Knee arthroscopy has in many cases replaced the classic arthrotomy that was performed in the past. Today knee arthroscopy is commonly performed for treating meniscus injury, reconstruction of the anterior cruciate ligament and for cartilage microfracturing. Arthroscopy can also be performed just for diagnosing and checking of the knee; however, the latter use has been mainly replaced by magnetic resonance imaging.
During an average knee arthroscopy, a small fiberoptic camera (the arthroscope) is inserted into the joint through a small incision, about 4 mm (1/8 inch) long. A special fluid is used to visualize the joint parts. More incisions might be performed in order to check other parts of the knee. Then other miniature instruments are used and the surgery is performed.