Supplements to Help Horses with Locked Stifle Joints
By: Dr. Lydia Gray | Updated August 28, 2025 by SmartPak Equine
"Hi there, I was wondering what supplement would be best for a Thoroughbred gelding that has luxation of his hind left stifle. And if a joint supplement alone will help his stifle locking issue."
- JS
Dear JS,
I’m going to assume your horse has upward fixation of the patella, not patellar luxation, as that condition is uncommon in adult horses and usually only seen in foals (especially miniature foals) at birth.
It is generally accepted that a horse that “locks” their patella (stifle joint), meaning the medial patellar ligament gets hooked over the medial trochlea of the femur, improve with conditioning or fitness training. Since it is the quadriceps, or the muscles on the front of the horse’s legs that most need to be strengthened, hill work is particularly recommended, as is driving, or pulling.
If your horse improves with additional, controlled exercise, then no more treatment may be necessary. However, if there is little to no improvement, your veterinarian may suggest other treatments to help your horse. These include:
- Corrective shoeing
- Estrogen therapy
- Infusion of a counterirritant or “blister”
- As a last resort, medial patellar desmotomy surgery, where the ligament that gets hooked over the femur is cut
I have been asked before if a supplement containing silica and collagen would be appropriate for a horse with upward fixation of the patella and my answer is: I don’t know. On the one hand, part of the conditioning or fitness training is to develop stronger tissues, and having the building blocks of strong ligaments available during this time would make sense. On the other hand, if the ligament develops without corresponding muscle development, would the problem get worse? I do think that supplementing with ingredients to support a normal response to inflammation may be indicated, but ask your veterinarian before starting your horse on one.
Video on Why Locked Stifles Happen in Horses
Watch this video as Dr. Gray explains how a horse's patella may become "locked" and whether this is a lifelong condition.