When Your Dog Suddenly Starts Limping: Sharon’s Story and What a Torn ACL Can Mean
There are certain things that make a veterinarian’s mind start working before the physical examination is even finished.
A medium- to large-breed dog walks into urgent care suddenly limping on a hind leg, and one of the first things that comes to my mind is a cranial cruciate ligament injury.
It is one of the most common causes of hind-limb lameness in dogs, particularly in larger dogs. And sometimes, the story is surprisingly familiar.
I know because it happened to my own dog.
Her name was Sharon.
Meet Sharon
Sharon was born on my bedroom floor.
Her mother, Swiffer, was a stray dog that my roommates and I took in while we were in veterinary school. Somehow, our temporary rescue situation turned into eight puppies being born right there in my bedroom.
Sharon was the first puppy to arrive.
She was also the biggest.
And, in my completely unbiased opinion, the cutest puppy I had ever seen.
At the time, I already had a one-year-old dog named Sheye, who was my constant companion throughout veterinary school. Sharon quickly became part of the family, and before long, she was a very large, very lovable dog.
Unfortunately, she also became a very large dog who was carrying a little more weight than her joints would have preferred.
Then one day, I noticed she was limping.
At first, it wasn't particularly alarming.
She would play hard at the park, come home limping on one of her back legs, rest for a couple of hours, and then seem almost completely normal.
If you've ever had a dog like this, you know exactly what I mean.
They limp.
You worry.
Then they suddenly decide they're fine and start running around the house again.
So you think, "Maybe she just pulled something."
But eventually, Sharon's limp stopped going away.
And that's when I knew we needed to take a closer look.
What happens when a dog comes to EVS limping?
When a dog comes into EVS Pet Urgent Care with sudden or persistent lameness, our first job is to figure out where the pain is coming from.
A limp doesn't automatically mean a torn cruciate ligament.
A dog can limp because of a muscle or tendon injury, paw or nail injury, arthritis, a fracture, a hip problem, a luxating patella, another orthopedic condition, or even a neurologic problem.
That's why the physical examination matters so much.
For dogs with suspected cranial cruciate ligament disease, veterinarians perform specific orthopedic tests to evaluate the stability of the knee, including the cranial drawer test and tibial thrust.
In Sharon's case, her examination was consistent with cranial cruciate ligament instability.
So what exactly is the cranial cruciate ligament?
The cranial cruciate ligament, often called the CCL or CrCL, is an important stabilizing ligament inside the dog's knee, which veterinarians call the stifle.
Think of it as one of the structures that keeps the femur and tibia moving together appropriately when your dog walks, runs and jumps.
When the ligament is partially or completely torn, the knee can become unstable.
That instability causes pain and inflammation and can eventually contribute to arthritis and other damage inside the joint. Meniscal injuries are also common in dogs with cranial cruciate ligament disease.
And here's something important for pet owners to understand:
A torn cruciate ligament doesn't always happen because a dog dramatically injured themselves.
In fact, many canine cruciate injuries are related to gradual degeneration of the ligament rather than one single traumatic event.
That means the first obvious limp you see may actually be the moment when a problem has been developing for quite some time.
Sharon's knee told us more
We took radiographs of Sharon's knee.
Radiographs cannot directly show the cranial cruciate ligament itself because it is soft tissue. However, X-rays can show changes associated with a cruciate injury, such as joint swelling, changes associated with arthritis, and, in some cases, abnormal positioning of the tibia. They are also valuable for ruling out other problems such as fractures and for helping with treatment planning.
Sharon had findings that supported what we were seeing on her orthopedic examination.
At that point, we knew she wasn't simply having a bad day at the dog park.
She had a significant knee problem.
Can medication fix a torn cruciate ligament?
This is one of the most important conversations I have with families.
Pain medication and anti-inflammatory medication can absolutely make a dog feel better.
Rest and activity modification can also be an important part of managing an orthopedic injury.
But making a dog feel better is not necessarily the same thing as fixing the underlying problem.
I often compare it to having a rock in your shoe.
You can take pain medication and feel better.
But the rock is still in your shoe.
For many larger, active dogs with significant knee instability, surgical stabilization is ultimately recommended. There are several surgical techniques, including TPLO, TTA and extracapsular procedures, and the appropriate option depends on the individual dog.
That's why an urgent-care visit can be so valuable.
Our job at EVS isn't necessarily to perform every procedure a pet might eventually need.
Our job is to figure out what is happening, relieve pain when appropriate, perform the diagnostics that can help answer the immediate questions, and help you understand what needs to happen next.
Sometimes that means treating the problem right here.
Sometimes it means referral to a veterinary surgeon or specialty hospital.
And sometimes, importantly, it means reassuring you that your pet does not need an emergency hospital at all.
Sharon's road to surgery
Sharon ultimately needed surgery to stabilize her knee.
Before her procedure, I was taking her to a specialty center and, naturally, I was approaching the whole experience as both a veterinarian and a worried dog mom.
The specialty team offered to prescribe a fentanyl patch for her to use for pain control around the time of surgery. They explained that I could have the prescription filled at my local pharmacy rather than having it dispensed through the specialty hospital.
So I called in the prescription and headed over to Jewel-Osco.
When I arrived, the pharmacist looked at me and asked:
"Do you know how to use it?"
"Yes," I said.
There was a pause.
"Wait. This is for a dog?"
"Yes. It's for my dog. She's having knee surgery."
Another pause.
"But this is a dermal patch."
"Yes."
"And it has to go on the skin."
"Yes."
"But dogs have fur."
At this point, I could practically see the pharmacist trying to figure out how on earth this was going to work.
I explained that we would clip the fur where the patch needed to go so that it could be properly applied.
He finally understood.
And I couldn't help but laugh.
The TPLO lesson I never forgot
Sharon's case also reminds me of something I saw during veterinary school.
At the time, TPLO surgery—tibial plateau leveling osteotomy—was becoming increasingly common as a surgical treatment for canine cranial cruciate ligament disease.
During my radiology rotation, I saw study after study involving dogs that had undergone TPLO procedures.
Many dogs with chronic cruciate disease showed evidence of degenerative joint changes. That makes sense: when a knee remains unstable, the body responds to that abnormal motion, and osteoarthritis can develop over time. Unfortunately, osteoarthritis can continue to progress even after treatment.
Then one day, I saw a radiograph that looked remarkably different.
The knee looked beautiful.
There was essentially no evidence of the arthritic change I had become accustomed to seeing in those cases.
I remember saying to the radiologist, "Wow. This dog's knee looks incredible."
She smiled and said:
"It's the surgeon's dog."
The surgeon knew that his own dog was at high risk for cruciate disease and had elected to perform surgery before the ligament actually tore.
Now, to be clear, that is an extremely unusual approach and is not standard treatment for dogs simply considered at risk for a cruciate tear.
But the story stuck with me.
What about the other knee?
