James L. Cook 1 , DVM, PhD, Diplomate ACVS 1 Comparative Orthopaedic Laboratory, College of Veterinary Medicine, University of Missouri, Columbia, MO Corresponding Author James L. Cook DVM, PhD, Comparative Orthopaedic Laboratory, College of Veterinary Medicine, University of Missouri, 900 Eas Veterinary Surgery April 2010 39 3 270-277 ABSTRACT The stifle joint of dogs is an organ comprised of multiple tissue types that must work in concert to maintain joint health and function. Cruciate disease in dogs is caused by a spectrum of causal and risk factors that result in a final common pathway of abnormal biomechanics and abnormal biology causing osteoarthritis, or organ failure, of the stifle and the clinical signs of lameness, pain, and limb dysfunction. It is vital to understand the components of the biologic and biomechanical pathologies to improve our understanding of cruciate disease in dogs so that we can improve preventative, diagnostic, and therapeutic strategies for our canine patients.