Comparison of Three Imaging Methods for the Evaluation of Osteoarthritis Induced by Cranial Cruciate Ligament Transection in Rabbits

Background:Osteoarthritis is a degenerative joint disease that affects specially cartilage, meniscus, and tendons. Ligaments, muscles, subchondral bone and synovium. This pathology is a common condition limiting the quality of life of patients. Imaging modalities have also been used for evaluation the progression of the osteoarthritis, or degenerative processes induced by acute injury. In order to use more accessible imaging modalities for experimentation, this study aimed to compare radiographic, computed tomography, and ultrasound findings in the evaluation of osteoarthritis induced by the cranial cruciate ligament transection model in rabbits.Materials, Methods & Results:Twenty-four male Norfolk rabbits aged approximately 5 months old were used. All rabbits were submitted to cranial cruciate ligament transection of the left stifle and evaluated 45 days after the surgery. The radiographic findings were subchondral bone sclerosis (33.33%); joint space narrowing (66%); presence of osteophytes at medial femoral condyle (4.16%), lateral femoral condyle (4.16%), medial fabela (20.83%), lateral fabela (8.33%) and sesamoid of the popliteal muscle (4.16%). No osteophytes were seen at medial and lateral tibial condyles. The tomographic computed findings were joint space narrowing (62.5%); presence of osteophytes at medial femoral condyle (75%), lateral femoral condyle (54.16%), medial fabela (66.66%), lateral fabela (37.5%), medial tibial condyle (75%), lateral tibial condyle (20.83%) and sesamoid of the popliteal muscle (37.5%). The ultrasound findings were synovial hypertrophy (95.83%); effusion in the suprapatellar recess (75%), distal tibial recess (16.66%) and cranial joint space (75%); changes (hyperechogenic foci and heterogeneity) of the lateral meniscus (50%) and medial meniscus (25%); increased thickness of the medial condyle (54.16%) and lateral condyle (45.83%); irregularity of the medial condyle (66.66%) and lateral condyle (58.33%); alterations of the patellar tendon (12.5%) and extensor ligament (effusion and increased echogenicity) (20.83%).Discussion: Osteoarthritis is a degenerative joint disease and is common condition which limiting the quality of life of patients. Many studies performed in rabbits have evaluated the development of osteoarthritis through post-mortem macroscopic or microscopic assessments. Imaging modalities have also been used for evaluation the progression of the osteoarthritis, or degenerative processes induced by acute injury. High quality radiographs are accurate in identifying structural changes resulted from osteoarthritis, but computed tomography allows earlier identification in relation to conventional radiography. The three imaging modalities were helpful to identify the osteoarthritis, but the findings were different and compatible with each analysis method. The computed tomographic detected a higher number of osteophytes than plain radiographs. Also, osteophytes did not visualized by radiographic examination, such as medial tibial condyle and lateral tibial condyle, were identified by computed tomography. In turn, the ultrasound examination enabled identification of lesions did not seen on radiographic and computed tomography examinations. Synovial hypertrophy and joint effusion had the highest percentage. In human patients, ultrasound examination has been used to assess hypertrophy and inflammation of the synovium due to osteoarthritis. In conclusion, computerized tomography images provided more information than plain X-ray images and can be complemented by ultrasound examination to identify osteoarthritis induced by cranial cruciate ligament transection in rabbits.Comparison of Three Imaging Methods for the Evaluation of Osteoarthritis Induced by Cranial Cruciate Ligament Transection in Rabbit

Diagnóstico e Tratamento da Piometra em um Tigre (Panthera tigris) mantida sob cuidados humanos

Background: Captive tigers can live a long life, around 26 years. Among the diseases described some of non-infectious origin are quite common, such as chronic kidney disease, spondylosis, and biliary cysts or tumors. On the other hand, pyometra has been frequently reported in lions, who have a higher risk of developing the disease than tigers and leopards. Pyometra is a disease with few descriptions in tigers and it may be related to the physiological features of the species. The animal is listed as Endangered on the International Union for the Conservation of Nature Red List of Threatened. The present report aims to describe the diagnosis and treatment of pyometra in a captive tigress. Case: A 7-year-old entire female tiger (Panthera tigris) weighing 140 kg was presented with a 3-day history of anorexia and prostration. For clinical examinations, collection of laboratory and imaging tests, the patient initially underwent dissociative anesthesia to allow catheterization of the cephalic vein and intravenous general anesthesia for orotracheal intubation followed by anesthetic maintenance in isoflurane. On general physical examination, the animal had normal colored mucosa, vital parameters within normal limits, and a body condition score of 6 on a scale of 9. There was no presence of vulvar secretion. The blood count and the biochemical exams showed values within the normal range for the species. The chest X-ray in the right and left views did not demonstrate pulmonary abnormalities. Ultrasonographic examination of the abdomen showed distension of the uterine body and horns, which have intraluminal hyperechoic fluid content without flocculation. Based on the imaging exam, the diagnosis was suggestive of pyometra. Exploratory celiotomy was performed via ventral midline, confirming the condition, which was treated by ovariohysterectomy. The surgical technique was performed as described for therapeutic ovariohysterectomy in dogs and cats. Culture of uterine content identified Escherichia coli. The histological analysis identified diffuse endometritis associated with follicular cysts. The tiger had complete recovery without any complications. The patient was releasing 13 days after the surgical procedure and in the last contact four months after the surgery, it was in perfect health conditions. Discussion: Pyometra in large exotic felids has been occasionally reported, mainly in animals more than 10 years of age. Although the tigress in the report is estimated to be seven years old. The patient in question started with anorexia and prostration and as there was already a history of cystic endometrial hyperplasia, a possible pyometra was suspected, despite being uncommon in the species. There was not vaginal discharge. The definitive diagnosis was by means of ultrasound examination and ovariohysterectomy was performed. Abdominal surgery for these large felids is complex, due to the intra-abdominal volume the flank approach or by laparoscopic is suggested, however in this case a ventral midline incision was performed without intercurrences and complications in the post-operative period. The surgical technique like that used in small animals was effective for the treatment of pyometra in the tigress with the use of ovariohysterectomy. Culture of uterine content identified Escherichia coli, which has been the most commonly isolated pathogen in pyometra of large felids. It was concluded that, as in bitches with pyometra, early diagnosis and surgical treatment is ideal for the patient's recovery. Keywords: ovariohysterectomy, treatment, bacteria, infection

Ligamentum teres reconstruction using autogenous semitendinosus tendon with toggle technique in rabbits

Background Ligamentum teres (LT) has traditionally been considered a vestigial or redundant structure in humans; however, based on new studies and the evolution of hip arthroscopy, the LT injury has been viewed as a source of hip pain. Therefore, LT reconstruction can be beneficial in some cases. Rabbits have been frequently used as a model for cranial cruciate ligament reconstruction but few studies are available for ligamentum teres reconstruction. Objective To evaluate the semitendinosus tendon to replace ligamentum teres with the toggle technique, using rabbits as an experimental model. Methods Twenty-six female Norfolk rabbits with approximately 3 months of age were divided into two equal groups after excision of ligamentum teres (LT) from the right hip joint: G1—no reconstruction of LT and capsulorrhaphy; G2—double—bundle reconstruction of the LT using semitendinosus tendon autograft. In both groups, the LT was removed from the right hip joint. In G2 the autograft was harvested from the left hind limb of the same rabbit. The rabbits were evaluated clinically at different time intervals; before surgery (M1), 48 h (M2), 15 days (M3), 30 days (M4) and 90 days (M5) after surgery. Results The rabbits supported their limbs on the ground in both the groups. As complications of the procedure, four hip joints showed subluxations in the radiographic evaluation of G1; three at M4 and one at M5. In G2; two luxations of hip joints at M3 and one subluxation at M4 were seen. On ultrasound, irregular articular surface was seen in 30.8% of the rabbits that had subluxation of hip joints. Gross evaluation identified tendon graft integrity in 76.92% of the rabbits. Histological analysis revealed graft adhesion to the bone in the early phase comprised of sharpey-like collagen fibers. Conclusion The double-bundle reconstruction of the LT using autologous semitendinosus tendon associated with the toggle rod shows an early phase of tendon graft ligamentization at 90 days post-operatively in young rabbits, but biomechanical bias suffered by the tendon during gait must be considered