An In-Depth Look: Cranial Cruciate Ligament (CCL) Rupture in Dogs

Cranial cruciate ligament (CCL) rupture, often referred to as a “torn ACL” in dogs, is one of the most common orthopedic injuries and a frequent reason pet owners seek surgical consultations. The CCL, located in the knee (stifle) joint, stabilizes the joint by connecting the femur (thigh bone) to the tibia (shin bone). A rupture results in knee instability, pain, lameness, and often arthritis.

Causes of CCL Rupture

Unlike humans, where ACL tears often result from acute trauma, CCL ruptures in dogs typically occur due to gradual weakening of the ligament over time, even during normal activity. Factors that contribute to this degeneration include:

• Genetics and Breed Predisposition: Breeds such as Rottweilers, Bichon Frises, West Highland White Terriers, Golden Retrievers, Labrador Retrievers, and Mastiffs may be more prone to CCL rupture.

• Obesity: Extra weight increases stress on the knee joint.

• Poor Physical Condition: Lack of regular exercise and core strengthening weakens ligaments and muscles that support the joint.

• Age: Most common in middle-aged to older dogs, but can occur in dogs as young as 1–2 years.

• Conformation: Certain tibial plateau shapes place continuous stress on the CCL.

• Simultaneous Rupture: Dogs with a rupture in one leg are at a higher risk of rupturing the CCL in the other leg within one to two years.

Signs of a CCL Tear

Early recognition is important for better outcomes. Signs may include:

• Hind limb lameness or limping

• Stiffness after rest or exercise

• Difficulty rising, jumping, or climbing stairs

• Pain when the leg is manipulated

• Swelling or thickening of the knee joint

• Decreased activity

• Muscle loss in the affected hind leg

• Sitting with the affected leg extended outward (sit sign)

• Clicking or popping noises, which may indicate a meniscus tear

Diagnosis

Veterinarians use:

• Physical Examination: Checking for swelling, instability, and performing “cranial drawer” and “tibial thrust” tests.

• Radiographs (X-rays): While X-rays cannot directly show the ligament, they reveal arthritis, inflammation, and bone changes. These images are essential for surgical planning if TPLO is considered.

Treatment Options

Treatment depends on tear severity, the dog’s size, activity level, age, and health.

Non-Surgical Treatment (for small, less active dogs or partial tears)

• Weight management

• Activity modification (limiting running/jumping)

• Physical therapy/hydrotherapy

• Anti-inflammatory medications and joint injections (as prescribed)

• Joint supplements

Surgical Treatment (often recommended for complete ruptures and larger or active dogs)

• Extracapsular Lateral Suture Repair: Mimics the ligament’s function using a suture outside the joint; best for smaller dogs.

• Tibial Plateau Leveling Osteotomy (TPLO): Reshapes the tibia to restore biomechanics; effective for larger dogs.

• Tibial Tuberosity Advancement (TTA): Adjusts patellar tendon alignment to stabilize the knee.

• Meniscectomy: Removes torn meniscus tissue to relieve pain.

Post-Surgical Care

• Strict activity restriction

• Pain management (and antibiotics if prescribed)

• Rehabilitation therapy

• Monitoring the incision

• Regular follow-up visits

Long-Term Outlook & Prevention

Osteoarthritis will eventually develop, but surgery slows progression and improves quality of life. Preventive measures include:

• Maintaining a healthy weight

• Regular, controlled exercise

• Avoiding high-impact activities

• Using joint supplements when appropriate

If you see signs of hind leg lameness or discomfort, early veterinary evaluation is essential for the best long-term outcome.