Psoriatic Arthritis

What is knee pain?

Having sore knees is common and isn’t usually a sign of anything serious. There are many possible causes, which can range from a simple muscle strain or tendonitis, to some kind of arthritis. Sometimes a cause can’t be found.

Knee pain can often be treated at home and you should start to feel better after a few days.

As you age, getting knee pain may become more common. You’re also more at risk of getting knee pain if you are overweight. Knee pain may sometimes be the result of a sports or other injury.

How is the knee structured?

The knee is the largest joint in your body.

It is made up of four main things: bones, ligaments, cartilage and tendons.


Your knee joint is formed where three bones meet. These are your:

  • thighbone, which is also known as the femur
  • shinbone, which is also known as the tibia
  • kneecap, which is also known as the patella.

These join bones to other bones. There are four main ligaments in your knee. They act like strong ropes to hold your bones together and keep your knee in place.

These ligaments in your knee are:

  • Collateral ligaments – which are found on the sides of your knee. One is on the inside and one is on the outside. They control the sideways movement of your knee.
  • Cruciate ligaments – which are found inside your knee joint. They cross each other to form an X shape. These ligaments control how your knee moves backwards and forwards.

There are two types of cartilage in your knee:

Articular cartilage

This covers the ends of your thighbone and shinbone, and the back of the kneecap. This is a slippery substance that helps your knee bones glide smoothly across each other as you bend or straighten your leg.

Meniscal cartilage (meniscus)

These are two wedge-shaped pieces that act as shock absorbers between your shinbone and thighbone.

The medial meniscus is on the inner side of the knee joint.

The lateral meniscus is on the outer side of the knee.

The meniscus helps to cushion and stabilise the joint, which is why they are tough and rubbery. When people say they have torn cartilage in the knee, they are usually talking about torn meniscus.


These connect muscles to your bones.

A healthy knee joint with no damage to the bone, cartilage or meniscus.