Cranial cruciate ligament disease (CCL rupture)

Symptoms an owner can spot at home

• Sudden non-weight-bearing lameness on a hind leg after play or a slip
• Chronic intermittent hindlimb stiffness that worsens after rest
• Sitting with the affected leg extended to the side ('sit test' positive)
• Muscle wasting on the affected thigh
• Difficulty rising from a down position

When to see a vet

• Any acute non-weight-bearing lameness lasting more than 24 hours
• Recurrent hindlimb lameness in a large-breed dog, CCL disease is degenerative and worsens without intervention
• Sudden lameness in a dog with a prior CCL surgery on the other side, contralateral rupture is common

What it is

The cranial cruciate ligament (CCL, the canine equivalent of the human ACL) stabilizes the femur on the tibia during weight bearing. Unlike the human ACL, canine CCL rupture is almost always the endpoint of a chronic degenerative process, not a single traumatic event. Immune-mediated inflammation, breed conformation (steep tibial plateau angle), obesity, and neutering age all contribute to the pathology.

Because the process is degenerative and often bilateral, the dog with an acute rupture on one side very often has subclinical partial-tear disease on the other, roughly 40-60% rupture the contralateral CCL within 1-2 years. Meniscal tears are a common concurrent injury and are one of the main drivers of chronic pain if not addressed.

How vets diagnose it

The definitive orthopedic tests are the cranial drawer sign and the tibial compression test, both performed under sedation for accuracy. Radiographs confirm joint effusion, osteoarthritis, and rule out other causes. Advanced imaging (MRI or arthroscopy) is occasionally used for suspected meniscal injury or in partial tears.

Treatment overview

This is editorial overview, not a treatment plan, your vet or a board-certified surgeon builds the plan. In dogs over roughly 15 kg the standard of care is surgical stabilization by tibial plateau leveling osteotomy (TPLO) or tibial tuberosity advancement (TTA), both of which change the joint biomechanics so the CCL is no longer needed. Extracapsular lateral suture repair is used in smaller dogs and select cases. Conservative management (rehab, weight loss, NSAID class analgesia) is an option in small dogs and non-surgical candidates but progresses more osteoarthritis.

Recovery from TPLO or TTA is typically 12-16 weeks of restricted activity followed by structured rehabilitation. Skipping the rehab phase is a common cause of poor long-term outcome.

What owners can do

• Maintain lean body condition (BCS 4-5/9), obesity is the largest modifiable risk factor.
• Avoid abrupt high-torque activities (frisbee twist-catches, ball chase on slippery floors) in adolescent large-breed dogs.
• Discuss neuter timing with your vet, several studies link early neutering to elevated CCL risk in some large breeds.
• Structured conditioning (walking, swimming, controlled fetch) protects joints; weekend-warrior activity spikes tear them.