Arthroscopy and arthroscopic surgery

Understanding joints

Cross-section diagram of a normal joint

The place where two bones meet is called a joint. Joints allow movement and flexibility of various parts of the body. The movement of the bones is cased by muscles which pull on tendons that are attached to bone.

Cartilage covers the end of bones. Between the cartilage of two bones which form a joint there is a small amount of thick fluid called synovial fluid. This fluid lubricates the joint which allows smooth movement between the bones.

The synovial fluid is made by the tissue surrounding a joint (the synovium). The outer part of the synovium is called the capsule. This is tough, gives the joint stability and stops the bones from moving 'out of joint'. Surrounding ligaments and muscles also help to give support and stability to joints.

In the knee joint, the cartilage covering the lower part of the joint is thickened in the inner and outer part of the joint. These two areas of cartilage are sometimes called menisci. The menisci act like shock absorbers in the knee and are sometimes torn following a knee injury. Also, there are two strong cross-shaped (cruciate) ligaments in the middle of the knee joints, which are attached to the ends of the calf bone (tibia) and the thigh bone (femur). These also can be torn following a knee injury.

What is an arthroscopy?

Arthroscopy is a procedure to look inside a joint by using an arthroscope. An arthroscope is like a thin telescope with a light source. It is used to light up and magnify the structures inside a joint. An arthroscope is passed through a small cut (incision) in the skin and into a joint.

Arthroscopy may be done to investigate symptoms such as pain, swelling, or instability of a joint. An arthroscopy may show damage to cartilage or ligaments within a joint, fragments of bone or cartilage which have broken off (loose bodies), or signs of arthritis.

What is arthroscopic surgery?

In addition to simply looking inside, a doctor can use fine instruments which are also passed into the joint through a small incision in the skin (keyhole surgery). These instruments are used to cut, trim, take a sample to be studied under a microscope (biopsy), grab, etc, inside the joint. Arthroscopic surgery can be used for various procedures which include:

• Taking out small bits of bone or cartilage that have broken off into the joint space.

• Repairing or taking out torn ligaments.

• Removing damaged cartilage.

• Removing tissue surrounding the joint (synovium), which has become inflamed.

About 17 in 20 arthroscopic procedures are done on the knee joint, about 2 in 20 involve the shoulder, and a small number are done on other joints, including the ankle, elbow, wrist and hip.

Arthroscopic surgery can often treat or repair joints without the need for a more traditional open surgery of a joint, which involves a large cut (incision). As a rule, compared with traditional surgery of a joint, with arthroscopic surgery there is usually:

• Less pain following the procedure.

• Less risk of complications.

• A shorter hospital stay (it is often done as a day-case procedure).

• A quicker recovery.

How is it done?

Arthroscopy and arthroscopic surgery may be done under local or general anaesthesia. The type of anaesthesia chosen depends on the joint being examined and on various other considerations. The skin over the joint will be cleaned. You will be asked to adopt a position best suited for the procedure. For example, you may need to lie on your back with your knee bent for knee procedures, or lie on your side for shoulder procedures, etc. For arthroscopy of the knee a pressure band (tourniquet) may be put around the upper part of the leg to restrict blood flow.

The surgeon makes a small cut (incision) next to the joint - just a few millimetres long. The thin telescope with a light source (the arthroscope) is pushed through the incision into the joint. An arthroscope used for the knee joint is about the width of a pencil. A thinner one is used for smaller joints such as the wrist and ankle. One or more separate incisions are made to enable the surgeon to insert:

• A thin examining probe into the joint; or

• Fine instruments which are used for surgery; or

• Fluid to make viewing easier and to flush out the joint.

The arthroscope transmits pictures through a camera attachment on to a viewing screen. By looking at the screen, the surgeon can see inside the joint, including the ends of the probe or operating instruments. So, for much of the time, the surgeon is watching the viewing screen to guide him or her in manipulating the instruments within the joint.

When the procedure is finished, the arthroscope and other instruments are removed. The incisions may need a stitch or two but stitches are often not needed, as the incisions are so small. A sterile dressing is put over the incisions. An ice pack may be applied for a while to minimise any swelling. Depending on what was done and the problem you have, a knee joint may then be covered with a large bandage or other knee support.

Many people can go home shortly after the procedure. The type of problems differ. Therefore, instructions for follow-up and what you should and should not do will be given to you by a doctor or nurse. (For example, if you should have physiotherapy, or if you should rest, or if you should exercise, etc.)

Are there any possible complications?

In most cases the procedure is done without any problems. Complications are generally rare but can include:

• Accidental damage to structures inside or near to the joint.

• Excessive bleeding inside the joint which can cause a lot of swelling and pain.

• Infection within the joint - this can be serious.

• As with any operation, there is a risk of allergy to local anaesthetics, or complications of anaesthesia if a general anaesthetic is used.

After arthroscopy or arthroscopic surgery, see a doctor urgently if you:

• Have pain or swelling in the joint, which becomes worse. In particular, if the joint is also hot, tender and red. (This may indicate bleeding or infection in the joint.)

• Develop a high temperature.

• See fluid, pus or blood coming from the site of the cut (incision).

• Develop numbness or tingling near to the joint (which may indicate nerve damage).