Diagnosing articular cartilage damage can be challenging because it cannot be confirmed through a physical examination. Also, the symptoms are often similar to other types of knee injures, such as a sprain or a damaged ligament.
Magnetic resonance imaging (MRI)
Magnetic resonance imaging (MRI) scans are often used for detecting cartilage damage. MRI scans use strong magnetic fields and radio waves to produce detailed images of the inside of your body.
However, access to MRI scans is limited in many primary care trusts (PCTs), and patients with life-threatening conditions are usually given priority. You may have to wait a considerable amount of time before you can have a MRI scan.
Arthroscopy
If you have articular cartilage damage, another option is to have an arthroscopy. This is a form of ‘keyhole surgery’ where the surgeon makes a small cut in your joint. They will then use an arthroscope (a small, flexible tube with a camera on the end) to look inside your joint.
Arthroscopies are often carried out under local anaesthetic where painkilling medication is used to numb the joint. This means that you may not have to spend the night in hospital.
Read more about having an arthroscopy.
Grading cartilage damage
After having an arthroscopy, your surgeon should be able to determine the extent of the damage. Cartilage damage is measured in grades from 0 to 4, where grade 0 indicates no damage and grade 4 indicates severe damage. The grades are described in more detail below.
- Grade 0: the cartilage is undamaged and intact
- Grade 1: the cartilage has some blistering and softening
- Grade 2: there is a minor defect (less than 50%) in the cartilage, or minor tears in the surface of the cartilage
- Grade 3: there is a deeper defect (more than 50%) in the cartilage
- Grade 4: the cartilage has lost all of its thickness, leaving the bones of the joint exposed
The grading of cartilage damage does not always correspond to the level of pain you feel.
For example, one person may feel severe pain as a result of grade 1 cartilage damage, whereas another person who has extensive damage may experience very little pain.
Therefore, a more important consideration is how the damaged cartilage affects the underlying structure and mechanics of the joint that it supports.
