What Is Arthroscopy?
Arthroscopy is a very common procedure for examining or repairing the inside of your knee joint. It is a minimally invasive procedure done with an arthroscope and other arthroscopic equipment. There are more than 800,000 arthroscopies performed in the United States each year, and more than 650,000 of them are done on the knee.
An arthroscope is a small, pencil-sized instrument with a miniature video camera. This scope is introduced into your joint through an incision about 1/4 inch in diameter. This small puncture hole is called a portal. Arthroscopy shows a clear view of the inside of the joint on a television or video monitor.
In diagnostic arthroscopy, your doctor looks inside your joint to evaluate the presence of disease or injury.
In surgical arthroscopy, your doctor operates using very small surgical tools, such as miniature scissors, arthroscopic knives, shavers, and other motorized and non motorized instruments. These long, narrow instruments are inserted into other small holes (secondary portals) around your knee.
Reasons for knee arthroscopy
Arthroscopy is commonly used to diagnose and/or treat the following conditions:
The most common reason for knee arthroscopy is a torn meniscus (or knee cartilage). The meniscus consists of two C-shaped pads of cartilage that cushion the bones of the knee joint. Your meniscus can tear if the joint is twisted and the bone pinches the cartilage.
There are several types of meniscus tears, such as a posterior longitudinal tear, a transverse tear, a horizontal cleavage tear, a radial tear, and a bucket-handle tear.
During the arthroscopy, your doctor may either remove the damaged cartilage or repair the section that is torn. Your doctor will decide whether to remove or repair the cartilage based on the location and type of tear, and how long the cartilage has been torn. These factors, of course, affect the healing potential.
Loose debris or "loose bodies"
In some cases, your doctor may use arthroscopic techniques to remove loose debris, which are broken pieces of bone or cartilage loose within the joint. Simple loose bodies can occur even at a young age. They are formed from direct trauma to the joint surfaces. Quite often in older patients, loose debris in the joint is associated with the pain and swelling of arthritis.
Ligaments keep your knee joint stable. They connect bone to bone (as opposed to tendons, which connect muscle to bone). The most commonly damaged ligaments are the anterior cruciate ligament (ACL) and the medial collateral ligament (MCL). Less frequently, injury occurs in the posterior cruciate ligament (PCL) and the lateral collateral ligament (LCL).
An ACL tear may be caused by a sudden twist beyond the knee's normal range of motion. Such tears can occur from a contact injury or from a sudden change in direction while participating in sports or other activities, without anything hitting the knee. MCL and LCL tears are usually caused by a strong force against the side of the knee.
A torn ligament will result in pain, swelling, and instability of the knee. It may cause the knee to "give way." Ligament tears may require surgery and/or a brace that protects the joint while restricting sideways motion.
Often, arthroscopy is needed to help diagnose these ligament injuries, particularly with the ACL and PCL. Arthroscopy may also be used when these torn ligaments are reconstructed.
Surface defects on articular cartilage
Surface defects (rough areas) on articular cartilage are a sign of osteoarthritis. With time, surface defects can break off and become loose bodies within the knee joint. Arthroscopy can be used to smooth out the surface defects in the knee's articular cartilage.
Disorders of the kneecap
The kneecap, also called the patella, should have smooth cartilage on the side that faces the joint surface. This cartilage can become rough when it's damaged, causing pain. Arthroscopy is commonly used to smooth the kneecap's cartilage surface. The kneecap can also slip out of its normal position, becoming dislocated and the arthoscope can be used to evaluate this disorder. There are also some advanced arthroscopic procedures used to stabilize a dislocated kneecap.