by Rosalyn Carson-DeWitt, MD

Anatomy and Physiology
The knee joint is made up of three bony parts: the femur, the tibia, and the patella. Normally, these bones glide freely when the joint bends, due to smooth cartilage and thin membranes that line the inside of the joint and produce lubricating synovial fluid.

These bones are held in position by four main ligaments: the lateral collateral, medial collateral, anterior cruciate, and posterior cruciate. In addition, two C-shaped fibrous pads separate the femur and tibia. These so-called menisci act as shock absorbers and provide support for the knee joint.

Reasons for Procedure
The most common knee joint problems are either due to osteoarthritis, a condition which tends to occur as joints age, or injuries related to athletics or work. These may result in tears of the ligaments or menisci, loose fragments of bone or cartilage, or instability of the joint.

Symptoms of osteoarthritis include: pain, usually worsened by weight-bearing activities, difficulty walking, swelling of the joint, pops, clicks, or grinding of the joint.

Similar symptoms may occur if you have injured any of the structures of your knee joint. In addition, you may notice: sudden buckling or giving way of the joint; a sense of the joint getting stuck in a certain position.

Treatments
Knee problems such as osteoarthritis or injuries are usually first treated with non-surgical methods such as: anti-inflammatory medications like ibuprofen, physical therapy or other prescribed exercises to strengthen the muscles that support the knee joint, a special device called a knee stabilizer to support the joint when the knee is stressed during weight-bearing activities, if needed, weight loss to reduce ongoing stress on the joint.

If noninvasive methods fail, steroid medications may be injected directly into your knee joint to decrease inflammation and pain and to improve mobility.

If pain and disability persist, knee arthroscopy may be recommended. This procedure is useful to treat tears of the menisci and to remove loose bodies in the knee. In knee arthroscopy, a fiberoptic instrument with a lighted tip is inserted into your knee joint in order to visualize, diagnose, and treat certain knee problems.

Arthroscopic procedures are designed to avoid open surgical procedures, which involve a single large incision and longer recovery periods.

Procedure
In the days leading up to your procedure: Arrange for a ride to and from the hospital and for help at home as you recover. The night before, eat a light meal and do not eat or drink anything after midnight. If you regularly take medications, ask your doctor if you need to temporarily discontinue them. Do not start taking any new medications before consulting your doctor.

Knee arthroscopy is usually done under spinal or local anesthesia. If this is the case, you will remain awake, but sedated, during the procedure and the lower half of your body will be rendered numb. If general anesthesia is used, you will be kept asleep.

Your surgeon will begin by using an instrument called a trocar to make an opening, or portal, into the joint. He or she will then instill a sterile solution into the joint to push the surfaces apart and allow the structures to be viewed more easily.

Next, your surgeon will insert an arthroscope, which contains a small lens and lighting system, to magnify and illuminate the structures inside the joint. He or she will also create one or two additional portals through which pencil-sized surgical instruments will be passed.

A camera attached to the arthroscope will take photographs and project images onto a monitor in the operating room.

Your surgeon will examine the interior structures of your knee joint. Bone or cartilage fragments and portions of torn menisci can be removed through the arthroscope. In addition, a torn ligament or meniscus may be repaired arthroscopically.

After the procedure has been completed, your surgeon will remove the arthroscope and suture the skin closed with stitches or clips. Your knee will be temporarily placed in an immobilizer.

Risks and Benefits
Complications of knee arthroscopy are rare, but may include: adverse reactions to anesthesia, infection, blood clots in the legs that could travel to the lungs, excessive swelling or bleeding at the joint, and/or damage to blood vessels or nerves in the affected leg.

Benefits of knee arthroscopy include: ability to visualize, diagnose, and treat injuries to ligaments, menisci, and other structures of the knee, repair or removal of meniscal tears, removal of loose bodies in the knee, less recovery time and scarring than open knee procedures.

In knee arthroscopy, or any procedure, you and your doctor must carefully weigh the risks and benefits to determine whether it's the most appropriate treatment choice for you.

After the Procedure
Because most knee arthroscopies are performed on an outpatient basis, you can usually go home the same day as your procedure.

For the first 24 to 48 hours after surgery, you'll usually be advised to keep your leg elevated and to ice your knee periodically. You will likely require a knee stabilizer, crutches, or a cane when moving around for the first few days.

Be sure to call your doctor immediately if you experience: A fever or chills, redness, swelling, increased pain, excessive bleeding, or discharge from the incision sites, nausea or vomiting, swelling, tingling, pain, or numbness in your toes that is not relieved by elevating your knee above heart level for one hour, coughing, shortness of breath, or chest pain.

Sources:

• Arthroscopy: A Boon for Damaged Joints. Mayo Clinic Website. Available at: http://www.mayoclinic.com/invoke.cfm?objectid=9F9D2C14-4D84-4007-8C641DBCE5584D42. Accessed January 22, 2004.
• Knee Arthroscopy. American Association of Orthopedic Surgeons. Available at: http://orthoinfo.aaos.org/booklet/thr_report.cfm?thread_id=8&topcategory=knee. Accessed January 22, 2004.
• Knee Arthroscopy. National Library of Medicine. Available at: Phillips BB. Arthroscopy of the Lower Extremities. In: Campbell's Operative Orthopedics. 10th edition. St. Louis: Mosby, Inc; 2003: 2515-2592.