By: Steve Siwy for Knee1Recent speculation that the New Jersey Nets may want to trade basketball player Jason Kidd has led to concurrent interest in microfracture knee surgery, a procedure Kidd underwent on July 1st of this year. The surgery, in which doctors replace worn-away cartilage by making tiny penetrations in the patient’s bone to stimulate the formation of a “super-clot” of blood and bone-marrow cells, has a long recovery time, and there is no guarantee that Kidd will be able to return to his former level of performance once he’s through with rehabilitation.
The procedure is called “microfracture” surgery because technically, any break in a bone’s surface is considered a fracture. In this case, the fractures are tiny holes in the bone about one eighth of an inch deep, at the site where the cartilage has eroded away. From these holes blood and marrow cells can enter the knee, where they form the super-clot which eventually becomes fibrocartilage. The surgery is performed arthroscopically, by inserting a thin scope and small-scale instruments through a small number of quarter-inch incisions.
Kidd isn’t the only NBA player to have had microfracture surgery. The Sacremento Kings’ Chris Webber, the Los Angeles Clippers’ Kerry Kittles, and Allan Houston and Anfernee Hardaway of the New York Knicks have all undergone the procedure, about which Hardaway recently told The Oregonian, “You have to be really careful with this type of surgery. You really have to give the procedure a chance to work and for the knee to heal. If you don’t, you’re asking for trouble.” Hardaway was one of the first NBA players to have the surgery, in May of 2000.
Doctors agree that a strictly-observed rehabilitation regimen is key to the success of the microfracture procedure. In the New York Daily News, Dr. Jonathan Glashow said, "When I do micro-fracture, I keep people on crutches for six weeks. Different people have different abilities to adapt.” One of the main components of the rehabilitation is continuous passive motion (CPM), usually involving a machine that very slowly and gently flexes and extends the leg. The machine is used in the weeks after surgery for six to eight hours a day, often while the patient is sleeping. During the day, crutches ensure that only 20% - 30% of the patient’s weight is put on the affected knee. After the first six weeks, the favored knee’s share of the load is gradually increased until it can bear the patent’s full weight.
During rehabilitation, the marrow clot slowly transforms itself into fibrocartilage. Normal articular cartilage, which cushions bones at the joints and keeps them from grinding against each other, includes a mixture of cartilage cells and type II collagen. The type II collagen is absent from fibrocartilage, which comprises cartilage cells and fibrous tissue cells. The fibrocartilage created by microfracture surgery still reduces friction between bones, and performs the cushioning function of the original cartilage, but is less durable, and breaks down over a period of years.
Kidd might return to playing as early as December, though some regard that estimate as optimistic. Of his own surgery, Hardaway said in the same Oregonian article, "I don't think six months was enough time for it to heal. I'm just now feeling like I'm getting back to where I was."
