Cranial Cruciate Ligament Rupture Diagnosis

CCL rupture signs and steps to diagnose.

Lameness

Lameness is the most common sign of CCL disease. In the early phases (i.e., partial tears), affected dogs may display a mild hind limb lameness following heavy activity. The lameness often improves with time and rest, but the lameness often returns after activity is resumed. Dogs may also have intermittent stiffness after rising. As the ligament progressively tears and the joint instability gets worse, lameness often becomes more consistent. Acute complete tears may initially cause a severe, non weight-bearing lameness, but the dog may intermittently use the limb as time goes on as some of the initial inflammation subsides. If the meniscus becomes injured, you may notice a clicking sound and there is frequently a non-weight bearing lameness present.

Transitioning Owners

Diagnosis

CCL rupture is usually diagnosed during the physical examination, however it can also be diagnosed with arthroscopy or an MRI scan. Dr. Bergh may use several tests to assess your dog for CCL rupture during the orthopedic examination, including:

Cranial drawer test

Once joint instability develops, it can be detected during palpation as the tibia can be moved forward in relation to the femur during a cranial drawer test. +

Tibial thrust test

To test for the presence of tibial thrust, weight bearing is mimicked and Dr. Bergh will watch to see if the front of the tibia can be seen pushing forward in relation to the femur. +

Hyperextension

One of the first signs present prior to instability may be pain upon full extension (i.e., hyperextension) of the stifle, likely due to stretching of the abnormal fibers of the CCL. +

It is important to keep in mind that many patients with a partial CCL tears may not display obvious joint instability during examination (i.e., they are for negative cranial drawer and tibial thrust), despite being lame and painful. These dogs still suffer from the condition and can be treated – you do not need to wait until they progress to a complete CCL tear.

Other signs that may be noted during your dog’s physical exam include

Lameness – may range mild or non-weight bearing, may be present in both back legs if CCL disease is bilateral.
Loss of muscle mass (i.e., muscle atrophy)
Joint effusion (i.e., extra joint fluid within the joint space)
Joint effusion (i.e., extra joint fluid within the joint space)
Thickening of the joint capsule on the inside of the stifle joint (i.e., medial buttress), which is the body’s natural response to attempt to stabilize the joint
Decreased range of motion in the stifle joint, which can be caused by long-term scar tissue formation or pain
A “clicking” sound, often indicative of a meniscal tear
A “positive sit test” or “sloppy sit” where your dog will sit with his hind legs to the side, instead of underneath him

Open Positions

X-Rays

Because the CCL is made up of soft tissue, it cannot be specifically visualized on X-rays (radiographs); however these are taken of the stifle joint to evaluate for other disease processes and assess the severity of osteoarthritic changes that are present. These changes may include effusion (i.e., excess fluid in the stifle), arthritis, and forward movement of the tibia relative to the femur. Radiographs are also used for pre-surgical planning and execution.