In this case report, the clinical and radiographic results of the treatment of Salter Harris Type II fracture in the left humerus of a 10-month-old female and crossbred dog with parallel pin technique was evaluated. The dog with complaining of lameness was brought to Siirt University, Faculty of Veterinary Medicine, Clinic of Surgery Department and local fracture findings were found in the distal 1/3 of the left humerus. On radiological examination, it was found that the distal physeal line of the left humerus was detached. Also, it was seen that the integrity of the bone cortex was disrupted through in a line that included the metaphysis at the medial angle. In the operation, following the reduction of the fracture fragments, 2 krischner pins with 2 mm in diameter parallel to each other were applied from the medial cortex of the humerus to the lateral side of the distal condule and fixation was achieved. After the operation, the limb was taken to a backed bandage. In the radiological examination of the case on post-op 3rd week, it was found that the formation of the collus began. On the post-op 21st day, the bandage was removed and physical therapy applications were started to apply. On the post-op 4th week, it was seen that the dog used the extremity functionally and it was discharged. As a result, it was concluded that parallel double pin applications can be used successfully in the treatment of Salter Harris Type II fractures that are formed in the distal of dog's humerus.

OBJECTIVE To perform 3-D inverse dynamics analysis of the entire forelimb of healthy dogs during a walk and trot. ANIMALS 5 healthy adult Beagles. PROCEDURES The left forelimb of each dog was instrumented with 19 anatomic markers. X-ray fluoroscopy was used to optimize marker positions and perform scientific rotoscoping for 1 dog. Inverse dynamics were computed for each dog during a walk and trot on the basis of data obtained from an infrared motion-capture system and instrumented quad-band treadmill. Morphometric data were obtained from a virtual reconstruction of the left forelimb generated from a CT scan of the same dog that underwent scientific rotoscoping. RESULTS Segmental angles, torque, and power patterns were described for the scapula, humerus, ulna, and carpus segments in body frame. For the scapula and humerus, the kinematics and dynamics determined from fluoroscopy-based data varied substantially from those determined from the marker-based data. The dominant action of scapular rotation for forelimb kinematics was confirmed. Directional changes in the torque and power patterns for each segment were fairly consistent between the 2 gaits, but the amplitude of those changes was often greater at a trot than at a walk. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that control of the forelimb joints of dogs is similar for both a walk and trot. Rotation of the forelimb around its longitudinal axis and motion of the scapula should be reconsidered in the evaluation of musculoskeletal diseases, especially before and after treatment or rehabilitation.

We evaluated the single-cycle structural properties for axial compression, torsion, and 4-point bending with a central load applied to the caudal or lateral surface of a diaphyseal segment from the normal adult equine humerus, radius, third metacarpal bone, femur, tibia, and third metatarsal bone. Stiffness values were determined from load-deformation curves for each bone and test mode. Compressive stiffness ranged from a low of 2,690 N/mm for the humerus to a high of 5,670 N/mm for the femur. Torsional stiffness ranged from 558 N.m/rad for the third metacarpal bone to 2,080 N.m/rad for the femur. Nondestructive 4-point bending stiffness ranged from 3,540 N.m/rad for the radius to 11,500 N.m/rad for the third metatarsal bone. For the humerus, radius, and tibia, there was no significant difference in stiffness between having the central load applied to the caudal or lateral surface. For the third metacarpal and metatarsal bones, stiffness was significantly (P < 0.05) greater with the central load applied to the lateral surface than the palmar or plantar surface. For the femur, bones were significantly (P < 0.05) stiffer with the central load applied to the caudal surface than the lateral surface. Four-point bending to failure load-deformation curves had a bilinear pattern in some instances, consisting of a linear region at lower bending moments that corresponded to stiffness values from the nondestructive tests and a second linear region at higher bending moments that had greater stiffness values. Stiffness values from the second linear region ranged from 4,420 N.m/rad for the humerus to 13,000 N.m/rad for the third metatarsal bone. Differences in stiffness between nondestructive tests and the second linear region of destructive tests were significant (P < 0.05) for the radius, third metacarpal bone, and third metatarsal bone. Difference between stiffness values of paired left and right bones was not detected for any test. Four-point bending ultimate failure bending moments ranged from 260 N.m for the femur to 940 N.m for the third metatarsal bone. There was no difference in failure bending moment between the directions of applied central load for a given bone.

OBJECTIVE To describe methods to measure the 3-D orientation of the proximal, diaphyseal, and distal segments of the canine radius by use of computer-aided design software (CADS) and to compare the repeatability and reliability of measurements derived by those methods. SAMPLE 31 canine radii with biapical deformities and 24 clinically normal (control) canine radii. PROCEDURES Select CT scans of radii were imported into a CADS program. Cartesian coordinate systems for the humerus and proximal, diaphyseal, and distal radial segments were developed. The orientation of each radial segment in the frontal, sagittal, and transverse planes was measured in triplicate by 3 methods. The repeatability and reliability of those measurements were calculated and compared among the 3 measurement methods. RESULTS The mean ± SD within-subject repeatability of radial angular measurements for all 3 methods was 1.40 ± 0.67° in the frontal plane, 3.17 ± 2.21° in the sagittal plane, and 3.01 ± 1.11° in the transverse plane for control radii and 2.56 ± 1.95° in the frontal plane, 3.59 ± 2.39° in the sagittal plane, and 3.47 ± 1.19° in the transverse plane for abnormal radii. Mean ± SD bias between radial measurement methods was 1.88 ± 2.07° in the frontal plane, 6.44 ± 6.80° in the sagittal plane, and 2.27 ± 2.81° in the transverse plane. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that use of CADS to assess the 3-D orientation of the proximal, diaphyseal, and distal segments of normal and abnormal canine radii yielded highly repeatable and reliable measurements.

Objective—To investigate topographic and age-dependent adaptation of subchondral bone density in the elbow joints of healthy dogs by means of computed tomographic osteoabsorptiometry (CTOAM). Animals—42 elbow joints of 29 clinically normal dogs of various breeds and ages. Procedures—Subchondral bone densities of the humeral, radial, and ulnar joint surfaces of the elbow relative to a water-hydroxyapatite phantom were assessed by means of CTOAM. Distribution patterns in juvenile, adult, and geriatric dogs (age, < 1 year, 1 to 8 years, and > 8 years, respectively) were determined and compared within and among groups. Results—An area of increased subchondral bone density was detected in the humerus distomedially and cranially on the trochlea and in the olecranon fossa. The ulna had maximum bone densities on the anconeal and medial coronoid processes. Increased bone density was detected in the craniomedial region of the joint surface of the radius. A significant age-dependent increase in subchondral bone density was revealed in elbow joint surfaces of the radius, ulna, and humerus. Mean subchondral bone density of the radius was significantly less than that of the ulna in paired comparisons for all dogs combined and in adult and geriatric, but not juvenile, dog groups. Conclusions and Clinical Relevance—An age-dependent increase in subchondral bone density at the elbow joint was revealed. Maximal relative subchondral bone densities were detected consistently at the medial coronoid process and central aspect of the humeral trochlea, regions that are commonly affected n dogs with elbow dysplasia.

Objective-To assess gait abnormalities associated with selective anesthesia of the suprascapular nerve (SSN) achieved by use of perineural catheterization and thereby determine the function of that nerve as it relates to gait in horses. Animals-3 adult horses with no preexisting clinically apparent lameness at a walk. Procedure-Each horse was anesthetized; the right SSN was exposed surgically for placement of a perineural catheter to permit delivery of 1 mL of 2% mepivacaine hydrochloride. Six hours after recovery from anesthesia, each horse was videotaped while walking (50-step data acquisition period) before and after administration of mepivacaine. Videotapes were reviewed and the proportion of abnormal steps before and after selective SSN anesthesia was assessed. A step was considered abnormal if a marked amount of scapulohumeral joint instability (ie, lateral luxation of the proximal portion of the humerus) was observed during the weight-bearing phase of the stride. Results-Clinically apparent gait dysfunction was detected in all 3 horses following perineural administration of the local anesthetic agent. Anesthesia of the SSN resulted in scapulohumeral joint instability as evidenced by consistent lateral excursion of the shoulder region during the weight-bearing phase of gait at a walk. The proportion of abnormal steps before and after SSN anesthesia was significantly different in all 3 horses. Conclusions and Clinical Relevance-These data support the role of the SSN in shoulder joint stability in horses and define SSN dysfunction as 1 mechanism by which the syndrome and gait dysfunction clinically referred to as sweeny may develop.

Of 143 Greyhounds necropsied consecutively, 6 (4%) had chondrocalcinosis of the scapulohumeral joint; lesions were identified in 6 additional dogs. Lesions were seen exclusively in the humeral head, mainly in the plateau region. The lesions in the dogs of the initial group were unilateral, but 2 of the 6 additional dogs had bilateral lesions. Focal mineralization of articular cartilage appeared as a white raised nidus, sometimes surrounded by a translucent halo in the opaque cartilage. Circular, small translucent cartilage foci, with or without beginning mineralization, were adjacent to definitive chondrocalcinosis lesions. Chondrocyte necrosis and matrix degradation were considered to antedate appearance of matrical mineral granules; mineralization of the cartilage was considered a secondary process, but not necessarily an epiphenomenon. Scanning electron microscopy indicated that the chondrocalcinosis lesion was composed of deposits of irregularly fused stone material that, in scanning and transmission electron micrographs, was composed of irregular spheroids, 0.05 to 0.5 micrometer in diameter. The spheroids contained poorly formed needle-like crystals of apatite. Sparse transformation of the mineral phase into hydroxyapatite was considered to be attributable to a biological mechanism that inhibited phase transition. Cartilage degeneration and chondrocalcinosis of the plateau region of the humeral head appear to be unique lesions that develop in young Greyhounds. It is possible that these lesions are the result of the biomechanical stress of training and racing.

Generation of free radicals and the ability of various antioxidants to attenuate radical production in freshly procured cancellous bone specimens was investigated, using spin-trapping and electron spin resonance (ESR) techniques. Seven core cancellous bone specimens, 10 mm long and 7.9 mm in diameter, were obtained using aseptic technique, from the proximal portion of the humerus of 9 adult mixed-breed dogs. One core cancellous bone specimen from each dog was incubated in spin trap alpha-phenyl-N-tert-butylnitrone in Eagle's minimum essential medium and served as a control. The other 6 specimens from each dog were incubated in alpha-phenyl-N-tert-butylnitrone/Eagle's minimum essential medium plus 1 of the following antioxidants: superoxide dismutase, catalase, superoxide dismutase/catalase, indomethacin, allopurinol, or deferoxamine mesylate. All specimens were incubated at 26 C for 90 minutes, then frozen at -20 C until they were prepared for analysis by ESR spectroscopy. Each specimen was thawed, homogenized, and extracted in a low-dielectric organic solvent prior to obtaining an ESR spectrum which was analyzed for hyperfine splitting constants to identify radicals. Each first-derivative spectrum was digitally double-integrated to obtain an area: these areas were used to compare intensities of the spin. For each treatment group, the areas from the treated specimens were compared with the areas from the control specimens, using a paired t-test. Significance was accepted at P less than or equal to 0.05. Spin adducts were detected in all cancellous bone specimens. Specimens incubated in deferoxamine (P = 0.0017) and superoxide dismutase/catalase (P = 0.0452) had significantly smaller areas than did control specimens. The areas for the other treatment groups did not differ significantly from controls. Our results substantiate free radical production in freshly procured cancellous bone specimens and that radical formation is attenuated by in vitro incubation with deferoxamine or superoxide dismutase/catalase.

As more sophisticated research is performed to refine fracture fixation techniques for horses, it is important that normal values for the geometric properties of the bones of the appendicular skeleton be determined and that suitable controls be available. We evaluated the geometric properties of total bone width, cortical bone width, and medullary canal/trabecular bone width measured from 2 radiographic projections of equine long bones (humerus, radius, third metacarpal bone, femur, tibia, and third metatarsal bone) obtained from a general population of horses. Measurements were performed on slices separated by intervals equal to 5% of the bone's length. Slices were then grouped into 5 regions: proximal epiphysis, proximal part of the metaphysis, diaphysis, distal part of the metaphysis, and distal epiphysis. Results validated use of the contralateral bone as a control for assessing experimental models or clinical cases. Of 858 homotypic slice comparisons between left and right bones, significant (P less than or equal to 0.05) differences were detected in 31 (3.6%) of the comparisons. Of 168 homotypic region comparisons, significant differences were observed in 3 (1.8%) of the comparisons. The greatest variation between left and right bones was observed in metaphyseal regions, areas with bony protuberances, and regions with prominent bone superimposition. At a power of 0.8 for the statistical tests performed in this study, the mean homotypic variation of bones in each region is < 5.8% for the proximal epiphysis, 11.3% for the proximal part of the metaphysis, 6.8% for the diaphysis, 12.2% for the distal part of the metaphysis, and 5.2% for the distal epiphysis.

We performed dual-energy x-ray absorptiometry (craniocaudal and lateromedial views) on 10 pairs of humeruses, radiuses, femurs, and tibias from dogs, using an alignment jig, to determine the homotypic bone mineral density variations of long bones. The bones were divided into 3 regions: proximal, middle, and distal parts of the diaphysis. The bone mineral density of cortical bone, medullary bone, and total bone was determined. Of 160 homotypic comparisons, 21 indicated significant (P less than or equal to 0.05) differences between right and left bones at either a region or location. These differences were observed most frequently in the craniocaudal view and were probably secondary to positioning errors. Evaluation of elliptical bones, such as the radius, also indicated that, when the thicker dimension, such as the lateromedial view of the radius was measured, the bone mineral density of regions-of-interest in that view was greater than that in the opposite view (ie, craniocaudal view of the radius). This study validates the concept of using the contralateral limb as the control condition in orthopedic studies of dogs, particularly when evaluating the densitometric properties of long bones. This study also emphasizes the importance of accurate positioning to prevent inadvertent alteration of bone mineral density results when using dual-energy x-ray absorptiometry. Dual-energy x-ray absorptiometry is particularly susceptible to positioning errors, because it converts a 3-dimensional structure into a 2-dimensional image.