Video: Treating Joint Injuries

Chronic pain has been going on for at least 2 or 3 months without an adequate explanation. Maybe there's an injury in the past--even a long time in the past. But over time, there's been some damage inside the knee joint and then it becomes painful. Why does it become painful? Cartilage is a cushion in all of our joints. In the knee joint, it's about 3/16"" thick, and it covers, just like a tread, the entire knee surface on the femur side and the tibia side. We in fact have that same cartilage in our knuckles, but in our knuckles, it's only paper thin because we don't walk on our knuckles. If you were to try to walk on our knuckles, it would hurt. So if there was a zone inside the knee joint that becomes damage, even the size of a quarter, then, whenever that piece of the knee joint is bearing the weight, it hurts. If the cartilage is gone, the force is going right to the bone, so it hurts with just about every step you take.

The source of chronic pain in the knee really depends on the circumstances--whether there's an injury in the past, how old you are, and if you have arthritis, it can cause chronic pain. All arthritis is a wearing away of the cartilage surface, either in multiple places in the knee, throughout the entire joint, or perhaps in a young person that's had significant trauma, playing football, soccer, or basketball, where they've had an injury to one spot of the cartilage in their knee. It can be as small as the size of a quarter or a fifty-cent piece. There are many things, depending on what's happened to you, luck, or genes that can cause a loss of cartilage in various places in the knee, which can cause chronic pain.

For someone who has a cartilage injury, we always start with the simplest and most conservative option. Starting with the use of anti-inflammatory medicine like Napacin, Motrin or Celebrex, and relative rest. We'll often have someone start some physical therapy. Physical therapy is mainly to make the joint much stronger, but to do so in a very protective fashion. If we said, ""just go to the gym and work out,"" you might work out in a way that actually aggravates the damage. A physical therapist can help you do the right exercises, to get it strong, without aggravating it. Sometimes that's enough to simply improve the situation. It may not cure it, but it may improve it so you do well for a while.

Then, if that doesn't work, we have to look into it a little further. We'll typically get an MRI scan of your knee, and it can show us the most accurate picture of the inside of your knee- almost as good as doing surgery and looking at it from a surgical point of view. X-rays are done, which are nothing more than a bone shadow. They don't see a lot of the things that are important inside a joint, particularly a knee joint. MRIs let us see the joint surface, cartilage, meniscus cartilage, and ligaments such as your ACL, PCL, and other ligaments that help hold a knee together.

For someone with a more significant, larger cartilage defect in their knee, like a crater in the joint surface, we have to go to more advanced procedures. Until the mid 1990s, there was nothing we could do for that. But for people who are young -- from teens until early 50s, we can transplant your own cartilage back into the defect. How this is done is, we do arthroscopy, a microsurgery about the size of a pencil, attached to a TV camera. We can examine the entire inside of the knee joint, we can treat areas, we can remove damage or degenerated cartilage, we can take out damaged parts of meniscus cartilage. Then, we can take a biopsy the size of two tic-tac candies. We take a couple pieces about that big from a little zone in your knee where you don't actually bear weight. We send it to a lab in Massachusetts called Genzyme Corporation, and they can culture it and turn those islands of cartilage into 12 million cartilage cells. That comes back in the form of a liquid that looks like milk. It's hardly even a teaspoon, but in there are 12 million teeming cartilage cells. We do a surgical procedure in which we open the knee via incision. We got to the area whether the cartilage damage is, which looks like a crater, and clean out all the damaged cartilage. It's surrounded by good, nice quality cartilage. We take a membrane that naturally occurs over your bone and harvest that, like doing a skin graft. We can also use a commercially-available membrane. We sew the membrane with sutures the size of a hair, all the way around that defect. It's very laborious, and it takes time to do it, but after the membrane is sewn over the top of that defect, we leave a space to inject the baby cartilage cells in there. The cells adhere to where the bone is and start to grow. They grow over the course of several months and eventually replace all that area that was damaged. You go from a zone where there's nothing, to a nice, fresh cartilage surface that's very long lasting.

The best candidate for autologous cartilage transplant, where your own condracite, which means baby cartilage cells are transplanted, is somebody who doesn't have arthritis. Arthritis is the cartilage through out the entire joint starting to degenerate, thin, and go away. There's no good treatment for that, unless it's bad enough to do a knee replacement. If you have one focal area, the size of a nickel or quarter, that's a defect, we can replace that cartilage as long as it's not arthritis, and as long as you're not too old. Generally, as you start to get into the late 40s and 50s, the results are not as good. Our ability to regenerate seems to go away. The younger you are, the more successful it is. Someone in their 20s tends to do extremely well. We've done cases with people into their late forties who have done well.

Cartilage is a very fragile substance. It has a fragile membrane with the baby cartilage underneath, so we need to protect that. People are using crutches from between 6 weeks to 3 months, depending on how big the defect is. If it's very small, people can start walking on it with partial weight almost right away. On the other hand, if it's a very large defect or several big defects, we're going to protect that for a lot longer. They might need crutches for as long as 3 months. But they can get around, put a little weight on it, and still protect it.

The cartilage transplant, after it starts to grow out, has the consistency of jello by 3 months. By 7 months, it has the consistency of window putty. And by a year, it's pretty solid, like the surrounding cartilage.

We've had a lot of questions about partial knee replacements. We can best answer that by first saying what a total knee replacement is. A total knee replacement is a replacement for the entire femur surface and the entire tibia surface because it has become very arthritic. We'll often replace the backside of the kneecap as well. If someone is relatively younger for arthritis, usually in their early 50s, and the arthritis only affects one side, we can do a partial knee replacement. This is not a very common situation, but if it exists, we can take care of it. In that situation, we can do a smaller incision and replace putting metal parts on the femural side, and metal or plastic part on the tibial side. Some partial knee replacements are bigger, so we can replace the valley the kneecap rides in, as well as the medial condile of the femur. The person who'd be a candidate for that is relatively older. If you're less than 50, we're going to think more of the cartilage transplant. If you're older than 50, it could be a partial knee replacement or a total knee replacement, depending on how extensive the knee damage is. Some people ask why only replace part of the knee? Why not replace the whole knee because the rest may go bad, too. That's a question we often wrestle with. If there's any doubt, and if we think the cartilage is looking not so good on the outer parts, we'll replace the entire knee. If someone's in a situation where, clearly, the cartilage is badly damaged, and it's good in other areas, the advantage is to do a lesser invasive surgery, with a smaller cut and faster recovery.

For a knee replacement, the recovery is shorter than for cartilage transplant. For cartilage transplant, we are waiting for your cells to very slowly grow and fill in a defect. For a knee replacement, we're taking the damaged cartilage and replacing them with metal and cartilage parts. There's no cartilage to heal, it's simply a new bearing surface which is metal and plastic. Of course, the ligaments, the skin, and the tendons have to heal. After a knee replacement, people are using crutches for a few week and then switch over to a cane. It varies how long that lasts, depending on how strong you are to begin with, how old you are, and other factors such as pain. Some people are able to go back to work in only 6-8 weeks, and others may need to weight 3 months or so before going back to work. A partial knee replacement has less invasiveness, less pain, and the recovery time is shorter. They may need to use crutches and then a cane for only about 3-6 weeks.

Studies have shown that knee replacements last somewhere in the neighborhood of 15-20 years, depending on how rough patients are on the implant. It's clear that if somebody has a total knee replacement at age 50, there's a better than even chance that in their mid-60s, they may need to have a revision or a new knee transplant, because the bond between the metal and the bone can, over a long period of time, start to weaken and become loose. It's painful when that happens. With a cartilage transplant, it's your own cells, they've grown in and completely covered the defect. There's nothing to loosen from anything else. It's simply your own cartilage. So as long as the surrounding cartilage is good, and you have good healing potential, the duration of that is indefinite.; That's why we tend to wait and do a knee replacement for as long as possible, so it decreases the needs to have a revision later on in life. If you have your first knee replacement when you're 70 years, old, by the way people's longevity is, that's probably the only one you need. Or, if you have good genes and live long enough, we can do that knee replacement and have it do well.