These are terms commonly used in knee arthroscopy. To understand what they mean we need to understand some basic anatomy of the knee. The menisci (plural of meniscus) are 2 c-shaped rubber gaskets that serve as shock absorbers to the knee (see below).
They are like rubber gaskets in your car in terms of function and in terms of how they feel– like pieces of rubber. Unfortunately, like rubber, as they age, they lose water content, become more brittle and can fissure and crack. The small tears can propagate and form a larger tear which can become a flap of tissue that gets stuck between the femur and the tibia, causing pain. This flap typically causes pain on flexion and twisting and in some instances can lock the knee up completely.
Most tears are degenerative in nature, ie. the rubber gets weak and a twisting injury can cause a larger tear and flap formation. In certain instances, tears can also occur in healthy meniscal tissue as well.
The treatment of meniscal tears is determined by the size, orientation, and location of the tear. If at all possible the surgeon will always attempt to repair the meniscus tear rather than to remove any meniscal tissue. Unfortunately, this is not usually possible and only about 15% of tears are repairable. The meniscus only has a blood supply in it’s outer third (the red zone) which is a little larger the younger you are.
Unfortunately, most tears occur in the inner two thirds of the meniscus in the avascular (white) zone and thus don’t have blood supply available to heal. The best treatment in this instance is to resect only the torn fragment of the meniscus which is causing the mechanical catching and locking. This doesn’t affect the long term shock absorption of the knee as that torn fragment was already effectively lost to the knee as a shock absorber anyway. It does however, eliminate the pain and restore function. An informative video can be viewed in our multimedia patient education section.
Repairable meniscal tears are usually in younger patients, are located in the red zone or red-white junction of the meniscus, and are usually vertical in orientation. These are often associated with ligamentous injuries (such as an ACL tear) and repair in these cases is usually more successful. Repair is performed with sutures, usually an all-inside arthroscopic technique and influences post operative rehabilitation. Repair is always the first option when possible as it can eliminate the symptoms but also restore the meniscus to its full glory as a shock absorber.
“Chondro” is the Greek word for cartilage and “plasty” means “to change”. Thus, chondroplasty refers to smoothing or trimming damaged articular cartilage in the joint. The articular cartilage is the slippery smooth covering of the ends of the bone which allows the bones to slide smoothly past each other [insert picture here]. This is similar to tread on a tire or teflon on a frying pan. When the articular cartilage is worn away bare bone can be exposed leading to painful sticking, catching, and rubbing. Also, flaps of the articular cartilage can develop leading to mechanical catching symptoms. Thru the arthoscope, we can smooth these rough surfaces, leading to better function for the knee. Unfortunately, it is not in our power yet to reverse arthritic damage–however research is ongoing.