Basic Knee Anatomy
On the WebMD message board the following post caught my eye:
"I have been hearing a scraping sound in my right knee every time I sit down or climb or go down stairs.... A couple years ago, I had alot of pain in that knee and had special x-rays done, and was told the meniscus was starting to wear down."
Here are a few anatomical tid-bits:
The knee joint is made up of 2 bones that ALWAYS touch each other: the femur (thigh bone) and the tibia (leg bone). The femur and tibia both have their ends covered with a 3/8" of cushion called cartilage. Cartilage is part of the femur and tibia so technically since the cartilage surface always rub against each other then the femur bone and the tibia bone technically rub against each other.
If this surface cartilage rubs away then the bone ends rub against each other. This sometimes causes pain, but not all the time.
The knee is unique in that there is a second type of cartilage that is there (just when you thought you knew it all...) This cartilage is called the meniscus cartilage. I tell my patients that it is called the "meniscus" cartilage. I do not call it a pancake cartilage as I have heard other refer to it because I cannot eat it and it tastes like crap with maple syrup. Also it does not look like a pancake, it looks like the letter C.
The meniscus cartilage sits on top of the tibia and is actually attached to the tibia. YOU DO NOT WALK ON THE MENISCUS CARTILAGE. There is a meniscus cartilage on the inside of your knee (the medial meniscus) and another on the outside (the lateral meniscus). Looking down on the tibia, one meniscus looks like a C and the other looks like a reverse C. When they come together they may an oval and effectively appears like a ring.
The meniscus cartilage therefore is more like a ring around the knee. It can be likened to a rubber gasket on a faucet. When you are sitting or standing with your knee straight the meniscus cartilages are hanging out around the edges of the ring, minding their own business. As you either bend your knee or twist it while walking the meniscus cartilages (the ring) engages and acts as a secondary support - just as you would expect from a ring support.
Sometime that meniscus ring can tear, just like a gasket on a faucet can tear. Since meniscus cartilage has NO NERVE ENDINGS it should not be painful. The problem is that when a meniscus tears in the center while there are no nerve endings there are many nerve endings at its attachment.
Think of it like a skin tag or earring. If you have a skin tag and look at it, it does not hurt. If you pull on it, ouch! Same with an earring. It looks nice, but pull on it -- WOW!. Based on this, the meniscus tears with a little tag of cartilage and when you walk or twist the tags gets caught between the femur and the tibia and pulls on the attachment. This causes pain and swelling.
This is why arthroscopic surgery is so successful for a meniscus tear. We have learned over the years that we only need to remove the torn "tag" part of the meniscus and we can leave the rest behind. This removes the pain almost immediately. More importantly, the more meniscus you can keep behind the less chance you have in developing arthritis at a later age. Removal of the entire meniscus leads to arthritis of that part of the joint eventually.
If you are interested in some excellent drawings about what I just explained you can go to www.walkandmove.com and click on the patient education section. This will take you to medical material produced by an excellent education company (Medical Multimedia Group). The material is called eOrthopod. You can easily access any of the material on my site for free.
Dr. K.
Related Topics: Is Chronic Knee Pain Limiting Your Life?, Common Knee Injury Strikes Women More than Men
Technorati Tags: meniscus, arthroscopic surgery, knee injury
"I have been hearing a scraping sound in my right knee every time I sit down or climb or go down stairs.... A couple years ago, I had alot of pain in that knee and had special x-rays done, and was told the meniscus was starting to wear down."
Here are a few anatomical tid-bits:
The knee joint is made up of 2 bones that ALWAYS touch each other: the femur (thigh bone) and the tibia (leg bone). The femur and tibia both have their ends covered with a 3/8" of cushion called cartilage. Cartilage is part of the femur and tibia so technically since the cartilage surface always rub against each other then the femur bone and the tibia bone technically rub against each other.
If this surface cartilage rubs away then the bone ends rub against each other. This sometimes causes pain, but not all the time.
The knee is unique in that there is a second type of cartilage that is there (just when you thought you knew it all...) This cartilage is called the meniscus cartilage. I tell my patients that it is called the "meniscus" cartilage. I do not call it a pancake cartilage as I have heard other refer to it because I cannot eat it and it tastes like crap with maple syrup. Also it does not look like a pancake, it looks like the letter C.
The meniscus cartilage sits on top of the tibia and is actually attached to the tibia. YOU DO NOT WALK ON THE MENISCUS CARTILAGE. There is a meniscus cartilage on the inside of your knee (the medial meniscus) and another on the outside (the lateral meniscus). Looking down on the tibia, one meniscus looks like a C and the other looks like a reverse C. When they come together they may an oval and effectively appears like a ring.
The meniscus cartilage therefore is more like a ring around the knee. It can be likened to a rubber gasket on a faucet. When you are sitting or standing with your knee straight the meniscus cartilages are hanging out around the edges of the ring, minding their own business. As you either bend your knee or twist it while walking the meniscus cartilages (the ring) engages and acts as a secondary support - just as you would expect from a ring support.
Sometime that meniscus ring can tear, just like a gasket on a faucet can tear. Since meniscus cartilage has NO NERVE ENDINGS it should not be painful. The problem is that when a meniscus tears in the center while there are no nerve endings there are many nerve endings at its attachment.
Think of it like a skin tag or earring. If you have a skin tag and look at it, it does not hurt. If you pull on it, ouch! Same with an earring. It looks nice, but pull on it -- WOW!. Based on this, the meniscus tears with a little tag of cartilage and when you walk or twist the tags gets caught between the femur and the tibia and pulls on the attachment. This causes pain and swelling.
This is why arthroscopic surgery is so successful for a meniscus tear. We have learned over the years that we only need to remove the torn "tag" part of the meniscus and we can leave the rest behind. This removes the pain almost immediately. More importantly, the more meniscus you can keep behind the less chance you have in developing arthritis at a later age. Removal of the entire meniscus leads to arthritis of that part of the joint eventually.
If you are interested in some excellent drawings about what I just explained you can go to www.walkandmove.com and click on the patient education section. This will take you to medical material produced by an excellent education company (Medical Multimedia Group). The material is called eOrthopod. You can easily access any of the material on my site for free.
Dr. K.
Related Topics: Is Chronic Knee Pain Limiting Your Life?, Common Knee Injury Strikes Women More than Men
Technorati Tags: meniscus, arthroscopic surgery, knee injury
8 Comments:
I always enjoy learning about my knee problems and I enjoyed this blog. I went to your website and accessed the information about patellofemoral problems from eOrthopod. I learned some more about the surgery I need should I choose to go that route. Luckily, right now I can control the pain with the excerises and taping I learned in physical therapy. I am only in my early 40's and have had grinding and popping in both of my knees for 20 years. However, the pain only started 2 years ago. Thanks for the information.
Thanks for the infomation regarding the meniscus. I had some of mine removed that was "catching" underneath the kneecap. Now if only that fixed the problems.
This is not a comment but a question about surgical intervention for chronic heel spurs. How is the heel spur removed? Is it cut even with the bone of the heel or does it have a root that will require deep surgical removal and why is it that the heel spur is not removed more often especially since they will continue to cause chronic inflammation as long as they are present even when wearing orthotics. It doesn't make sense to treat the fascitis and not remove the offending cause!!!
I am an ageing athlete and have developed pain on both legs @ the laterial epicondyle - the slightly protruding bone at the laterial (outer) side of each leg. Can anyone expl,ain what might be the cause?
Chris
one year on viaxx now naproxin and celebrex , my little finger , knits, tole have redness ,swallowing and the pain in huge I'm 31 years .
I had miniscus surgery 12 weeks ago and still have a lot of pain and swelling. I try to stay off my feet as much as possible. My doctor told me it was just fluid and would go away. Is this normall with this kind of surgery?
Thanks!
Anonymous said
I have be diagnosed with Chondromalacia of the Patella. I went to the ortopedic doctor. He stated that there are bone spurs on my left kneecap as well as the thigh being weak. He suggested three things 1. take Glucosamine daily 2. Water Aerobics 3. Injections done to the left knee. No more walking as a exercise. I just wanted to know if surgery should be an option down the road?
I had surgery to remove the lateral meniscus on my right knee 6 months ago. The pain is worse now than it was before surgery and my entire knee swells and is painful. Celebrex does not help and it is almost impossible to stand or even sit for an extended period of time. I've tried ice but it is still very painful. I can ride a stationary exercise bike but that does not help the pain - it is constant and wakes me up a night.
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