Surgical model of osteoarthritis secondary to medial patellar luxation in dogs

This study was performed to make a surgical model of osteoarthritis (OA) in the dog. Experimental medial patellar luxation (MPL) was surgically produced in the left stifle (index) of 24 skeletally mature mixed small breed dogs (age two to six years and weight 2.8 to 9 kg). The animals were randomly allocated in 2 groups; sham group (n = 12), where the right stifle was sham operated and control group (n = 12) with intact right stifle. Physical and radiographic examinations of both stifles were performed at 1.5 months intervals over a one-year experimental period. One dog was euthanatized every three months, and both stifles were explored, gross examination was performed and tissue samples from the articular cartilage, cranial cruciate ligament (CCL) and synovium were collected for histomorphology. The clinical signs of OA were obvious in the experimental dogs by 12 weeks of surgical induction of MPL, which was also evidenced in the histopathology of the joint tissues and electron microscopy of the articular cartilage. The radiographic changes of OA were not obvious until remarkable degenerative changes became abvious six months postoperatively. Surgically induced MPL can be a successful tool for experimental induction of OA in dogs.