An essential piece of knee anatomy, the meniscus absorbs the shock of impact to the knee with every step. This fibrocartilage ring protects, stabilizes and nourishes the joint. Without it, the bones and cartilage of the knee are subject to added stress and often experience degeneration over time. The breakdown of the knee joint due to the absence of the meniscus is referred to as meniscal deficiency. This condition can contribute to the onset of arthritis and/or can cause the misalignment of the bones of the knee joint.
Causes & Symptoms
Meniscal tears are the most commonly occurring knee injury. Because of the essential role of the meniscus, repair is always preferable to removal of a torn meniscus. However, in some cases, repair is not attainable and an arthroscopic procedure called a partial or total meniscectomy is used to remove part or all of the meniscus after it is damaged.
The history of previous surgery on the knee is usually the cause of meniscal deficiency. Some patients do not experience any problems following the removal of a torn meniscus, but for others, symptoms begin to set in after several years of living without the shock absorbing aid of the critical fibrocartilage ring.
Patients complain of knee pain in the area where the meniscus was removed. They often experience swelling, and at times also report a "locking" sensation, which occurs when the remaining part of a partially removed meniscus gets wedged in between the bones of the knee. Symptoms usually worsen with increased activity.
In addition to performing a physical examination of the affected knee, an orthopaedic physician may also order one or more of the following tests:
MRI: may be used to confirm the absence of the meniscus and look for associated knee injuries, such as ligament damage
X-ray: can provide helpful information about the alignment of the leg bones as well as the presence of arthritis in the joint
Bone scan: looks at the level of stress being sustained by the bones where the meniscus is missing
For patients diagnosed with meniscal deficiency, there are usually two potential treatment options. In younger, active patients in whom the diagnosis has been made early enough to potentially prevent arthritis, meniscal transplant surgery is preferred.
However, for older patients with meniscal deficiency that has already produced arthritic degeneration, total joint replacement is often the right option.