Alberto Salvaggio

Effect of pelvic inclination and torsional deformity on canine acetabular morphology with computed tomography. A phantom study.

OBJECTIVES To evaluate how the inclination and torsional deformity of the hemipelvis using extra-rotation as a model affect acetabular angle (AA) and dorsal acetabular rim angle (DARA) assessment with computed tomography (CT). METHODS A normal canine hemipelvis positioned in dorsal recumbency was scanned with a 16-slice multidetector CT scanner, with different degrees of torsional deformity, using extra-rotation around the long axis (0-5-10-15°) of the hemipelvis. Each degree of extra-rotation was acquired at 0°, +20° and -20° of gantry tilt, to mimic different pelvic inclinations on its transverse axis. Cranial and central individual acetabular angles (IAA) and central DARA were calculated and correlated with inclination and torsional deformity. RESULTS A very strong negative correlation was found between cranial and central IAA, pelvic inclination, and torsional deformity. A very strong positive correlation was found between DARA, pelvic inclination, and torsional deformity. CLINICAL SIGNIFICANCE Pelvic inclination and torsional deformity affect acetabular angles assessment with CT. The greater the inclination (ilia far from the tabletop in dorsal recumbency) and torsional deformity of the pelvis, the worse the acetabulum appeared. A standardized scanning protocol for acetabular morphology assessment is needed and it should consider pelvic inclination. The actual relevance of pelvic torsional deformity is not well known and it should be investigated more thoroughly.

Sonoelastographic Features of the Patellar Ligament in Clinically Normal Dogs

OBJECTIVE  This article describes the sonoelastographic features of the patellar ligament of sound dogs and tests feasibility, reproducibility and repeatability. METHODS  Clinically healthy medium-to-large breed dogs were enrolled. Sonoelastographic images of the patellar ligaments were obtained in lateral recumbency with the stifle flexed by an experienced operator and by a senior veterinary student. The elasticity colour map included red (soft), green (intermediate) and blue (hard). Tissue elasticity was measured by calculating the percentage of softness with dedicated software. Categorical, qualitative data analysis was performed using a weighted kappa statistic for repeatability and reproducibility. A categorical qualitative assessment was performed based on a grading scale of 1 to 5 (soft, mostly soft, intermediate, mostly hard and hard). RESULTS  Fourteen clinically normal dogs were considered. A total of 28 patellar ligaments were examined. Overall, 25 of the patellar ligaments were graded as soft or mostly soft and the remaining 3 as intermediate. Repeatability was 86.2%, with a weighted kappa of 0.64 (good), for the well-trained sonographer and 83.3%, with a weighted kappa of 0.53 (moderate), for the senior student. Reproducibility was 86.2%, with a weighed kappa of 0.65 (good). CLINICAL SIGNIFICANCE  Sonoelastography of the canine patellar ligament is a feasible and reproducible technique. Patellar ligaments in clinically normal dogs showed highly elastic biomechanical properties.

Use of Wallace Distractor in Canine Stifle Arthroscopy

Objectives: To assess the value of the intra-articular Wallace distractor in stifle arthroscopy in the dog. Methods-Ex-vivo study: ten cadaver limbs of dogs were used to explore the stifle joints by arthroscopy each once without and once with the aid of a Wallace distractor. Radiographs and observational data were used to assess the degree of joint distraction and to evaluate any collateral intra-articular damages. In vivo study: distractor-assisted arthroscopy was thereafter performed in 12 consecutive clinical cases of dogs with cranial cruciate ligament rupture. The use of the Wallace distractor, clinical setting, time to complete joint evaluation were recorded. Results: In the cadaver study, radiographic findings showed a significant increase of the joint space after the insertion of the distractor. Visual range during arthroscopy employing the Wallace distractor increased substantially and facilitated the assessment of all visible intra-articular structures. Mean time to evaluate the femoropatellar space was 4,1 minutes, to observe cruciate ligaments 6,5 minutes and to complete joint inspection 10,1 minutes. In the clinical study, the use of Wallace distractor allowed improved arthroscopic observation of all relevant structures, without sub-patellar fat pad removal. Mean time to complete joint inspection was 28,5 minutes. Clinical significance: The use of the Wallace joint distractor may be helpful in the arthroscopic assessment of the canine stifle. It is easy to insert, it allows a considerable distraction of the joint making it easier visibility and reducing the possible need to remove the sub patellar fat pad. With its blunt pins Wallace joint distractor limits the risk of iatrogenic damage and can be easy to use even for surgeons who do not have much experience in knee arthroscopy.