Lateral patellar luxation and Ehlers Danlos Syndrome (EDS) in a dog

ABSTRACT

Background: Ehlers Danlos Syndrome (EDS) is a rare genetic disease characterized by a deficiency in collagen synthesis,which can result in joint laxity. Patellar luxation is one of the main orthopedic conditions that affect the canine knee joint,with limited descriptions of its association with EDS in dogs. The purpose of this report is to describe the surgical management and postoperative evolution of a 1-year-old Chow Chow dog with grade II patellar luxation, tibial valgus and EDS.Case A 1-year-old Chow Chow dog was referred to the University Veterinary Hospital due to lameness of the left pelvicfor 3 months. At the orthopedic examination were verified severe lameness and lateral deviation of the left stifle joint during the ambulation of the animal. Additionally, it was verified bilateral hyperextension of the tibiotarsal joint and grade IIpatellar luxation of both pelvic limbs with painful hyperextension of the left stifle joint. Radiographic evaluation showedlateral displacement of the patella from both femoral trochlear groove, and a valgus deviation of the proximal left tibialshaft. In addition, it was verified cutaneous hyperextensibility and an extensibility index suggestive of EDS. The animalwas submitted to trochlear block resection technique and medial imbrication, followed by corrective tibial osteotomy.Furthermore, skin biopsies of the scapular and lumbar folds were performed during the corrective tibial osteotomy. Thesamples were sent for histopathological examination, which revealed fragmented and unorganized collagen fibers in thedermis. Histopathological findings were compatible with EDS. The absence of lameness and correct positioning of thepatella in the trochlear sulcus were verified in the post-surgical follow-up. Complete bone consolidation of the closingwedge osteotomy to correct the tibial...