The CORA-Based Leveling Osteotomy (CBLO) technique was founded as a response to the limitations of traditional methods like the Tibial Plateau Leveling Osteotomy (TPLO) in treating cranial cruciate ligament deficiency (CCLD) in dogs. Studies had revealed significant joint mechanical alterations associated with TPLO, potentially leading to adverse effects such as articular cartilage lesions. One critical observation was that the standard Slocum osteotomy used in TPLO does not consider the mechanical or anatomic Center of Rotation of Angulation (CORA). This resulted in misalignment of the anatomic/mechanical axis, secondary translation, and the creation of a caudal thrust. The long-term consequence of this caudal thrust includes the loss of compliance of cranial supporting structures and potential abrasion of the articular cartilage. 

A 2010 study¹ authored by D. Hulse, B. Beale, and M. Kowaleski introduced the concept and technique of CBLO. The primary goal of CBLO is to align the anatomic/mechanical axis of the stifle joint by basing the osteotomy on the anatomic CORA. This approach aims to preserve the proximal tibial epiphysis, maintain normal stress distribution and kinematics of the stifle, and establish a 90-degree plateau/patella tendon angle postoperatively. The authors hypothesized that CBLO would effectively address the issues associated with TPLO by preserving the proximal tibial epiphysis, aligning the anatomic/mechanical axis of the stifle, and establishing a 90-degree plateau/patella tendon angle. This alignment was expected to maintain normal stress distribution and kinematics of the stifle, thereby reducing the risk of adverse effects such as articular cartilage lesions. Furthermore, by eliminating the caudal thrust generated by TPLO, CBLO was anticipated to prevent cranial abrasion lesions and maintain long-term stability of the stifle joint. The study demonstrated the concept through anatomic dissection, radiographic analysis of cadaver specimens, and application in clinical cases involving ligament injury to the stifle, encompassing 55 cases with various degrees of instability and injury.