Ok, so Carlos went out and got either microfracture surgery or just got his knee scoped and cleaned up. We’re not sure at this point as far as I can tell, but how about a little bit on what a microfracture is and what microfracture surgery entails?
So the first point of clarification is that a microfracture isn’t actually a fracture in the true sense (i.e. a broken bone). It’s actually a surgical technique to repair cartilage (flexible connective tissue found between joints).
The basic idea of the surgery is that the surgeon creates microfractures, which in turn help the athlete heal. Weird, right? Well, the mechanism behind it is that you hurt the body so the body takes care of itself. Almost like a vaccine where you give a little of something bad for a lot of good produced by the body itself (in the case of vaccines the 'good' would be antibodies). When a player has a chronic injury that has progressed slowly through time, the body often does not respond to this injury. However, if you have an acute injury, this often leads to the body kicking into action. In the case of microfracture surgery, you inflict an acute injury so the body can heal itself. The exact details are murky, but there are many types of cells that play a roll in the healing. In the most basic sense, these are stem cells that can come in and form into new cartilage.
How the surgery is actually done is through an arthroscope (a small camera on the end of a long instrument). See the image below. This means there is no huge scalpel cutting but rather a few small "ports" made around the knee to get the camera in and the instruments needed. This cuts recovery time and still allows the surgeon to do what needs to be done. Once into the knee, the surgeon basically starts creating tiny fractures with his instruments. As soon as those fractures are there you get the release of all the body’s systems to help them heal. One can imagine that if your body is old and doesn’t have many stem cells (simplification), then this surgery might not work so well and could actually result in just more injury. But the hope in Beltran’s case would be that his body can respond adequately and form new cartilage. There are other options for this type of surgery out there (e.g. how about just putting the stem cells directly into the knee, or rebuilding the cartilage itself without the help of the body), but those discussions are for another time.
Does it work? Well, studies have been out there, including Outcomes of microfracture for traumatic chondral defects of the knee: Average 11-year follow-up by Dr. Steadman (who actually invented the procedure, so bias?). He found that Over the 7- to 17-year follow-up period (average, 11.3 years), patients 45 years and younger who underwent the microfracture procedure for full-thickness chondral defects, without associated meniscus or ligament pathology, showed statistically significant improvement in function and indicated that they had less pain. How does that translate to performance on the field? I couldn't find any studies on that.
And as for recovery, Wikipedia actually had a nice blurb on this:
Microfracture surgery itself is relatively minor. It is an outpatient procedure and causes only small discomfort. The harder part is the restrictions that are placed on the patient during the post-operative recovery period. This can be a major challenge for many patients. For optimal re-growth of joint surface, the patients need to be very patient and also extremely cooperative. They usually need to be on crutches for four to six weeks (sometimes longer). Sometimes a brace is needed. This all depends on the size and/or location of the joint surface defect that is being repaired or regenerated. The patients are encouraged to spend approximately 6-8 hours a day on a Continuous Passive Motion machine that helps with optimal re-growth of joint surface. Patients usually feel pretty good and think they can avoid these critically important steps, and even start running and jumping (or playing sports) before the internal aspects of the knee, and the joint surface, are ready.
So how does this all relate to Carlos, if he even had this surgery? Well, he’ll be out for a while at least and we can only hope that his stem cells kick into gear and help him heal.