CBLO Operationsprotokoll

This step-by-step guide details the management of a cruciate deficient stifle using the CBLO Technique. 


The CORA-Based Leveling Osteotomy (CBLO) surgical procedure represents a groundbreaking advancement in orthopedic surgery for patients with cranial cruciate ligament (CCL) rupture. Developed as an innovative alternative to techniques like Tibial Plateau Leveling Osteotomy (TPLO) and Tibial Tuberosity Advancement (TTA), CBLO offers a refined approach to addressing CCL pathology by targeting the Center of Rotation of Angulation (CORA) within the stifle joint.
In this procedure, precise adjustments are made to the tibial plateau angle by centering the saw blade at the location of the CORA. The cut is performed in an inverted position relative to the tibia head, and the proximal tibia is rotated forward leading to levelling of the tibial plateau. This not only reduces the tendency of the femur to push the tibia forward during weight-bearing, but also leads the femur to load directly onto the tibia rather than behind the tibia as is the case after a TPLO procedure.
This forward rotation also tightens the patella tendon, increasing stability by preventing the tibia to move forward relative to the femur during loading.
So by targeting the CORA, CBLO aims to minimize secondary translations and axis shifts, reduce stress on the caudal cruciate ligament, and mitigate the risk of secondary meniscal injuries. Furthermore, CBLO allows for the advancement of the tibial tuberosity, contributing to overall joint stability.
The following video will provide an overview of a CBLO Surgery.

Pre-Operative Assessment and Planning

CBLO Surgery

IMPORTANT REMINDER: We strongly advise attending one of the CBLO workshops to acquire the necessary skills for performing CBLO surgery independently. This article is designed to provide an overview of the technique and to merely offer guidance.


CBLO surgery is typically indicated for patients suffering from cranial cruciate ligament (CCL) rupture, especially in cases where other surgical options such as Tibial Tuberosity Advancement (TTA) may not be suitable. While TTA RAPID® is often preferred due to its less invasive nature and lower risk of complications compared to CBLO, there are specific scenarios where CBLO may be warranted.
  • Patients with high Tibial Plateau Angle (TPA): CBLO is particularly beneficial for dogs with a very steep tibia plateau angle (TPA), where a Tibial Tuberosity Advancement (TTA) procedure may be insufficient (would require too wide of an advancement). In such cases, CBLO allows for precise correction of extreme TPAs, including the option for a double circular wedge osteotomy.
  • Juvenile Patients: As CBLO surgery does not involve the growth plate, it may be of particular benefit for very young patients.
It is important to note that each case is unique, and the decision to proceed with CBLO surgery should be based on a thorough evaluation, considering factors such as the dog's age, size, overall health, activity level, severity of CrCL injury, and owner's preferences and expectations.

Radiographic Planning: Positioning

Proper positioning is crucial for accurate planning.  Orthogonal radiographs are taken with the stifle positioned at 90 degrees and the tarsus at 90 degrees for the lateral projection. The AP projection must have the stifle and tarsus included for the attending surgeon to assess limb alignment. 
The patient is best sedated for radiographs to ensure optimal positioning. Magnification must be accounted for with a measuring device.
Here's a general guideline for positioning:
  • Lateral Recumbency: Position the patient in lateral recumbency, ensuring the contralateral limb is extended forward and the knee (stifle) and ankle (tarsus) joints of the limb being X-rayed are flexed to a 90° angle. Place the contralateral (opposite) hindlimb just in front of the limb being radiographed.
  • Maintain Limb Position: Limb positioners or tape can be used to mantain the position, so that a handler will not be necessary.
  • Alignment: Ensure that the femur and tibia are parallel to the table and at the same height. This alignment may be achieved by using a foam wedge under the stifle, hip, or tarsus.
  • Center the X-ray beam precisely over the stifle joint with collimation to capture the entire length of the tibia, preventing any distortion that could affect the assessment of Tibial Plateau Angle (TPA) landmarks.
  • Calibration: To facilitate image calibration, include an object of known size, such as a calibration ball, positioned at the same height and in close proximity to the knee joint.
It is important to note that any internal or external rotation of the tibia can affect how the tibial plateau appears on the X-ray, which in turn impacts the measurement of the tibial plateau angle by about 1 degree. This rotation can occur due to incorrect positioning of the affected limb or failure to center the X-ray beam accurately over the stifle joint.

Determining the CORA

FA - Draw the distal mid-diaphyseal line. The distal mid-diaphyseal line bisects the marrow cavity at the distal extent of the tibial crest & 1-2 cm below; it generally exits the joint line at Gerdy’s tubercle.

TP - Draw a second line across the slope of the medial tibial condyle. This is the tibial plateau (TP) line. 

PA - Draw the proximal axis (PA) line. The proximal axis is determined from the intersection point on the tibia plateau (TP) with the angle α [normally 80° = 90° - 10° (post-operative required TP angle)].

CORA - The intersection point of FA and PA is the CORA. The angle β is then the correction.

Saw Blade Radius and Positioning

The required saw blade is determined by a circle with CORA as the center point. The saw blade is positioned so that the cranial edge of the blade crosses the cranial cortex. The caudal edge of the blade should cross in a more horizontal plane for ease of rotation.

D1 - Draw and measure a line (D1) from the insertion of the patella tendon to the point at which the saw blade crosses the cranial cortex.

D2 - Draw and measure a second line (D2) from the joint line at a point where the MCL crosses the joint to the location where the saw blade crosses the caudal cortex.

D1 and D2 are helping measurements to position the saw blade correctly during the surgery.

Determining the Correction

Based on the measured correction angle β and the selected saw blade, you will find the rotation for correction with the help of the LeiLOX CBLO Rotation Chart (See field “Rotation”).

What you will need

Essential Instruments

X-Ray Calibration Ball

For radiographic calibration, it is recommended to position an object of known dimensions near the targeted joint or bone, ideally using an X-Ray Calibration Ball. While image calibration does not alter Tibial Plateau Angle (TPA) measurement, since the angle remains consistent regardless of image size, it enables the radiographs to be utilized for surgical planning in addition to diagnostic purposes.

Product Code



X-Ray Calibration Ball, 25mm diameter

TPLO Saw Blade

The RITA LEIBINGER TPLO Saw Blades are coated with Titanium Nitride (TiN), one of the hardest and toughest materials in the medical field.

Product Code

Width (in mm)



















TPLO / CBLO Essential Instruments

Here are just some of the instruments. Please visit our shop or ask for our catalog to see all instrument size variants and details.

Product Code



Screwdriver Handle, silicone, compact, approved for 2.0/2.4 TPLO


Screwdriver Shaft Star Drive T10


Drill Bit, 2.5 mm diameter


Compression Drill Guide for 2.4mm screws and 1.8mm drills


Depth Gauge for 2.7/3.5 mm screws


Depth Gauge for 2.0/2.4 mm screws


TPLO Jig for 2.7 mm


TPLO Jig for 2.0 / 2.4 mm


Castroviejo, Caliper





Locking Drill Guide for 2.0 mm screws

Locking Drill Guide for 2.4 mm screws 

Locking Drill Guide for 2.7 mm screws

Locking Drill Guide for 3.5 mm screws

TPLO / CBLO Instrument Set and Screw Racks

The LeiLOX TPLO / CBLO Instrument Set contains the essential instruments that you would need to perform a TPLO or CBLO surgery. Screw Racks are also available to facilitate easy access to screws during surgery, and help maintain efficiency and organization in the operating room.

Product Code

Set Description


TPLO / CBLO Instrument Set







Screw Rack for 2.0 mm screws

Screw Rack for 2.4 mm screws

Screw Rack for 2.7 mm screws

Screw Rack for 3.5 mm screws

Screw Rack for 2.7 mm screws, extended

Screw Rack for 3.5 mm screws, extended

LeiLOX CBLO Titanium Implants and Screws

Our LeiLOX CBLO System is suitable for small to giant breed dogs. 
Featuring multiaxial locking screws that can be locked in a 90° angle with a 12° deviation in any direction, it allows you to angle the screws away from vital structures. Two precisely designed compression holes enable a very tight compression of the osteotomy, which supports bone healing.

LeiLOX CBLO - Patient Weight Guide

Weight Range

LeiLOX CBLO Implant Size

less than 10 kg

2.0 mm 

8 to 18 kg

2.4 mm

15 to 30 kg

2.7 mm

25 to 40 kg

3.5 mm

more than 35 kg

3.5 mm broad

IMPORTANT NOTE: The table above only serves as a guide and the weight ranges are merely suggestions. It is up to the veterinarian to assess and determine the correct implant size, material type, and configuration to use for his patient, as well as its application and the technique to be employed.

CBLO Surgery Protocol

A step-by-step guide

The following describes the CBLO procedure with the aid of a jig. The jig was developed to maintain a fixed plane orientation of the tibial segments during rotation and can aid in the perpendicular alignment of the osteotomy, and its use when performing a leveling osteotomy such as CBLO is recommended.

1. Placement of the Patient

The dog is placed in a dorsal recumbency with the affected limb suspended from a stand. Make sure that the dog’s paws are not fixed too tightly, since the affected limb will be put against the table later in the surgery.

CBLO is performed through a medial skin incision. The internal structures of the joint should be examined, this is accomplished arthroscopically or with a medial open mini arthrotomy. Most importantly, the caudal horn of the medial meniscus must be examined closely and torn meniscus parts excised if present. Next, the insertion of the sartorius muscle is reflected from the medial tibia to expose the MCL. Limited reflection of the popliteal muscle and protection of the popliteal artery with gauze packing or Hohmann retractor is optional. D1 and D2 measurements are marked distal to the insertion of the patella tendon (D1) and distal to the joint line at the MCL (D2).

The surgeon may choose to use a jig or can perform the osteotomy without a jig if he/she has experience performing a CBLO without a jig.

2. Using the Jig

The proximal pin of the jig is inserted about 3-4mm below the joint surface caudal to the MCL.
The pin must be absolutely parallel to the joint surface. The jig is slid over the proximal pin.

The jig can be used as a guide for placing the distal pin. Both pins must be parallel to each other, and the jig must be in a right angle to the pins. After the positions are correct, the screws as well as the grub screws can be tightened.

3. Making the osteotomy and rotating the bone fragment

The appropriate saw blade determined during the pre-operative planning is positioned at D1/D2 and a circular osteotomy begins. The osteotomy is stopped when 1/3 to 1/2 complete. Move the saw circularly so that it won’t stick. The pre-operatively determined correction measurements (in mm) should be marked for example by a small chisel and mallet.
At the insertion point of the patella, a 2.0mm pin may be pre-placed without crossing the osteotomy.
Complete the cut and rotate the bone fragment. The rotation is made with the pin so that the marks are aligned. The osteotomy is then stabilized with the pin. Carefully avoid a rotation or valgus mistake. The pre-placed pin is directed across the osteotomy under the medial cortex to exit the caudal cortex of the tibia distal to the osteotomy.

4. Stabilization of the osteotomy with plate compression

The CBLO procedure not only levels the tibial plateau, but also involves cranially advancing the tibial crest. This advancement enhances the structural moment arm of the tibia, consequently increasing quadriceps force on the osteotomy site. To increase stability and promote faster healing, compression of the osteotomy is essential.

The LeiLOX CBLO plate facilitates this compression, particularly when the distal portion of the plate sits flush on the tibial surface without exerting lateral pressure on the proximal tibia. By positioning the LeiLOX CBLO plate at the desired location and pre-fixing it with a 1mm positioning pin in the plate shaft, precise compression and stabilization of the osteotomy can be achieved.

5. Sequence of screw insertion 

The screws are inserted in the following (recommended) sequence:
The first screws to be placed are the two cortical screws in the two compression holes in the plate (marked as 1 and 2 in the image). Drill the holes with the matching compression drill guide facing distal. Place the screws but do not tighten yet.
Place the proximal locking screws 3, 4, and then 5 into the plate head. Drill the holes with the matching locking drill guide and insert the screws one by one and fully tighten.
Note: The locking mechanism of the LeiLOX CBLO Plate is multi-axial, offering versatility and adaptability during surgical procedures. If there is a concern about screws entering the joint when drilling at a 90° angle, simply adjust the angle of the drill guide to face distally. This adjustment allows for precise screw placement while minimizing the risk of intra-articular penetration. 
Remove the stabilizing pin and the positioning pin.
Tighten the compression screws 1 and 2.
Insert locking screw 6 and tighten.
To counteract the pull of the quadriceps muscle, a screw should be placed in the same location as the pin through the crest in a caudo-distal location.
In large dogs, it is advised to place two cranial screws to counteract the quadriceps force. In giant breed dogs, the placement of a second plate should be considered.
Check tightness of all screws. Close the wound using standard techniques.
(IMPORTANT: It is crucial to properly close the periosteum and soft tissue layers to safeguard the plate site. Ensure not to overlook the closure of the incision made for the distal jig pin.)


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CBLO Titanimplantate

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