Locked Stifle Joints in Horses

a horses hind leg will appear obviously locked making it hard to overlook. It may stretch its leg out behind it when trying to walk or it may kick backward and step oddly to get the stifle joint to release. Your horse may not be able to alleviate its locked joint on its own and may drag its leg behind. Then for no visible reason the leg may snap back into a normal position you may even hear a click. If this happenseven if everything appears fineget it checked by a professional.
What Causes Locked Stifle Joints in Horses?
Locked stifles are most common in ponies foals and horses that are unfit although the exact cause remains unknown. However there are a few theories that may explain why your horses joint becomes locked in place.
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 2 Even a small growth spurt can change the angle of a horses 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 reasonsthe joint angle suddenly becomes compromised and therefore locks.
How Do Vets Diagnose Locked Stifle Joints in Horses?
In severe cases a locked stifle will be very obvious. The horse will have difficulty moving its leg normally. However a locked stifle could also be mistaken for stringhalta neurological disease that causes exaggerated and uncontrollable movement sometimes making your horse jerk its hind leg up high while stepping 3 In any case a veterinarian will need to examine your horse and manipulate its stifle joint to see if they can manually induce the unlocking mechanism. After that a radiograph may be performed to see if the lameness is caused by something else such as a bony abnormality. Lastly your vet may administer a local nerve block to determine if the lameness is actually caused by pain or if it is truly a mechanical issue.
How to Treat Locked Stifle Joints
For mild locked stifle cases exercise and a balanced hoof trim may help your horse. Lack of fitness causes weak muscles and ligaments so simply conditioning your horse can sometimes help solve the stifle problem 2 For severe locking ask your farrier to rocker or roll the toe of the hoof. They can also fit your horse with corrective shoes and pads to help the hoof break over before the locking occurs.
Certain cases that do not respond to conditioning or corrective farrier work may call for surgery performed by a veterinary surgeon called a medial patellar desmotomy 4 During the surgery a vet makes small incisions in
the patellar ligament while the horse is sedated and standing. This frees the strain of the ligament allowing for ample movement within the joint and alleviating the catching. However since freeing the ligament often causes instability in the patella itself the downside to this surgical treatment is the potential development of both arthritis and bone spurs.