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Biomedical subjects

K T Gibson

Publications and source records attributed to K T Gibson.

18 recordsLinked to original sources

The effects of polyester (terylene) fibre implants on normal equine superficial digital flexor tendon.

AIM: To determine the effect of polyester (terylene) fibre implants on normal equine superficial digital flexor (SDF) tendon structure. METHODS: Normal forelimb SDF tendons (n=24) of 12 horses were divided into unoperated, sham-operated, and implanted (terylene fibre implant) groups. Horses were assessed for lameness and ultrasonographic changes to SDF tendons at intervals up to 48 weeks post-operatively. After euthanasia, SDF tendons were collected for histological and ultrastructural examination. Histological sections were examined for alcian blue staining intensity, cellularity, fibril bundle alignment, fascicle separation and crimp morphology. Mass-average diameters (MADs) of collagen fibrils were calculated from electron micrographs and compared between treatment groups. RESULTS: Insertion of terylene fibre implants resulted in short-term (8 weeks) lameness in implanted limbs. Ultrasonographically, the implants could be detected in 50% of implanted tendons, but were associated with tendon swelling and the presence of hypoechoic core lesions in 7/8 implanted limbs. There were significant alterations in alcian blue staining, cellularity and crimp morphology in the central fascicles of sham-operated and implanted tendons, and alteration in fibril alignment in the central fascicles of implanted tendons. Unoperated tendons remained histologically normal. MADs of collagen fibrils did not differ between sham-operated, implanted and unoperated limbs. CONCLUSIONS: Both the sham procedure and the insertion of terylene fibre implants led to alterations in tendon structure that persisted for up to 48 weeks. Persistence of disorganised connective tissue at the proximal and distal ends of the terylene fibre implants may predispose implanted tendons to continued risk of injury. CLINICAL RELEVANCE: It is unlikely that terylene fibre implants offer any advantage over standard non-surgical treatments for mild to moderate cases of SDF tendonitis in the horse.

Journal Article↗

Non-surgical management of rectal tears in two mares.

Two mares presented with life-threatening rectal tears were successfully treated with intensive medical management. Although surgery has been regarded as mandatory for grade 3 or 4 rectal tears in the past, recent reports have indicated the value of medical management alone. The case reports presented in this article detail the use of antibiotics, flunixin meglumine, laxative diets and faecal softeners in the medical management of two mares presented with grade 3 rectal tears.

Animals↗

Tendonitis of the branches of insertion of the superficial digital flexor tendon in horses.

OBJECTIVE: To describe clinical findings, ultrasonographic features and outcome of injury to the branches of insertion of the superficial digital flexor (SDF) tendon in horses. DESIGN: Retrospective study of 14 cases. PROCEDURE: Fourteen Thoroughbred horses with tendonitis affecting the branches of insertion of the SDF tendon were examined for lameness, location and amount of swelling, and the presence of other musculoskeletal abnormalities. The flexor tendons were assessed by ultrasonographic examination, and recommendations were made for management of the cases. Outcome was assessed by re-examination of some horses, direct communication with the owner or trainer, and examination of race records. RESULTS: The lateral SDF branch was affected in 10 horses; the medial branch in three, and both branches in one horse. Two horses had concurrent injuries to the SDF tendon in the metacarpal region of the contralateral limb. Ultrasonographic findings included swelling of the affected SDF branch, peritendinous fluid accumulation, disruption of normal fibre alignment on sagittal scan, and variable loss of echogenicity. As healing occurred, there was return of normal echogenicity, but normal fibre alignment did not return completely and apparent adhesions formed between the affected SDF branch and adjacent structures. Seven of 10 horses which returned to their previous use were able to compete without further tendon injury. Recurrence of injury occurred in one case, and another two horses developed tendonitis in the metacarpal region. One horse was retired from racing but was able to compete at dressage without recurrence of injury. Two horses were retired for breeding without returning to training, and one horse was sold and lost to follow up but did not race. CONCLUSION: The prognosis is fair for return to previous use following injury to the branches of insertion of the SDF tendon in athletic horses.

Animals↗

Superficial digital flexor tendonitis in thoroughbred race horses: outcome following non-surgical treatment and superior check desmotomy.

OBJECTIVE: This study documents the results of non-surgical treatment and treatment by superior check desmotomy in Thoroughbred racehorses with superficial digital flexor (SDF) tendonitis. DESIGN: A prospective study was made of 124 thoroughbred racehorses with unilateral or bilateral SDF tendonitis. PROCEDURE: The flexor tendons were assessed by physical and ultrasonographic examination before treatment, and the lesions detected in affected tendons were characterised according to lesion type, length and cross-sectional area. Ninety three horses were managed non-surgically and 31 by superior check desmotomy. Recurrent or new injuries were defined as injuries affecting a previously injured superficial digital flexor tendon, the contralateral SDF tendon, or the suspensory ligament (interosseous muscle) in either forelimb. RESULTS: No statistically significant difference was found in ultrasonographic lesion severity between treatment groups. Horses managed by superior check desmotomy were 1.3 times more likely to complete five or more races than horses managed non-surgically (95% confidence limits 0.93-1.82). Horses treated surgically were 1.2 times more likely to develop recurrent or new injuries after returning to training than horses managed non-surgically (95% CL 0.95-1.55). Horses undergoing superior check desmotomy were 5.5 times more likely to develop suspensory desmitis than horses treated non-surgically (95% CL 1.13-26.4). There was no difference in the time to recurrent or new injury between treatment groups. CONCLUSION: There was no statistically significant difference between treatment groups in the proportions of horses able to complete five or more races after an episode of superficial digital flexor tendonitis. Superior check desmotomy did not appear to offer an advantage over non-surgical treatment in preventing recurrent or new injuries in Thoroughbred racehorses. Horses undergoing superior check desmotomy appeared to be at greater risk of developing suspensory ligament injuries than horses managed non-surgically.

Animals↗

Inflammatory mediators in equine synovial fluid.

Enzyme immunoassay for prostaglandin E2 (PGE2), and radioimmunoassays for prostaglandin F2 alpha (PGF2 alpha), 6-keto-PGF1 alpha, and leukotriene B4 (LTB4) were performed on synovial fluid from normal middle carpal joints of 10 horses, and from 30 middle carpal or antebrachiocarpal joints of horses affected by degenerative joint disease and chip fractures to compare the concentrations of inflammatory mediators. Significantly greater concentrations of PGE2 were detected in fluid from affected than from control joints, but there were no significant differences in the mean concentrations of PGF2 alpha, 6-keto-PGF1 alpha, and LTB4.

Animals↗

Treatment and outcome of chronic tenosynovitis in three horses.

Three horses were presented for treatment of chronic infections of the digital flexor tendon sheath. Clinical signs included severe lameness, and heat, pain and swelling of the digital flexor tendon sheath. The horses were treated with surgical lavage of the tendon sheath, systemic and local antibiotics, and analgesics. In each case, resolution of the lameness occurred over weeks to months. Only one horse returned to athletic activity, while the other two became comfortable at pasture. Response to treatment in cases of chronic tenosynovitis may not be as rapid or complete as that reported for acute tendon sheath infections.

Journal Article↗

Conservative management of uroperitoneum in a gelding.

Uroperitoneum as a sequela to urethral calculus in an adult gelding was successfully managed by use of subischial urethrotomy and abdominal drainage. Necrosis of bladder mucosa was seen endoscopically, but a tear or rupture was never identified. Peritonitis developed but was controlled with antibacterial treatment. Although uroperitoneum is usually a sequela to bladder rupture and the ideal treatment is surgical repair, conservative management may be warranted in selected cases.

Animals↗

Open joint injuries in horses: 58 cases (1980-1986).

A retrospective study was made of 58 horses with open joint injuries admitted to the veterinary teaching hospital. Twenty-five (43%) were admitted within 24 hours of injury, 15 (26%) were examined 2 to 7 days after injury, and 18 (31%) were evaluated a week or more after the initial injury. The joints of the lower portions of the limbs most commonly were affected, with injuries that varied from puncture wounds to severe lacerations with soft tissue deficits. Diagnosis was made on the basis of clinical signs and results of synovial fluid analysis and radiography. Radiography was found to be an important diagnostic tool, indicating joint involvement in 80% of horses on which it was done. Sixteen horses were euthanatized on the day of admission; of the horses treated, 53% that were examined within the first 24 hours developed septic arthritis, and the overall survival was 65%. Ninety-two percent of horses examined within 2 to 7 days of injury developed septic arthritis, with 38.5% surviving; all horses evaluated a week or more after joint injury had septic arthritis, and 50% survived. The prognosis for return to function was best in horses that were examined within the first 24 hours. Horses examined more than 24 hours after injury had a significantly (P less than 0.05) higher chance of developing septic arthritis, and thus, were significantly (P less than 0.0014) less likely to survive the injury.

Animals↗

An evaluation of an oral glucose-glycine-electrolyte solution for the treatment of experimentally induced dehydration in the horse.

Five standardbred geldings were given 1 mg/kg bodyweight of frusemide by intramuscular injection to induce mild dehydration. After food and water deprivation overnight, the mean weight loss was 24.4 +/- 1.8 kg (5.5 per cent of bodyweight). The horses were then given an equivalent volume of an oral glucose-glycine-electrolyte solution by stomach tube. No more than 10 litres was given every 30 minutes until the calculated bodyweight loss had been replaced. Measurements made before, during and after the fluid administration included bodyweight, arterial blood haematocrit, PCO2, pH, standard bicarbonate, base excess and plasma concentrations of sodium, potassium, chloride, total protein, glucose, urea and creatinine. The final measurement was taken eight hours after the last dose of fluid and no food or water was offered to the horses during this time. Administration of the solution caused a rapid correction of the frusemide-induced dehydration and metabolic alkalosis. Absorption of the fluid from the gastrointestinal tract appeared to be very rapid because by 30 minutes after the last dose of the solution, plasma protein values were not significantly different from those before administration of frusemide. Plasma glucose concentrations became significantly increased for up to three hours after the fluid was given and an increase in creatinine and urea concentrations, which was observed after the administration of frusemide, was still evident at eight hours. The glucose-glycine-electrolyte solution was well retained, there being a mean bodyweight loss of 2.8 kg at three hours and 6.2 kg at eight hours after the last dose of fluid.

Animals↗

Effects of superior check desmotomy on flexor tendon and suspensory ligament strain in equine cadaver limbs.

OBJECTIVE: To measure the effects of transection of the accessory ligament of the superficial digital flexor (SDF) muscle (superior check desmotomy) on flexor tendon and suspensory ligament (SL) strain in vitro. STUDY DESIGN: In vitro experimental biomechanical investigation. ANIMALS USED: Ten equine cadaver forelimbs. METHODS: The effects of superior check desmotomy were determined using equine cadaver forelimbs secured in a servocontrolled hydraulic testing machine. Strain sensors were used to measure strain on the superficial and deep digital flexor tendons and SL, and a goniometer was used to measure joint angles when the limb was loaded at 890 N and 3,115 N before desmotomy, and at 3,115 N after desmotomy. RESULTS: Superior check desmotomy was associated with significantly increased strains on the SDF tendon and SL, and significant alterations in the angles of the metacarpophalangeal and carpal joints. CONCLUSIONS: The superior check ligament has an important role in maintaining joint angles and load distribution in the forelimb. Lengthening of the SDF musculotendinous unit after superior check desmotomy may be associated with increased strain on the SL. CLINICAL RELEVANCE: Transection of the accessory ligament of the SDF muscle may predispose horses to SL desmitis postoperatively.

Animals↗

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.

Abdominal Muscles↗

Production of patellar lesions by medial patellar desmotomy in normal horses.

Medial patellar desmotomy was performed on one (treated) hindlimb, and a sham operation on the other (control) hindlimb, of 12 normal horses. The horses were examined for lameness before medial patellar desmotomy and at months 1, 2, and 3. The femoropatellar joints were examined radiographically and arthroscopically at month 3. All horses were lame on the treated limb at months 1, 2, or 3. Radiographic changes, including fragment formation at the distal aspect of the patella and bone production at the attachment of the middle patellar ligament on the patella, were present in 11 horses at month 3. Articular cartilage fibrillation or detachment was seen arthroscopically on the patellas of all treated limbs. In six horses, loosely attached fragments of bone and cartilage were removed arthroscopically from the distal aspect of the patella of the treated limb. The control limbs were clinically, radiographically, and arthroscopically normal throughout the study. Medial patellar desmotomy results in pathologic changes in the articular cartilage of the patella and adjacent soft tissues. Use of this surgical procedure should be reserved for persistent and confirmed cases of upward fixation of the patella.

Animals↗

Occurrence of gastrointestinal parasites in horses in metropolitan Perth, Western Australia.

OBJECTIVE: To assess the occurrence of gastrointestinal parasites in horses in Perth. To apply polymerase chain reaction (PCR) for the identification of some species of encysted larval cyathostomes. DESIGN: Between February and September of 2000, the gastrointestinal tracts of 29 horses submitted to a local knackery and Murdoch University Veterinary hospital in Perth were examined post mortem for the presence of gastrointestinal parasites. PROCEDURE: The gastrointestinal tract was divided into six sections, which were screened for the presence of parasites such as Gasterophilus sp, Anoplocephala sp and Parascaris equorum. Samples of contents were taken for worm counts. RESULTS: Cyathostomes were found in 28 of the 29 horses. Eighteen species of gastrointestinal helminths were identified. Twelve of these were cyathostomes, with the four most common species being Cyathostomum catinatum, Cylicocyclus nassatus, Cylicostephanus longibursatus and Cylicostephanus goldi. The large strongyle, Triodontophorus serratus, was found in three of the horses but species of Strongylus were not found. CONCLUSIONS: In contrast to a study conducted on horses from this region in 1985, cyathostomes were the most common gastrointestinal parasites found. The four most common cyathostome species found in the present study correlated well with findings of studies in other locations. The high number of cyathostomes may be due to the increase in resistance to anthelmintics among the species, and to improper anthelmintic use. The apparent reduction in number of large strongyles may be due to the widespread use of ivermectin, which is very effective against these parasites, and also possibly because some larvae may not have been detected.

Animals↗