Relationship between the degree of stifle flexion and the proximal patellofemoral angle in the sagittal plane: A radiographic study.

The objective of this study was to evaluate the position of the patella in relation to the proximal femoral axis in the sagittal plane and to assess its reliability as a surgical landmark for femoral component placement in canine hip replacement. The relationship between the patella and the proximal femoral axis was assessed by defining the proximal patellofemoral angle in medio-lateral radiographic projections with 3 different stifle angles (full flexion, 90°, full extension) in medium to large breed skeletally mature dogs (N = 14). Proximal patellofemoral angle measurements were compared between the 3 different groups of stifle position using ANOVA for statistical analysis. The mean proximal patellofemoral angle measurements were -7.4° (± 1.3°) in the flexion group, -1.6° (± 1.5°) in the 90° group, and 2.1° (± 1.8°) in the extension group. Statistically significant differences were seen in the proximal patellofemoral angle between groups (P ≤ 0.001). These results confirm that position of the patella related to the proximal femoral axis differs depending on the degree of stifle flexion. The degree of stifle flexion should be considered in the preoperative planning and intraoperatively when using the patella as a surgical landmark in the sagittal plane for femoral canal broaching in canine total hip replacement.

L'objectif de cette étude était d'évaluer la position de la rotule par rapport à l'axe fémoral proximal dans le plan sagittal et d'évaluer sa fiabilité en tant que repère chirurgical pour le placement du composant fémoral dans le remplacement de la hanche canine. La relation entre la rotule et l'axe fémoral proximal a été évaluée en définissant l'angle fémoro-patellaire proximal dans des projections radiographiques médio-latérales avec trois angles de grasset différents (flexion complète, 90°, extension complète) chez des chiens de race moyenne à grande (N = 14). Les mesures de l'angle fémoro-patellaire proximal ont été comparées entre les trois groupes différents de position de grasset en utilisant l'ANOVA pour l'analyse statistique. Les mesures moyennes de l'angle fémoro-patellaire proximal étaient de −7,4° (± 1,3°) dans le groupe flexion, −1,6° (± 1,5°) dans le groupe 90° et 2,1° (± 1,8°) dans le groupe extension. Des différences statistiquement significatives ont été observées dans l'angle fémoro-patellaire proximal entre les groupes (P ≤ 0,001). Ces résultats confirment que la position de la rotule par rapport à l'axe fémoral proximal diffère selon le degré de flexion du grasset. Le degré de flexion du grasset doit être pris en compte dans la planification préopératoire et peropératoire lors de l'utilisation de la rotule comme repère chirurgical dans le plan sagittal pour la présentation du canal fémoral dans le cadre d'une arthroplastie totale de hanche canine.(Traduit par Docteur Serge Messier).

Conservative management of sacroiliac luxation fracture in cats: medium- to long-term functional outcome.

OBJECTIVES: The aim of this study was to determine the functional medium- to long-term outcome for cats with a conservatively managed sacroiliac luxation fracture (SILF). METHODS: Inclusion criteria were conservative management of SILF in cats with no other concurrent fractures of the pelvic weightbearing axis and availability of radiographs for review. Radiographic measurements of percentage displacement of the sacroiliac joint and the sacral index were obtained and fracture configuration was assessed. A specific owner questionnaire was completed a minimum of 6 months after the injury. The questionnaire assessed the ability of the cat to perform normal activities, the time to recovery, any behavioural changes and any requirement for long-term analgesia. RESULTS: Seventeen cats met the inclusion criteria, and 13 owners completed the questionnaire. Twelve cats had an excellent outcome, with no difficulty performing normal activities. One cat had a good outcome, with slight or occasional difficulty performing normal activities. CONCLUSIONS AND RELEVANCE: Our study provides evidence to support the current guidelines of conservative management of SILF. The inherent bias of case selection in our population implies that this treatment cannot be recommended for all cases of SILF.

Complications Following Surgical Correction of Medial Patellar Luxation in Small-to-Medium-Size Dogs.

OBJECTIVE: The main aim of this study was to describe complications in dogs weighing < 20 kg treated for medial patellar luxation and to determine risk factors associated with these complications. MATERIALS AND METHODS: Medical records were reviewed and cases were grouped based on four techniques of stabilization for the tibial tuberosity transposition (TTT). Variables including animal signalment, clinical presentation, TTT technique, other concurrent surgical techniques and associated complications were investigated. Multiple logistic regression was used to determine the association of the same variables with specific complications such as tibial tuberosity fractures or avulsions, patellar reluxation and implant-related complications. RESULTS: Of the 100 procedures performed, 37 suffered a complication. There were no significant differences in the overall complication rate between TTT stabilization techniques. Preservation of the tibial tuberosity distal cortical attachment was associated with a reduced risk of implant-related complications, whereas adding a medial release to the surgical techniques was associated with an increased risk of medial patellar reluxation. The type of trochleoplasty performed did not affect the complication rate. CONCLUSIONS: In the current study, a high rate of complications was found in dogs < 20 kg undergoing medial patellar luxation surgery. Performing a medial release and preserving the distal cortical attachment of the tibial tuberosity were the only variables associated respectively with an increase and a reduction in the risk of postsurgical complications.

Optimal safe implantation corridors in feline cervical vertebrae (C2-T1): CT study in 16 domestic shorthair cats.

OBJECTIVES: The objective of this study was to define safe corridors for the optimal placement of bicortical implants in the feline cervical spine (C2-T1) using CT. METHODS: CT images of feline cervical spines (n = 16) were reviewed retrospectively. Multiplanar reconstructions were used to define the optimal safe corridors. Safe corridors were defined by their angle of insertion, width and length. The insertion point within the vertebral body was also described. Vertebral measurements were compared between vertebrae using multilevel linear regression, and left and right measurements within vertebrae were compared with the paired samples Wilcoxon signed-rank test. A P value <0.05 was considered significant for all analyses. RESULTS: The safe corridor insertion points were located within the caudal third of the vertebral body in C2 (mean cranial vertebral ratio 0.73) and in the cranial third of the vertebral bodies from C3-T1 (mean cranial vertebral ratios 0.34-0.38). Mean safe corridor widths ranged from 1.04 mm in C2 to 2.30 mm in C7 and T1. The mean right and left optimal angles of implantation were, respectively, 21.79° and 21.49° for C2, 45.26° and 46.19° for C3, 51.48° and 51.04° for C4, 53.52° and 54.30° for C5, 56.36° and 56.65° for C6, 63.40° and 64.92° for C7, and 53.90° and 52.90° for T1. There were statistically significant differences between vertebrae in almost every measurement. CONCLUSIONS AND RELEVANCE: Cervical vertebral safe corridors in cats are narrow and differ to those reported in dogs. Safe corridors are located in the caudal third of C2 and cranial third of the C3-T1 vertebral bodies. Current recommendations for implant sizes should be reviewed, as 1.5-2 mm implants would be oversized for bicortical implantation in most of the feline cervical vertebrae.

Use of computed tomography to define a sacral safe corridor for placement of 2.7 mm cortical screws in feline sacroiliac luxation.

Objectives This study aimed to define a safe corridor for 2.7 mm cortical sacroiliac screw insertion in the dorsal plane (craniocaudal direction) using radiography and CT, and in the transverse plane (dorsoventral direction) using CT in feline cadavers. A further aim was to compare the values obtained by CT with those previously reported by radiography in the transverse plane. Methods Thirteen pelvises were retrieved from feline cadavers and dissected to expose one of the articular surfaces of the sacrum. A 2.7 mm screw was placed in the sacrum to a depth of approximately 1 cm in each exposed articular surface. Dorsoventral radiography and CT scanning of each specimen were performed. Multiplanar reconstructions were performed to allow CT evaluation in both the dorsal and transverse planes. Calculations were made to find the maximum, minimum and optimum angles for screw placement in craniocaudal (radiography and CT) and dorsoventral (CT) directions when using a 2.7 mm cortical screw. Results Radiographic measurement showed a mean optimum craniocaudal angle of 106° (range 97-112°). The mean minimum angle was 95° (range 87-107°), whereas the mean maximum angle was 117° (108-124°). Measurement of the dorsal CT scan images showed a mean optimum craniocaudal angle of 101° (range 94-110°). The mean minimum angle was 90° (range 83-99°), whereas the mean maximum angle was 113° (104-125°). The transverse CT scan images showed a mean dorsoventral minimum angle of 103° (range 95-113°), mean maximum angle of 115° (104-125°) and mean optimum dorsoventral angle of 111° (102-119°). Conclusions and relevance An optimum craniocaudal angle of 101° is recommended for 2.7 mm cortical screw placement in the feline sacral body, with a safety margin between 99° and 104°. No single angle can be recommended in the dorsoventral direction and therefore preoperative measuring on individual cats using CT images is recommended to establish the ideal individual angle in the transverse plane.

Ultrasonographic identification of the dorsal atlantoaxial ligament in dogs.

OBJECTIVE: To determine the ability to identify the dorsal atlantoaxial ligament during ultrasonographic examination of dogs. STUDY DESIGN: Canine cadaveric study. SAMPLE POPULATION: Canine cervical spines (n = 35). METHODS: Thirty-five canine cadavers with an estimated body weight of 6-35 kg were retrieved. Five cervical spines were dissected to assess the length and thickness of the dorsal atlantoaxial ligament and correlate ultrasound-guided injection of ink with anatomical dissection. Ultrasonographic evaluation of the dorsal atlantoaxial ligament was performed on 30 cadavers. The visibility of the dorsal atlantoaxial ligament in both the transverse and the sagittal planes was subjectively scored (0-3). RESULTS: The dorsal atlantoaxial ligament was detectable on ultrasonographic examination in all cadavers: 27/30 and 28/30 were graded as moderately visible (grade 2) or clearly visible (grade 3) in the sagittal and transverse view, respectively. Only 1/30 cadaver specimen of a large breed dog was graded as 1 (indistinct) in both the sagittal and transverse planes. None of the cadavers were graded as 0 (not visible) in any view. CONCLUSION: The dorsal atlantoaxial ligament can be identified in ultrasonographic examination of normal canine cadavers. Future studies on animals with clinical atlantoaxial instability/subluxation are needed to evaluate the role of this imaging technique in providing a safer diagnosis of this condition. CLINICAL RELEVANCE: Ultrasonographic examination of the dorsal atlantoaxial ligament could potentially provide a noninvasive and safe imaging technique that may contribute to the diagnosis of atlantoaxial instability/subluxation in dogs.

Extra-nodal subcutaneous Hodgkin's-like lymphoma and subsequent regression in a cat.

Hodgkin's-like lymphoma is a slow growing neoplasm, usually affecting the lymph nodes of the head and neck, which has been sporadically described in veterinary patients. This report describes the clinical and histopathological features in a 9-year-old male neutered Siamese cat that presented with a 6 week history of mid-dorsocranial swelling. Immunohistochemistry demonstrated positive staining for CD79a, paired box protein and B lymphocyte antigen-36, with variable, weak-to-moderate cytoplasmic staining for human leukocyte antigen-DR and CD18, and negative staining for antimacrophage antibody. The diagnosis based on incisional biopsy was Hodgkin's-like lymphoma; however, no evidence of neoplasia was found following wide surgical excision. This case report demonstrates two unreported items of note: the novel extranodal site of Hodgkin's-like lymphoma in a cat and tumour regression following initial biopsy. It is hypothesised that the surgical trauma of biopsying the lesion or the introduction of foreign material may have caused the regression of the neoplastic cells through induction of an anti-tumour immune or inflammatory response.

Splanchnic Th(2) and Th(1) cytokine redistribution in microsurgical cholestatic rats.

BACKGROUND: Long-term extrahepatic cholestasis in the rat induces ductular proliferation and fibrosis in the liver, portal hypertension, splenomegaly, portosystemic collateral circulation, and ascites. These splanchnic alterations could have an inflammatory pathophysiology. MATERIAL AND METHODS: We measured serum levels of hepatobiliary injury markers and the acute phase proteins, alpha-1-major acid protein (alpha(1)-MAP) and alpha-1-acid glycoprotein (alpha(1)-GPA) in rats 6 wk after microsurgical extrahepatic cholestasis. We also assayed Th(1) (TNF-alpha and IL-1beta) and Th(2) (IL-4 and IL-10) cytokine levels in the liver, ileum, spleen, and mesenteric lymph complex by enzyme-linked immunosorbent assay (ELISA) techniques. Liver fibrosis was measured by Sirius red stain and by using an image system computer-assisted method and mast cell liver infiltration by Giemsa stain. RESULTS: The cholestatic rats showed an increase (P<0.001) in serum levels of bile acids, total and direct bilirubin, AST, ALT, AST/ALT index, gamma-GT, alkaline phosphatase, alpha(1)- MAP, alpha(1)-GPA, and LDH (P<0.05) in relation to sham-operated rats. TNF-alpha, IL-1beta, IL-4, and IL-10 increased in the ileum (P<0.01) and mesenteric lymph complex (P<0.001), and decreased in the liver (P<0.001). A marked bile proliferation associated with fibrosis (P<0.001) and mast cell infiltration was also shown in the liver of cholestatic rats. CONCLUSION: The splanchnic redistribution of cytokines, with an increase of Th(1) and Th(2) production in the small bowel and in the mesenteric lymph complex, supports the key role of inflammatory mechanisms in rats with secondary biliary fibrosis.

Evolutive phases of experimental prehepatic portal hypertension.

Partial portal vein ligation is the experimental model most frequently used to study prehepatic portal hypertension. Different systemic and splanchnic biochemical and histological alterations in short-term (28-45 days) and long-term (12-14 months) evolutive phases which has been described in this experimental model suggest the existence of different pathophysiological mechanisms involved in their production. The enteropathy produced could develop in three phases: an early or acute phase with vasomotor hemodynamic alterations (ischemia-reperfusion associated with intestinal hyperemia, edema and oxidative stress); an intermediate phase with immunological alterations (mesenteric lymphadenopathy, increased mucosal infiltration by mast cells and the hepato-intestinal release of pro- and anti-inflammatory mediators); and a late or chronic phase with intestinal remodeling (vascular and epithelial). The alterations which are produced in these three evolutive phases make it possible to propose an inflammatory etiopathogeny for hypertensive portal enteropathy.