Knee microfracture surgery is a common procedure used to repair damaged knee cartilage. Cartilage is the material that helps cushion and cover the area where bones meet in the joints.

Cartilage regeneration - knee

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

• Medicine to relax you, and numbing the knee using shots of pain killers
• Spinal (regional) anesthesia
• General anesthesia, where you will be asleep and pain-free.

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

• A long, thin device called an arthroscope is placed through this cut. It is like a camera. It is attached to a video monitor in the operating room. This tool 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.
• These holes release cells in your bones that build new cartilage. Your body will build new cartilage to replace the damaged cartilage.

Your doctor may recommend this procedure if you have some damage to the cartilage in the knee joint and on the underside of the kneecap.

The goal of this surgery is to prevent or slow further damage to the cartilage, preventing knee arthritis. It can help you avoid the need for a partial or total knee replacement.

This procedure is also used to treat knee pain due to cartilage injuries.

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

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.

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

During the 2 weeks before your 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 others.
• 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.

Physical therapy may begin in the recovery room right after your surgery. A machine 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 it.

Your doctor will increase the exercises you do over time until you can fully move your knee again. The exercises may make new cartilage grow faster.

You will need to keep your weight off your knee for 6 to 8 weeks unless told otherwise. You will need crutches to get around. Keeping the weight off the knee helps the new cartilage grow.

You will need to go to physical therapy and do exercises at home for 3-6 months after surgery.

Many people do well after this surgery, but recovery is slow. Many people 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.

The best results are usually seen on people under age 40 with a recent cartilage injury. Results are also better for people that are not overweight.

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.

Vanlauwe J, Saris DB, Victor J, et al. Five-year outcome of characterized chondrocyte implantation versus microfracture for symptomatic cartilage defects of the knee: early treatment matters. Am J Sports Med. 2011 Dec;39(12):2566-74.