Cruciate Ligament Rupture

The cranial cruciate ligament is a tough band deep inside the knee that stops the shin bone sliding forward on the thigh bone and keeps the joint stable through every step and leap. When it tears, the knee becomes wobbly and painful, and the cat suddenly favours the leg. Cruciate rupture is a classic and very common injury in dogs; in cats it is much rarer, which is partly why it can be overlooked, but it does happen — usually from a twisting injury when a jump or landing goes wrong, from a road accident, or from the ligament gradually fraying and finally giving way.

The signs are those of any painful knee: a sudden limp, holding the leg up or only toe-touching, swelling around the joint and stiffness that is worst after rest. A vet can often feel the tell-tale abnormal forward slide of the joint and will usually confirm the picture with X-rays, which also reveal any early arthritis.

Cats have a real advantage over dogs here: they are light and supple, and a good number recover well with conservative care alone — a spell of strict rest, careful weight control, and pain relief, followed by a slow, controlled return to normal activity over several weeks. Heavier, larger or particularly active cats, and those that fail to improve, may need surgery to stabilise the joint. Whatever the treatment, some degree of arthritis tends to set in over the following months, so keeping the cat slim and supporting the joint for the long term matters as much as fixing the original injury. Prevention comes down to weight management, safe surfaces and steps for the less agile, and keeping cats away from the traffic that causes so many high-impact injuries.