Arthritis in the knee: What you need to know

Arthritis of the knee can make taking a step painful. Swelling, pain, and stiffness in the joint are just some of the symptoms that can occur when a person has this condition.

The knee joint is a hinge joint, named for its movement that is similar to the opening and closing of a door.

The joint consists of three main bones. Where two bones meet, each bone meets has a protective covering of cartilage. Additional pieces of cartilage, known as the meniscus, further support the knee.

All of these protective pieces of cartilage keep the bones in the knee from rubbing together. If this happens, it can be very painful.

The daily demands on the knee and its potential for injury make it a common source for arthritisdamage. Different types of arthritis exist, and the type determines which treatment a physician recommends.

 Types

According to the American Academy of Orthopaedic Surgeons (AAOS), there are over 100 types of arthritis, and some of them are common in the knee.

Osteoarthritis

Osteoarthritis (OA) is the most common type of knee arthritis.

It happens when the protective cartilage that covers the bones wears away.

As the cartilage erodes, the bones of the knee joint start to rub together.

This causes bone spurs to develop on the ends of the bones. Bone spurs may be painful and can limit a person's movement.

Find out more here about osteoarthritis of the knee. 

Post-traumatic arthritis

Old injuries to the knee and surrounding joints can continue to affect a person and cause post-traumatic arthritis, a type of arthritis that can develop after an injury.

The injury causes extra wear to the knee joint, leading to osteoarthritis. There may be painful swelling in the knee joint. 

Gouty arthritis

Gout is a form of arthritis in which uric acid crystals collect in the joints, including the knee joint. Uric acid is a waste product that forms when body tissues break down.

The crystals are like tiny needles to the knee joint. They can trigger inflammation, pain, and swelling.

Rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disorder. This means the body's immune system attacks healthy cells.

The condition tricks the body into thinking healthy tissues, such as protective cartilage, are harmful. As a result, the immune system destroys and damages these tissues. This can eventually destroy the joint.

RA can also cause joint swelling and soften the knee bones.

Source: Medical News Today

Causes

Each type of arthritis in the knee has different causes.

 

Osteoarthritis

Doctors consider OA a "wear-and-tear" condition, because the use of the knee joint eventually wears out the cartilage. OA usually appears after the age of 50 years because it involves overuse.

 

Gouty arthritis

Gouty arthritis may have several causes or risk factors. These include:

·         getting older

·         having a family history of gouty arthritis

·         being male, as it more often affects men

·         obesity, as excess weight means there is more tissue that can be broken down into uric acid

·         using certain medications

Gout often starts in the big toe. A person may also have kidney stones and lumps under the skin.