Knee microfracture surgery is a common procedure used to repair damaged knee cartilage. Cartilage helps cushion and cover the area where bones meet in the joints.
Cartilage regeneration - knee
Three types of anesthesia may be used for knee arthroscopy surgery:
Medicine to relax you, and shots of pain killers to numb the knee
Spinal (regional) anesthesia
General anesthesia (you will be asleep and pain-free)
The surgeon will make a 1/4-inch surgical cut (incision) on your knee.
A long, thin tube with a camera on the end is placed through this cut. This is called an arthroscope. The camera is attached to a video monitor in the operating room. This tool lets the surgeon to look inside your knee area and work on the joint.
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 in the bone near the damaged cartilage. These are called microfractures.
These holes release cells in your bones that build new cartilage that replaces the damaged tissue.
Why the Procedure Is Performed
You may need this procedure if you have damage to the cartilage in the knee joint and under the kneecap.
The goal of this surgery is to prevent or slow further damage to the cartilage. This will help prevent 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.
A surgery called autologous chondrocyte implantation is done for similar reasons.
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.
Increase stiffness of the knee.
Before the Procedure
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 need 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.
After the Procedure
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 the new cartilage heal better.
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 to 6 months after surgery.
Many people do well after this surgery. Recovery time can be slow. Many people can go back to sports or other intense activities in about 4 to 6 months. Athletes in very intense sports may not be able to return to their former level.
People under age 40 with a recent cartilage injury often have the best results. People that are not overweight also have better results.
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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.
C. Benjamin Ma, MD, Assistant Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.