Physeal Fractures in the Horse II. Management and Outcome

Seventy physeal fractures in horses were initially managed by euthanasia (18), stall confinement (25), application of a cast (7), or internal fixation (20). Of the 52 physeal fractures initially managed with stall confinement, a cast, or internal fixation, 23 (44%) healed and 13 (25%) of these horses became sound. The number of horses less than 4.5 months of age with pressure physeal fractures that became sound was significantly higher (p < 0.05) than the number of horses greater than 4.5 months of age. The number of horses with functional, pain-free limbs (sound horses) or functional limbs (lame horses) was not significantly different (p > 0.05) for Salter-Harris Type I, II, III, or IV pressure physeal fractures; however, critical examination for growth disturbances was not performed. The number of horses with pressure or traction physeal fractures of less than 5 days duration prior to presentation that healed or became sound was not significantly different (p > 0.05) when compared with those horses with fractures of greater than or equal to 5 days duration.     

Femoral Capital Physeal Fractures in 25 Foals

The medical records of 25 horses 1 year of age or younger affected with femoral head and neck fractures during an 18 year period were reviewed. Each fracture involved the capital physis. The foals were 11 days to 12 months of age (mean, 5 months). No femoral capital physeal fractures occurred in horses older than 1 year of age during the same period. The history in each case included acute onset of severe unilateral hindlimb lameness, 3 hours to 2 months (mean, 12 days) before presentation. Injuries observed were violent falls, struggles, and kicks. Crepitation, swelling, pain with manipulation or palpation or both, and apparent fracture fragment displacement were inconsistently noted. Tentative clinical diagnoses were confirmed by radiography in 24 foals and by necropsy alone in one foal. Twenty-one foals were euthanatized due to poor prognosis. One foal sent home for stall rest was lost to follow-up. Surgical repair was attempted in three foals. Two fractures were repaired with multiple intramedullary pins and the foals were euthanatized within 2 weeks due to surgical failure and, in one case, contralateral limb breakdown. The third fracture was repaired with a compressing screw and plate device; the animal was pasture sound at month 20.     

Incisional Hernias in the Horse Incidence and Predisposing Factors

Medical records of 210 horses that survived ventral midline celiotomy for at least 4 months were examined and owners were queried to determine factors contributing to incisional hernia formation. The incidence rate of incisional hernias within 4 months was 16%. Factors significantly associated with occurrence of incisional hernias were incisional drainage, closure of the linea alba with chromic gut suture material, previous midline celiotomy, excessive incisional edema, castrated male sex, postoperative leukopenia, and postoperative pain (colic). Factors not significantly associated with occurrence of incisional hernias were suture pattern used for linea alba closure, concurrent enterotomy or intestinal resection, postoperative bandage or stent, postoperative fever, hypoproteinemia, diarrhea, respiratory disease (coughing), and peritonitis. Hernias developed in horses within 12 weeks of surgery, with the earliest hernia recognized at week 2. Of 30 horses for which information was available, only one hernia developed in 24 (80%) and two or more hernias developed in 6 (20%) along the incision. Multiple hernias tended to be smaller than single hernias.     

Dorsal Frontal Fractures of the First Phalanx in the Horse

Dorsal frontal fractures of the first phalanx in nine horses are described. All fractures were in hindlimbs, and two horses were affected bilaterally. Of the eleven fractures, seven were incomplete and nondisplaced, one was complete and nondisplaced, and three were complete and displaced. Two horses with complete displaced fractures had their fractures repaired with lag screw fixation combined with open reduction, and the other seven horses were treated nonsurgically.
All horses were sound on the injured limb within 3 to 6 months of the injury. Lag screw fixation was recommended for horses with complete, displaced dorsal frontal fractures in order to reduce the articular defect and help prevent secondary joint changes. Nonsurgical therapy in the form of stall rest with a heavy support wrap resulted in bony healing of the fracture in 4 to 6 months.
Follow-up was obtained on all nine horses: two were retired for breeding; five performed equal to or better than their previous level of racing performance; one was performing successfully as a combined training horse; and one returned to a lower level of performance due to an unrelated forelimb lameness.     

Surgical Management of Proximal Splint Bone Fractures in the Horse

Fractures of Metacarpal and Metatarsal II and IV (the splint bones) were treated in 283 horses over an 11 year period. In 21 cases the proximal portion of the fractured bone was stabilized with metallic implants. One or more cortical bone screws were used in 11 horses, and bone plates were applied in 11 horses. One horse received both treatments. Complications of screw fixation included bone failure, implant failure, radiographic lucency around the screws, and proliferative new bone at the ostectomy site. Only two of the horses treated with screw fixation returned to their intended use. Complications of plate fixation included partial fixation failure (backing out of screws), wound drainage, and proliferative bony response around the plate. Six of the 11 horses treated by plate fixation returned to their intended use. The authors recommend consideration of plate fixation techniques for repair of fractures in the proximal third of the splint bone.     

Lag Screw Fixation of Rostral Mandibular Fractures in the Horse

Seven cases of rostral mandibular fractures in the horse are reviewed, A lag screw technique for compression and fixation of rostral mandibular fractures is described. The outcome of all seven cases in this series was extremely favorable. Follow-up inquiries to either referring veterinarians or owners revealed no cases of orthopedic appliance failure. No evidence of persistent mandibular osteomyelitis or delayed dental eruption was noted. The application of lag screw techniques to rostral mandibular body fractures appears to be an effective surgical treatment.     

Fixation of Femoral Capital Physeal Fractures with 7.0 mm Cannulated Screws in Five Bulls

Salter-Harris type I fractures of the femoral capital physis were repaired in five Holstein bulls with three 7.0 mm cannulated screws placed in lag fashion. Radiographically at months 7 to 10, the fractures were healed and there was periarticular bone production on the femoral necks and the dorsal acetabular rims. Four bulls had normal gaits, and one bull had muscle atrophy and barely detectable lameness.     

Bilateral Catastrophic Metacarpal Fractures in a Quarter Horse Gelding

A 5 year-old, 450 kg, American Quarter Horse gelding was presented for postmortem examination. The horse had sustained multiple fractures of the metacarpal bones of both fore limbs while being ridden at a canter. Based on the radiographic presence of parasagittal fractures in the condyles of the distal third metacarpus, we theorized that the fractures in this horse likely originated in the metacarpophalangeal joint and propagated into the diaphysis resulting in catastrophic failure. The unique finding in this case is that these injuries occurred in a horse that was not being trained for racing. Owners and trainers should be aware that horses trained for disciplines other than racing can develop condylar fractures similar to racing Thoroughbreds and Quarter Horses.     

Noninvasive Technique for Reduction of Zygomatic Process Fractures in the Horse

Zygomatic (supraorbital) process fracture of the horse is a common injury; if untreated, permanent injury to the eye or an undesirable cosmetic appearance may result. A noninvasive surgical reduction technique is described that requires minimal instrumentation and can easily be performed in a surgical facility or under field conditions. This technique has resulted in successful reduction and healing in 12 of 13 cases of zygomatic process fractures.     

Determination of Proximal Femoral Epiphyseal Depth for Repair of Physeal Fractures in Immature Dogs

Objective—To determine the depth that implants may be safely placed for repair of proximal femoral physeal fractures.
Study Design—Relationships were determined between the depth of the proximal femoral epiphysis (PFE) and the contralateral PFE, and the PFE and pubic bone width.
Animals or Sample Population—20 immature dog cadavers.
Methods—Actual PFE depths were determined at the center of the physeal surface and at four other eccentric points. The contralateral intact PFE depth and the width of the cranial aspect of the pubic bone were measured from radiographs.
Results—Mean ratios of actual central PFE depth to radiographically measured (1) contralateral PFE depth and (2) pubic bone width were 1.04:1 and 1.09:1, and ratios of actual eccentric PFE depths were 0.89:1 and 0.93:1. Body weight was not useful in estimating depth of the PFE.
Conclusions —For the central epiphysis, pins may safely be placed a distance equal to 75% to 80% of the contralateral intact PFE depth or pubic bone width, measured from a ventrodorsal radiograph, with minimal risk of penetration through the articular surface. Pins placed eccentrically may be safely driven a depth equal to 65% of the radiographically measured contralateral intact PFE depth or pubic bone width.
Clinical Relevance —Estimating the safe depth of implant placement into the PFE avoids penetration of the articular surface.     

Surgical Treatment of Complicated Fractures of the Splint Bones in the Horse

The clinical signs, diagnosis, surgical treatment, and postoperative results in 8 horses with comminuted or open fractures of the splint bone are described. Surgical therapy was chosen to hasten the convalescent period, prevent large callus formation, improve cosmetic appearance, and, in open fractures, for aggressive wound management. Four horses used for nonracing purposes had full recovery following surgery. Two of four racehorses had residual lameness after surgery. Three of four racehorses eventually raced with decreased performance.     

Accessory Carpal Bone Fractures in the Racing Greyhound: Classification and Pathology

Fractures of the accessory carpal bone in 35 racing Greyhounds were classified into five types. Type I fractures (27 fractures) involved the distal articular surface of the accessory carpal bone, type II (6 fractures) were of the proximal articular margin, type III (1 fracture) were at the origin of the accessorometacarpal ligaments, type IV (6 fractures) were avulsion fractures at the tendon of insertion of the flexor carpi ulnaris muscle, and type V (3 fractures) were comminuted fractures.     

Evaluation of an Interfragmentary Compression System for the Repair of Equine Femoral Capital Physeal Fractures

Femoral neck and proximal epiphyseal lengths were measured in 37 femurs from 19 cadaver foals that were 1 day to 12 months old to determine the applicability of a human interfragmentary compression system to equine femoral capital physeal fractures. Because components of the implant system are available only in fixed sizes, its use was possible in foals older than 5 weeks of age, but not in younger foals. The 135 degree angle plate conformed best to the equine femur. Femoral capital physeal fractures were created surgically and repaired with the implant system in three foals. Fracture stability was evident clinically and radiographically in all three foals until euthanasia at month 3. At necropsy, the treated femurs were 4, 8, and 27 mm shorter than their mates. Epiphyseal viability was verified in all three foals by tetracycline deposition and new appositional bone growth comparable with that in the contralateral control epiphyses. The treated capital physis was open but reduced in thickness in one foal, disorganized in one foal, and closed in one foal. Fixation by compression with the implant system resulted in stability sufficient for fracture healing and maintenance of epiphyseal viability, although it was associated with reduced longitudinal femoral growth.     

Nonsurgical Management of Ulnar Fractures in the Horse: A Retrospective Study of 43 Cases

Forty-three cases of nonsurgically managed ulnar fractures in the horse were reviewed. Twenty-three per cent of the horses were euthanized, 44% survived but were unsound, and 33% of the horses were sound when surveyed 6 months to 11 years following fracture. Best results were obtained when treating distal semilunar notch fractures (70% sound). Prognosis was poorest for horses with fractures of the olecranon affecting the semilunar notch (0% sound).     

The Kinetics of Hematopoiesis in the Light Horse I. The Lifespan of Peripheral Blood Cells in the Normal Horse

Three Standardbred horses were given 0.2 mg (1 mCi) of ⁷⁵selenomethionine intravenously and a second group of three were given 10 mCi of tritiated diisopropylfluorophosphate (0.5 mg) intravenously. Observations on labeled cells were continued for 250 days after radioselenium injection and 160 days after tritium injection.

The lifespan of erythrocytes using ⁷⁵selenmethionine was 155 ± 10 days and 148 ± 7.8 days using tritiated diisopropylfluorophosphate. There was no significant difference at the 10% level between the lifespans, using these labels. The uptake of radioselenium into erythrocytes reached a mean maximum of 11.5% at 82 ± 18.9 days after injection of the label. There was an elution of from 17.6% of the injected dose of tritium label down to 7.5% eight days after injection of this isotope. From this study both of these labels appear to be satisfactory for determining the erythrocyte lifespan of the horse.

The mean time of the curve of mean radioselenium activity of peripheral blood leukocytes for the three horses was 5.54 days and the lifespan of these cells was seven days. The mean lifespan of peripheral blood leukocytes of the three horses after in vivo labelling with tritiated diisopropylfluorophosphate was 17.3 hours. No specific labelling was found in bone marrow or peripheral blood cells at this level of tritium labelling by dipping emulsion autoradiography.

The mean lifespan of equine platelets for three horses using radioselenomethionine was 9.2 days and the mean lifespan of equine platelets using tritiated diisopropylfluorophosphate was 6.6 days in a group of three horses.

     

马骡便秘疝的发病规律探讨

本文探讨了马骡便秘疝的发病与气候的关系，便秘疝的发生与使役和休闲失调的关系、饲养方法的改变与饲草种类的变换以及便秘疝与饮水的关系，同时认为饿马贪食，喂后即使，役后即喂，也是发生马骡便秘疝的主要原因。