromuscular control strategy. Ten healthy young adults (5 male, 5 female) with their dominant foot fixed within a boot mounted to a force platform participated twice in a target matching protocol, requiring subjects to control both the direction and magnitude of GRF along the horizontal plane while maintaining constant inferior-superior loads of 50% body-weight. Subjects were asked to manoeuvre a cursor with their dominant leg to match a series of targets projected on a screen. Targets appeared at random one at-a-time, separated by 30o around a circular trajectory. Subjects applied loads to the force platform in various horizontal directions to move the cursor while also controlling body weight. A successful target match required subjects to maintain 50% body weight and 30% of their peak horizontal load for one second. Electromyography (EMG) of eight muscles that cross the knee joint, ground reaction forces, and kinematic data were recorded for each successful match. EMG was normalized to percent maximum voluntary isometric contractions collected on an isokinetic dynamometer. Each target matching session was separated by two-three days. A random model, single measures intra-class correlation analysed the reliability for both test-retest and intra-day results, in addition to intersubject reliability. We observed moderate to high ICC values (0.60 – 0.993) for most muscles in most directions, indicating low within-subject variance. In addition, moderate to high between-subject reliability was observed in all eight muscle activation profiles, indicating subjects used similar neuromuscular control strategies to achieve the desired GRFs. Our findings support that groups who have undergone the same number of testing sessions can be compared, and that a single testing session is all that is required to compare neuromuscular control strategies used by a group to achieve target locations. The second aim of this investigation was to evaluate age related differences in neuromuscular control about the knee joint using our target match protocol. Thirty-three healthy adults (17 younger 24 years ±2, 16 older 59 years ±5), completed the same protocol evaluated above. The mean magnitude of muscle activity, specificity index, and mean direction of muscle activity were calculated in each target direction. Older adults presented with significantly lower strength in knee flexion and extension, hip abduction, and ankle plantar flexion. Significantly (p<0.25) higher mean activation magnitudes in the rectus femoris, vastus lateralis, vastus medialis, biceps femoris, semitendinosus, medial gastrocnemius, and tensor facia lata were also observed. Intraclass correlations (ICC) magnitudes indicate the percentage of global variance that can be explained by within subject and between trial variability. Muscle activation patterns were found to be similar in all muscles (ICC≤0.82). Similar patterns are supported by non-significant differences in mean direction of activation and muscle activation specificity. These results indicated that healthy older adults utilise different activation magnitudes for stabilising the knee while maintain similar muscle activation synergies in all muscles to younger adults.

We developed a novel approach that requires subjects to produce and finely tune ground reaction forces (GRFs) while standing. Using this method we were able to identify specific contributions of individual muscles and how these contributions change with the effects of age. One of the aims of this investigation was to determine whether electromyographic data in our findings was due to random muscle activation or representative of a neuromuscular control strategy. Ten healthy young adults (5 male, 5 female) with their dominant foot fixed within a boot mounted to a force platform participated twice in a target matching protocol, requiring subjects to control both the direction and magnitude of GRF along the horizontal plane while maintaining constant inferior-superior loads of 50% body-weight. Subjects were asked to manoeuvre a cursor with their dominant leg to match a series of targets projected on a screen. Targets appeared at random one at-a-time, separated by 30o around a circular trajectory. Subjects applied loads to the force platform in various horizontal directions to move the cursor while also controlling body weight. A successful target match required subjects to maintain 50% body weight and 30% of their peak horizontal load for one second. Electromyography (EMG) of eight muscles that cross the knee joint, ground reaction forces, and kinematic data were recorded for each successful match. EMG was normalized to percent maximum voluntary isometric contractions collected on an isokinetic dynamometer. Each target matching session was separated by two-three days. A random model, single measures intra-class correlation analysed the reliability for both test-retest and intra-day results, in addition to intersubject reliability. We observed moderate to high ICC values (0.60 – 0.993) for most muscles in most directions, indicating low within-subject variance. In addition, moderate to high between-subject reliability was observed in all eight muscle activation profiles, indicating subjects used similar neuromuscular control strategies to achieve the desired GRFs. Our findings support that groups who have undergone the same number of testing sessions can be compared, and that a single testing session is all that is required to compare neuromuscular control strategies used by a group to achieve target locations. The second aim of this investigation was to evaluate age related differences in neuromuscular control about the knee joint using our target match protocol. Thirty-three healthy adults (17 younger 24 years ±2, 16 older 59 years ±5), completed the same protocol evaluated above. The mean magnitude of muscle activity, specificity index, and mean direction of muscle activity were calculated in each target direction. Older adults presented with significantly lower strength in knee flexion and extension, hip abduction, and ankle plantar flexion. Significantly (p<0.25) higher mean activation magnitudes in the rectus femoris, vastus lateralis, vastus medialis, biceps femoris, semitendinosus, medial gastrocnemius, and tensor facia lata were also observed. Intraclass correlations (ICC) magnitudes indicate the percentage of global variance that can be explained by within subject and between trial variability. Muscle activation patterns were found to be similar in all muscles (ICC≤0.82). Similar patterns are supported by non-significant differences in mean direction of activation and muscle activation specificity. These results indicated that healthy older adults utilise different activation magnitudes for stabilising the knee while maintain similar muscle activation synergies in all muscles to younger adults.

国立情報学研究所で電子化したコンテンツを使用している。

Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.

We developed a novel approach that requires subjects to produce and finely tune ground reaction forces (GRFs) while standing. Using this method we were able to identify specific contributions of individual muscles and how these contributions change with the effects of age. One of the aims of this investigation was to determine whether electromyographic data in our findings was due to random muscle activation or representative of a neuromuscular control strategy. Ten healthy young adults (5 male, 5 female) with their dominant foot fixed within a boot mounted to a force platform participated twice in a target matching protocol, requiring subjects to control both the direction and magnitude of GRF along the horizontal plane while maintaining constant inferior-superior loads of 50% body-weight. Subjects were asked to manoeuvre a cursor with their dominant leg to match a series of targets projected on a screen. Targets appeared at random one at-a-time, separated by 30o around a circular trajectory. Subjects applied loads to the force platform in various horizontal directions to move the cursor while also controlling body weight. A successful target match required subjects to maintain 50% body weight and 30% of their peak horizontal load for one second. Electromyography (EMG) of eight muscles that cross the knee joint, ground reaction forces, and kinematic data were recorded for each successful match. EMG was normalized to percent maximum voluntary isometric contractions collected on an isokinetic dynamometer. Each target matching session was separated by two-three days. A random model, single measures intra-class correlation analysed the reliability for both test-retest and intra-day results, in addition to intersubject reliability. We observed moderate to high ICC values (0.60 – 0.993) for most muscles in most directions, indicating low within-subject variance. In addition, moderate to high between-subject reliability was observed in all eight muscle activation profiles, indicating subjects used similar neuromuscular control strategies to achieve the desired GRFs. Our findings support that groups who have undergone the same number of testing sessions can be compared, and that a single testing session is all that is required to compare neuromuscular control strategies used by a group to achieve target locations. The second aim of this investigation was to evaluate age related differences in neuromuscular control about the knee joint using our target match protocol. Thirty-three healthy adults (17 younger 24 years ±2, 16 older 59 years ±5), completed the same protocol evaluated above. The mean magnitude of muscle activity, specificity index, and mean direction of muscle activity were calculated in each target direction. Older adults presented with significantly lower strength in knee flexion and extension, hip abduction, and ankle plantar flexion. Significantly (p<0.25) higher mean activation magnitudes in the rectus femoris, vastus lateralis, vastus medialis, biceps femoris, semitendinosus, medial gastrocnemius, and tensor facia lata were also observed. Intraclass correlations (ICC) magnitudes indicate the percentage of global variance that can be explained by within subject and between trial variability. Muscle activation patterns were found to be similar in all muscles (ICC≤0.82). Similar patterns are supported by non-significant differences in mean direction of activation and muscle activation specificity. These results indicated that healthy older adults utilise different activation magnitudes for stabilising the knee while maintain similar muscle activation synergies in all muscles to younger adults.