Locked Stifle Joints in Horses

Causes Treatment and Prevention
Similar to the human knee a horses stifle joints are like hingessome of the largest in its skeletal system. Occasionally a stifle joint becomes locked due to overstraining or genetic joint problems and predisposing conformation. When this happens its hind leg appears to be stuck in extension often causing alarm. But dont stresslocked stifles are relatively common. This condition can happen to any breed of horse or pony but those with upright hind legs and straighter angles on their hock and stifle joints may be more susceptible 1 Mild cases may only cause slight lameness and there are ways to make your horse sound again often without invasive procedures.

Sometimes simply backing the horse will release the locked stifle. However if left untreated horses that display regular locking stifles may be unsafe to ride and require surgery.
What Is a Locked Stifle Joint?
A locked stifle joint happens when one of the horses ligaments remains hooked over a ridge on the head of its femur bone during movement. Stifle joints help the horse bend its rear legs and stabilize itself and these joints are actually meant to lock when standing. This important function is part of a horses stay apparatus an arrangement of muscles tendons and ligaments in the horses hind limbs that work together so it can remain standing using very little muscular effort
This action comes into play when horses sleep keeping them upright on their feet. Normally the horse can flex the joint with little effort to unlock it. However in some horses unlocking becomes delayed. A small delay will cause mild symptoms but long delays result in more severe symptoms. Medically this condition is called upward fixation of the patella.
Symptoms of Locked Stifle Joints in Horses
A horse with a locked stifle may develop a slight lameness in the hindquarters which when mild can be easily overlooked. In more serious cases locked stifle joints can cause the horse to struggle to move normally or even lock the leg fully. You may notice the following symptoms
A simple hesitancy can result as the horse responds to discomfort and stiffness especially after standing still for long periods of time 2 The horse can stumble or knuckle in the back end especially on downward transitions like a trail ride with a descending slope. A locked stifle may also cause a horse to short step and display difficulty changing leads at the canter.