Wednesday, May 25, 2011

CONFORMATION FAULT: Three Common Knee Problems

No Perfect Horse: Three Knee Problems

As we mentioned in the last installment in this series, the knee of the horse is a complex structure that is subject to a great variety of conformation faults. Today we’ll take a look at three knee deviations, all of which are best observed from a lateral (side) view.

Back at the Knee (aka calf or sheep knee)

This is a serious fault in which there is a slight to marked ‘bowing’ backwards of the leg from a lateral view. A plumb line would fall closer to the front of the knee and further behind the heel bulb. This puts similar strain on the limb as if the horse were continually traveling downhill. Such conformation can put excess strain on various parts of the limb, including the flexor tendons, inferior check ligament, and suspensory ligament.  Horses with this fault may not move well and may be prone to stumbling, as well as bone chips in the knees and soft-tissue injuries such as bowed tendons. Working these horses in deep footing should be avoided, and it is worthwhile to x-ray the knees of any horse that is back at the knee before purchasing it. Unfortunately, many horses with this structural fault do not remain sound.

Over at the Knee (aka buck or goat knee, knee-sprung, forward at the knee)


Over at the knee is the most common of the “lateral view” structural deviations. Horses over at the knee will demonstrate a slight to marked ‘bowing’ forward of the leg, when viewed from the side. A plumb line falls closer to the back of the knee and slightly forward of the heel bulb. In some cases, the limb may vibrate or shake, and it may buckle easily if you push it from behind.  The strain placed on the limb is similar to what the horse would experience if constantly traveling uphill.  You may see a shortened stride, and the horse may place excessive strain  on the superficial flexor tendon, suspensory ligament, and sesamoid bones. Riders often report feeling that they are “lurching” forward and backwards when mounted on these horses.  In severe cases, horses may actually buckle at the knee and go down, putting both themselves and their riders at risk. However, many horses with this condition have long, productive performance careers.

Tied in Knee (aka tied in behind or below the knee)


From the side, this conformation fault will appear as an indentation under the back of the knee at the top of the cannon bone. It is actually caused by an abnormally small carpal canal, a structure through which several tendons and ligaments must move. The result is inhibited forward movement, as the soft tissue structures behind the cannon bone – the superficial and deep digital flexor tendons and the suspensory ligament – are prevented from moving freely.  Be aware that some horses may have a thick or heavy fetlock that can give the appearance of the knee being tied in, when it really isn’t. Tied in knees typically do not present the same sort of lameness risks as the previous two.

If your adult horse has any type of knee deviation, it is important to realize that you cannot change it, and efforts to alter or improve his balance through corrective shoeing are more likely to cause harm than good. The best strategy is to go cautiously with any activity, and back off if your horse starts to show any signs of soreness.  Stay out of deep footing that can cause extra strain, and be avoid steep hills if you have a horse that tends to trip or buckle.  If your horse is getting sore and backing off on work isn’t providing relief, talk to your veterinarian about pain medication or joint injections, both of which can be helpful in some cases. Remember that faulty conformation does not automatically mean a horse will go lame – it only shows us potential areas of weakness. It is probably best to avoid young prospects with moderate to severe knee deviations, but if you are looking at a proven campaigner with a slight fault, and the horse has not shown signs of lameness, the horse will likely continue to do just fine.