Step 3: Dog Knee Proper Diagnosis

Step 3: Proper Diagnosis

Clinical signs of early (partial) CCLR may include an acute onset of hind limb lameness following activity (can be weight bearing or non-weight bearing) that improves with time and is followed by intermittent stiffness after rising, or mild to moderate lameness following heavy activity. As the disease advances and the ligament progressively tears, the lameness may become more consistent. Acute complete tears may initially result in a non-weight bearing lameness on the limb, but as time goes on the dog may intermittently use the limb. Instability in the joint associated with CCLR can also lead to injury of the meniscus. Meniscal tears can be extremely painful for pets and may, for a period of time, result in a non-weight bearing lameness.

There are multiple tests your veterinarian can perform to help diagnose a cranial cruciate ligament tear. One of the first signs present prior to instability may be pain with full extension (hyperextension) of the knee. This pain is likely due to stretching of the intact or strained fibers of the cruciate ligament. Once the ligament tears to a certain degree the tibia can be manually manipulated to show instability in what is called the “cranial drawer test” in which the tibia can be moved forward in relation to the femur. Another sign referred to as tibial thrust, may be elicited as well. With this test, weight bearing is mimicked and the front of the tibia can be noted to be pushing forward in relation to the femur. It is important to keep in mind that many patients with clinical signs of pain and lameness may have a partial tear of the CCL. In these cases, there may not be any obvious instability (cranial drawer or tibial thrust) on the exam, however, the patient has a torn CCL that will likely progress to a complete tear.

Other signs that may be noted on the physical exam include loss of muscle mass (atrophy), detection of effusion (excess fluid in the stifle) within the joint, and scar tissue formation around the knee (buttress). This scar tissue is the body’s natural response to try and stabilize an unstable joint. Long-term this scar tissue leads to a decreased range of motion in the knee. Finally, a “clicking” sound may be noted in a small percentage of patients with meniscal tears.

Though the cranial cruciate ligament is not visible on an x-ray, radiographs can help confirm a diagnosis of a CCLR by detection of changes that occur in the joint following CCL injury. These changes may include effusion, arthritis, and forward movement of the tibia relative to the femur. Radiographs can also help rule out other concurrent injuries.

Ready to move on to the next step?


"Just a quick note to express our sincerest gratitude on how you helped our dog, Yoshi. You are truly an angel with a very special gift. Yoshi is doing well and is pretty much back to her same old lazy self. She is back to chasing her two cat brothers and enjoying the snow and cold weather."

-Stephanie, Robert and Yoshi Hansen

"We have had many dogs over the years that have had many surgeries..., but we have never found a more skilled, caring and dedicated surgeon before we met Dr. Collins. If you love your pet as much as we do, please trust Dr. Collins to keep them well."

-Ed and Carol Kachurik

"Thank you for the gift of our beloved Bear's good health. Bear is back to the park, in touch with nature and once again in love with long walks. Thank you again for the gift of your talents and the caring way you impart them."

-The Huss Family

"We just wanted to drop you another thank you card, Carah is as far as we can tell recovered 100%, we are so happy , it was worth all the work and expense. Thank you again for being here and your amazing talent."

-Much appreciation, Barb, Ken and Carah

"Nikii is 14 this year. Although he is a senior, he is growing old gracefully. He is able to walk well and has remained very mobile thanks to your wonderful care. Thank you again for everything"

-Mitch and Joanne

"I can't thank you enough for all you did for Dakota during his recent surgery. Thanks to your professional and caring attention; he is again the dog he used to be. I highly recommend you to anyone who needs a fabulous surgeon."


Have a question we didn't answer?

This field is for validation purposes and should be left unchanged.