HISTOLOGICAL CHANGES IN SPONTANEOUS RUPTURE OF THE CRANIAL CRUCIATE LIGAMENT IN THE DOG

Abstract

Introduction and aim of the work: The rupture of the cranial cruciate ligament (CrCL) is among the most common causes of pelvic limb lameness in dogs. The objective of this study was to investigate the histological changes in dogs with cranial cruciate ligament rupture and to compare the result using three different score systems Materials and Methods: The study cohort comprised of 30 dogs of various breeds, ages, genders and body weights with spontaneous cranial cruciate ligament rupture divided into 3 groups (1 week, 2 weeks and 3 weeks’ post-rupture). All tissue samples from CrCL were collected after open medial or lateral arthrotomy and histology slides were prepared and stained with hematoxylin-eosin. Three different score systems were used for grading the histological changes-synovitis score modified Bonar and modified Vasseur score. Results: Our results showed that no inflammatory cells were observed in groups II and III and a very limited number in group I. We also found the highest erythrocytes deposition and larger lumen of blood vessels, uneven arrangement of the collagen fibers as well as fibrocytes transformation into chondrocytes in group I. In group II multiple blood vessel were also filled with erythrocytes and the number of chondrocytes is increased in comparison to group I. In group III blood vessels size and number were reduced in comparison to group I and II and many sections of the collagen fibers showed hyalinization. Conclusion: In summary, degenerative changes were seen in all samples examined of cranial cruciate ligaments with different grades of chondroid metaplasia, increased cellularity and vascularity. Inflammatory changes were rarely detected by lymphoplasmacytic infiltrates with or without lymphoid aggregate deposition. No correlation was noted between age and all histological scores.

Keywords

• dog
• cruciate ligament
• histological changes
• score system