CBLO vs TPLO: A Review of the Evidence

Objective outcomes in advanced leveling osteotomies

For over two decades, the Tibial Plateau Leveling Osteotomy (TPLO) has been the undisputed gold standard for the surgical management of canine cranial cruciate ligament (CCL) disease. However, veterinary orthopaedics is continually evolving. In recent years, the CORA-Based Leveling Osteotomy (CBLO) has emerged as an alternative technique.

Both surgeries share the same fundamental biomechanical goal: to neutralize cranial tibial thrust by altering the slope of the tibial plateau using a radial bone cut. The primary difference lies in the location of that cut. While a TPLO cut is made in the proximal (upper) section of the tibia, a CBLO cut is made further distally (lower) and is centered over the bone's Center of Rotation of Angulation (CORA).

When is a CBLO advantageous?

While TPLO remains the procedure of choice for the vast majority of adult dogs, the veterinary literature supports CBLO as a highly effective procedure for specific anatomical challenges:

Juvenile Patients: Because the CBLO bone cut is located further down the tibia, it avoids the proximal growth plate. This makes it an excellent option for puppies who suffer early cruciate ruptures while their bones are still growing.
Excessive Tibial Plateau Angle (eTPA): In dogs with an extremely steep natural tibial slope, achieving a level plateau with a standard TPLO can be geometrically challenging or impossible. CBLO (sometimes combined with a wedge osteotomy) allows surgeons to correct these extreme angles safely.

Why TPLO remains the Gold Standard

While CBLO is a valuable tool in the surgeon's arsenal, TPLO retains its position as the gold standard for standard cruciate repairs due to an overwhelming mountain of objective data. Biomechanical and kinematic studies consistently demonstrate that TPLO causes fewer morphometric changes to the bone and generates lower stress forces on the surrounding ligaments compared to CBLO.

The excerpts presented below highlight the most recent objective kinetic, kinematic, and in-silico morphometric data comparing TPLO and CBLO.

At a Glance: Soundbites from the Literature

"TPLO caused the fewest morphometric changes [to the tibia] compared to CBLO and CCWO."

— In Silico Morphometric Analysis (2024)

"TPLO generates lower forces in the patellar ligament and quadriceps muscle, compared to CBLO."

— Multibody Comparative Analysis (2019)

"CBLO mitigated but did not fully resolve abnormal craniocaudal translation during walking."

— In-vivo Kinematic Study (2022)

"TPLO and [modified CORA osteotomies] are associated with similar complication rates and clinical outcomes when performed by experienced surgeons."

— Prospective Cohort Study (2013)

Detailed Study Summaries

In Silico Morphometric Analysis of the Tibia Following Four Virtual Proximal Levelling Osteotomies

Veterinary and Comparative Orthopaedics and Traumatology — 2024

Method: A computer-simulated (in silico) analysis using dedicated radiographic digital planning software to virtually perform four different osteotomy techniques (including TPLO and CBLO) to evaluate how each procedure structurally alters the tibia.

Results: All procedures significantly affected the morphometric parameters of the tibia. CBLO resulted in the most significant reduction of the distal/proximal tibial axis angle. TPLO caused the least disruption to the natural anatomy of the bone.

Conclusion: Proximal tibial osteotomy techniques cause morphometric changes to the tibia, but TPLO caused the fewest morphometric changes compared to CBLO and wedge osteotomies.

Stifle kinematics in dogs with cranial cruciate ligament insufficiency treated by CORA-based leveling osteotomy

Veterinary Surgery — 2022

Method: An objective, in-vivo 3D kinematic tracking study measuring the exact craniocaudal translation (instability) of the stifle joint during treadmill walking before and 6 months after CBLO surgery.

Results: After CBLO, the abnormal forward slipping of the tibia was reduced by a median of 43% over the complete gait cycle, resulting in significantly improved ground reaction forces on the force plate.

Conclusion: While CBLO successfully improved weight-bearing and reduced clinical lameness, it mitigated but did not fully resolve abnormal craniocaudal translation (persistent subluxation remained during the stance phase).

Surgical Treatments for Canine Anterior Cruciate Ligament Rupture: Assessing Functional Recovery Through Multibody Comparative Analysis

Frontiers in Bioengineering and Biotechnology — 2019

Method: A complex biomechanical simulation comparing the intra-articular compressive forces, patellar ligament strain, and quadriceps muscle forces generated during a weight-bearing squat in stifles treated with TPLO versus CBLO.

Results: Both TPLO and CBLO successfully neutralized cranial tibial thrust. Both procedures resulted in increased compressive forces on the joint compared to a healthy, uninjured knee. However, CBLO increased compressive forces significantly more than TPLO at a 90-degree flexion angle.

Conclusion: TPLO generates lower forces in the patellar ligament and quadriceps muscle compared to CBLO, suggesting a potentially more favorable biomechanical environment for the extensor mechanism during recovery.