Checking for stifle stability
Instability in the stifles is a very common, but often underrecognized, issue. Here are some things to look out for in your horse.
A very common stance indicating stifle instability (among other things).
One of the more common issues I regularly see in horses of all breeds and all levels is a lack of stability in the stifle joint. This can range from a slight imbalance in the muscle groups to a full-blown locking stifle. (In case you missed it, here's a post on sticky stifles)
Most often, people do not realise this is something that the horse is dealing with until it becomes very obvious. So, here are some red flags when it comes to issues with stifle stability. One of the hallmarks of a lack of stability around the stifle is muscular imbalance. Most often, the horse will have overdeveloped hamstrings, tight inner thigh muscles and weak quadriceps (the muscles on the side of the thigh – the ones that have to work as the horse starts to carry more weight on the hind end). This will often be accompanied by a camped under stance and either a noticeable crease at the stifle joint or a soft-looking lump around the stifle.
Instability of the stifle can be better observed when the horse is in movement. There are a couple of things to be mindful of. Any rotation of the hoof after landing and during the stance phase can be a sign of knee instability. This can also be caused by issues in the hoof, so whenever we see this kind of rotation, call both the bodyworker and the trimmer (and the trainer too, eventually). The next thing to be mindful of is what the hock joint, specifically the calcaneus is doing. When we are dealing with sticky stifles, there will most often be an additional vibration present in the hock joint. This happens as the ligament that stabilizes the patella unlocks and the patella jumps back into place. I realise that the words »additional vibration« are very hard to imagine, but trust me, you'll know it when you see it. In some horses, this will be more obvious in trot. The next thing we should be looking at is the activation of the tensor fasciae latae muscle. This is a very fibrous muscle that goes from the tuber coxae down to the crural fascia, patellar ligaments and the tibia. It is very much involved with the stifle joint, so it's no wonder that it can tell us a lot about it. In some horses the action of this muscle is very apparent – it will be noticeable as a tight band going from the tuber coxae down to the stifle with every step the horse takes. Excess tightness here is a big sign of stifle instability. This action might be more pronounced in green horses, so don't panic if you see this on your youngster, but if the horse is in regular work, this should be a red flag.
These are some of the more obvious signs of stifle joint instability. If you find your horse ticks some or all of these boxes, you will probably need to make some changes if you want to keep him healthy long term. If you look up »sticky stifles« and what to do about them, you will most likely find strengthening recommendations. And yes, the muscles surrounding the stifles will need to be strengthened at some stage. But, before you go riding uphill and working over poles, you need to figure out why this happened in the first place. Most often, the reason will be some dysfunction either higher up (the pelvis, lumbar area...) or lower down (hoof imbalance, lower leg lameness...). In order for and rehab programme to be successful, you need to address the cause first.
Associated content: