Horses with locked stifle joints

A vet checks a problem with a horses stifle.

A horse's stifle joints, like the human knee, are hinges—some of the biggest in its skeletal system. Overtraining or congenital joint disorders might cause a stifle joint to become locked. Its hind limb looks to be locked in extension when this happens, which can be alarming. Don't worry, though; locked stifles are rather frequent. This ailment can affect any horse or pony, but those with erect hind legs and straighter hock and are more likely to be affected. Mild instances may only result in little lameness, but there are techniques to get your horse back to normal (often without invasive procedures). Regular locking stifles, on the other hand, may be dangerous to ride if left untreated and need surgery.

What Is a Locked Stifle Joint?

When one of the horse's ligaments remains hooked over a ridge on the head of its femur bone during movement, it is called a locked stifle joint. Stifle joints allow the horse to flex and stabilize its back legs, and they are designed to lock when the animal is standing. This critical function is part of a horse's stay apparatus (a collection of muscles, tendons, and ligaments in the hind limbs that act together to allow the horse to stand with minimal physical exertion).

When horses are sleeping, this motion keeps them erect on their feet. The horse can normally free the joint by flexing it with little effort. However, unlocking is delayed in certain horses. Small delays generate moderate symptoms, whereas longer delays cause more severe symptoms. The medical term for this is "upward fixation of the patella."

Symptoms of Locked Stifle Joints in Horses

A horse with a locked stifle may develop a little lameness in the hindquarters, which can be readily unnoticed if it is moderate. Locked stifle joints can make it difficult for the horse to move normally or perhaps cause the leg to lock completely. You may experience the following signs and symptoms:


  • Hesitancy to walk, stumbling, or difficulty changing positions
  • Short steps and slight hops
  • Dragging toes
  • Obvious locks in a straight position
  • Kicking backward or odd step patterns

As the horse reacts to pain and stiffness, especially after standing motionless for lengthy periods of time, reluctance might develop. On downhill transitions, such as a trail ride on a falling slope, the horse may stumble or knuckle in the rear end. A horse with a locked stifle may also take small steps and have difficulties changing leads at the canter. It can also cause your on separate front and rear leads or jump slightly while throwing its back leg. If you find your horse dragging its foot or having trouble moving in a circle, don't dismiss it as bad behavior or a bad habit. Consult your veterinarian to determine the problem and begin therapy.

A horse's rear limb would seem visibly locked in extreme cases, making it difficult to miss. When attempting to walk, it may extend its leg behind it or kick backward and stride in an unusual manner in order to loosen the stifle joint. Your horse may be unable to free itself from its locked joint and drag its leg after it. The leg may then snap back into its natural posture for no apparent reason (you may even hear a click). If this occurs, even if everything appears to be in order, consult a specialist.

Causes of Locked Stifle Joints

Although the specific reason is unknown, locked stifles are more frequent in unsuitable ponies, foals, and horses. However, there are a few hypotheses as to why your horse's joint becomes stuck:

  • Rapid growth spurts: There is speculation that young horses may develop this condition due to rapid growth spurts when the bones grow faster than the muscles develop. Even a small growth spurt can change the angle of a horse's joint, causing inappropriate functioning.
  • Lack of muscle tone: Another theory suggests that an unfit horse (or one that has suddenly lost muscle tone) may develop this condition for similar reasons—the joint angle suddenly becomes compromised and, therefore, locks.

Diagnosing Locked Stifle Joints

A locked stifle will be visible in extreme situations. The horse will struggle to move its limb normally. A locked stifle, on the other hand, might be misinterpreted for stringhalt, a neurological condition that produces excessive and uncontrolled movement, causing your horse's hind leg to jolt up high while stepping. A veterinarian will need to inspect your horse and handle its stifle joint to check if the unlocking mechanism can be manually induced. A radiograph may be taken after that to check if the lameness is due to something else, such as a bone deformity. Finally, your veterinarian may do a local nerve block to evaluate if the lameness is due to discomfort or a mechanical condition.


Exercise and a balanced foot trim may help your horse with minor locked stifles. Because lack of fitness leads to weak muscles and ligaments, just exercising your horse can help alleviate the stifle problem. Request that your farrier "rocker," or roll, the toe of the hoof if the locking is severe. They can also put and pads on your horse to assist the hoof break over before it locks.

Certain situations that do not respond to conditioning or corrective farrier treatment may require a veterinary surgeon to conduct a medial patellar desmotomy. While the horse is sedated and standing, a veterinarian makes tiny incisions in the patellar ligament. This relieves the ligament's tension, enabling the joint to move freely (and alleviating the catching). The drawback of this surgical procedure is the possible development of both arthritis and bone spurs, as releasing the ligament typically creates instability in the patella itself.

Prognosis for Horses With Locked Stifle Joints

Stifle joint lock is a common condition that may be treated with exercise, corrected shoeing, and hoof trims that allow the horse to free the joint through natural motions. After being treated by a physician or having surgery, horses with badly locked stifle joints can still live happy, healthy lives. Horse owners who have had medial patellar desmotomy surgery should be aware of any subsequent changes that might suggest or bone spurs. If any of these symptoms begin to show, get veterinarian assistance.

How to Prevent Locked Stifle Joints

Although certain horses are more prone to locked stifle joints than others, owners may take precautions to maintain their horses' muscles strong and healthy. Regular exercise on a plan tailored to each horse's individual demands can benefit all horses:

Gradual Exercise

Horses should be gradually exercised since a lack of muscular tone can contribute to locked stifles. Trail riding, for example, may help a horse attain its optimal fitness level in a safe manner by gradually increasing distance and pace over several weeks.

Strengthening Specific Muscles

Cavaletti training over or pole work that requires your horse to pick up its feet are two options. When done in tiny, gradually increasing intervals, lunging your horse on a line or riding it on a modest inclination (so that it drives with its hindquarters) also provides for safe training. If your horse has previously suffered locked stifles, it's critical to start cautiously, avoid overworking him, and properly discuss your approach with a veterinarian before commencing any training routine.

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.