In sports medicine, we don’t just treat athletes. Sports medicine is the care of anyone who is active, and sports medicine specialists have a goal of keeping you moving. Your moving may be sports, it may be recreation, or it may be simply walking. And we use every tool available to keep you moving.
What is cartilage?
Cartilage is the lubricant that allows you to move. Each joint has cartilage. Cartilage almost has the consistency of a coconut. It’s precious, it’s soft, it’s irreplaceable. When you have a cartilage injury, or when you have a joint that’s “bone-on-bone”, you’ve lost the cartilage. Losing cartilage is like losing the white part of the inside of the coconut and just having the shell. Once you start to lose cartilage, you can’t replace it. We have techniques to try to restore cartilage or to prevent the loss of cartilage, but it doesn’t make it original.
The best analogy I give, outside of the coconut, is that your cartilage is sort of like the surface of a road. It allows you to move. The surface needs to be smooth. When you start to lose the original surface of the road, due to wear-and-tear or an accident, it needs to be fixed – just like when you start to lose your cartilage, due to wear-and-tear or an injury.
For example, think of a pothole in the center of the road. The road around the pothole is pristine, but the pothole is going to cause problems if you drive over it. You may be able to drive your car around the pothole and avoid it, while other times you may not be able to avoid driving over it and see effects. The cartilage injury is like the pothole. Depending on where the cartilage injury is, you may or may not have symptoms.
Where do cartilage injuries come from?
You can get cartilage injuries from a specific event, from overuse, or from another injury. One of the most common ways in sports medicine to see a cartilage injury is after an ACL tear. An ACL tear is an injury to the ligament and the knee is unstable. You can then injure either the hard cartilage or the soft cartilage, which in the knee we call the meniscus, and then you become symptomatic from that cartilage injury.
In kids, we sometimes see cartilage injuries from overuse, a condition called osteochondritis dissecans. It usually heals with activity modification without any surgery needed.
Some cartilage injuries are associated with the alignment of your joints. Certain conditions where you have extra pressure on the bone or extra pressure on the cartilage can lead to cartilage injuries. These osteochondral defects may be treated with surgery and may involve correcting the bone and bone alignment.
Cartilage injuries can come from repetitive stress, and may be a cause of pain without a known injury. As long as the remaining cartilage is intact, we isolate these injuries and specifically call them cartilage injuries.
How do cartilage injuries and arthritis intersect?
Arthritis is inflammation of cartilage. However, it is very different from the isolated cartilage injury.
Arthritis may include post-traumatic arthritis, where arthritis develops in the joint decades after a previous injury. However, arthritis is usually caused when your body creates inflammation that targets ligaments, tendons, cartilage or bone. For example, rheumatoid arthritis, psoriatic arthritis, gout, and pseudo gout are all variations of this. An infection such as Lyme disease may also cause arthritis. Other factors such as obesity and diabetes can lead to increased inflammation.
With all these causes, the cartilage has many sources of inflammation. It’s like a road that is covered with potholes: you can’t avoid just one pothole. If you drive down the road, you may drive over multiple potholes on any given day. It doesn’t matter the speed or how you drive the car – the potholes are unavoidable.
How do you treat cartilage injuries and arthritis?
Conservative treatment for arthritis is the same idea as driving along the road full of potholes as long as you can. You can make yourself more comfortable using medications that can treat things like rheumatoid arthritis, gout or infections, as well as anti-inflammatories, weight loss, physical therapy, exercises, and sometimes braces.
A surgical treatment for arthritis is the same idea as entirely resurfacing the road filled with potholes. You can’t successfully patch the individual potholes, so you resurface the entire road – or for arthritis, you can get a joint replaced.
Treating cartilage injuries is a little more complicated. Treatment options depend on the size and location of the injury, as well as your alignment. I always have the patient get x-rays because the x-rays give us a good sense of how much the cartilage injury involves the bone, a good sense of the presence of arthritis and a good sense of ways that we can treat these cartilage injuries.
Often we repair a cartilage injury, preserving as much of your cartilage as we can. For some conditions where the bone is loose, we try to internally fix cartilage injuries by holding the bone stable.
Other times we try to regenerate cartilage, and use techniques to provide a healing response. Dr. Richard Stedman pioneered a technique called microfracture, where you drill the bone below the cartilage to stimulate a healing response.
Finally, sometimes we have to reconstruct the cartilage. We’ll use your cartilage from another location or cadaver cartilage that has live cartilage cells and fill in the defects with the new cartilage. Reconstructing cartilage often means that you’re able to put pressure on it and use your joint sooner.
Frequently Asked Questions
What can be done for thinning cartilage in the knee? Are there supplements that can help?
Some areas of the knee start to get early cartilage thinning, and therapy and strengthening exercises can help unload the cartilage. Many times it’s cartilage overload that leads to the thinning, although it may be genetics or may be multifactorial and more medical in nature.
It's challenging to regulate the different types of available supplements that exist. Studies often are inconclusive but I tell patients as long as it doesn't interact with other medications, you can certainly try different types of supplements. In most cases, there are no supplements we would recommend.
How young is too young for surgery to repair or reconstruct cartilage?
It depends on where the injury is, how severe the injury is, and the patient’s age. When children get osteochondritis dissecans and the growth plate is open, there’s a high likelihood that the cartilage can heal itself with conservative treatment. However, there are instances where the injured fragment may become unstable or loose, which would lead to arthritis in the future if not treated with surgery.
ACL injuries are becoming more prevalent and in younger patients, and some of those patients may have cartilage injuries as well. If there’s other injuries associated with the cartilage like post-traumatic injuries or patellar dislocations, they may need cartilage surgery. I’ve worked on young teen patients, as young as 13, for this type of surgery.
The specifics of the injury matter more than the age of the patient. Will the injury heal on its own? Will it get worse with time?
How do you tell if it's a cartilage injury or arthritis or something else like a rotator cuff tear?
Determining the nature of these injuries starts with the history: talking with patients and trying to understand how their joint hurts. What activities do they do? What are they not able to do? What treatments have they tried? Talking to them helps narrow down the treatment options.
X-rays are extremely valuable. Some conditions show changes on the x-ray even before we order an MRI, which is always helpful in determining what condition it is.
The MRI determines how we treat it. MRIs look at ligament, tendon, cartilage and bone. Ligament connects bone to bone. Tendon connects muscle to bone. If you have an unstable knee, you’ve often torn a ligament and we can look for the bone bruise patterns from that ligament injury. We’re able to discern if an injury is older or newer based off of how the bone looks. For tendon injuries, we’re able to see on an MRI if the tendons are retracted. When a tendon tears, the muscle pulls back on the tendon. A recent injury will have the tendon not pulled back far, while injuries that occurred a while ago will have the tendon more retracted.
Do stem cells or PRP help cartilage?
Yes, they can. PRP stands for platelet-rich plasma. It's a process where your blood is spun by a centrifuge and certain elements that help stimulate inflammation are separated. The PRP is then injected into the joint with the problem.
PRP is among several different biologic techniques, including some types of stem cells, which are used to provide relief of symptoms. We use it as an additional treatment to help with symptoms and help promote a healing response, especially at the time of surgery.
Some good evidence suggests that compared with cortisone, PRP provider longer relief with fewer side effects. As a result, we’ve increased its use as an option to help manage symptoms. However, PRP is not a cure for arthritis or for cartilage injuries. It can help with symptoms and sometimes allows you to either delay or avoid cartilage surgery.
PRP doesn’t always make sense if there’s an injury that needs to be repaired or reconstructed, but it’s an option for many patients and I encourage patients to explore all options.