Evaluation of Osteotomy Healing in Boxer Dogs Undergoing Tibial Plateau Levelling Osteotomy Using Two Radiographic Scoring Systems.

OBJECTIVE: The aim of this study was to (1) compare 5-point and 10-point bone healing radiographic scoring systems using postoperative tibial plateau levelling osteotomy (TPLO) radiographs and (2) determine whether Boxer osteotomy healing time differs from age-matched Labrador Retrievers. STUDY DESIGN: This was a multicentre retrospective study. Fifty-eight client-owned dogs undergoing TPLO (29 Boxers and 29 Labrador Retrievers) were included. Five board-certified surgeons evaluated the radiographs three independent times. Osteotomy healing approximately 8 weeks postoperatively was graded using previously reported 5-point and 10-point scoring systems and immediate postoperative radiographs were assessed for the presence of an osteotomy gap of ≥1 mm. RESULTS: Both scoring systems had good consistency among observers. Intraobserver consistency was good in three out of five observers using the 5-point system and in four out of five observers using the 10-point system. Boxers had significantly lower radiographic healing scores at 8 weeks postoperatively compared with Labrador Retrievers using both scoring systems (p ≤ 0.001). The presence of an osteotomy gap postoperatively resulted in significantly lower healing scores at 8 weeks using both scoring systems (p < 0.001) in both breeds. CONCLUSION: No difference was found in inter- and intraobserver variability between scoring systems. Boxer dogs had lower healing scores at 8 weeks after TPLO compared with Labrador Retrievers. An osteotomy gap of ≥1 mm was associated with lower healing scores.

Biomechanical Comparison of External Fixation and Double Plating for Stabilization of a Canine Cadaveric Supracondylar Humeral Fracture Gap Model.

OBJECTIVE: Successful stabilization of comminuted supracondylar humeral fractures is challenging, and biomechanical studies are scarce. This study compares double-plate (DB-PLATE) and linear external fixator with an intramedullary pin tie-in (ESF-IMP) fixation techniques in a cadaveric gap model. The hypothesis was the DB-PLATE construct would be stiffer, stronger and more resistant to repeated loading than the ESF-IMP construct in both cyclic and load-to-failure axial compression testing. STUDY DESIGN: A 2 cm ostectomy was performed on 10 pairs of canine cadaveric humeri proximal to the supratrochlear foramen. Stabilization was with DB-PLATE (n = 10) or ESF-IMP (n = 10). Cyclic testing was performed by applying a 200 N load at 2 Hz for 63,000 cycles. Axial compressive load to failure testing followed. Data analysed included dynamic stiffness, stiffness and yield load. RESULTS: No constructs failed during cyclic testing or lost stiffness over time. Mean dynamic stiffness over the final 100 cycles was greater for DB-PLATE compared with ESF-IMP. Mean stiffness of DB-PLATE in load-to-failure testing was not different than ESF-IMP. Yield load of DB-PLATE was higher than ESF-IMP. CONCLUSION: Both DB-PLATE and ESF-IMP survived cyclic testing with no change in dynamic stiffness. DB-PLATE was stronger than ESF-IMP in load-to-failure testing, which may make this construct preferable when prolonged healing or poor patient compliance is anticipated. Results suggest that either method may be appropriate for fixation of comminuted supracondylar humeral fractures.

Physeal Acetabular Fracture in a Dog Treated with External Fixation.

An acetabular physeal fracture in a 13 wk old dog was treated with open fixation using Kirschner wire cross pins and a four-pin Type 1A external fixator, resulting in successful healing of the fracture. Three years following the surgery, marked osteoarthrosis of the affected hip was noted, although clinical function of the hip was good. The authors suggest this fixation method be considered a viable option for fixation of acetabular physeal fractures in dogs.

Hip Dysplasia: Clinical Signs and Physical Examination Findings.

Hip dysplasia is a common developmental disorder of the dog, consisting of varying degrees of hip laxity, progressive remodeling of the structures of the hip, and subsequent development of osteoarthritis. It is a juvenile-onset condition, with clinical signs often first evident at 4 to 12 months of age. A tentative diagnosis of hip dysplasia can be made based on signalment, history, and physical examination findings. The Ortolani test is a valuable tool for identifying juvenile dogs affected with this condition. Further diagnostics can then be prioritized, contributing to prompt diagnosis and appropriate treatment.

Pullout strength of monocortical and bicortical screws in metaphyseal and diaphyseal regions of the canine humerus.

OBJECTIVE: Monocortical screws are commonly employed in locking plate fixation, but specific recommendations for their placement are lacking and use of short monocortical screws in metaphyseal bone may be contraindicated. Objectives of this study were to evaluate axial pullout strength of two different lengths of monocortical screws placed in various regions of the canine humerus compared to bicortical screws, and to derive cortical thickness and bone density values for those regions using quantitative computed tomography analysis (QCT). METHODS: The QCT analysis was performed on 36 cadaveric canine humeri for six regions of interest (ROI). A bicortical, short monocortical, or 50% transcortical 3.5 mm screw was implanted in each ROI and axial pullout testing was performed. RESULTS: Bicortical screws were stronger than monocortical screws in all ROI except the lateral epicondylar crest. Short monocortical metaphyseal screws were weaker than those placed in other regions. The 50% transcortical screws were stronger than the short monocortical screws in the condyle. A linear relationship between screw length and pullout strength was observed. CLINICAL SIGNIFICANCE: Cortical thickness and bone density measurements were obtained from multiple regions of the canine humerus using QCT. Use of short monocortical screws may contribute to failure of locking plate fixation of humeral fractures, especially when placed in the condyle. When bicortical screw placement is not possible, maximizing monocortical screw length may optimize fixation stability for distal humeral fractures.

Canine giant hypertrophic gastritis treated successfully with partial gastrectomy.

A 4 yr old castrated male Jack Russell terrier was presented with a 2 mo history of vomiting, anorexia, and weight loss. Abdominal radiographs and ultrasound supported the diagnosis of gastric outflow obstruction. Celiotomy and gastrotomy revealed a large, narrowly based mass originating from the mucosa of the dorsal gastric body, occupying the lumen of the stomach and protruding through the pylorus into the duodenum. A partial gastrectomy was performed to excise the mass along with a 1 cm margin of grossly normal tissue. Giant hypertrophic gastritis was diagnosed via histopathology of the excised tissue. Giant hypertrophic gastritis is a rarely diagnosed disease of canines, characterized by giant gastric folds, hypoalbuminemia, and mucosal hypertrophy. Long-term treatment success has not been previously reported. In the case described herein, surgical excision of the affected gastric tissue provided complete resolution of clinical signs. Twelve mo following surgery, no recurrence of either vomiting or weight loss had been noted and the dog was clinically normal.

Treatment of pyloric stenosis in a cat via pylorectomy and gastroduodenostomy (Billroth I procedure).

CASE DESCRIPTION: A 5-month-old 1.9-kg (4.2-lb) spayed female Siamese cat was evaluated because of a history of decreased appetite, regurgitation, vomiting, and lack of weight gain. CLINICAL FINDINGS: Radiographic findings included a fluid- and gas-distended stomach with a small accumulation of mineral opacities. Ultrasonographic examination confirmed severe fluid distention of the stomach with multiple hyperechoic structures present and revealed protrusion of the thickened pylorus into the gastric lumen, with normal pylorogastric serosal continuity. Endoscopy of the upper gastrointestinal tract revealed an abnormally shortened pyloric antrum and stenotic pyloric outflow orifice. Pyloric stenosis resulting in pyloric outflow obstruction was diagnosed. TREATMENT AND OUTCOME: A pylorectomy with end-to-end gastroduodenostomy (Billroth I procedure) was successfully performed, and a temporary gastrostomy tube was placed. Six days after surgery, the cat was eating and drinking normally, with the tube only used for administration of medications. The gastrostomy tube was removed 12 days after surgery. Results of follow-up examination by the referring veterinarian 3 weeks after surgery were normal. Occasional vomiting approximately 2 months after surgery was managed medically. Fifteen months after surgery, the owners reported that the cat seemed completely normal in appearance and behavior. CLINICAL RELEVANCE: Pyloric stenosis should be considered a differential diagnosis for young cats with pyloric outflow obstruction. The cat of this report was treated successfully with a Billroth I procedure. Histologic examination and immunohistochemical analysis of the excised tissue showed the stenosis to be associated with hypertrophy of the tunica muscularis.

Retrospective evaluation of lingual tumors in 42 dogs: 1999-2005.

In this retrospective study of 42 cases of lingual tumors in dogs, 27 (64%) were malignant, and 15 (36%) were benign. Median survival time for dogs with benign tumors was >1607 days, compared to 286 days for malignant tumors. Prognostic factors significantly associated with increased survival included complete histological margins (P=0.036), smaller tumor size (P=0.003), and benign tumor type (P=0.011). Smaller tumors were more likely to be completely resected (P=0.008) and were less likely to recur (P=0.001). Partial or subtotal glossectomies were performed in 13 cases. Short-term morbidity associated with glossectomy included ptyalism and dehiscence. Long-term morbidity included minor changes in eating and drinking habits.