Canine Ruptured Cranial Cruciate Ligament Study Guide

Overview and Clinical Importance

Cranial cruciate ligament (CrCL) rupture is the most common cause of hindlimb lameness in dogs and represents a significant portion of NAVLE orthopedic questions. Unlike humans where ACL tears are typically traumatic, canine CrCL disease is predominantly a degenerative condition affecting the ligament over time. Understanding the pathophysiology, diagnosis, and treatment options is essential for clinical practice and board examination success.

The condition carries substantial economic impact, with estimated annual treatment costs exceeding $1 billion in the United States alone. Approximately 30-50% of dogs with unilateral CrCL rupture will develop contralateral rupture within 1-2 years, making this a bilateral disease in many cases.

Anatomy of the Stifle Joint

The canine stifle (knee) joint is a complex synovial joint consisting of three articulations: the femoropatellar joint, the medial femorotibial joint, and the lateral femorotibial joint. The joint is stabilized by four primary ligaments: the cranial and caudal cruciate ligaments (intra-articular) and the medial and lateral collateral ligaments (extra-articular).