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In joints throughout the body, articular cartilage coats the ends of bones. Normal cartilage is smooth, allowing the joint to glide easily. When cartilage is damaged, the smooth surface of the cartilage can become hard. Occasionally, knee cartilage damage results in the exposure of the underlying tissue. Microfracture is a procedure that may be used to repair an infection or defect in the articular cartilage that exposes bone.

This procedure is most often performed on the knee (it can be used in the elbow, hip, ankle, and other joints as well). It is an arthroscopic operation that involves creating a network of holes at the base of the articular cartilage injury with a small sharp pick.

These holes cause blood to pool in the wounded region. This clot eventually transforms into ordered tissue known as fibrocartilage, which fills in the damaged region. This tissue mimics native cartilage in its ability to preserve joint function and alleviate complications such as discomfort and swelling.

Who would be a good candidate for microfracture?

  • Patients with only a limited damaged cartilage regions
  • Patients who are physically fit but unable to participate in the things they enjoy
  • Patients experiencing discomfort or swelling as a result of a weakened cartilage

Cartilage injury symptoms

  • Pain may occur as a result of excessive walking or ascending stairs.
  • As weight is added to the knee, it can buckle or give way.
  • Locking or catching: When the joint twists, loose, floating cartilage fragments may grab, causing the joint to lock or have reduced motion.
  • The joint can create noise when it is in motion. It’s a “snap, crackle, and pop.”


Following the diagnosis of articular cartilage injury, multiple factors may suggest the need for microfracture:

  • The patient has lost articular cartilage all the way to the bone in a weight-bearing area.
  • The patient’s joint is no longer functional.
  • The patient’s cartilage is unstable.

Important considerations to remember when performing a microfracture operation include the following:

  • Age of the patient, as a relative indicator
  • The patient’s level of physical activities

Microfracture Procedure

A microfracture is a procedure that is performed during arthroscopic surgery. Some joints should be handled in a similar manner, arthroscopically. Microfracture has been used to treat foot, back, hip, and elbow joints, among others. Although it is by far the most often practiced procedure for knee joint complications, it is also useful for other joints in the body.

To begin, the area to be microfractured is cleaned of any loose or broken cartilage. Microfracture can be performed on an area that is less than around 2 centimeters in diameter and has fine, stable underlying cartilage. Then, using a thin, sharp pick (awl), small microfracture holes are created in the bone.

The number of microfractures produced is proportional to the size of the treated joint. Five to fifteen small microfracture holes in the bone are typically required for patients with a 1- to 2-centimeter region of trauma.

The penetration of the outer layers of the bone enables the formation of a clot in the region of the cartilage defect by blood and stem cells. Within the mutation, these cells have the capacity to form a cartilage sheet. Essentially, the body can heal weakened cartilage by increasing blood flow to the region.

Rehabilitation after microfracture surgery is critical to patient progress. Rehabilitation must safeguard the microfractured region while still restoring the knee joint’s strength and motion. Consequently, most patients use crutches after surgery, a knee brace is often prescribed, and in some cases, a motion system to bend the knee can be required.

Microfracture Outcomes

When performed on the appropriate patient, microfracture can be an effective treatment that provides significant pain relief. One of the criticisms leveled at microfracture is that it does not promote natural joint cartilage formation.

There are many kinds of cartilage, and one of them (hyaline cartilage) is usually located on the surface of the joint. Microfracture promotes the formation of a different kind of cartilage that is often present in scar tissue (called fibrocartilage). Unlike hyaline cartilage, fibrocartilage lacks the consistency and resiliency of regular joint cartilage. As a result, the cartilage stimulated by a microfracture operation cannot hold up over time.

A diagram of microfracture

Microfracture surgery is common because it is relatively safe, simple to administer, and inexpensive as compared to other cartilage stimulation surgical procedures.

However, does it work? Numerous studies have been conducted on the effects of microfracture surgery. In general, individuals who undergo microfracture surgery perform better in short- to medium-term.

However, there are concerns about the quality of microfracture repair, and the cartilage that repairs inside a microfracture defect is not quite as resilient as standard cartilage.

Microfracture Rehabilitation

Microfracture recovery is a long process. Patients also use crutches for six weeks, depending on the site of the articular cartilage fracture. Patients will be able to bear weight on their knees in some situations but may wear a brace for six weeks to keep the knee straight while walking. It is advised to use a device to bend the knee (referred to as a continuous passive motion or CPM machine) for 6-8 hours per day for six weeks after surgery. Return to athletic activities is often postponed for six to nine months after surgery.


Due to the long recovery time involved with microfracture surgery, it is wise to explore other less invasive procedures such as the Prolozone injections that we offer at the clinic, which involve no downtime and have very few minor side effects.


  • Pridie K (1959) A method of resurfacing osteoarthritic knee joints. J Bone Joint Surg Br 41-B(3):618-619
  • Ficat RP, Ficat C, Gedeon P, Toussaint JB (1979) Spongialization: a new treatment for diseased patellae. Clin Orthop Relat Res (144):74-83
  • Johnson LL (1986) Arthroscopic abrasion arthroplasty historical and pathologic perspective: present status. Arthroscopy 2(1):54-69
  • Key JA (1931) Experimental arthritis: The changes in joints produced by creating defects in the articular cartilage. J Bone Joint Surg Am 13(4):725-739
  • Alford JW, Cole BJ (2005) Cartilage restoration, part 2: techniques, outcomes, and future directions. Am J Sports Med 33(3):443-460

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