Many athletes experience knee injuries during their career. Some are simply “walk it off” type of injuries. However, others are obviously serious injuries from start.

Somewhere in the middle are those knee injuries that seem to come or go and may be more like a “trick knee”. In this blog I will cover some of the basics about Meniscus knee injury.

Many times the mechanism of injury tells us with wrong a patient’s knee. Other times the location of the pain is a clue. Timing of the swelling or any limitations that are experienced can also help us diagnose a condition.

kneeTo understand how knee injuries differ, you must first understand the structures within the knee and how they respond when injured. There are two types of cartilage within the knee that are commonly injured. The most commonly injured structure in the knee that requires surgical treatment is the meniscus.

A meniscus is a semi-circular disc : thick on outside and thin on the inside. This structure has an excellent blood flow on the outer rim but not much blood flow occurs in the center portion. When injured, the meniscus can: 1. Lie flat and be asymptomatic, 2. Flip up and limit the motion of the knee, and 3. Change between these two positions intermittently.

A meniscus is often called a “trick knee” when it is injured. That is because when it lies flat it may not have symptoms but when flipped up symptoms can be quite prominent. In addition, a meniscus may not cause swelling immediately when injured, but may swell later after irritation causes inflammation.

When a knee swells right away from a meniscus tear, it is typically a tear near the outside edge where the blood flow is higher.

When the knee swells later with a meniscus tear, it is often a degenerative tear. These mostly occur in older patients. As it ages, the meniscus often becomes “stiff” and more brittle, much like the red ring of Grandma’s canning jar after a couple seasons.

When a large portion of the meniscus is injured, it will flip up like a bucket handle and get trapped between the ends of the knee and shin bone. This can cause a “locked knee”.

Catching, swelling and locking symptoms are signs of a meniscus tear. If these happen off and on, the meniscus is likely flipping in and out of the joint.

If untreated, a meniscus that is caught between the bones can injure the articular cartilage of the knee joint.  rticular cartilage is the smooth, white cartilage we see when we take a drumstick of a turkey joint. This white cartilage coats every bone in our body where two bones meet. Once articular cartilage is damage, it cannot be replaced.

When damage progresses, the end result is arthritis. People often think that arthritis is something that is in the joint, but by definition arthritis is a loss of the coating from the end of the bone on x-rays. Articular Cartilage makes the space between the bones. When enough of the coating is missing, the bones touch – this is known as bone to bone arthritis.

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