Knee Microfracture
A cartilage repair technique that stimulates new tissue growth in areas of joint damage
Knee microfracture is a minimally invasive surgical technique used to treat areas of damaged cartilage in the knee. The goal of the procedure is to stimulate the growth of new cartilage-like tissue to cover areas where the natural cartilage has been lost or worn away.
This technique may be recommended when there is a small, localised area of cartilage loss, particularly in younger, active individuals who do not yet require joint replacement.
Understanding cartilage damage
Cartilage is the smooth, protective tissue that covers the ends of bones within your knee joint. It allows for pain-free, low-friction movement. Once damaged, cartilage does not heal easily on its own due to its limited blood supply.
When an area of cartilage becomes worn down or breaks away — due to injury, overuse, or degenerative changes — it can expose the underlying bone. This may lead to:
Pain during movement
Swelling and inflammation
Catching, locking, or mechanical symptoms in the joint
Progressive joint wear if left untreated
How is Microfracture performed?
Microfracture is performed using arthroscopy, a minimally invasive technique. Small incisions are made, and an arthroscope; a thin tube with a camera, is inserted into the knee joint, allowing Dr Liddell to view the inside of the knee with precision.
The procedure involves several steps:
- Debridement: Dr Liddell will clean the damaged area by removing any loose or unstable cartilage. This prepares the site for the microfracture technique.
- Creating Microfractures: Using a specialised tool called an awl, Dr Liddell makes small holes, or “microfractures,” in the bone beneath the damaged cartilage. These tiny holes allow blood and bone marrow cells to enter the damaged area.
- Formation of a Blood Clot: The blood and bone marrow cells form a clot in the affected area, which contains stem cells and growth factors that promote new cartilage formation.
- New Cartilage Formation: Over time, the clot develops into a new layer of cartilage. It’s important to note that this new cartilage, known as fibrocartilage, is not as strong or durable as the original hyaline cartilage but can still offer functional improvement.
When is microfracture surgery recommended?
Microfracture may be suitable for you if:
You have a small, contained area of cartilage loss (often less than 2cm²)
You are under 50 years old or biologically active and healthy
Your knee has good stability, alignment, and range of motion
You are not yet a candidate for joint replacement
You are committed to following a structured rehabilitation plan
It is not typically recommended for widespread arthritis, severe joint misalignment, or when the bone beneath the cartilage (subchondral bone) is significantly damaged.
Recovery after microfracture surgery
Recovery from microfracture is longer than many other arthroscopic procedures, as the new tissue needs time to form and mature. A strict rehabilitation program is essential to protect the healing cartilage and achieve the best possible outcome.
Typical recovery timeline:
Crutches and non-weight bearing: Required for 6 to 8 weeks to avoid pressure on the healing site
Physiotherapy: Starts early and continues for several months to restore movement and strength
Return to driving: Usually 6–8 weeks, depending on the leg involved and recovery progress
Return to sport or high-impact activity: Generally 6–9 months or longer
Recovery from microfracture requires dedication to a structured rehabilitation plan to protect the new cartilage and promote healing.
Here’s what to expect:
- Initial Recovery (First Few Weeks): After surgery, you will likely need to avoid putting weight on the affected knee for several weeks. Crutches are often used to assist with mobility and protect the healing cartilage.
- Physiotherapy: A tailored physiotherapy program is essential. Early stages focus on restoring range of motion, while later stages strengthen the muscles around the knee to support the joint.
- Gradual Return to Activity: You’ll gradually resume normal activities over several months, but high-impact activities such as running or jumping should be avoided until the knee is fully healed, and Dr Liddell gives clearance.
Benefits of Microfracture
Microfracture can be an effective option for patients with small areas of cartilage damage.
Some potential benefits include:
- Minimally Invasive: Because microfracture is performed arthroscopically, it involves smaller incisions, which can result in less postoperative pain and a quicker recovery compared to more invasive procedures.
- Stimulates Natural Healing: The procedure uses your body’s natural healing mechanisms to repair the damaged cartilage, making it a less complex option for suitable patients.
- Delays the Progression of Osteoarthritis: Repairing damaged cartilage early may help slow the development of osteoarthritis, potentially postponing the need for more extensive surgery like a joint replacement.
- Improves Knee Function: Patients may experience reduced pain and improved mobility, which can allow them to return to daily activities more comfortably.
Limitations of Microfracture
While microfracture can be beneficial, it’s important to understand its limitations:
- Fibrocartilage Formation: The new cartilage formed after the procedure is fibrocartilage, which is not as strong or durable as the original hyaline cartilage. This may affect the long-term success of the procedure, particularly in individuals who are very physically active.
- Recovery Time: Recovery from microfracture can take several months and requires a period of non-weight-bearing to allow the new cartilage to form properly. A strict rehabilitation plan is necessary for optimal results.
- Not Suitable for Large Defects: Microfracture is most effective for small, isolated areas of cartilage damage. Patients with larger or more widespread damage may need alternative treatments.
Is Microfracture Right for You?
Microfracture may be a suitable option for patients with small, localised cartilage damage who wish to repair their knee without undergoing more invasive surgery. It is particularly effective for younger patients or those with early-stage damage who are looking to delay the progression of osteoarthritis.
Dr Liddell will carefully evaluate your knee condition, including the size and location of the cartilage damage, to determine if microfracture is the most appropriate treatment option for you.