What is Knee Lock & Knee Locking?
The knee locks when the leg is stuck in one position, making it impossible to bend or straighten the knee. We will try our best to provide you practical knowledge about knee lock.
A blocked knee can last only a few seconds, it can last longer. It all depends on what causes it. Most cases fall into one of two categories:
True knee lock:
The true knee lock is where the knee is physically blocked and you can not physically move your knee for a while. The actual knee blockage is caused by a mechanical blockage where something gets stuck in the joint, preventing any movement. True locking is quite rare and usually occurs when you move the knee in full extension, that is, to the fully straight position.
Pseudo-knee locking is far more common than real lock. Here, knee movement is temporarily limited by muscle spasms as the body tries to protect itself from pain.
We will examine here the common causes of both types of knee blockage and the different treatment options.
True causes of knee blockage
The knee joint is designed to bend up and down (flexion and extension) and rotate slightly.
If something gets stuck in the joint, the motion is blocked and the leg gets stuck. When this happens, the knee is totally blocked, unable to move at all. It often takes a few minutes for the knee to move slowly or, as patients often say, to agitate it, or sometimes the intervention of a professional is necessary for the fragment to move out of the way, before you can not move the leg.
This is called real locking, which means that something physically prevents the joint from moving and is usually caused by:
1. The tear of the meniscus
A torn meniscus is by far the most common cause of knee blockage.
A meniscus tear by a bucket handle is a common cause of true knee blockage
The meniscus is a thick cartilage lining the knee joint to cushion and allow smooth movement. If it tears, the detached fragment can get stuck in the joint, preventing it from moving.
The most common type of meniscus tear resulting in knee blockage is known as the tear in the bucket handle. This is where part of the cartilage tears, but remains partially attached, producing a movable flap, usually “C” shaped.
When the knee moves, if the cartilage flap is large enough, it can get stuck in the wrong position, blocking the joint and causing a knee blockage. Your knee simply will not move until you can move the flap free to release the joint.
If you find that your knee hangs and lifts up, it is probably due to a tear in the meniscus.
A torn meniscus can be caused by an injury, usually due to twisting or progressive wear of the joint. You can find out more in the meniscus tears section.
2. Loose body:
Another thing that can block the joint and cause a real blockage of the knee is when a small piece of bone is detached from the knee joint, called a loose body, and floats around.
X-ray showing a loose body in the knee joint – a typical cause of knee blockage
As with a meniscus tear, if it moves to the wrong place, it can stall and cause the joint to lock in a specific position.
The bone fragment may have become detached from an injury or as a result of a disease such as arthritis or osteochondritis dissecans.
The actual blockage of the knee may or may not be accompanied by pain, depending on the cause.
It is usually the extension that is limited in this type of knee blockage, preventing you from being able to fully extend your leg.
Causes of the pseudo-locked knee
The pseudo-locking of the knee is always accompanied by pain. If knee pain is severe enough, body protection mechanisms come into play, limiting movement when the body tries to prevent damage. To do this, it usually causes spasms in the muscles and keeps the leg in position.
The difference with the actual lock is that there is nothing really stuck inside the joint, and although the knee may seem stuck at first, it usually unlocks quickly. It is often a “captivating” sensation that inhibits movement but disappears quickly.
Pseudo-locking can limit both flexion and extension, bending and straightening the knee, while verifying