Understanding Cranial Cruciate Ligament Rupture in the Knee
The knee is supported by several ligaments that provide joint stability. Among them, the cranial cruciate ligament (CCL) is key in limiting internal tibial rotation, forward tibial movement, and knee hyperextension. In dogs—and less commonly in cats—this ligament can rupture due to either degenerative or traumatic causes. Degenerated ligaments are more fragile and prone to injury. In dogs, degeneration is often a contributing factor, while in cats, obesity is a primary risk factor.
Bilateral involvement is common in dogs, with both knees typically affected within one to two years. The rupture can be partial or complete. As the CCL comprises two bands, a partial rupture affects only one, while a complete rupture involves the entire ligament. This instability contributes to osteoarthritis and causes significant pain.
Diagnosing Cranial Cruciate Ligament Rupture
An orthopedic exam helps assess knee pain. A complete rupture presents with a “drawer motion,” where the tibia shifts forward when the leg is flexed or extended. Partial ruptures may be harder to detect, especially in large, muscular dogs, and may require sedation for confirmation.
Additional signs include joint swelling (effusion) in acute cases and muscle atrophy in chronic ones. X-rays help rule out other causes such as fractures or tumors and assess arthritic changes. For a more detailed diagnosis, MRI may be used to examine the menisci, which are often damaged in CCL injuries.
Treatment Options
CCL rupture can be managed medically or surgically. Surgery is typically recommended, especially for large-breed dogs. However, for smaller dogs and cats, medical management may be considered based on budget and lifestyle factors.
Medical Treatment
This is suitable for dogs under 10 kg with sedentary lifestyles. It includes strict rest for six weeks and anti-inflammatory medication. However, this approach does not restore normal joint movement and can accelerate osteoarthritis. Additionally, 40% of dogs will injure the other knee within 12 to 18 months—rising to 60% if joint degeneration is already present.
Surgical Treatment
Various surgical techniques stabilize the joint and improve comfort. The choice depends on the dog’s weight, lifestyle, and owner budget. Studies show 85–90% of operated dogs regain satisfactory mobility.
- Flo Technique: Commonly used for small dogs, this extracapsular repair involves placing non-absorbable nylon suture through a hole in the tibial crest and around the fabella. Over time, the suture breaks, but the joint has stabilized sufficiently. This method is not ideal for large dogs, as the implant may fail prematurely.
- TPLO (Tibial Plateau Leveling Osteotomy): This technique alters the knee’s anatomy to eliminate abnormal tibial motion. A cut is made in the tibial plateau, which is repositioned and secured with a plate and screws. It stabilizes the joint and significantly slows osteoarthritis progression. Preoperative X-rays are required to measure the tibial plateau angle and plan the correction.
Post-Surgical Care and Recovery
A bandage is applied for the first 24 to 48 hours post-op. A rehabilitation program then supports muscle recovery and gradual return to mobility. Strict rest is essential until follow-up X-rays confirm healing. Recovery varies by animal but generally takes 4 to 12 weeks. Gradual return to exercise is key to preventing complications. Without rest, implant failure may occur, hindering healing.
If your pet shows signs of lameness, consult us to determine the best treatment plan.
