Micro Fractures

The knee often doesn't get enough credit for all it manages to accomplish. The knee, the biggest joint in the human body, is an amalgamation of a variety of components such as bone, cartilage, tendon, muscle, ligament, and nerves, all of which work in tandem in order to produce an impressive range of powerful motion. Of course, due to its many moving parts, the knee is notoriously vulnerable to injury. One increasingly common form of treatment for certain knee injuries is the microfracture, which will be dissected in this article.

Almost any movement that stems from the legs is thanks to the knee.

What Is A Microfracture?

A microfracture, despite what one might assume at first glance, is not a type of injury; it is instead a type of surgery for repairing and treating damaged knee cartilage. Cartilage crucially acts as padding between and surrounding the three bones that make up the knee (the femur, tibia, and patella), preventing the pain of having any of these bones touch directly. Cartilage slowly wears away as one grows older, so a microfracture can help one mitigate knee arthritis and even stall the need for a knee replacement.

This technique was conceived in the early 1980s and can be performed in three main ways. Microfracture is mostly performed through arthroscopy, which involves inserting a fiber-optic camera into the relevant joint, or through a mini-open approach, which provides surgeons with good visibility while still being relatively minimally invasive. It is also possible to perform a microfracture with the traditional, fully-open approach. In all cases, an arthroscopic shaver is used to carefully get rid of damaged cartilage while keeping any healthy tissue intact. Then, the same tool scrapes at the bone, hence the surgery name, in order to stimulate bone marrow into creating new but weaker cartilage.

By creating microfractures in the bone and causing bleeding, some cartilage can regenerate.

Post-Procedure Recovery:

After the surgery, patients must transition very slowly back to daily life, since the vulnerable knee will not be able to bear much weight for many weeks post-operation. Physical therapy usually commences immediately after surgery and, in some instances, involves a continuous passive motion (CPM) machine, which automatically keeps the knee in a slow, pre-set range of motion. By gradually increasing the amount of exercise the knee gets over time, the cartilage is more likely to heal better. Recommended exercises include toe-touch weight bearing.

After six to eight weeks bearing little to no weight, the knee will be well enough to use without crutches. It is usual for postoperative patients to stay at home for up to six months in order to let the knee fully heal. All in all, most patients will be back to sports and other intense physical activity about nine to twelve months following their surgery, which has a ~70-90% success rate.

Drawbacks:

Though microfractures are certainly effective and provide relief, the treatment has faced criticism for its lack of durability. As aforementioned, the new cartilage isn't as strong as that given at birth, so it too wears away after just a few years. In other words, the strain from repeated and constant weight borne by the knee prevents the surgery’s effects from lasting. Fortunately, doctors have been developing alternative ways to battle arthritis throughout the years, like cartilage replacements. Their most promising innovation yet is articular cartilage paste grafting, which involves injecting "stem-derived repair cells, growth factors, and hyaluronic acid lubrication" into microfractures to strengthen the new cartilage.

A CPM machine is a great resource for those recovering from surgery.

Conclusion:

Even though recovery takes many months, microfracture surgeries can help slow the onset of articular disorders like arthritis by replenishing the affected joint's supply of cartilage. It is ideal to preserve existing cartilage with stretching and low-impact aerobic exercise.

Sources:

“Knee Microfracture Surgery: Medlineplus Medical Encyclopedia.” MedlinePlus, U.S. National Library of Medicine, medlineplus.gov/ency/article/007255.htm. Accessed 2 Feb. 2025. 

“Microfracture Surgery and Recovery Information.” Washington University Orthopedics, www.ortho.wustl.edu/content/Patient-Care/2893/Services/Sports-Medicine/Overview/Knee/Microfracture.aspx. Accessed 2 Feb. 2025. 

Northwestern Medicine. “Microfracture.” Northwestern Medicine, www.nm.org/conditions-and-care-areas/treatments/microfracture. Accessed 2 Feb. 2025. 

professional, Cleveland Clinic medical. “Knee Joint: Function & Anatomy.” Cleveland Clinic, 1 May 2024, my.clevelandclinic.org/health/body/24777-knee-joint. 

Stone, Kevin R., and Orthopaedic surgeon. “Why Microfracture Fails.” Why Microfracture Knee Surgery Success Rate Fails over Time, 10 Dec. 2021, www.stoneclinic.com/blog/why-microfracture-fails.