Microfracture is an arthroscopic procedure that is suitable for smaller defects in the articular cartilage. A small tool is used to make “pick” holes in the bone, approximately 3mm deep, which stimulate bleeding. This allows stem cells within the bone marrow to form fibrocartilage, which is a substitute for the body’s own articular cartilage, and to create a new joint surface.
This is done as a day case procedure at the same time as an arthroscopy. You will have stitches at the front of the knee that will need to be removed after 7 to 10 days. Following the operation, you will need to use crutches and restrict the weight that you put through the knee for six weeks. A brace is not normally needed. You will be shown exercises to maintain your knee movement. The knee will be swollen and ice packs should be used to control this swelling, along with painkillers and anti-inflammatory drugs as needed.
You will be able to return to a static exercise bike after 1-2 weeks, with cycling under load or a cross-trainer from 6 weeks. Generally you should not return to running before 3 months, and contact sports are unlikely before 4 to 6 months.
Outcomes of Microfracture
70% of patients get a significant improvement in their pain following microfracture. The results are better in those who have small cartilage defects and where the damaged area is surrounded by normal healthy cartilage.
In the long term, almost 90% of microfracture patients have had no further operations at five years, and 70% at 10 years. Microfracture is likely to be more successful in smaller cartilage defects, and if your area of damage is larger than 1.5 to 2cm2, I am likely to recommend an alternative treatment, such as an OATS Procedure or an AMIC Procedure, depending on the size of the lesion. This is because the outcome of these operations is worse if you have had an unsuccessful microfracture treatment first.
Microfracture is more likely to be successful in the femoral condyles than in the patellofemoral joint, and this is true of all cartilage restoration surgery.