Earlier this year, we wrote a piece on “inside knee pain” and suggested seven potential causes.
One of those possibilities was a chondral injury. This is a problem that can affect just about anyone, since it can be caused by wear-and-tear damage through age (osteoarthritis). But we also see it in young people who get injured during sport. So what exactly do we mean by chondral injuries, and how are they treated?
What does chondral mean?
The word “chondral” refers to cartilage. Cartilage, as you probably know, is the protective material that reduces friction in your joints and keeps them running smoothly. But there are different types. A chondral injury usually means damage to the articular cartilage, which is the shock-absorbing tissue that lines the ends of your thighbone (femur) and shinbone (tibia).
How do people damage it?
You could hurt your articular cartilage in a few different ways. One is through wear and tear, as mentioned, when that surface material begins to break down and fragment. A common reason for younger people is trauma (ie an accident). This could be a major blow to the knee, a nasty fall or a direct-impact or twisting injury during sport. Chondral issues can also happen in conjunction with other serious knee injuries, such as ACL or kneecap damage.
What do the injuries feel like?
Aside from pain, a common symptom following a traumatic chondral injury is persistent swelling around the knee. With a sporting injury, the initial event might be relatively innocuous: a twist or a bump, something you’d expect to shake off in a day or two. But then the knee swells up and the pain persists and seems out of proportion to the size of the injury.
What’s actually happening inside the knee?
We usually refer to chondral damage as a lesion. Basically, the impact assaults and even breaks up the surface of the cartilage. This can leave the bone underneath exposed. It could also mean that part of the cartilage literally shears off and floats in the joint’s synovial fluid. These chunks of free-floating cartilage are known as loose bodies, and they have the potential to cause mechanical issues like knee locking, when the broken cartilage gets caught between the joint bones. For more detail, see: What are loose bodies in the knee – and what can you do about them?
How would you know it’s chondral damage?
Chondral injuries can be quite difficult to detect, because they often won’t show up on x-rays. So we’d probably look to do an MRI scan, which would give us a better view of the tissues in your knee. If you do have a cartilage lesion, the main thing we’ll be assessing is the extent of the damage. How big is it? Is the cartilage still in place? Or has it broken away and started to cause other problems?
How can you treat it?
This really depends on the answer to those questions above. If the cartilage is in situ and you can bear weight on your knee, it may be best to rest and see how it heals on its own. Although the body can’t regrow articular cartilage, it does have the ability to generate fibrocartilage, which can have a protective impact within the damaged joint. You can help this by doing the first-aid management basics of RICE (rest, ice, compression and elevation). On the other hand, if the cartilage has broken away and formed a loose body, we may need to intervene with keyhole surgery (arthroscopy).
What do the surgical options look like?
Again, it depends on the damage. Sometimes the best approach is simply to remove the loose bodies and see how the knee heals over the coming weeks and months. Younger knees with good blood supply to the focal area of damage, for example, tend to have quite a good potential for healing. If the damage is down to the bare bone, however, we may look at microfracture, which is a technique that encourages the joint to create fibrocartilage.
What happens if the articular damage is more extensive?
If the lesion is very large – generally meaning greater than 2cm x 2cm – there are other avenues to consider. These include techniques like chondral resurfacing, matrix-associated implantations, allografts and cartilage transplantation, and we would usually look to refer these cases to a specialist surgical centre. Fortunately, though, this type of damage is pretty rare. For the most part, chondral injuries can be tackled conservatively, or with less invasive keyhole surgery.