The most common fracture of the carpus presented for internal fixation is the slab fracture of th... more The most common fracture of the carpus presented for internal fixation is the slab fracture of the anterior or anteromedial aspect of the third carpal bone.
Angular limb deformity due to metaphyseal dysplasia (Fig. 6.1) is a common malady afflicting the ... more Angular limb deformity due to metaphyseal dysplasia (Fig. 6.1) is a common malady afflicting the distal radius in the young growing foal. The deformity responds well to growth plate retardation. The affected animal shows an abnormal curvature of the radius proximal to the growth plate causing the limb distal to that point to deviate laterally. The lateral aspect of the distal radius is strongly concave or “dished,” although radiographically, the true epiphysis of the bone will show the normal rectangular configuration. In making the diagnosis, care should be taken to differentiate the condition from the various other abnormalities of the carpus that can result in similar clinical appearances. A similar condition may affect the distal tibia and can be treated by essentially the same surgical procedure.
A lateral approach to the elbow by proximal ulnar diaphyseal osteotomy was developed as an altern... more A lateral approach to the elbow by proximal ulnar diaphyseal osteotomy was developed as an alternative to a number of currently used surgical approaches to that joint. The technique was easily performed, and it provided better visualization of the multiple joint compartments of the elbow than does any other technique. Repair of the osteotomy required a minimum of specialized equipment, and closure afforded excellent stabilization of the elbow and early return to function. In 3 cases, the versatility of the approach was demonstrated.
Twenty-two horses with ulnar fractures were treated, using tension band wires alone or tension ba... more Twenty-two horses with ulnar fractures were treated, using tension band wires alone or tension band wires in combination with pins or cortical bone screws. Age of the horses ranged from 2 weeks to 12 years (median, 4 months), and body weight ranged from 68 to 477 kg (median, 181 kg). Fractures were classified according to the Donecker and Bramlage ulnar fracture classification and included type 1-a (4 horses), type 1-b (4), type-2 (6), type-3 (1), type-4 (3), and type-5 (4), fractures. Tension band wires alone were used in 7 horses. Tension band wires were used in conjunction with unthreaded pins in 10 horses. In 3 horses, 5.5-mm cortical bone screws were inserted longitudinally instead of pins. A combination of a 5.5-mm cortical bone screw and a pin was used in 2 horses. In addition to pins and tension band wires, 4.5-mm cortical bone screws were placed in lag fashion to aid reduction of comminuted or oblique fractures in 7 of the 22 horses. Fractures healed in 18 (82%) horses. Four horses were euthanatized because of complications that included catastrophic failure of fixation during recovery from general anesthesia in 1 foal, septic arthritis and hyperextension of the contralateral metacarpophalangeal joint in 1 foal, and wound infection with partial disruption of repair in 2 horses. Nonfatal complications developed in 6 horses and included incision infection, partial wound dehiscence, carpal contraction, carpus varus of the contralateral forelimb, slight distraction of proximal fragments of the fractures, bent implants, and distal migration of pins. Long-term monitoring was performed on 17 horses.(ABSTRACT TRUNCATED AT 250 WORDS)
Eight untrained 2-year-old Thoroughbred horses were used in a study of the remodeling response of... more Eight untrained 2-year-old Thoroughbred horses were used in a study of the remodeling response of the proximal sesamoid bone (PSB) to training-related stimuli. Two horses each were assigned to 1 of 4 groups: group 1, untrained, pasture turnout (control); group 2, modified-classically trained, dirt track; group 3, classically trained, dirt track; and group 4, classically trained, wood chip track. Horses were given fluorochromic bone labels every 28 days during training. All horses were euthanatized after 5 months of training, and the proximal sesamoid bones (PSB) were removed. A midsagittal section of bone 85- to 95-microns thick was prepared for histomorphometric analysis by use of computerized image analysis and epifluorescent microscopy. Porosity (percent), trabecular width (micrometer), extent of anisotropy (percent), mineralizing surface (percent), fractional mineralizing surface (percent), and mineral apposition rate (micrometers per day) were determined at 5 circular regions of each specimen. Region 1 was located within the apex of the PSB, regions 2, 3, and 4 were subjacent to the subchondral plate, and region 5 was within the basilar articular margin. Data were pooled to allow comparison by training group and by region. The PSB from horses trained on dirt tracks (groups 2 and 3) had significantly (P less than 0.05) lower porosities and greater trabecular width, compared with the control group. The PSB from all training group specimens had significantly larger mineralizing surfaces than control group specimens. The fractional mineralizing surface revealed a rapid and vigorous response of the endosteal surface of the PSB in horses trained on dirt tracks.(ABSTRACT TRUNCATED AT 250 WORDS)
A device is needed to safely and wirelessly evaluate accelerations experienced by the horse hoof ... more A device is needed to safely and wirelessly evaluate accelerations experienced by the horse hoof under a variety of surface conditions with the horse exercising at training or racing speeds. To develop a miniaturised wireless data acquisition system (WDAS) which reliably records hoof accelerations and the times over which they occur in a minimally invasive manner in the exercising Thoroughbred. The following criteria were set for device development: production of a lightweight and minimally invasive system, which provides an adequate acceleration range, appropriate frequency response to capture high speed events, and compatibility with a low power wireless telemetry system. Following device development, the WDAS was calibrated, and tested in 6 Thoroughbred horses over a variety of surfaces. Collection of acceleration in seven trials using 6 horses over a variety of surfaces resulted in repeatable acceleration data with respect to the overall characteristic shape of the impact profile. Impact accelerations varied with surface, ranging 34.8-191.7 g. Accelerations on take off were in a similar range, although higher in some trials. Peak impact accelerations tended to larger over the grass paddock surface, than either the indoor arena or the dirt track. During dirt track trials, accelerations on take-off were often comparably larger than those observed on impact within the same footfall. This study reports the development of a wireless system that successfully measures hoof acceleration in a minimally invasive manner over a variety of surface and exercise conditions. The WDAS will be used in further studies to evaluate various components of the horse-racetrack interface, in an attempt to identify risk factors for musculoskeletal injury in the Thoroughbred racehorse.
Veterinary and comparative orthopaedics and traumatology, 1990
SummaryWith internal fixation of fractures using a plate and screws, the stability of the fixatio... more SummaryWith internal fixation of fractures using a plate and screws, the stability of the fixation is achieved mainly by the force generated by either lag screws or plate screws. The plate protects the bone from overload. The important mechanism in the function of plate fixation is the friction between the undersurface of the plate and the bone surface. It has become evident that plate luting, i. e. interposition of a bone cement layer between the plate and the bone, will alter the transmission of expected forces due to improved contact between the plate and the bone. The purpose of this project was to evaluate the load/strain relationships that occurred following plate luting and to understand why this procedure improved the mechanical behaviour of plate fixation in equine bone. We measured the strain patterns that occurred in unplated, plated and luted equine third metacarpal and metatarsal bones under simulated physiological conditions. Plate application resulted in reduced strain under the plate and increased strain at the opposite cortex. Following plate luting, this effect was more pronounced. Hysteresis between the loading-unloading cycle was less pronounced in the luted plates. This indicated that plate luting increased the effect of strain protection.Plate luting was shown to reduce the strain under the plate and to increase it in the transcortex, effectively increasing the effect of strain protection.
The most common fracture of the carpus presented for internal fixation is the slab fracture of th... more The most common fracture of the carpus presented for internal fixation is the slab fracture of the anterior or anteromedial aspect of the third carpal bone.
Angular limb deformity due to metaphyseal dysplasia (Fig. 6.1) is a common malady afflicting the ... more Angular limb deformity due to metaphyseal dysplasia (Fig. 6.1) is a common malady afflicting the distal radius in the young growing foal. The deformity responds well to growth plate retardation. The affected animal shows an abnormal curvature of the radius proximal to the growth plate causing the limb distal to that point to deviate laterally. The lateral aspect of the distal radius is strongly concave or “dished,” although radiographically, the true epiphysis of the bone will show the normal rectangular configuration. In making the diagnosis, care should be taken to differentiate the condition from the various other abnormalities of the carpus that can result in similar clinical appearances. A similar condition may affect the distal tibia and can be treated by essentially the same surgical procedure.
A lateral approach to the elbow by proximal ulnar diaphyseal osteotomy was developed as an altern... more A lateral approach to the elbow by proximal ulnar diaphyseal osteotomy was developed as an alternative to a number of currently used surgical approaches to that joint. The technique was easily performed, and it provided better visualization of the multiple joint compartments of the elbow than does any other technique. Repair of the osteotomy required a minimum of specialized equipment, and closure afforded excellent stabilization of the elbow and early return to function. In 3 cases, the versatility of the approach was demonstrated.
Twenty-two horses with ulnar fractures were treated, using tension band wires alone or tension ba... more Twenty-two horses with ulnar fractures were treated, using tension band wires alone or tension band wires in combination with pins or cortical bone screws. Age of the horses ranged from 2 weeks to 12 years (median, 4 months), and body weight ranged from 68 to 477 kg (median, 181 kg). Fractures were classified according to the Donecker and Bramlage ulnar fracture classification and included type 1-a (4 horses), type 1-b (4), type-2 (6), type-3 (1), type-4 (3), and type-5 (4), fractures. Tension band wires alone were used in 7 horses. Tension band wires were used in conjunction with unthreaded pins in 10 horses. In 3 horses, 5.5-mm cortical bone screws were inserted longitudinally instead of pins. A combination of a 5.5-mm cortical bone screw and a pin was used in 2 horses. In addition to pins and tension band wires, 4.5-mm cortical bone screws were placed in lag fashion to aid reduction of comminuted or oblique fractures in 7 of the 22 horses. Fractures healed in 18 (82%) horses. Four horses were euthanatized because of complications that included catastrophic failure of fixation during recovery from general anesthesia in 1 foal, septic arthritis and hyperextension of the contralateral metacarpophalangeal joint in 1 foal, and wound infection with partial disruption of repair in 2 horses. Nonfatal complications developed in 6 horses and included incision infection, partial wound dehiscence, carpal contraction, carpus varus of the contralateral forelimb, slight distraction of proximal fragments of the fractures, bent implants, and distal migration of pins. Long-term monitoring was performed on 17 horses.(ABSTRACT TRUNCATED AT 250 WORDS)
Eight untrained 2-year-old Thoroughbred horses were used in a study of the remodeling response of... more Eight untrained 2-year-old Thoroughbred horses were used in a study of the remodeling response of the proximal sesamoid bone (PSB) to training-related stimuli. Two horses each were assigned to 1 of 4 groups: group 1, untrained, pasture turnout (control); group 2, modified-classically trained, dirt track; group 3, classically trained, dirt track; and group 4, classically trained, wood chip track. Horses were given fluorochromic bone labels every 28 days during training. All horses were euthanatized after 5 months of training, and the proximal sesamoid bones (PSB) were removed. A midsagittal section of bone 85- to 95-microns thick was prepared for histomorphometric analysis by use of computerized image analysis and epifluorescent microscopy. Porosity (percent), trabecular width (micrometer), extent of anisotropy (percent), mineralizing surface (percent), fractional mineralizing surface (percent), and mineral apposition rate (micrometers per day) were determined at 5 circular regions of each specimen. Region 1 was located within the apex of the PSB, regions 2, 3, and 4 were subjacent to the subchondral plate, and region 5 was within the basilar articular margin. Data were pooled to allow comparison by training group and by region. The PSB from horses trained on dirt tracks (groups 2 and 3) had significantly (P less than 0.05) lower porosities and greater trabecular width, compared with the control group. The PSB from all training group specimens had significantly larger mineralizing surfaces than control group specimens. The fractional mineralizing surface revealed a rapid and vigorous response of the endosteal surface of the PSB in horses trained on dirt tracks.(ABSTRACT TRUNCATED AT 250 WORDS)
A device is needed to safely and wirelessly evaluate accelerations experienced by the horse hoof ... more A device is needed to safely and wirelessly evaluate accelerations experienced by the horse hoof under a variety of surface conditions with the horse exercising at training or racing speeds. To develop a miniaturised wireless data acquisition system (WDAS) which reliably records hoof accelerations and the times over which they occur in a minimally invasive manner in the exercising Thoroughbred. The following criteria were set for device development: production of a lightweight and minimally invasive system, which provides an adequate acceleration range, appropriate frequency response to capture high speed events, and compatibility with a low power wireless telemetry system. Following device development, the WDAS was calibrated, and tested in 6 Thoroughbred horses over a variety of surfaces. Collection of acceleration in seven trials using 6 horses over a variety of surfaces resulted in repeatable acceleration data with respect to the overall characteristic shape of the impact profile. Impact accelerations varied with surface, ranging 34.8-191.7 g. Accelerations on take off were in a similar range, although higher in some trials. Peak impact accelerations tended to larger over the grass paddock surface, than either the indoor arena or the dirt track. During dirt track trials, accelerations on take-off were often comparably larger than those observed on impact within the same footfall. This study reports the development of a wireless system that successfully measures hoof acceleration in a minimally invasive manner over a variety of surface and exercise conditions. The WDAS will be used in further studies to evaluate various components of the horse-racetrack interface, in an attempt to identify risk factors for musculoskeletal injury in the Thoroughbred racehorse.
Veterinary and comparative orthopaedics and traumatology, 1990
SummaryWith internal fixation of fractures using a plate and screws, the stability of the fixatio... more SummaryWith internal fixation of fractures using a plate and screws, the stability of the fixation is achieved mainly by the force generated by either lag screws or plate screws. The plate protects the bone from overload. The important mechanism in the function of plate fixation is the friction between the undersurface of the plate and the bone surface. It has become evident that plate luting, i. e. interposition of a bone cement layer between the plate and the bone, will alter the transmission of expected forces due to improved contact between the plate and the bone. The purpose of this project was to evaluate the load/strain relationships that occurred following plate luting and to understand why this procedure improved the mechanical behaviour of plate fixation in equine bone. We measured the strain patterns that occurred in unplated, plated and luted equine third metacarpal and metatarsal bones under simulated physiological conditions. Plate application resulted in reduced strain under the plate and increased strain at the opposite cortex. Following plate luting, this effect was more pronounced. Hysteresis between the loading-unloading cycle was less pronounced in the luted plates. This indicated that plate luting increased the effect of strain protection.Plate luting was shown to reduce the strain under the plate and to increase it in the transcortex, effectively increasing the effect of strain protection.
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