Arthroscopic surgical techniques are commonly utilized to diagnose and repair cartilage, tendon, and ligament damage within the knee.
The chondral surface of the knee is the articular, or coating, cartilage on the ends of the tibia and femur. Just like the white cartilage on the end of a chicken bone, we have the same white cartilage on the ends of our bones.
When this cartilage wears down (like the tread on a tire), this is arthritis, namely osteoarthritis. We all get osteoarthritis as we age. However, young athletic people can sustain an area of focal chondral damage from a sudden twisting injury to the knee. This can lead to a painful flap of cartilage that catches the knee. The cartilage on the end of the femur or tibia can peel away, much like an orange peel.
In an arthroscopic chondroplasty, these flaps or rough areas of cartilage catching the knee are smoothed with a motorized shaver smaller than a pencil. Attached to this motorized resector is suction tubing, which literally sucks up small torn fragments of articular cartilage after they are trimmed off.
Microfracture is a marrow stimulation technique that has been around for over 30 years. It is a relatively simple arthroscopic technique that is employed in certain cases to try to fill an articular cartilage defect. If there is a focal area of articular (or coating) cartilage loss seen on the end of the femur or tibia, where there is exposed bone, then this technique can be somewhat useful.
In this technique, the area of exposed bone is scraped to get down to hard or "subchondral" bone. Then a small pick (imagine a metal toothpick) is used to puncture this hard bone every 3-4 mm, going 3-4 mm deep into the bone. In turn, the bone marrow bleeds and fills the defect with a blood clot. Within the bone marrow are cells, which can differentiate into fibrocartilage or a kind of scar cartilage. This scar cartilage is of lesser quality than the articular cartilage which once existed in this defect, but it can at least partially fill the defect, and thus is better than having an area of exposed bone in the knee joint.
Dr. Cunningham finds this technique effective only for small (1cm), contained (good surrounding cartilage) defects and in patients under the age of 40. Bigger defects are better treated with newer cartilage repair technologies or partial knee resurfacing.
Depending on where the lesion is located in the knee, the rehabilitation after microfracture is quite entailed. If the lesion was over one of the femoral condyles, the patient should be nonweightbearing for 6–8 weeks. Moreover, the patient should be in a continuous passive motion machine (CPM) for up to 8 hours a day.
Arthroscopic Lateral Release
Anterior knee pain localized around the patella is a common problem, especially in female patients. In very specific instances where the patella is tethered down by a contracted band of tissue, patients may benefit from a lateral release.
In a lateral release, an arthroscope is inserted into the knee and a small cautery device is used to cut the lateral retinaculum, thus unweighting the patella. This can take pressure off the underlying cartilage and in turn give very good pain relief. However, if the correct diagnosis is not made and a lateral release is done for generalized kneecap pain or instability, the patient may not see any improvement, and pain may actually increase.
Arthroscopic Loose Body Removal
If your knee suddenly locks or catches, then there may be a loose fragment of cartilage floating around your knee. However, there are more common causes of catching in the knee, such as a meniscus tear or areas of worn cartilage catching on one another.
Loose bodies can occur when a piece of cartilage peels off the end of the femur or tibia. They can also occur with trauma, such as after a patella (knee cap) dislocation. Young patients who develop osteochondritis dessicans can also have loose bodies.
Loose bodies may not remain "loose" in the knee for very long. Rather, they can stick to the synovium (joint lining tissue) and scar to it, and thus no longer catch the knee. However, if there is a persistent loose body in the knee, arthroscopically removing it can relieve all of one's symptoms.