There are certain knee problems in horses that are hereditary and which affect their conformation and movement. However, others knee issues are acquired through knocks, falls and other kinds of impact injuries. All too often this leads to something called hygroma which is when fluid builds up in the knee causing a swelling at the front of it.
Hygromas can also be caused by a kick or even a fall on their knees although the problem can also occur when horses are travelling and continuously bang their knees on partitions or the sides of a truck. This type of trauma can result in a horse developing a hygroma because they are effectively injuring the front of their carpus.
The majority of hygromas are not really that much of a problem and are considered more unsightly than anything else. They do not generally affect a horse's soundness nor do they become infected. Most vets recommend draining the fluid from the knee and then applying a compression bandage which needs to be done sooner rather than later for it to be an effective therapy.
Should a horse develop a hygroma for whatever reason and it interferes with their movement, the chances are there is another underlying issue responsible for their lameness which could typically be osteoarthritis, an old carpal injury or ever a fibrous joint capsular restriction. Sometimes, a hygroma may develop and affect tendons or a horse's joints where fluid continues to be secreted even after it has been drained and treated.
Many young horses damage their knees when playing with other youngsters when they are turned out together in a paddock. It's estimated that around 15% of youngsters do manage to injure themselves in this way. Repetitive bangs to their knees can also cause chip fractures which is a more serious problem. Once chipped, it opens the door to all sorts of knee issues namely osteochondral (OC) fragments with osteoarthritis following close behind.
Most vets would recommend surgery should a horse develop carpal osteochrondral fragmentation because if any bits remain in the joint, it can cause swelling and even cause joint degeneration. With this said, if a vet finds there are larger fragment in the knee or if there is too much scar tissue involved, they generally recommend leaving things alone.
Any acute injury to any joint in the carpus can lead to all sorts of inflammatory issues which are known as Carpitis. Treatment needs to be started as soon as possible in order to reduce any damage that might be caused to an affected joint. A vet would normally want to take an X-ray of the joint and maybe an ultrasound to see just how badly any soft tissue and underlying bone has been damaged. They would then recommend a treatment which could involve cold therapy, a course of NSAIDs and box rest.
A horse's carpus is made up of a lot of soft tissue parts, all of which can be damaged through trauma. If a vet suspects a horse has suffered a soft tissue injury to their knee, they would be able to establish their diagnosis by taking a diagnostic ultrasound of the affected joint.
Vets always recommend that owners take carpal injuries seriously and get them treated sooner rather than later because by not doing so, it opens the door to all sorts of knee and movement problems further down the line. This includes osteoarthritis which is a progressive and degenerative condition that can often be quite debilitating for a horse. It the condition is very severe, it's just a question of keeping a horse comfortable and sound so they can be retired from and work and turned away.
Treatment typically includes giving horses with osteoarthritis NSAIDs and other specific medication with the end goal being to improve synovial fluids in the knee. A vet might also suggest adding certain nutritional supplements to a horse's diet to make them more comfortable. If all else fails, the last alternative would be to fuse all or part of a horse's carpus.
A horse's knee is frequently put under a tremendous amount of pressure especially when training and competing. The carpus is also very susceptible to injury and getting damaged in many different ways. Trauma and repetitive impacts as well as incorrect conformation may be responsible, but whatever the cause vets always recommend that any inflammation be dealt with sooner rather than later to avoid other knee issues developing further down the line which includes Carpal Osteoarthritis (OA) a painful condition that typically results in horses being retired from work.