Arthroscopic surgery of the knee involves the use of fiberoptic cameras and small surgical instruments to visualize the intraarticular structures of the knee and to treat many abnormalities or injuries of the knee. This includes trimming of meniscal tears, which is the most common abnormality treated, removal of loose bodies, trimming of articular cartilage flaps, debridement of scar tissue, and other abnormalities of the knee.
In addition, arthroscopic instruments can be used to obtain a more accurate diagnosis of abnormalities of the knee. While many of today's MRIs are very high quality, there are still times when a specific diagnosis may be in doubt, especially to look at articular cartilage lesions, and the arthroscope can be utilized to diagnose the size, depth, and condition of these articular cartilage lesions.
In addition to the primary treatment of injuries and abnormalities to the knee, the arthroscope can be used to assist in much larger surgical procedures of the knee through the use of small incisions. This would include using the arthroscope to assist with meniscal repairs and cruciate ligament reconstructions. In fact, refinement in the type of tools used for arthroscopic surgery has resulted in smaller incisions, less surgical time, and actual better placement of surgical reconstructions for many procedures compared to techniques of only 5-10 years ago.
The technique of arthroscopic surgery involves the placement of small incisions around the knee. The standard arthroscopic incisions are a small fluid outflow (or in some cases inflow) portal over the proximomedial portion of the knee and through the vastus medialis obloquus muscle. This portal will allow access to the suprapatella pouch of the knee and is the main portal used for fluid outflow from the knee. Arthroscopists use fluid in the joint to allow for better visualization of structures and to remove any blood that might be present from the surgical incisions or injuries of the knee.
The next standard arthroscopy portal is placed along the lateral joint line, just lateral to the patella tendon. For most arthroscopists, this arthroscopic portal is used for placement of the arthroscopic camera for the majority of work inside the knee. In most instances, we use an arthroscope that is angled 30º to visualize around the corners of the knee. Most arthroscopic camera setups have the fluid enter the joint through this arthroscopic portal such that any blood or surgical debris from trimmings is pushed away from the camera rather than towards it.
Placement of other arthroscopic portals will depend upon the area of the pathology in the knee. In the majority of cases, it is placed along the medal joint line. We prefer to use a spinal needle placed into the joint to help to define the exact location necessary to place the portal to probe the structures of the knee and to trim up any meniscal tears. This arthroscopic portal is created by the use of a knife blade placed horizontally into the knee under direct visualization. We prefer to have the knife blade enter the knee and create a large enough arthroscopic such that this portal can be easily entered and exited on multiple occasions with the use of arthroscopic instruments. We do not like to create a blunt entering of the joint with an instrument, because this tends to create more trauma and potentially more scar tissue after surgery.
It is important to realize that while these three arthroscopic incisions are the main incisions utilized, in some instances additional arthroscopic portals are necessary to properly treat the pathology in the knee joint. Arthroscopists should not feel limited to utilizing just three incisions, and should know the placement of the more complex portals around the knee to allow access for the arthroscope and surgical instruments to otherwise inaccessible areas. This would include the posteromedial arthroscopic portal for PCL reconstructions and loose body removals and the posterolateral arthroscopic portal for loose body removal and for passing sutures for meniscal allograft procedures.
Almost all arthroscopic knee surgeries are now performed on an outpatient basis. We primarily use Steristrips over the arthroscopic portals to allow the skin incisions to heal and to minimize scarring. A loose, sterile dressing is then applied which can be removed in three to four days. Patients are allowed to weightbear as tolerated with the use of crutches, and may wean off the crutches when they can walk without a limp. Patients need to work on knee motion and leg raises as soon as their surgeon permits so that their knee does not become stiff or that their muscles atrophy. Showers are generally allowed at 3 or 4 days after surgery and bandaids should be placed over the incisions until they completely heal. Most patients recover fully from simple menisectomies within a few weeks after surgery.