Atrial cardiomyopathy in an adult Labrador retriever dog.

INTRODUCTION: A 7-year-old castrated male Labrador retriever was examined for a 10-day history of weakness and syncope. Physical examination revealed bradycardia and a grade III/VI left apical systolic heart murmur. Electrocardiography demonstrated bradycardia, absence of P waves and an atrio-ventricular nodal escape rhythm. Echocardiography revealed marked biatrial enlargement. Thoracic radiographs showed no evidence of pulmonary edema. Routine plasma biochemistry and electrolytes, basal serum cortisol, total thyroxin concentration, and complete blood count were within normal limits. Serum cardiac troponin I concentration was moderately increased. Serological examinations for antibodies against vector-borne diseases were negative. A pacemaker was implanted one month after the initial presentation due to worsening of the dog's clinical condition despite medical treatment. The dog remained asymptomatic for 18 months but was then re-presented with a gastric dilatation volvulus and subsequently euthanized. Necropsy and histology of the heart yielded a diagnosis of atrial cardiomyopathy.

Complications and outcome of a new modified Maquet technique for treatment of cranial cruciate ligament rupture in 82 dogs.

OBJECTIVES: To describe the complications, short and long-term outcome and owner satisfaction of dogs with cranial cruciate ligament rupture treated with a recently described new osteotomy for the modified Maquet technique (N-MMT). MATERIALS AND METHODS: Medical records and radiographs of 82 dogs (84 stifles) were reviewed. Details regarding short-term outcome and complications were recorded from the medical records. Long-term follow-up information was obtained by telephone interview. Historical data and complications were statistically analysed. RESULTS: Major complications occurred in 34/84 stifles. Intra-operative complications occurred in 26/84 stifles, all of which were fissures or fractures of the cortical hinge. Twenty-one of these fractures or fissures were repaired with a figure-of-eight wire. The second most common major complication was late meniscal tears in 3/84 stifles. One dog sustained a complete tibial fracture. Non-displaced fracture of the cortical hinge was the most common postoperative minor complication, which occurred in 5/84 stifles. The median preoperative lameness score was 3 out of 6. Final in-hospital re-evaluation of limb function was available in 58 dogs. The median lameness score at that time was 0 out of 6. Development of osteotomy related complications was not associated with a significant change in the postoperative lameness score. CLINICAL SIGNIFICANCE: Subjectively assessed clinical outcome with the N-MMT was good to excellent in this cohort of dogs. However, a high rate of intra- and postoperative complications of the N-MMT procedure was also present in these dogs.

Tumor necrosis factor-alpha concentration in the aqueous humor of healthy and diseased dogs: a preliminary pilot study.

OBJECTIVES: To determine reference values of tumor necrosis factor-alpha (TNF-α) concentrations in the aqueous humor of control dogs. To show whether these values are significantly different from those obtained in dogs affected with intraocular pathology: acute anterior uveitis (AAU) or chronic primary angle closure glaucoma (PACG). METHODS: Forty-four dogs were included in the study and were divided into two groups: a control group and a group with intraocular disease. Twenty-seven dogs (9 males and 18 females) were examined and found to be normal after a complete ophthalmological examination (control group), 7 (6 females and 1 male) presented with PACG, and 10 (7 females and 3 males) presented with AAU secondary to corneal perforation. One aqueous humor sample (volume ≥ 0.2 mL) was collected from one eye of all dogs. The aqueous TNF-α concentration was determined with an Elisa kit. RESULTS: TNF-α levels were detectable in all dogs. TNF-α levels were significantly higher in the group with intraocular disease compared to the normal control group (P=0.001). In the group with intraocular disease, TNF-α levels were significantly higher in the aqueous humor of the AAU group compared with the PACG group (P=0.001). CONCLUSIONS: In the dog, it is possible to measure the concentration of TNF-α in the aqueous humor. The level of TNF-α was significantly higher in the case of AAU. TNF-α is an interesting biomarker for longitudinal follow-up studies of comparative ophthalmology.

Biomechanical testing of a ß-tricalcium phosphate wedge for advancement of the tibial tuberosity.

OBJECTIVES: to evaluate in vitro the strength of different compositions of beta-tricalcium phosphate (ß-TCP) wedges in comparison with titanium foam and cages. To study the response to cyclic loading of the strongest ß-TCP wedge, titanium foam and titanium cage. METHODS: Compression test: Twenty-five tibiae were prepared for tibial tuberosity advancement using the modified Maquet technique. Five groups were defined depending on the material used to maintain the tibial tuberosity: Group 1=titanium cage; Group 2=wedges of porous titanium foam with 50% porosity (OrthoFoam®); Group 3=blocks of biphasic synthetic bone (60% hydroxyapatite [HAP] and 40% ß-TCP, porosity 80%); Group 4=blocks of biphasic synthetic bone (60% HAP and 40% ß-TCP, porosity 70%) and Group 5=blocks of biphasic synthetic bone (65% HAP and 35% ß-TCP, porosity 60%). Loads to failure were calculated for each implant. Cyclic study: Five additional tibiaes of group 1, 2 and 5 were fatigue tested from 100 to 500 N at a rate of 4 Hz for 200,000 cycles or until failure. RESULTS: Compression test: For the five groups, the mean load at failure was 1895 N, 1917 N, 178 N, 562 N and 1370 N respectively. Cyclical study: All samples in the three groups tested withstood 200,000 cycles without failure. CLINICAL SIGNIFICANCE: The ideal implant to maintain tibial tuberosity advancement after the modified Maquet technique would be absorbable and allow osteoconduction and osteoinduction. As such, ß-TCP wedges have many advantages and our study shows that they can withstand loads in the patellar tendon up to 500 N over 200,000 cycles in vitro and deserve more investigation.

Measurement of the patellar tendon-tibial plateau angle and tuberosity advancement in dogs with cranial cruciate ligament rupture. Reliability of the common tangent and tibial plateau methods of measurement.

OBJECTIVES: To (i) compare agreement of the common tangent (CT) and tibial plateau angle (TP) methods in terms of measuring the patellar tendon angle (PTA) and required advancement and (ii) determine the intra- and inter-observer reliability of observers who measured PTA and the advancement. METHODS: Six observers were divided into three groups based on their level of experience. They measured the PTA and the required advancement on 43 radiographic images of the tibiae of dogs affected by cranial cruciate ligament rupture. Each observer repeated the measurements three times with each method. The inter-technique (interT), intra-observer (intraO), and interobserver (interO) reliabilities were evaluated, assessed by calculating the intraclass correlation coefficient (ICC), and represented by Jones plots. RESULTS: The agreement between PTA-CT and PTA-TP was low (the ICC interT values ranged from 0.11 to 0.4). The PTA-CT was associated with moderate intra-observer reliability (ICC intraO, CT = 0.61) and poor interobserver reliability (ICC interO, CT = 0.33). The PTA-TP was associated with good intra-observer reliability (ICC intraO, TP = 0.75) and moderate interobserver reliability (ICC interO, TP = 0.59). Interobserver reliability did not depend on the level of experience. The advancement measurements were associated with reliability results similar to those obtained for PTA. Jones' plots showed that the CT method consistently yielded lower PTA and advancement values than the TP method. CONCLUSION: Given its poor reliability, the CT method is not recommended.

Comparative anatomy of the proximal tibia in healthy Labrador Retrievers and Yorkshire Terriers.

OBJECTIVES: 1) To provide specific quantitative data of tibial conformation in Labrador Retrievers and Yorkshire Terriers; 2) To compare the tibial conformation of these two breeds; and 3) To compare these data with previously reported data. METHODS: Mediolateral radiographs of the stifle were obtained from 30 consecutive Labrador Retrievers and 30 consecutive Yorkshire Terriers with an angle of extension of 135°. The tibial plateau angle (TPA), the angle between the tibial plateau and the patellar tendon (PTA), the Z angle, the distal tibial axis/proximal tibial axis angle (DPA), and the relative tibial tuberosity width (rTTW) were measured and compared among the two breeds. RESULTS: The breed had a significant effect on all of the measured variables (p <0.01): Labrador Retrievers had a lower TPA (25 ± 3° compared to 30 ± 4°), a lower Z angle (58.8 ± 3.2° compared to 69.2 ± 4.5°), a lower DPA (4.5 ± 2.3° compared to 10.8 ± 4.3°), and a lower rTTW (0.74 ± 0.1 compared to 0.86 ± 0.1) than Yorkshire Terriers. The PTA was greater in Labrador Retrievers compared to Yorkshire Terriers (106.9 ± 3.9° compared to 103.7 ± 6.5°). Four correlations were found to be significant: the DPA angle was correlated with the TPA, the Z angle, and the rTTW. The TPA was also correlated with the Z angle. CLINICAL SIGNIFICANCE: The variation in tibial conformation between breeds should be taken into account when studying the role of each measured parameter in the pathology of cruciate disease. When the relevance of each of the aforementioned measured parameters is better understood, it may help determine the most appropriate surgical treatment.

Mechanical testing of a new osteotomy design for tibial tuberosity advancement using the Modified Maquet Technique.

OBJECTIVES: To evaluate the mechanical properties of the distal cortical hinge associated with a new osteotomy design for the Modified Maquet Technique (MMT). STUDY DESIGN: Ex vivo mechanical study. METHODS: The osteotomy was started 10 mm caudal to the tibial tuberosity and extended over 150% of the length of the tibial crest; it was slightly curved distally to stay at a distance of 2 to 4 mm from the cranial cortex, according to the body weight. Ninety-six tibiae were tested in advancement, and 60 tibiae were axially loaded perpendicular to the tibial plateau, until failure of the crest. Desired advancement was measured using the common tangent method in 60 tibiae. Angle of opening, thickness, and area of the cortical hinge were recorded. RESULTS: Desired advancement of 6 mm, 9 mm, 12 mm and 15 mm was recorded in 16, 12, 18 and 14 tibiae respectively. Mean maximal advancement in these bones was 15.6 ± 6.4 mm, 20.8 ± 5.2 mm, 21.3 ± 5.2 mm and 22.7 ± 5.2 mm respectively. The desired advancement was reached in all but one tibia. Advancement was mainly influenced by the angle of opening and the stiffness of the cortical hinge. Mean ultimate load to failure was 6.12 ± 2.4 times the body weight. It was significantly associated with the body weight, thickness, and area of the cortical hinge. CLINICAL RELEVANCE: Mean maximal advancement was higher than clinically required without occurrence of fissure or fracture. Ultimate load to failure and maximal advancement could be predicted using calculated formulae.

Preliminary experience of a modified Maquet technique for repair of cranial cruciate ligament rupture in dogs.

The modified Maquet technique (MMT) uses the same principle as the tibial tuberosity advancement (TTA) for stabilization of the cranial cruciate ligament-deficient stifle in the dog. In the MMT, the tibial tuberosity is advanced in a similar manner to that used in the TTA, however the means by which the tibial crest is stabilized differs. The plate and fork originally described by Montavon et al. are not used (7). The MMT was first described by Maquet for use on humans; it leaves intact a distal bony attachment to the tibial shaft, and the tuberosity is either reinforced or not by a figure-of-eight wire. In this paper, we describe the MMT, and we report the results of our first 20 canine patients with cranial cruciate ligament rupture that were treated by the MMT. Mean clinical bone healing time was 6.8 weeks (range 4 to 12 weeks). The evidence provided by this clinical communication suggests that it is technically possible to achieve an advancement of the tibial tuberosity without the need for a plate. The MMT deserves consideration as a primary treatment option for cranial cruciate ligament rupture in dogs, and further evaluation in large clinical studies. Long-term follow-up and force plate analysis would be necessary to compare the MMT to both the TTA and the tibial plateau levelling osteotomy.

Theoretical discrepancy between cage size and efficient tibial tuberosity advancement in dogs treated for cranial cruciate ligament rupture.

OBJECTIVES: To calculate the difference between the desired tibial tuberosity advancement (TTA) along the tibial plateau axis and the advancement truly achieved in that direction when cage size has been determined using the method of Montavon and colleagues. To measure the effect of this difference on the final patellar tendon-tibial plateau angle (PTA) in relation to the ideal 90°. METHODS: Trigonometry was used to calculate the theoretical actual advancement of the tibial tuberosity in a direction parallel to the tibial plateau that would be achieved by the placement of a cage at the level of the tibial tuberosity in the osteotomy plane of the tibial crest. The same principle was used to calculate the size of the cage that would have been required to achieve the desired advancement. The effect of the difference between the desired advancement and the actual advancement achieved on the final PTA was calculated. RESULTS: For a given desired advancement, the greater the tibial plateau angle (TPA), the greater the difference between the desired advancement and the actual advancement achieved. The maximum discrepancy calculated was 5.8 mm for a 12 mm advancement in a case of extreme TPA (59°). When the TPA was less than 31°, the PTA was in the range of 90° to 95°. CLINICAL SIGNIFICANCE: A discrepancy does exist between the desired tibial tuberosity advancement and the actual advancement in a direction parallel to the TPA, when the tibial tuberosity is not translated proximally. Although this has an influence on the final PTA, further studies are warranted to evaluate whether this is clinically significant.

Use of tamoxifen in a German shepherd dog with sclerosing encapsulating peritonitis.

A German shepherd dog was diagnosed with sclerosing encapsulating peritonitis after an episode of peritonitis caused by a free intra-abdominal foreign body (stick). The foreign body had initially been treated by surgical removal and abdominal lavage. Postoperatively, peritoneal effusion persisted despite the use of methylprednisolone for 1 month and a second surgical exploration and abdominal lavage. After a third surgery at our institution (to breakdown abdominal adhesions) followed by open abdominal drainage, treatment with tamoxifen orally was initiated and within 2 weeks the dog's condition improved dramatically. Two months later, no fluid was present in the abdomen. The only apparent adverse reaction to tamoxifen therapy was swelling of the vulva. In humans, sclerosing encapsulating peritonitis is a known life-threatening complication following peritoneal dialysis. In veterinary medicine, most animals with sclerosing encapsulating peritonitis die because of chronic weight loss, peritoneal effusion and progression of concurrent disease. This dog's condition was unresponsive to methylprednisolone alone but was successfully treated with aggressive surgery including enterolysis and open abdominal lavage and the addition of tamoxifen.

Mechanical testing of a modified stabilisation method for tibial tuberosity advancement.

OBJECTIVES: This in vitro study evaluated three modified techniques of tibial tuberosity advancement (TTA). Loads to failure were calculated for each technique. METHODS: A 9 mm TTA procedure was performed in the tibiae of dogs weighing between 32 and 38 kg. In group 1 (n = 12), the distal part of the tibial crest was left attached to the tibia by the cranial cortex, and a figure-of-eight wire was added for stabilisation. In group 2 (n = 12), the tibial crest was left attached but no additional device was used for stabilisation. In group 3 (n = 12), the tibial crest was completely separated from the tibia and fixed by a figure-of-eight wire so that, in this group, only the wire opposed avulsion of the tibial crest. Unidirectional axial force was applied via the patella to determine the maximal load to failure of the model. RESULTS: There was no significant difference between group 1 and group 2. These two groups both had a significantly stronger construct than that of group 3. CLINICAL SIGNIFICANCE: We described modifications to the TTA procedure without plate fixation that warrant clinical investigation. When the crest is broken during its advancement, the tension sustained by the repair is significantly weaker from a biomechanical point of view and the use of such a repair clinically is not recommended by the authors.

Vertebral canal location of a broken drill bit.

A 2 mm drill broke during plate fixation of an ilial fracture. Postoperative radiographs showed the tip of the drill bit to be within the L7 vertebral canal. It was retrieved 10 days later via dorsal laminectomy, immediately restoring weight bearing.