Effect of screw insertion angle and speed on the incidence of transcortical fracture development in a canine tibial diaphyseal model.

OBJECTIVE: To assess the incidence of transcortical fracture (TCF) development based on screw insertion angle and screw insertion speed. STUDY DESIGN: Cadaveric experimental study. SAMPLE POPULATION: Sixty-six canine tibiae. METHODS: Sixty-six cadaveric tibiae were randomly assigned to one of six groups that varied based on screw insertion angle relative to the pilot hole (0, 5, or 10°) and screw insertion speed (650 or 1350 revolutions per minute [rpm]). Each tibia was mounted in a custom jig. Locking self-tapping screws (3.5 mm) were inserted at varying speeds and insertion angles, based on group assignment. Orthogonal radiographs were evaluated for TCFs. Fisher's exact tests with a Bonferroni correction were performed to evaluate differences in the frequency of TCF between groups. RESULTS: In Group A (0°/650 rpm: control), a 0% TCF rate was observed (n = 0/80). Group B (5°/650 rpm) had a 3.75% TCF rate (n = 3/80). Group C (10°/650 rpm) had a 12.5% TCF rate (n = 10/80). Group D (10°/hand insertion) had a 3.75% TCF rate (n = 3/80). Group E (10°/1350 rpm) had a 17.5% TCF rate (n = 14/80). Group F (0°/1350 rpm) had a 0% TCF rate (n = 0/80). Groups C and E had the highest TCF rates with a difference in TCF rates observed between the control group and Group C (p = .001) and between the control group and Group E (p < .001). CONCLUSION: Increased screw insertion angle and insertion speed appear to be predisposing factors for TCF development in cadaveric bone. CLINICAL SIGNIFICANCE: Ensuring screw insertion is coaxial with the pilot hole and using slower screw insertion speeds may help reduce the risk of TCF development.

Fluoroscopic Categorization of Cementless Acetabular Component Positioning.

OBJECTIVES: The purpose of this study was to evaluate a fluoroscopic method of angle of lateral opening (ALO) categorization based on identification of the visible portion of a pre-existing, circular recess within the metal shell of the BioMedtrix BFX acetabular component, which projects as an ellipse at clinically relevant ALO values. Our hypothesis was that there will be an association between the actual ALO and the categorization of ALO based on identification of the visible portion of the elliptical recess on a lateral fluoroscopic image at clinically relevant values. STUDY DESIGN: A custom plexiglass jig was fitted with a two-axis inclinometer and a 24 mm BFX acetabular component attached to its tabletop. Fluoroscopic reference images were obtained with the cup positioned at an ALO of 35, 45 and 55 degrees with a fixed 10 degrees of retroversion. Thirty study fluoroscopic images (10 images at each ALO) were obtained based on randomization at an ALO of 35, 45 and 55 degrees (±0.5 degrees) with 10 degrees of retroversion. The order of the study images was randomized, and a single, blinded observer categorized the 30 study images as representing an ALO of 35, 45 or 55 degrees by comparison to the reference images. RESULTS: Analysis showed perfect (30/30) agreement with a weighted kappa coefficient of 1 (95% confidence interval: -0.717 to 1). CLINICAL RELEVANCE: The results demonstrate that accurate categorization of ALO can be achieved using this fluoroscopic method. This method may prove to be a simple but effective method of estimating intraoperative ALO.

Veterinary student urethral catheterization of small female cats and dogs using 2 urethral catheterization techniques.

Objective: Compare veterinary student success at urethral catheterization of small female cats and dogs using traditional and novel 2-catheter techniques. Animal: Healthy anesthetized female cats (n = 23) and dogs (n = 6) weighing < 10 kg undergoing elective ovariohysterectomy. Procedure: Two junior (Year 3) veterinary students with no previous urethral catheterization experience participated. Each pet was catheterized by 1 student using both the traditional blind technique and the novel 2-catheter method (placement of a large red rubber catheter into the vaginal canal prior to insertion of the conventional catheter). Technique order was randomized and attempts for each technique was allowed for up to 3 min. Time to successful catheterization and catheterization success within the allotted time were recorded. Results: Successful urethral catheterization was performed using the traditional blind and novel 2-catheter techniques in 56.3 and 87.5% of cases, respectively. Conclusion: Students had a higher rate of successful catheterization with the 2-catheter catheterization technique in this report. Clinical relevance: Urethral catheterization in small female cats and dogs is technically challenging, which is compounded by the inability to consistently and reliably palpate loco-regional anatomic landmarks due to the small sized vestibules. Data from this report will be used to design future studies to assess the utility of this novel urethral catheterization technique for teaching inexperienced students this challenging clinical skill.

Résumé. Objectif: Comparez le succès des étudiants vétérinaires lors du cathétérisme urétral de petites chattes et chiennes en utilisant des techniques traditionnelles et nouvelles à deux cathéters. Animal: Chattes (n = 23) et chiennes (n = 6) en bonne santé et anesthésiées pesant < 10 kg subissant une ovariohystérectomie élective. Procédure: Deux étudiants vétérinaires juniors (3e année) sans expérience préalable en cathétérisme urétral ont participé. Chaque animal a été cathétérisé par un étudiant en utilisant à la fois la technique traditionnelle à l'aveugle et la nouvelle méthode à deux cathéters (placement d'un gros cathéter en caoutchouc rouge dans le canal vaginal avant l'insertion du cathéter conventionnel). L'ordre des techniques a été randomisé et les tentatives pour chaque technique ont été autorisées jusqu'à 3 minutes. Le temps de cathétérisme réussi et le succès du cathétérisme dans le temps accordé ont été enregistrés. Résultats: Un cathétérisme urétral réussi a été réalisé en utilisant les techniques traditionnelles à l'aveugle et les nouvelles techniques à deux cathéters dans 56,3 et 87,5 % des cas, respectivement. Conclusion: Les étudiants avaient un taux plus élevé de cathétérisme réussi avec la technique de cathétérisme à deux cathéters dans ce rapport. Pertinence clinique: Le cathétérisme urétral chez les petites chattes et chiennes est techniquement difficile, ce qui est aggravé par l'incapacité de palper de manière cohérente et fiable les repères anatomiques loco-régionaux en raison des vestibules de petite taille. Les données de ce rapport seront utilisées pour concevoir de futures études afin d'évaluer l'utilité de cette nouvelle technique de cathétérisme urétral pour enseigner aux étudiants inexpérimentés cette habileté clinique difficile.(Traduit par Dr Serge Messier).