Understanding Knee Cartilage Injuries and Meniscus Tears

Knee cartilage is a type of connective tissue in your knee. A tear that occurs in the knee cartilage may be called a "cartilage tear" or a "meniscus tear," but the terms are not always interchangeable.

The meniscus is a cushion in the knee joint. It is made up of one of two types of cartilage found in the knee. The other type is called articular cartilage. A meniscus tear is one type of knee cartilage tear, but tears can occur in both types. Both types of injury can cause symptoms like knee pain, buckling of the knee joint, and difficulty putting weight on the knee. 

This article looks at the difference between a meniscus tear and a cartilage tear. It also discusses other types of knee cartilage injury and some possible treatments.

Knee Cartilage Types

The knee joint contains two types of cartilage: articular and meniscus.

Articular cartilage forms the smooth layer of the joint that covers the ends of bones. A layer of this cartilage covers the end of the thigh bone, the top of the shin bone, and the back of the kneecap.

The meniscus is a different type of cartilage. This type acts as a shock absorber between bones. The meniscus is not attached to the bone like articular cartilage. Instead, it sits between the bone ends to cushion the joint.

The purpose of both types of cartilage is to protect the knee joint by keeping the bones from rubbing together. They also help the knee move smoothly.

Cartilage Injuries

Knee cartilage can be damaged in a few different ways, including:

• Traumatic injury
• Degenerative arthritis
• Chronic overuse

Depending on the type of injury, different types of cartilage may be damaged. When cartilage is damaged, it is often described as a tear of the cartilage.

Meniscus tears are common knee injuries, but tears can also happen in the articular cartilage.

Words that describe an injury to the articular cartilage include:

• Fissuring: A fissure is a crack in a layer of cartilage. This causes a separation in the layer. Sometimes this causes no symptoms. In other cases it can cause a "catching" sensation if it blocks movement of the knee joint.
• Thinning: Cartilage thinning can occur after an injury. It may also be an early sign of arthritis in the knee. Thin cartilage may not appear as smooth as normal cartilage. It also may not glide as easily.
• Flaps: Flaps in the articular cartilage occur when part of the cartilage separates from the bone and can be lifted from its normal position. This can also lead to catching sensations with knee movement.
• Defects: Cartilage defects can lead to exposed bone within the joint. This can occur after traumatic injuries. It can also occur as a result of knee arthritis.

Symptoms of a Knee Cartilage Tear

The symptoms of a meniscus tear and an articular cartilage tear are similar. A healthcare provider will be able to determine which type of tear you have, since it is very difficult to differentiate the two based on symptoms alone.

Both injuries can cause:

• Swelling of the knee joint
• Pain
• Buckling of the knee joint
• Difficulty bearing weight on the knee
• A popping sensation in the knee
• Difficulty fully straightening the knee
  

When to Call a Healthcare Provider

It can be hard to know when you should see a healthcare provider for knee pain. Pain that comes on slowly or happens as a result of a minor injury or overuse may resolve without treatment. In general, however, you should see a healthcare provider if:

• The injury happened as a result of a hard impact
• There is significant swelling or pain
• The joint feels warm or you have a fever

Seek emergency care if:

• The pain is significant
• You experience sudden swelling of the joint
• Your knee looks out of place
• There's a popping noise
• You can't bear weight on your knee

Treatment of Cartilage Injury

Meniscus tears usually require treatment. The good news is that not all meniscus tears need surgery. Some meniscus tears, though, do respond best to surgical intervention.

Damage to both types of cartilage is often the result of long-term degeneration and arthritis. This type of damage may cause serious symptoms such as pain and disability. Still, in many cases, surgery is no better than nonsurgical treatment.

Nonsurgical treatment of meniscus tears may include:

• Rest
• Icing the knee and keeping it elevated
• Anti-inflammatory medications
• Physical therapy
  

Always see a doctor if you have a knee injury. A doctor can help determine if surgery is necessary.

Summary

There are two types of cartilage in the knee. Tears can happen in both articular cartilage and a meniscus. 

Meniscus tears are common. When you hear someone refer to a cartilage tear, they are usually talking about the meniscus.

Tears can be caused by injury, arthritis, or chronic overuse. Not all tears require surgery, but many do.