With a microfracture, a surgeon pricks the bare, cartilage-less bone to create small holes, through which blood and bone marrow seep, forming a clot that releases cells that create cartilage. With autologous chondrocyte implantation, such as Carticel, your own cartilage (autologous) is basically grown in a petri dish, and the mature tissue (which has cartilage-producing cells, or chrondrocytes) is implanted in your knee.
The big knock against a microfracture: the cartilage produced isn't the good, mature variety, but rather a rubbery sort that's less durable (called "fibrocartilage").
ACI is the new, sexy, cutting-edge procedure. So if I had a choice, I would have a …
Here are six reasons why:
1. The surgery is less invasive. ACI involves an operation that peels the knee wide open. Unfortunately, extensive surgery may entail a higher risk of something going wrong/side effects.
2. The cost is cheaper. It appears that the microfracture is a fourth or fifth the cost of an ACI.
3. The procedure is more "natural." The microfracture spurs the bone to form replacement cartilage on its own. The ACI requires cartilage to be grown in a laboratory, then inserted into your knee.
4. 100 NBA players can't be wrong. Okay, it's not a hundred -- more like a dozen or so -- yet the point holds. Professional basketball players make multimillion-dollar salaries. They are attended to by the finest trainers and doctors. They can afford any kind of surgery.
When was the last time you heard of an active player undergoing an ACI instead of a microfracture? Granted, the microfracture doesn't always succeed. Still, players such as Jason Kidd, John Stockton and Amar'e Stoudemire have regained their old form after the operation.
Today, Stoudemire is renowned for his athleticism and leaping ability. He's an all-star, pounding up and down the court for the New York Knicks in what may be the most demanding sport for knee joints. That he has maintained his skills, post-surgery, while putting his knees under such stress, shows microfracture can be effective.
(Update: As is obvious to anyone who follows the NBA, I might have chosen a better example here than Stoudemire, who had knee surgery again during the 2012-2013 NBA season. Oh well. Basketball is a very hard sport on the knee joints.)
That leads us to my fifth reason …
5. This study
Which dispels the belief that the only cartilage you get with a microfracture is inferior fibrocartilage. (That never made sense to me anyway: how could NBA players compete in such an intense game if their replacement tissue was solely fibrocartilage?)
In a study published in Arthroscopy in April 2006, researchers who took biopsies to inspect the cartilage that was formed after a microfracture observed (my bold):
This healed tissue is a combination, or hybrid, of fibrocartilage and hyaline-like cartilage [note: that's hyaline articular cartilage, the good stuff]What's more, they examined the tissue after only a year, leading me to wonder -- had they done a biopsy after two, three or four years, might they have discovered an even higher proportion of hyaline cartilage compared to fibrocartilage?
Why do I wonder this? Well, when Robert Salter did his famous continuous passive motion experiment involving rabbits 30 years ago (the animals had small holes drilled in their knee cartilage to simulate defects), he found a few curious things (besides the banner news that motion, of the continuous and passive variety, is great for knees post-surgery).
One was this: The cartilage that grew back to fill the holes was at first immature, then gradually took on the characteristics of mature cartilage, complete with chondrocytes.
6. And this study too
For the study, 33 patients had a microfracture and 34 the ACI procedure. Then, at various times over the next two years, the condition of their repaired knees was assessed. Their ability to do one-leg hops was measured. Also knee mobility and strength were checked.
The researchers expected to find the ACI patients with a decided advantage over the microfracture group after two years. But this is what they discovered instead:
The most important finding of the present study was that the functional recovery at 2 years is comparable for both groups. The results show no superiority of ACI over microfracture at 2 years.What's more:
More patients in the microfracture group recovered overall functional performance at 9 and 12 months.Okay, that's why I'd prefer a microfracture over ACI. What about you?