Horse Side Vet Guide ®

Equine Health Resource

Buck Kneed, Over-In-The-Knee

Code Yellow - Contact Your Vet at Your Convenience for an Appointment

Code Yellow - Contact Your Vet at Your Convenience for an Appointment

    In normal horses standing squarely, the front limb at the carpus (knee) forms a straight vertical line when viewed from the side. This alignment provides for normal functioning of the limb. It also allows the engagement of the passive stay apparatus, which allows the limb to lock in an extended position and the horse to stand with minimal muscular effort.

    If the carpus cannot extend fully because of anatomic abnormality, then this locking mechanism cannot function, and a horse cannot stand without some muscular effort.

    Young horses are frequently flexed at the knee or “over in the knee.” This is due to relative tightening of the joint capsule and tendons in the caudal (back) part of the carpus. Most foals grow out of this condition. Nevertheless, it is wise to discuss this condition with your vet.

    Many grown horses perform fine with mild buck knee, but severely affected horses might tend to buckle at the carpus (knee) and stumble during work. As mentioned, severely buck kneed horses may not be able to rest with the carpus (knee) locked, and may tremble when asked to stand for long periods.


    If you are aware of this defect, you can adapt your expectations accordingly. If you are considering the purchase of a horse with this abnormality, it is best to have a pre-purchase exam conducted by your vet.

    If this is a young horse, talk to your vet about any management that could minimize this problem as the foal matures. Regardless, assess the area for heat and swelling, and assess the horse for lameness at the walk. Consider taking a photo to share it with your vet for discussion.


    Your vet considers the situation (horse for purchase, already-owned horse, growing foal), the cause of and severity of the conformational abnormality, and whether or not lameness exists, and can help you come up with a plan accordingly. Radiography and other diagnostics may provide additional information.

    What Not To Do

    Do not purchase a horse without a veterinary purchase evaluation.

    Author: Doug Thal DVM Dipl. ABVP


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