What are Carpitis?
This condition is usually caused by some type of rigorous exercise or training, but it may also be from poor conformation There are many types of conformation problems such as knock-kneed, bow legged, toed out, bench kneed, wide, and narrow base. This may not just be the way your horse stands, but may have to do with the angles of your horse’s joints, length of the bones, the proportions and balance. Some of these conditions can be fixed with splints, air casts, and certain medications such as oxytetracycline.
Carpitis is the swelling (inflammation) of the soft connective tissues on the surface of the bones in the knee joint, which is also commonly referred to as a knee sprain. This condition may be acute or chronic and can affect the bones, ligaments, synovial membrane, and fibrous joint capsule. Carpitis usually shows up after exercise and can affect any kind of horse at any age, but is more common in horses that are used in cross country events, jumping, hunting, and racing.
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Symptoms of Carpitis in Horses
Some of the most common signs of carpitis are:
- Swelling of the knee joint
- Joint hot to the touch
- Reluctance to bend the knee
- Favoring of the affected limb
- Acute carpitis happens suddenly after a jump or race or during a training session
- Chronic carpitis is a gradual condition that builds up slowly over weeks or months of repetitive stress on the knee
Causes of Carpitis in Horses
Carpitis can be caused by many different factors including, but not limited to:
- Cross country events (with jumps)
- Heavy exercise
- Incorrect alignment of the knee joint
- Jumping (especially jumping over obstacles landing with a slope that goes up and away from the jump)
Diagnosis of Carpitis in Horses
After getting a history from you, the veterinarian will do a complete comprehensive physical exam. Although physical examination varies with different veterinary professionals, the basic steps include body temperature, heart rate, blood pressure, conformation, height, weight, body condition, behavior, and breath sounds. A lameness check will be done with and without a joint block to determine whether the lameness goes away after the block. The lameness examination is a detailed check of each of your horse’s legs to determine where the pain is. With carpitis, the knee will be obviously swollen, but the veterinarian will want to check the other knees to make sure there is no damage to them. Then the veterinarian will have you trot your horse while watching the movements of the knees and body language. A flexion test is done next. This procedure is done by applying pressure on the suspected knee for a certain amount of time and then having your horse trot away, looking for an increase in lameness.
Once the veterinarian determines exactly which knee is affected, imaging will need to be done to verify the exact cause of the injury. This will likely include diagnostic radiographs (x-rays) to view the bones and an ultrasound to see the soft tissues around the knee. Sometimes an MRI, CT scan, or bone scan (nuclear scintigraphy) will be needed. In some cases, the veterinarian may also decide to do a joint tap (arthrocentesis) to test the fluid in the knee joint. This is done by restraining your horse while the veterinarian uses a needle to extract fluid from the affected knee. Diagnostic testing is also needed, including a complete blood count (CBC), blood chemical analysis, and a blood culture test.
Treatment of Carpitis in Horses
Treating the carpitis depends on what is causing the inflammation. If the damage is not bad, the veterinarian may just give your horse some medication and instructions to rest your horse for 7-10 days. There are other treatments, however, for more complicated injury.
Some of the medications your veterinarian may give your horse are non-steroidal anti-inflammatories (NSAIDS), sodium hyaluronate, glucosamine, corticosteroids, platelet-rich-plasma (PRP), bisphosphonates, and polysulfated glycosaminoglycans (Adequan).
To reduce the inflammation, the veterinarian may suggest ice and cold water immersion. There are cold packs that claim to do the same thing, but immersion is the best form of cold therapy for carpitis.
Extracorporeal Shockwave Therapy (ESWT)
According to some veterinary professionals, high energy sound waves increase blood flow to the area to increase healing. This is done by placing a probe over the area (covered with coupling gel) and used for about 15 minutes. This procedure is the same one used in humans that is referred to as TENS (transcutaneous electrical nerve stimulation) therapy for pain and rehabilitation.
This is the most common procedure done for horse’s with carpitis because it can be used in diagnosis and treatment at the same time. This is done by inserting a tiny scope (arthroscope) with a camera on the end into the joint while using a tool or instrument inserted into another tiny incision to perform the work.
Recovery of Carpitis in Horses
The veterinarian will likely recommend that you keep your horse in a quiet area of the stable and continue to provide rest and medication for several weeks. Your veterinarian will have to evaluate horse before you allow your horse to go back to exercising or training, working up from a gentle walk to a trot over several weeks or months. This depends on your veterinarian’s recommendations.