A 9-year-old, neutered, male, Cairn terrier dog presented with a 3-year history of progressive pain and lameness of the right hindlimb. After an acute episode of severe pain and non-weight-bearing lameness, the dog was referred to our clinic for evaluation.
The physical examination was unremarkable; the orthopaedic examination revealed a positive cranial drawer sign and medial patellar luxation grade 3/4. Orthogonal radiographs were taken. Chronic degenerative changes consistent with cranial cruciate ligament insufficiency and medial patellar luxation were noted.