Cruciate disease or tearing of the cruciate ligament is the most common injury in dogs. There are 2 cruciate ligaments in the knee joint of the dogs. They join the femur and tibia (the bones above and below the knee joint) together so that the knee works as a stable, hinged joint. The word cruciate means 'to cross over' or 'form a cross'. One ligament runs from the inside to the outside of the knee joint and the other from the outside to the inside, crossing over each other in the middle. In dogs and cats, the ligaments are called the cranial and caudal cruciate ligament.
Cranial cruciate (or ACL in humans) is the most commonly injured ligament out of the two cruciates and frequently requires surgery like TPLO.
4 Signs Cruciate Disease in dogs:
1. Lameness or Painful leg
Vast majority of the dogs are painful when cruciate ligament injury happens. There could be mild pain and lameness or some animals don't put any weight on it. Alternatively, some dogs show a gradually worsening, on-and-off lameness over weeks or months. They might seem to get better with rest, but then become lame again as they become more active. Dogs with chronic or slow CCL injury usually show symptoms associated with arthritis (decreased activity, stiffness, unwillingness to play, pain etc.).
Some dogs may seem to be “stiff” in the hind end, or be reluctant to go for their normal walks or get up at all if both cruciates are injured at once. That is we always assess both knees when an injury happens on one side.
2. Sitting abnormally
Dogs may sit or lie with their legs sticking out to the side rather than tucked in like normal, as it hurts to bend the knee. The worse the injury the more likely animals are to not sit squarely.
3. Knee thickening or clicking
Cruciate or CCL injuries cause inflammation and swelling in the knee and over time scar tissue develops. This makes the injured knee look bigger than the normal knee. Meniscus injury within the knee also causes clicking noise in some dogs.
4. Muscle loss or shifting weight.
Many dogs will shift their weight away from the damaged leg when they stand but the lameness is less obvious during walking especially with partial tears of the CCL. Muscle loss can happen if the injury persists for a long time and the animal is not using its leg.
What are the causes of cruciate injury in cats and dogs?
Yes, cats can get this injury as well. Vast majority of the animals have cruciate injury due to wear and tear with age. Some factors do make them more prone to developing it
4 Causes of cruciate injury:
Cruciate injury in the other leg: 60% of dogs with injury in one leg tend to get injury in the other leg as they start to shift weight onto the healthy leg causing more wear and tear.
Leg confirmation: Some dogs have patellar luxation making them prone to developing arthritis and injuring the cruciate ligament later in life.
Traumatic injury: Some very active dogs will have a traumatic injury while playing and tear their cruciate ligament while playing etc.
Obesity: Overweight animals are by far the most prone to developing cruciate issues. We see this problem less commonly in normal weight animals.
Since the CCL becomes injured due to it being too weak, it unfortunately will not heal with rest or medication. Braces don't work either. Though the scar tissue that forms around the knee over time does help, the only way to truly resolve the lameness is with surgery. Thankfully this is usually very effective, and with current surgical procedures such as the “TPLO” , even extremely large dogs can get back to being active and comfortable. Call your local vet today to get more information on these procedures.