When you think about knee injuries, what comes to mind? For most people, it will be things like fractures, dislocations and ligament tears.
It’s true, of course, that a fall, twist or similar accident can lead to exactly this kind of damage. But there’s another, related type of injury that tends to get overlooked, and that’s cartilage damage.
The cartilage we mean here is articular cartilage. Not the thick meniscus pads that sit within the knee joint but the thin, hard substance that covers bone endings. The function of articular cartilage is to reduce the friction between bones as they slide against each other. This gives us smooth, pain-free movement. It’s a very tough substance. But it’s not indestructible.
Two types of cartilage damage
In essence, there are two ways we can damage the articular cartilage in our knees:
Degeneration – this is the long-term wear and tear that slowly depletes the cartilage coating: we call it osteoarthritis
Trauma – this is the sudden, one-off impact that rips up part of the cartilage surface (or a repetitive action that leads to similar damage): this is known as a chondral injury
Traumatic cartilage damage can happen right alongside the injuries we mentioned at the start of this piece. A nasty twist that pushes your ACL to breaking point, for example, could also harm the nearby articular cartilage.
Several nasty symptoms
So what might happen if you tear your articular cartilage? One possibility is that the smooth surface becomes disrupted or broken up. The frayed cartilage begins to nick and rub within the joint, resulting in symptoms like:
- A “catching” sensation when you flex the knee or bend down
- Stiffness and swelling as the knee produces fluid to protect itself
- A crackling and popping sound when you move (crepitus)
Another possibility is that little pieces of torn cartilage break away from the bone. These fragments of cartilage are known as “loose bodies”. As they move freely within your knee, they can become caught in the joint, causing the knee to lock up.
The other problem with cartilage trauma is that, left untreated, it can lead to the degeneration we mentioned earlier – in other words, to the onset of osteoarthritis.
So what can you do to limit and treat the damage? The key medical approaches look like this:
Approach 1: Non-surgical
You may have heard that articular cartilage can’t properly regenerate after it has been damaged. The reason for this is that, unlike many other parts of our bodies, it lacks a blood supply (it’s avascular). That said, the body does have a limited capacity to generate some fibrocartilage after injury. Fibrocartilage is a type of cartilage that’s found in places like the joint capsules and spine. We sometimes see evidence of this regeneration when we investigate patients’ knees during keyhole surgery. Little patches of material start to form in the lesions on the articular surface. While fibrocartilage doesn’t have the same qualities as the original (hyaline cartilage), it’s better than none.
Sometimes, then, the best course of action is to treat the injury conservatively and let the recovery take its course. This helps to relieve those initial symptoms prevent further erosion of the healthy cartilage. Conservative treatments can include things like:
- Resting from normal activities
- Ice treatment
- Anti-inflammatory painkillers such as ibuprofen, if you can take them
- A knee brace
- Strength and stabilising exercises from a physiotherapist
Approach 2: Surgical
After investigating the injury, however, it sometimes becomes clear that conservative treatment won’t be enough on its own. What then? Depending on the type of damage, there are a few different options. We’ll look at some of these in depth in future blogs, but here’s an overview:
Debridement – this is where the surgeon trims away the frayed cartilage to create a smooth surface
Microfracture – this is a technique that introduces tiny holes in the bone to stimulate the formation of new fibrocartilage
Loose body removal– this is a keyhole operation to locate and remove the broken chunks of cartilage
Cartilage grafts or mosaicplasty – this is a procedure that involves taking a plug of healthy cartilage from a non-weightbearing part of the joint and transplants it into the damaged area
ACI or MACI – this is where cells from healthy cartilage are removed, grown in a lab, then implanted into the damaged area
OCD fixation – this is an operation to pin down a lesion of bone or cartilage that has separated from the joint
Focal surface replacement – this procedure replaces a portion of the joint surface, avoiding the need for a larger partial knee replacement
The bottom line
Once damaged, articular cartilage is difficult to restore. But many patients find that, after diagnosis, it can be managed quite effectively with non-surgical treatment, and they can return to regular activities. Where pain and other symptoms persist, though, there are lots of things we can do to alleviate the problems and prevent further damage. A cartilage injury can be frustrating, but it doesn’t have to be a life sentence.
If you’re worried about your knees – or experiencing pain, stiffness or other problems in your joints – it’s always a good idea to get them properly looked at. You can book an appointment with Mr Bailey through our website, or call us direct on 01962 826107. We’ll be really pleased to get you the help you need.
