What is a CBLO Surgery?

This is a surgery that’s weighted down in acronyms, so let’s first clear the air by defining some of those acronyms that may cause confusion. CBLO stands for CORA Based Leveling Osteotomy. CORA stands for Center Of Rotation of Angulation. This just refers to the intersection between the axis of two bones, basically how they rotate in relation to each other. This is a surgery that was created to fix injured CCL’s (there’s another one!). CCL stands for cranial cruciate ligament.

Now that we’re hopefully on the same page, the CBLO method for CCL repair is similar to a TPLO and a TTA in that it involves cutting bone in order to decrease the angle of, and sort of flatten, the knee joint in dogs with a torn CCL.

The idea with any of the above three surgeries is to change the basic shape of the knee joint so that the CCL isn’t needed anymore to prevent abnormal movement in the joint.

Here’s how it goes about it:

Every dog’s knee joint is the junction of the thigh bone, or the femur, and the shin bone, or the tibia. These bones are held together by ligaments on the sides of the joint and by two ligaments in the center of the joint. These two ligaments, the cranial and caudal cruciate ligaments, form an X that anchors the thigh bone to the shin bone. The cranial cruciate keeps the thigh bone from sliding backward when weight is put on the leg and the caudal cruciate keeps it from sliding forward.

When the CCL is injured, such as during twisting or jumping maneuvers, it allows that thigh bone to slide around on top of the shin bone. This excess movement causes inflammation and instability, both of which are ingredients in the recipe for arthritis, not to mention pain and discomfort for your dog.

In humans with an ACL tear, the ligament itself is often repaired or replaced. Unfortunately, this isn’t an option for our four-legged friends since their CCL’s are too tiny to fix and the cost is too high. Instead, veterinarians must choose between different surgeries that aim to mimic the action of the CCL or ones that change the joint in such a way that the CCL isn’t needed at all.

The CBLO falls into the latter category. As you can imagine, the area where the thigh bone meets the shin bone isn’t a nice, flat, or level landscape. That’s simply because neither bone is flat at the end where they come together, creating a slanted surface that’s similar to a ramp. When that CCL gets torn, there is nothing to keep the thigh bone at the top of the ramp where it should be. It instead slides naturally down towards the bottom of the ramp and then moves up and down it with weight-bearing or bending of the leg.

During a CBLO surgery, the veterinarian makes specific cuts in the knee end of the shin bone and then reorients that cut section pitched forward in order to decrease the angle of the ramp, flattening it out to minimize that forward and backsliding of the thigh bone. The degree to which the cut and realignment are made is based on pre-op x-rays that show how severe the angle of incline is and what changes need to be made to level it out. The cut piece of bone is then screwed in place and held there with a special CBLO plate.

X-rays are repeated post-surgery to make sure that the new ramp is at less of an incline, or flatter, to prevent movement in the joint.


What Conditions Can Be Treated With a CBLO Surgery?

The CBLO was created to treat either partial or complete cranial cruciate ligament tears.


What Is the Cost of a CBLO Surgery

CCL repair surgeries that involve cutting bone are going to be more expensive than the extracapsular methods that aim to mimic the action of the CCL. This is because they require special tools and special training. Most general veterinarians are going to refer these types of surgeries to specialty clinics which increases the cost.

With that being said, a CBLO surgery is going to run anywhere from $3,500 to 4,500. This should include all pre-and post-op work and rehab. Keep in mind, there may be additional diagnostic costs from the referring veterinarian.


What Are the Surgical Alternatives to a CBLO Surgery?

Injuries to the CCL are a very common condition in dogs. The good news to come out of this is that there are many ways to go about fixing it. Some of those ways involve the addition of an implant that acts like a CCL in order to stabilize the joint, while other methods reorient sections of the shin bone in order to cut down the need for a CCL in the first place.

Implant-type procedures

Both of these use implants or heavy-duty suture material to stabilize the knee from outside of the joint capsule, working like an external CCL.

Leveling procedures

These surgeries require cutting of the shin bone and realignment of the cut piece to make a surface that is more level in order to decrease movement.

What Are the Non-surgical Alternatives to a CBLO Surgery?

Surgery is the best way to treat an injured CCL, but not every dog is a good choice for surgery. Some dogs have other health conditions that make anesthesia a risk, and sometimes surgery fiscally just isn’t an option. For those dogs, conservative treatment is the best option.

Conservative treatment works best for CCLs that are partially, instead of completely, torn. This is because there is some chance of getting that partial tear to lay down enough scar tissue to make the joint stable again. Complete tears simply allow too much movement for that scar tissue to correctly form.

These dogs undergoing conservative treatment need to rest. No running, jumping, or playing allowed. Anti-inflammatories help to reduce inflammation and make a dog more comfortable. Conservative treatment of an injured CCL means less money, less surgical risk, but also less chance of a positive outcome.


What Are the Advantages and Disadvantages of a CBLO Surgery?

Let’s get down to the nitty-gritty. Why should a CBLO surgery be considered for your dog and what is the dirt on it?


The CBLO is basically a combination of the TPLO and the TTA surgeries. Both surgeries have a high success rate but they also have their downfalls. The CBLO was created to decrease those negative aspects of both surgeries and focus more on the positives.

With that said, let’s try to remember back to high school physics…sorry, but it will be extremely important in helping you understand the advantages over a TPLO. TPLO’s have been considered as[U2]  one of the top choices of CCL repair for larger dogs. However, when looking at the finished product, you may notice that when weight is put on a TPLO repaired leg, the force from the thigh bone drives down behind the axis of the shin bone. With physical forces in mind, we all know that there’s a possibility that it will create problems down the road, and indeed it does. Increased stress on the joint due to this alteration in weight-bearing can lead to other ligamental injuries. Now with a CBLO procedure, that thigh bone is moved back to a more centrally located position so that the weight-bearing force goes down more directly over the shin bone, decreasing the strain on the knee joint.

There are also the benefits of not cutting into the joint capsule like is done in a TPLO and increased stability over extracapsular methods. This makes it more ideal for larger or bouncing-off-the-wall type dogs that wouldn’t do well with the TightRope or lateral fabellar suture surgeries.


Even though the CBLO may sound like it’s all roses, the fact remains that it involves cutting into bone. Now, bones typically heal very quickly, and with proper stabilization from the CBLO plate, there should be no issues, but it’s still the basic equivalent to a broken bone. Extra precautions will need to be taken to ensure that dogs don’t exercise too soon and cause damage to that area.

Like the TPLO, the CBLO isn’t something that just any veterinarian is going to take on. It requires special tools and special training that make it a procedure for referral or specialty clinics. While this isn’t always a deal-breaker, it can mean some long-distance travel or a long wait period in your future.


What is the Post-op Recovery From a CBLO Surgery?

Similar to other CCL surgeries, it’s going to take some time before your dog is chasing Frisbees again. And it’s important to note, the stricter that you follow the post-op instructions, the more chance of success the CBLO surgery will have.

Dogs will go home the next day following surgery with antibiotics, anti-inflammatories, and possibly an E-collar if they can’t keep their tongues to themselves. At-home care starts now with passive range of motion exercises, icing and massage. If you have access to a professional rehabilitation facility, use them. Otherwise, the Cruciate Home Rehab Guide will walk you through the helpful exercises and get your dog on the right track to recovery.

Dogs should be leash walked only for 4-6 weeks. No running, jumping or playing, no walking without a leash even in a fenced yard. Your dog isn’t going to like this, but don’t let those puppy dog eyes talk you into something that you may regret later. Uncontrolled exercise can lead to breakage of the plate or other complications meaning all of that work was for nothing.

An x-ray will be taken at 8-12 weeks to see if the cut bone has healed and to determine if your pup can start to amp up their exercise routine. Don’t get too excited, this doesn’t mean let them go free-for-all. Instead, it means longer leash walks and possibly some off-leash, but still controlled, time.

The joint supplements GlycanAid HA, Flexerna Omega and MSM Joint Boost are important partners in your dog’s recovery. These supplements provide glucosamine, chondroitin, MSM, omega fatty acids, and hyaluronic acid to nourish the joint and help ward off arthritis for as long as possible.

Weight loss plays an important hand in the recovery journey as well. Excess weight puts a lot of pressure on joints, especially newly fixed ones. For the best results and to help delay arthritis, keep your dog slim and trim with a proper diet.


What Are the Possible Risks and Complications of CBLO Surgery?

Anesthesia has come a long way since the use of ether or chloroform, but today’s anesthetics aren’t without their risks. Your vet will perform pre-anesthetic blood work and exams to ensure that your dog is healthy enough for this anesthetic undertaking. They will also monitor your dog throughout the surgery to make sure they’re taking everything in stride.

Another potential issue with any type of surgery is infection. Skin likes to stay intact; it’s how it works best after all. Any time there is cutting of skin, there’s a chance of infection. These chances are drastically decreased with antibiotics and keeping the incision clean and away from busy tongues and nibbling teeth.

With the CBLO, there’s always a chance that the plate or screws will fail. This chance is increased immensely by letting your dog run, jump, or unrestrictedly play too soon after surgery. Let’s put it this way, if the plate or screws break, you’re basically dealing with a broken-off chunk of bone and will need to find another way to fix their unstable knee joint.

Along with that, obviously, the metal CBLO plate and screws are nothing like the natural parts of a dog’s body, and sometimes their immune system becomes unhappy with that. A small number of dogs’ bodies may try to reject the plate or screws by mounting a localized response of redness, swelling, or discharge from the healed surgical site. This may happen weeks or months down the road and bring back your dog’s lameness and discomfort as well.

What is the Prognosis of CBLO Surgery?

The CBLO is a relatively new surgery in the CCL world, but it’s having great results. Around 95% of dogs have a successful outcome, meaning no discomfort or wiggle left in their knee joint. This success rate is dependent on how soon the repair happened after the injury and how well the recovery period went. That other 5% may be due to a plate or screw failure, an exercise mishap, or to the development of arthritis or other injuries soon following surgery.

With any damage or inflammation of a joint, arthritis will ensue, it’s just a matter of when and how bad. That means that dogs with a CCL injury will develop arthritis. But before you throw your hands up in the air, it’s important to know that proper surgical stabilization and joint supplementation can slow the development and decrease the severity of arthritis. GlycanAid HA, Flexerna Omega and MSM Joint Boost are your best defenders against arthritis. They provide the joint with all of the goodies that it needs to rebuild and maintain cartilage and joint fluid and to decrease inflammation.

Final Thoughts

The TPLO has long been the near gold standard for CCL repair in larger or active dogs. However, it isn’t with its faults. Enter the CBLO, a relatively new method that combines the benefits of the TPLO and the TTA but decreases the negative effects that these surgeries can have. The CBLO is a great choice for larger, can’t-get-enough-action dogs assuming you have a specialty or referral veterinary clinic in your vicinity.

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