Yes, cats can tear the equivalent of an ACL. In veterinary medicine, the ligament is called the cranial cruciate ligament (CCL) rather than the anterior cruciate ligament, but it serves the same function: preventing the lower leg bone from sliding forward relative to the thigh bone during movement. While less common than in dogs, a torn CCL is a well-recognized injury in cats that typically requires surgical repair.
Why It’s Called the CCL in Cats
A cat’s knee is one of the weakest joints in its body. Unlike a hip or elbow, the knee has no interlocking bones for natural stability. Instead, it relies entirely on ligaments to hold it together, including two cruciate ligaments that cross inside the joint. These ligaments allow the knee to hinge forward and back while restricting abnormal side-to-side and front-to-back sliding. The cranial cruciate ligament is the main stabilizer. When it tears, the lower leg shifts forward with each step, creating pain and instability.
Trauma Is the Primary Cause in Cats
In dogs, cruciate tears are often the result of slow, progressive degeneration of the ligament over months or years, eventually snapping during a routine movement. Cats appear to be different. A 2024 study in the Journal of Feline Medicine and Surgery examined the ligament tissue of cats with cruciate ruptures and found that the degenerative changes seen in dogs were absent. Roughly 79% of the cats in the study tore their CCL during a known traumatic event, such as a fall, an awkward jump, or a collision. The remaining 21% were indoor-only cats whose owners could not identify a specific injury, but even in those cases the tissue did not show signs of chronic degeneration.
This means a cat’s cruciate tear is more likely to be a sudden accident than a slow-building problem. That said, body weight plays a role. In an epidemiological study of 50 cats with cruciate disease, 40% were registered as overweight. The average weight of affected cats was 6.5 kg (about 14.3 pounds), significantly higher than the general cat population in the same veterinary practice. Carrying extra weight puts more strain on the knee with every jump and landing.
Signs of a Torn Ligament
The most obvious sign is sudden limping on a back leg, often appearing immediately after a jump or fall. Because cats are relatively small and skilled at hiding pain, you may also notice subtler changes: reluctance to jump onto furniture, stiffness when standing up after rest, or sitting with one leg extended to the side rather than tucked underneath. Over time, a cat with an untreated tear will shift weight away from the injured leg and toward the other limbs, which can lead to muscle loss in the affected thigh.
How Veterinarians Diagnose It
Your vet will manipulate the knee to check for abnormal movement. The primary test involves grasping the thigh bone and lower leg bone and attempting to slide them in opposite directions. In a healthy knee, the cruciate ligament prevents this motion. If the lower leg slides forward, the ligament is likely torn. However, this hands-on test isn’t perfectly reliable. Studies on the drawer test show it correctly identifies a cranial cruciate tear only about 69% of the time, because cats tend to tense their leg muscles during the exam, masking the instability. Many cats need sedation for an accurate assessment. X-rays help confirm swelling in the joint and rule out fractures, and some cases require advanced imaging.
Surgery Is Now the Preferred Treatment
For years, the standard recommendation for cats with cruciate tears was conservative management: strict rest, anti-inflammatory medication, and time. That advice was based largely on a single study of 16 cats. The current consensus has shifted toward surgical repair, which produces a faster return to normal function.
The two most common surgical approaches are lateral extracapsular suture stabilization and tibial plateau leveling osteotomy (TPLO). In the extracapsular technique, the surgeon places a strong suture outside the joint capsule to mimic the stabilizing role of the torn ligament. TPLO changes the angle of the top of the shin bone so that the knee no longer requires a cruciate ligament to stay stable during weight bearing. Biomechanical studies in cats have shown that both approaches restore joint stability comparable to an intact ligament. Your vet will recommend one approach over the other based on your cat’s size, activity level, and the condition of the joint.
What Recovery Looks Like
Most cats begin putting some weight on the surgical leg within the first week. By two weeks, they’re typically bearing a moderate amount of weight. Full resolution of lameness takes about four months.
The biggest challenge of recovery is keeping your cat confined and calm. Expect eight weeks of strict activity restriction in a small room with no elevated surfaces for jumping, or in a large crate. No stairs, no rough play with other pets, and no access to high furniture. This is often harder on the owner than the cat, but it is essential for the repair to hold.
Physical therapy starts early. For the first three days, you’ll apply a cold compress to the knee three times daily for 20 minutes each session. Starting on day four, each session shifts to a warm compress for 10 minutes, followed by gentle range-of-motion exercises where you slowly flex and extend the knee, hip, and ankle for about five minutes, then finish with a cold compress. The goal is to bend the knee fully so the heel nearly touches the rump, then straighten it completely. Massaging the thigh muscles, particularly the front of the thigh, helps prevent cramping. These exercises continue three times daily through week eight, after which they can stop.
From weeks nine through twelve, your cat can roam the house freely and begin jumping onto low surfaces of two feet or less, but should stay indoors. By the four-month mark, healing is considered complete.
Long-Term Joint Health
Even after successful treatment, a cat’s injured knee may not return to perfectly normal function. Research using pressure-sensitive walkways has shown that cats with a previous cruciate injury distribute their weight differently than healthy cats, shifting load away from the affected leg. Their owners also report subtle behavioral differences compared to before the injury. These changes likely reflect some degree of ongoing joint stiffness or early arthritis developing in the damaged knee. If you notice persistent stiffness after the four-month healing window, that warrants a follow-up with your vet to discuss pain management options and weight control strategies that can slow arthritis progression.