Dr. Phil Zeltzman’s Blog

Pet owners sometimes ask what would happen if we didn’t address a torn anterior cruciate ligament (ACL). Dr. Google and random people will suggest conservative treatment as a perfectly valid option.

A non-surgeon colleague even wrote elsewhere that since people often don’t need surgery for an ACL tear, then we shouldn’t need it in dogs. Respectfully, this shows a basic misunderstanding of the differences in functional anatomy between dogs and humans. Let’s mention two:

. Humans are straight legged. Dogs always have their knees flexed when standing.

. The human tibial plateau angle is somewhere around 7 degrees. Dogs’ tibial plateau angles vary from around 20 to over 60 degrees, with a back-of-the-envelope average of 24 to 28 degrees in most of my tibial plateau leveling osteotomy (TPLO) patients.

How many reasonable, objective, ethical, honest reasons can you find to recommend conservative treatment as opposed to surgery?

Here are 10 consequences of untreated ACL tears:

1. Pain

Patients with a torn ACL are in pain.

Please remember that limping or favoring or babying a leg = pain.

Pets are not crazy! Holding the affected leg up or limping hurts less than putting full weight on the leg.

When the tear becomes older, pain might subside to some degree, but it stills hurts.

Another reason patients are limping is because the knee is unstable or wobbly.

2. Arthritis

We routinely notice during surgery that patients with long-standing (chronic) ACL tears have more arthritis than patients with a recent injury. This, in turn, leads to pain.

Patients with partial tears typically have less arthritis than patients with complete tears. Recent tears also regularly lead to less arthritis than older (chronic) tears.

Therefore, the sooner we perform the surgery, the better for the patient.

3. Scar tissue

Scar tissue is what we rely on after conservative treatment for an ACL tear. Experience proves that scar tissue alone is not enough to provide good function, at least in medium- and large-breed dogs.

Scar tissue is manifested by what we call the “medial buttress,” which can be a very prominent bulge inside a pet’s knee.

In turn, scar tissue leads to our next point.

4. Decreased range of motion

A long-term consequence of arthritis and scar tissue is a decreased range of motion of the knee.

Patients with older (chronic) ACL tears commonly experience a decreased range of motion. This might not matter much to a couch potato, but it will affect the performance of an active family pet or a working dog.

5. Muscle atrophy

Patients who favor a hind leg classically show various degrees of muscle atrophy because of poor use of the leg.

This can be assessed easily by measuring the circumference of the thigh with a simple tape measure.

6. Exercise intolerance

Obviously, a family pet or working dog will have a tough time running around with a sore knee.

Dogs with a torn ACL are reluctant to play or go for walks. Exercise intolerance or poor athletic performance classically leads to weight gain, because these pets often receive the same amount of food (and sometimes more, along with more treats).

7. Weight gain

A consequence of many of the above changes is decreased activity, which invariably causes weight gain.

This is a common observation in ACL patients. Unless you decrease your pet’s food intake to match the decrease in activity, weight gain is inevitable.

8. Opposite ACL tear

Arguably, weight shifting may lead to a tear of the opposite ACL. While this might be manageable in a yorkie or a cocker, it becomes a much bigger problem with a Labrador or a mastiff. Helping a 100 lb dog who has both ACLs torn at the same time is not easy!

9. Tear of the meniscus

Instability in the knee can lead to a tear of the meniscus (see picture below), which is a pad of cartilage in the knee. This can cause even more pain.

On the opposite, once the knee is stabilized, the risk of a tear of the meniscus is minimized.

10. Distant problems

The changes in gait and posture can affect all three other legs, as well as the spine. Weight shifting may cause or exacerbate an orthopedic problem in another leg.

A doggie physical therapist told me once: “An ACL rupture is the beginning of a cascade of events in other body parts – joints, muscles – that we can’t forget.”

To a degree, some of the above changes can be used to “date” an ACL tear. From experience:

. A patient with a recent ACL tear classically is lame and painful.

A patient with an old (chronic) ACL tear typically presents with limping, pain, arthritis, decreased range of motion, muscle atrophy and weight gain. In surgery, we certainly see much more bone spurs in a dog with a chronic tear than with a recent tear.

From a surgeon’s standpoint, an ACL tear is a very fixable problem.

Sure, it is possible to live with a torn ACL. Certainly, it might be the only option if you absolutely cannot afford surgery.

ACL surgery has changed dramatically over the past few years. I now expect a return of at least 95 % of normal function in at least 95 % of my patients of any size after ACL surgery, of any type.

So it’s hard for me to believe that affected dogs, especially large ones, have (and will have) a good quality of life with an untreated ACL tear.

Phil Zeltzman, DVM, DACVS, CVJ, Fear Free Certified

www.DrPhilZeltzman.com

Nestle, a 6 year old pit bull, started limping on her left hind leg. Her owner took her to her family vet to figure out what was wrong.

The vet took one X-ray of the leg and gave the owner some devastating news: Nestle had bone cancer – most likely osteosarcoma. He recommended that she been seen by a surgeon to discuss what options were available.

Nestle’s dedicated owner immediately took her to see the surgeon. He reviewed the X-ray taken by the family vet and agreed with the diagnosis. Then he recommended to take her to surgery right away to have her leg amputated. Amputation is indeed the standard of care for bone cancer.

But Nestle’s owner didn’t feel right about the whole situation. He couldn’t explain it. It just didn’t sit right with him. “I knew we had to get a second opinion. When I looked at Nestle, something just told me I wasn’t getting the most accurate information.”

Trusting his gut, he reached out to me for a second opinion about his dog’s unfortunate situation. I asked him to send me the X-ray his vet had taken for me to review. After looking it over thoroughly, and with all due respect, I didn’t see anything convincing on the X-ray.

That put me in a diplomatically tricky position…

I told him that I would not feel comfortable amputating Nestle based on that X-ray only.

Instead, I recommended doing a full “workup” – by the book.

X-rays of the bone in question, in addition to the knees and the hips to be thorough. I also recommended chest X-rays since bone cancer readily spreads to the lungs. And full blood work for good measure, to make sure Nestle was a good candidate for anesthesia.

That was a big leap of faith, and a significant expense, but Nestle’s owner trusted me enough to follow my advice.

Once I received the X-rays from the clinic I referred him to, there was no question in my mind. Nestle did not have bone cancer. To be extra safe, I even emailed the X-rays to several surgeon friends. They all agreed with my opinion: no sign of bone cancer.

So what did Nestle have? A torn ACL.

Rather than an amputation, she needed a TPLO (Tibial Plateau Leveling Osteotomy).

Both happy and a bit uneasy (i.e. going against a family vet’s and another surgeon’s opinion), I delivered the news to Nestle’s owner. He was beyond grateful for the amazing news.

Can you imagine the emotional roller coaster?

We set up surgery for her TPLO procedure the following week. She had a successful surgery and recovered uneventfully.

The owner and his family were so happy. They were relieved that they trusted their gut and pursued a second opinion for their dog.

What’s the moral of the story? My point is certainly not to pretend that I am smarter than the other surgeon.

Here are a few points to never forget if you get in a similar situation:

. A thorough vet will always do specific things rather than cut corners. For example, we almost always need “2 views” or 2 X-rays, to get a better idea of the anatomy in 3D: one from the front and one from the side. Nestle’s vet, with all due respect, only took a view from the side. I always ask for “2 views” of the bone.

. When cancer is suspected, we usually take chest X-rays to make sure the cancer hasn’t spread to the lung (I say usually because in some cases we need to look inside the belly for spreading). Can you imagine amputating a dog’s leg, and then later realizing that the lungs are full of metastasis?

Incidentally, a thorough vet will take not 2 but 3 views of the chest: one of the front, and one from each side. Again, don’t cut corners.

. And of course, we always perform full blood work before putting a patient under anesthesia, to ensure they are a good candidate, ie internal organs such as the kidneys and the liver, are healthy enough.

. And here is my final and most important point: whenever something doesn’t seem or feel right about a practice, a vet or a treatment recommendation, you should trust your gut. It is your absolute right to get a second opinion if you aren’t comfortable.

You should never feel embarrassed or ashamed to seek a second opinion. You need to be your pet’s best advocate.

The diagnosis and the outcome may not be any different, but at least you can rest assured that you will make the best possible decision for your pet.

“The initial thought of losing Nestle to bone cancer absolutely crushed my family and I. Nestle is a rescue & since the day I rescued her, I vowed to do everything in my power to keep her safe and comfortable throughout her life after a rough beginning. After her initial diagnosis, I felt like I had failed her. But there was something about Nestle’s demeanor, I can’t explain it, I knew there was more to the initial diagnosis. And I knew I wanted a second opinion, especially after such a serious diagnosis.”

And he concludes:

“Without a doubt, Dr. Zeltzman and the staff at the clinic changed Nestle‘s life for the absolute best, and they gave me back my best friend when I thought I’d lost her for good.”

Phil Zeltzman, DVM, DACVS, CVJ, Fear Free certified