Description

Three different types of anesthesia may be used for knee arthroscopy surgery:

• Your knee may be numbed with injections of painkilling medicine, along with medicines to relax you
• Spinal (regional) anesthesia
• General anesthesia, where you will be unconscious and pain-free.

The surgeon will make a 1/4-inch-long surgical cut (incision) on your knee.

• Then the surgeon will insert a long, thin device called an arthroscope through this incision. The arthroscope is like a camera. It is attached to a video monitor in the operating room. It allows the surgeon to look inside your knee area and work directly on the joint. See also: Knee arthroscopy
• The surgeon makes another surgical cut and passes tools through this opening. A small pointed tool called an awl is used to make very small holes, called microfractures (tiny breaks), in the bone near the damaged cartilage.
• The holes the surgeon makes in your bone release the cells in your bones that build new cartilage. Your body then builds new cartilage to replace the damaged cartilage.

Why the Procedure is Performed

Microfracture surgery is done on people who have small amounts of damage in the cartilage of their knee joint and on the underside of their kneecap.

The goal of this surgery is to prevent or slow further damage to the cartilage from developing, and as a result knee arthritis. It can help people avoid the need for a partial or total knee replacement. It is also used to treat pain in the knee from cartilage injuries.

Another surgery, autologous chondrocyte implantation, is done for similar reasons.

Risks

Risks for any anesthesia are:

• Allergic reactions to medicines
• Breathing problems The risks for any surgery are:
• Bleeding
• Infection
• Blood clot

Risks for microfracture surgery are:

• Cartilage breakdown over time. The new cartilage made by microfracture surgery is not as strong as the body’s original cartilage. It can break down more easily.
• Increased stiffness of the knee.

Before the Procedure

Always tell your doctor or nurse what drugs you are taking, even drugs, supplements, or herbs you bought without a prescription.

During 2 weeks before your surgery:

• Two weeks before surgery, you may be asked to stop taking drugs that make it harder for your blood to clot. These include aspirin, ibuprofen (Advil, Motrin), naproxen (Naprosyn, Aleve), and other similar drugs.
• Ask your doctor which drugs you should still take on the day of your surgery.
• If you have diabetes, heart disease, or other medical conditions, your surgeon will ask you to see your doctor who treats you for these conditions.
• Tell your doctor if you have been drinking a lot of alcohol, more than 1 or 2 drinks a day.
• If you smoke, try to stop. Ask your doctor for help. Smoking can slow down wound and bone healing.
• Always let your doctor know about any cold, flu, fever, herpes breakout, or other illness you may have before your surgery.

On the day of your surgery:

• You will usually be asked not to drink or eat anything for 6 to 12 hours before the procedure.
• Take your drugs your doctor told you to take with a small sip of water.
• Your doctor or nurse will tell you when to arrive at the hospital.

After the Procedure

Physical therapy may begin in the recovery room right after surgery. A continuous passive motion machine (CPM) gently exercises your leg for 6 to 8 hours a day for several weeks. This machine is usually used for 6 weeks after surgery. Ask your surgeon how long you will use the CPM machine.

Your exercises will increase over time until you regain full range of motion in your knee. These exercises may speed up the new cartilage growth.

You will need to keep your weight off your knee for 6 to 8 weeks unless instructed otherwise. You will need crutches to get around. Keeping the weight off the knee will allow the new cartilage to regrow and form better tissue.

Physical therapy and doing exercises at home are needed for 3 to 6 months after surgery to get the best results.

Outlook (Prognosis)

Many people improve after this surgery, but recovery is slow. Many can return to sports or other intense activities in about 4 months. Athletes in very intense sports may not be able to return to their former level of competition.

Results are best when this surgery is done on people younger than 40 whose cartilage injury is recent. Results are also better for people that are not overweight. It is also most successful for small amounts of damage in the knee cartilage.

Alternative Names

Cartilage regeneration - knee

References

Beynnon BD, Johnson RJ, Brown L. Knee. In: DeLee JC, Drez D Jr, Miller MD, eds. DeLee and Drez’s Orthopaedic Sports Medicine. 3rd ed. Philadelphia, Pa: Saunders Elsevier; 2009:chap 23.

Saris DB, Vanlauwe J, Victor J, Almqvist KF, Verdonk R, Bellemans J, et al. Treatment of symptomatic cartilage defects of the knee: characterized chondrocyte implantation results in better clinical outcome at 36 months in a randomized trial compared to microfracture. Am J Sports Med. 2009 Nov;37 Suppl 1:10S-19S.

Basad E, Ishaque B, Bachmann G, Stürz H, Steinmeyer J. Matrix-inducedautologous chondrocyte implantation versus microfracture in the treatment ofcartilage defects of the knee: a 2-year randomised study. Knee Surg SportsTraumatol Arthrosc. 2010 Apr;18(4):519-27.

Hurst JM, Steadman JR, O'Brien L, Rodkey WG, Briggs KK. Rehabilitation following microfracture for chondral injury in the knee. Clin Sports Med. 2010 Apr;29(2):257-65, viii.

Update Date: 4/23/2012

Reviewed by: David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc; C. Benjamin Ma, MD, Assistant Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery.