Medial Collateral Ligament Hypertrophy – What You Should Know

MCL Hypertrophy

Feel your dog’s knees. Do you feel that ‘knot’ on the inside surface of one or both knees?

This is a ligament on the INSIDE (medial or inner) surface of the knee(s) and it’s doing something important.

But first, some background.

A knee is “held together” and stabilized by a couple ligaments referred to as the Anterior Cruciate Ligaments. These are the ligaments that football players are ripping to shreds all the time. They’re important. And dogs tear them up a lot too. Especially if they’re about 5 years old and overweight.

When the ACL ligaments are torn, either completely asunder or just partially, it’s possible for OTHER LIGAMENTS TO TAKE OVER PART OF THE JOB and the Medial Collateral Ligaments (MCL) are just those actors.
So as the medial collateral ligaments step up to carry the knee, you’ll feel a little ‘nut’ like an almond or walnut popping up inside the knee.
That’s the big medial collateral tryna stabilize the joint.
It’s a Good Thing. Feed the ligaments PHYCOX. It”ll grow better faster and stronger.
Past that, it’s also a bunch of scar tissue and fibrin that coats the knee and makes it “sort of” stable. Or, “stable enough” to at least serve the dog. So, sometimes they don’t have to get surgery. Which is nice if the dog is already 13 when an ACL goes. It’ll heal “well enough to carry”. Most of the time.

To close: MCL’s are just hard globs of ligament that pop up as the knee remodels to a new configuration to carry the dog. And most of the time it’s a “Good Thing” unless it’s happening just because the dog’s super-fat*.


*Yeah sometimes the dog is SO FAT that the MCL’s hypertrophy because all the other ligaments are not “enough” to carry it’s ponderous weight. How fat is your dog? It’s easy to actually tell.

Author: Dr. Erik Johnson
Dr. Erik Johnson is the author of several texts on companion animal and fish health. Johnson Veterinary Services has been operating in Marietta, GA since 1996. Dr Johnson graduated from the University of Georgia College of Veterinary Medicine in 1991. Dr Johnson has lived in Marietta Georgia since 1976.