Diagnosis

When the ligament is completely ruptured it is easy to make a diagnosis of complete rupture based on physical examination because the knee is palpably unstable. However, when there is only a “partial” tear, the degree of instability can be subtle and subjective and it is not possible to make a definitive diagnosis based on the physical exam alone.

​Radiographs (X-rays) provide additional information that can be helpful. It allows the veterinarian to see effusion (fluid) in the knee and bone spurs (osteophytes) around the knee, both of which indicate there is a problem in the knee. In some cases, one can also see that the femur (thigh bone) has slid backward on top of the tibia (shin bone), which does indicate CCL rupture. However, in cases of “partial rupture” there are times when both the physical exam and the radiographs are subtly abnormal. Since the CCL cannot be seen on an X-ray, the diagnosis is considered presumptive, or tentative, at this point.

To confirm a diagnosis an MRI can be performed, and is frequently performed in people. However, in dogs MRI is rarely performed to assess the CCL. Rather, in most cases the diagnosis of CCL disease or rupture is made at the time of surgery as this is when the surgeon can see the CCL and confirm the diagnosis. There are two ways to do this. One way is to do an arthrotomy. This is where the surgeon incises and “opens” the knee to look inside with his/her naked eye. Conversely, the more advanced way to do this is to make a small incision and insert a camera (and arthroscope) and evaluate the interior of the knee, including the CCL, on a video screen. Arthroscopy provides a more thorough and less invasive way of evaluating the interior of the knee than does cutting the knee open to inspect it. One of the important points to take away is that the diagnosis of CCL disease or rupture is not confirmed until visualization of the CCL is performed. In rare cases of suspect “partial tear”, the CCL is found to be normal on inspection and some other problem is identified, such as an isolated meniscal tear, posterior cruciate ligament rupture, or cartilage injury. These other causes of lameness are far less common than CCL disease, but they can occur.

Recovery

Since the tibia (shin bone) has been cut and stabilized, the first major objective following surgery is to have the tibia (shin bone) heal without complication. It usually takes bone 8-12 weeks to heal with most dogs having substantial healing by 8 weeks post-operatively. Additional time is needed for the dog to reach their full potential. A brief review of post-op timelines includes:

1. 2 weeks post-op: The incision is healed. The dog should be “toe-touching” on the limb at this point most of the time when walking.

2. During month 1: The patient is allowed to walk about 15-30 minutes per day (on leash) and should use the limb >90% of the time when doing so by the end of the first month.

3. During month 2: The patient is allowed to walk 30-45 minutes per day (on leash) and should use the limb the vast majority of the time, although not entirely normally.

4. 8 weeks: Radiographs (X-rays) are usually checked at about this time to make sure that the bone is healing appropriately and most dogs have about 85% healing of their bone at this point in time.

5. During month 3: Most dogs need to get “back in shape”. They can have extensive leashed walking, jogging, and hiking during this month. Moderated and supervised periods of off leash running and play can be performed during this month.

6. End of month 3: Dogs are usually released to unlimited activity at the end of month 3.