Search Results

Abstract

Objective—To determine whether joint lavage performed simultaneously with IV regional limb perfusion (IVRLP) reduces the effectiveness of IVRLP and to compare 2 types of tourniquets used for this procedure in horses.

Animals—11 adult horses.

Procedures—2 groups of 6 horses were tested by use of a pneumatic or an Esmarch tourniquet (1 horse was tested twice [once in each group]). Standing IVRLP with amikacin (500 mg) was performed for 30 minutes. Simultaneously, the metacarpophalangeal joint was lavaged with 2 L of lactated Ringer's solution and the egress fluids were collected. Samples of the distal interphalangeal joint synovial fluid and blood from the digital and jugular veins were collected at set time intervals. Amikacin concentrations in all fluids were determined via fluorescence polarization immunoassay.

Results—Less amikacin was measured in the systemic circulation with the Esmarch tourniquet than with the pneumatic tourniquet. Amikacin concentrations in the synovial fluid from the distal interphalangeal joints of the Esmarch tourniquet group ranged from 45.1 to 1,968 μg/mL and in the pneumatic tourniquet group ranged from 1.7 to 92.3 μg/mL after 30 minutes of IVRLP. Total loss of amikacin in the egress fluids from the joint lavage ranged from < 1.36 to 7.72 mg for the Esmarch tourniquet group and from < 1.20 to 1.75 mg for the pneumatic tourniquet group.

Conclusions and Clinical Relevance—On standing horses, IVRLP performed simultaneously with joint lavage resulted in negligible loss of amikacin in the egress lavage fluids. The Esmarch tourniquet was more effective in preventing loss of amikacin from the distal portion of the limb, easier to use, and less expensive than the pneumatic tourniquet.

Abstract

Objective—To compare gentamicin concentrations achieved in synovial fluid and joint tissues during IV administration and continuous intra-articular (IA) infusion of the tarsocrural joint in horses.

Animals—18 horses with clinically normal tarsocrural joints.

Procedure—Horses were assigned to 3 groups (6 horses/group) and administered gentamicin (6.6 mg/kg, IV, q 24 h for 4 days; group 1), a continuous IA infusion of gentamicin into the tarsocrural joint (50 mg/h for 73 hours; group 2), or both treatments (group 3). Serum, synovial fluid, and joint tissue samples were collected for measurement of gentamicin at various time points during and 73 hours after initiation of treatment. Gentamicin concentrations were compared by use of a Kruskal-Wallis ANOVA.

Results—At 73 hours, mean ± SE gentamicin concentrations in synovial fluid, synovial membrane, joint capsule, subchondral bone, and collateral ligament of group 1 horses were 11.5 ± 1.5 μg/mL, 21.1 ± 3.0 μg/g, 17.1 ± 1.4 μg/g, 9.8 ± 2.0 μg/g, and 5.9 ± 0.7 μg/g, respectively. Corresponding concentrations in group 2 horses were 458.7 ± 130.3 μg/mL, 496.8 ± 126.5 μg/g, 128.5 ± 74.2 μg/g, 99.4 ± 47.3 μg/g, and 13.5 ± 7.6 μg/g, respectively. Gentamicin concentrations in synovial fluid, synovial membrane, and joint capsule of group 1 horses were significantly lower than concentrations in those samples for horses in groups 2 and 3.

Conclusions and Clinical Relevance—Continuous IA infusion of gentamicin achieves higher drug concentrations in joint tissues of normal tarsocrural joints of horses, compared with concentrations after IV administration.

Abstract

Objective—To develop a method for continuous infusion of gentamicin into the tarsocrural joint of horses, to determine pharmacokinetics of gentamicin in synovial fluid of the tarsocrural joint during continuous infusion, and to evaluate effects of continuous infusion of gentamicin on characteristics of the synovial fluid.

Animals—12 healthy adult horses.

Procedure—An infusion catheter consisting of flow control tubing connected to a balloon infuser was used. Gentamicin solution (100 mg/ml) was infused in the right tarsocrural joint and balanced electrolyte solution was infused in the left tarsocrural joint for 5 days. Synovial fluid and serum gentamicin concentrations were measured by use of a fluorescence polarization immunoassay.

Results—17 of the 24 (71%) infusion catheters initially placed functioned without complications for the entire 5-day infusion period. Median gentamicin concentration in synovial fluid from treated joints during the 5-day infusion period ranged from 287.5 to 982 μg/ml. Median serum gentamicin concentration during this period ranged from 2.31 to 2.59 μg/ml. Mean (± SD) elimination half-life and total clearance of gentamicin from the synovial fluid were 6.25 ± 1.01 hours and 1.52 ± 0.96 ml/min, respectively.

Conclusions and Clinical Relevance—An infusion catheter can be used for continuous infusion of gentamicin into the tarsocrural joints of horses for up to 5 days. At a gentamicin dosage of 0.17 ± 0.02 mg/kg/h, continuous intra-articular infusion results in synovial fluid gentamicin concentrations greater than 100 times the minimal inhibitory concentration reported for common equine pathogens. (Am J Vet Res 2000;61:407–412)

Abstract

Objective—To determine the extent to which a hydroxyapatite coating promotes pin stability in the third metacarpal bone during transfixation casting in horses.

Animals—14 adult horses.

Procedures—7 horses each were assigned to either an uncoated or hydroxyapatite-coated pin group. Three transcortical pins were placed in the third metacarpal bone of each horse and incorporated into a cast for 8 weeks. Insertion and extraction torque were measured, and torque reduction was calculated. Radiography was performed at 0, 4, and 8 weeks. Lameness evaluation was performed at 2, 4, 6, and 8 weeks. Bacteriologic culture of pins and pin holes was performed at pin removal.

Results—All horses used casts without major complication throughout the study. Insertion torque was higher in uncoated pins. There was no effect of group on extraction torque. Hydroxyapatite-coated pins had lower torque reduction. Five of 15 hydroxyapatite-coated pins maintained or increased stability, whereas all uncoated pins loosened. Pin hole radiolucency, lameness grades, and positive bacteriologic culture rates were not different between groups.

Conclusions and Clinical Relevance—Hydroxyapatite coating increased pin stability within the third metacarpal bone of horses during 8 weeks of transfixation casting but did not improve pin performance on clinical assessments. Clinical use of hydroxyapatite-coated transfixation pins may result in greater pin stability; however, further research is necessary to improve the consistency of pin osteointegration and elucidate whether clinical benefits will ultimately result from this approach in horses.

Abstract

Objective—To determine the effects of a continuous intra-articular infusion of gentamicin on the synovial membrane and articular cartilage in the tarsocrural joint of horses.

Animals—6 healthy adult horses.

Procedure—A balloon infusion system attached to a catheter placed in the plantarolateral pouch of both tarsocrural joints in each horse was used for continuous gentamicin solution (GM) or balanced electrolyte solution (BES) delivery for 5 days. Cartilage and synovial membrane specimens were collected on day 5 from 3 horses and on day 14 from the remaining 3 horses. Both infused joints from each horse were assessed, using gross evaluation and histologic scoring systems.

Results—Significant differences in the histologic scores of synovial membrane specimens between the GM- and BES-treated joints at either 5 or 14 days were not observed. Safranin-O-fast green staining scores were similar between cartilage specimens from GM- and BES-treated joints. Although the synovial membrane histologic scores and safranin-O-fast green staining scores improved from day 5 to 14, the changes in scores were not significant. Loss of synovial intimal cells from villi was found more commonly in sections of synovial membrane from GM-treated joints, compared with BES-treated joints.

Conclusions and Clinical Relevance—Continuous infusion of GM into the tarsocrural joint of horses does not have significant effects on histologic scores of articular cartilage or synovial membrane, compared with those infused with BES. Continuous infusion of GM into the tarsocrural joint of horses for 5 days is an acceptable method for the treatment of septic arthritis. (Am J Vet Res 2002;63:683–687)

Abstract

Objective—To determine clinical findings, complications, and outcome of septic synovitis in which continuous intrasynovial antimicrobial infusion (CIAI) was used for local antimicrobial delivery in horses.

Design—Retrospective case series.

Animals—22 adult horses and 9 foals (horses < 1 year of age).

Procedures—Records of horses with septic synovitis that had CIAI during treatment were reviewed. The association between clinical variables and whether horses performed their intended use following treatment was determined.

Results—42 synovial cavities were treated via CIAI. Twenty-nine cases were chronic (> 7 days) in nature, 15 had been refractory to standard treatments, and 13 synovial infections had associated osteomyelitis. Mean duration from infection to initiation of CIAI was 19.7 days, and mean duration of CIAI was 6.1 days. Temporary discharge from the catheter site at the time of removal was evident in 8 horses. Dysfunction of the infusion system occurred in 2 horses and was corrected during the course of treatment. No long-term complications were reported. Thirty-nine (93%) synovial infections in 29 (94%) horses were resolved. Twenty adult horses and 8 foals were discharged from the hospital, and 19 of 24 horses with long-term follow-up performed their intended use.

Conclusions and Clinical Relevance—CIAI was a useful adjunctive treatment for septic synovitis and allowed intrasynovial antimicrobial delivery into a variety of synovial cavities.

Abstract

Objective—To determine synovial fluid gentamicin concentrations and evaluate adverse effects on the synovial membrane and articular cartilage of tarsocrural joints after implantation of a gentamicin-impregnated collagen sponge.

Animals—6 healthy adult mares.

Procedures—A purified bovine type I collagen sponge impregnated with 130 mg of gentamicin was implanted in the plantarolateral pouch of 1 tarsocrural joint of each horse, with the contralateral joint used as a sham-operated control joint. Gentamicin concentrations in synovial fluid and serum were determined for 120 hours after implantation by use of a fluorescence polarization immunoassay. Synovial membrane and cartilage specimens were collected 120 hours after implantation and evaluated histologically.

Results—Median peak synovial fluid gentamicin concentration of 168.9 μg/mL (range, 115.6 to 332 μg/mL) was achieved 3 hours after implantation. Synovial fluid gentamicin concentrations were < 4 μg/mL by 48 hours. Major histologic differences were not observed in the synovial membrane between control joints and joints implanted with gentamicin-impregnated sponges. Safranin-O fast green stain was not reduced in cartilage specimens obtained from treated joints, compared with those from control joints.

Conclusions and Clinical Relevance—Implantation of a gentamicin-impregnated collagen sponge in the tarsocrural joint of horses resulted in rapid release of gentamicin, with peak concentrations > 20 times the minimum inhibitory concentration reported for common pathogens that infect horses. A rapid decrease in synovial fluid gentamicin concentrations was detected. The purified bovine type I collagen sponges did not elicit substantial inflammation in the synovial membrane or cause mechanical trauma to the articular cartilage.

Abstract

Objective—To determine whether heavy (≥ 680 kg [≥ 1,500 lb]) draft horses undergoing surgical treatment for acute signs of abdominal pain were at a greater risk for anesthetic and postoperative complications and lower postoperative survival rates than light (< 680 kg) draft horses.

Design—Retrospective case series.

Animals—72 draft horses.

Procedures—Medical records of draft horses that underwent exploratory celiotomy for signs of acute abdominal pain from October 1983 to December 2002 were reviewed. Medical records of draft horses in which a celiotomy was performed for correction of reproductive abnormalities were not included in the study.

Results—When compared with light draft horses, heavy draft horses had longer durations of anesthesia, more postoperative complications, and lower survival rates. Seventy-six percent of horses that recovered from anesthesia had postoperative complications. Postoperative complications associated with low survival rates included myopathy and neuropathy, ileus, diarrhea, and endotoxemia. All horses with postoperative myopathy and neuropathy died or were euthanized. The short-term survival rate for horses that recovered from anesthesia was 60%. Horses undergoing small intestinal surgery had a worse prognosis for short-term survival than those undergoing large intestinal surgery. The survival rate for horses for which long-term (> 1 year) follow-up information was available was 50%.

Conclusions and Clinical Relevance—Draft horses weighing > 680 kg that underwent surgery because of acute signs of abdominal pain had longer durations of anesthesia, more postoperative complications, and higher mortality rates than draft horses weighing < 680 kg.

Abstract

Objective—To evaluate the management of equids undergoing cryptorchidectomy at a referral hospital.

Design—Retrospective case series.

Animals—604 client-owned equids.

Procedures—Medical records of all equids undergoing surgical treatment of cryptorchidism from 1977 to 2010 were retrospectively reviewed. Analyses of breed, location of retained testes, accuracy of palpation per rectum for determining the location of retained testes, surgical technique, and postoperative complications were performed.

Results—The most frequently affected breed was the Quarter Horse (282/604 [47%]), which was significantly overrepresented. Of the 604 equids, 90 (15%) had undergone previous surgical attempts at castration. Preoperative palpation per rectum was performed in 395/604 (65.4%) patients, and was accurate in predicting the location of the retained testes in 354/395 (89.6%). Surgeons were significantly more likely to be incorrect in determining the location of the retained testis by means of palpation per rectum in patients that had undergone a prior attempt at castration. For equids with abdominal cryptorchidism (360/604 [59.6%]), the most common surgical technique was noninvasive cryptorchidectomy (298/360 [82.8%]). In unilateral cryptorchids (521/604 [86.3%]), the 2 most common sites were left abdominal (184/521 [35.3%]) and right inguinal (148/521 [28.4%]). For bilateral retention (80/604 [13.2%]), abdominal cryptorchidism was most common (48/80 [60%]). Fever was present in 138/324 (43%) equids on the first day after surgery. Postoperative fever was not significantly associated with any variables evaluated. Including postoperative (≤ 24 hours) fever, 150 of 604 (25%) patients developed postoperative complications. Excluding postoperative fever, 18 of 604 (3%) patients developed major postoperative complications; complications in 10 of 604 patients were deemed surgically related, and 3 of 604 patients died.

Conclusions and Clinical Relevance—Results indicated that cryptorchidectomy in equids performed with a variety of surgical approaches was associated with minimal postoperative complications. A history of previous attempts at castration decreased the ability to accurately predict the location of the retained testis.