Alan M. Reznik, M.D.
The Medial and Lateral meniscal cartilages are gasket like cushions in the knee. Positioned between the femur and tibia, they distribute the weight transferred from the larger femur above to the smaller tibia below. The Menisci also help with the stability of the knee joint. Healthy Menisci convert the relatively flat tibial surface into a more stable shallow socket
Meniscal tears can occur in any age group. In younger people, the meniscus is a fairly tough and rubbery structure. Tears in the meniscus usually occur as a result of a forceful twisting injury or with hyperflexion of the knee. In younger age groups, meniscal tears are more likely to be caused by a sports injury. In more mature individuals, it can occur with squatting down, twisting or a fall. In older individuals, the meniscus can be weaker and easier to tear. Sometimes meniscal tears can occur as a result of a minor injury, even from the up and down motion of simple squatting. Degenerative tears of the meniscus can also be seen as a part of osteoarthritis of the knee, gout and other arthritic conditions.
In many cases, knee pain is the most common complaint and the patient cannot recall one clear associated injury that leads to the meniscus tear. The pain may be felt along the joint line where the meniscus is located. Sometimes the symptoms are much more vague and occasionally they involve the whole knee. If the torn portion of the meniscus is large enough, locking may occur. Locking simply refers to the inability to fully straighten the knee or loss of the ability to move the knee. Locking occurs when a piece of torn cartilage, or meniscus, is stuck between the bones (see the picture above). In other words, the meniscus is caught in the hinge mechanism of the knee. Once stuck, it will not let the knee straighten out or move completely. (To see Dr. Reznik's video, "The Locking Knee", go to Youtube.com/DrAReznik.)
Left alone, over time the locking and/or constant rubbing of the torn meniscus on the articular cartilage will cause damage or degeneration of the knee joint. As a result, the knee may also become swollen, stiff and tight.
Once a meniscus is torn, it won’t heal on its own. The tear can be treated safely with an Arthroscopic procedure that Dr. Reznik performs as an outpatient. It is often done under a light anesthetic with a local injection for post operative comfort. When the tear is repaired, Dr Reznik uses the arthroscope to place tiny sutures or stitches to fix the tear. Of the tears below the ones nearest the outer edge are more often repaired, depending on the overall condition of the cartilage. That is where the blood supply is best and the cartilage has the best chance of healing (the first, second and fourth images below). Radial tears (image eight below) can be repaired on rare occasions.
Locking, Buckling and Giving Way
By Alan M. Reznik, M.D., MBA
“Standing still, I turned to get something off a shelf behind me, and bam, my knee just went.” “Everytime I get up from a squatting position, my knee won’t straighten.” “Going down stairs, my knee gives out. I just don’t trust it.” Frequently, statements like these are the first clue that a patient has an unstable knee. So why does this happen, and what should be done?
The knee is the joint connecting the femur, the “thigh” bone, to the tibia, the “shin” bone. In the knee joint, the end of the thigh bone is rounded and the top of the shin is relatively flat. The two together are very much like a rolling pin sitting on a narrow table. Given even a small push, the rolling pin will fall off. That’s why the knee’s cartilage and ligaments are so important. They hold the two together and still allow the knee to bend and straighten smoothly. Without the ligaments and the cartilage we wouldn’t be able to run, jump, twist, turn, squat or pivot; and it’s when they are injured or not working properly we have problems.
The examples above are stories of locking, the knee gets stuck in one position and won’t move, buckling. The knee is made unstable by a twist or a turn, and giving way. The force of a routine activity causes the knee to stop supporting the body’s weight.
Locking, can be caused by a piece of torn cartilage (the meniscus) stuck between the bones. Until it’s pushed back into place the knee remains locked and often difficult to straighten. This can be both painful and disabling. If an examination is positive for signs of injury to the cartilage a tear may be the reason for the problem. A Magnetic Resonance Image, MRI, or a diagnostic arthroscopy, looking into the knee with a fiber optic telescope can show the cartilage tear so the problem can be treated properly.
Giving way, can be caused by a cartilage tear or a ligament problem. Here’s where the physician’s examination of the knee is key. Telling the difference can be difficult. This is especially true, if the knee is swollen or if it is painful, both common findings in a recent injury. Fortunately, there are specific clinical tests, parts of a good routine knee exam, to help us find the cause. Sometimes special instruments like the KT-1000 (a very sensitive knee testing device that allows us to measure small movements between the femur and the tibia) can help us decide if one of the major ligaments like the ACL (anterior cruciate ligament) of PCL (posterior cruciate ligament) is damaged.
Buckling, can be caused by cartilage problems, ligament injury or knee cap problems. The knee cap is part of the quads mechanism. This muscle and tendon unit allows us to kick, jump, and squat. It also prevents us from falling when going down hill or down stairs. The body can sense when the knee cap is going to hurt and frequently casues the quads mechanism to release or give (hence the term give-way) to protect itself and you from the pain.
Once your doctor makes the diagnosis, the treatment for these problems varies. They can include simple exercises, physical therapy, bracing, and arthroscopy (fiber optic, outpatient surgery.) The early correction of these mechanical problems can lead to a speedy recovery greatly reducing the risk of recurrence, future injury, long term problems, and early degenerative arthritis.
© 2008 The Orthopaedic Group, LLC Not to be reproduced without the express permission of the author