Microfracture surgery is a common arthroscopic procedure aimed at repairing damaged cartilage within a joint, particularly the knee. This technique is frequently considered for individuals experiencing pain and impaired function due to specific cartilage defects. Patients often wonder about its effectiveness and long-term value. This article explores the mechanics of the procedure, who might benefit from it, the recovery process, and what outcomes can be expected, providing context for informed decisions about cartilage repair.
How Microfracture Surgery Works
Microfracture surgery is a minimally invasive procedure performed arthroscopically, using small incisions and a camera to operate inside the joint. The process begins with the removal of any loose or damaged cartilage surrounding the defect to create a stable edge. A small, sharp tool is then used to create tiny holes, typically 3 to 4 millimeters apart, in the subchondral bone directly beneath the cartilage defect.
These controlled perforations allow blood and bone marrow, which contain stem cells and growth factors, to seep out and form a clot over the damaged area. This clot serves as a scaffold for new tissue formation, stimulating the body’s natural healing response. Over time, this blood clot matures into what is known as fibrocartilage, which helps fill the defect.
Patient Suitability for the Procedure
Patient selection is important for the success of microfracture surgery. Generally, candidates are individuals with isolated cartilage damage, rather than widespread joint arthritis. The size and location of the cartilage defect are significant factors, with smaller lesions, typically less than 2 to 2.5 centimeters in diameter, showing more favorable outcomes.
Younger, active patients who experience pain or swelling from their cartilage injury are often considered good candidates, especially if they are motivated to participate in a dedicated rehabilitation program. Conversely, patients with extensive arthritis, those who are inactive, or individuals unwilling to commit to post-operative physical therapy are generally not recommended for this procedure. Overall joint health, including ligament stability and lower extremity alignment, also plays a role in determining suitability.
The Recovery Journey
Recovery following microfracture surgery is a gradual process, demanding patience and adherence to a structured rehabilitation plan. Immediately after the procedure, patients typically need to keep weight off the operated leg for several weeks, often using crutches for four to eight weeks, depending on the defect size and location.
Physical therapy usually begins within a few days of surgery and is integral to overall success. This often involves the use of a continuous passive motion (CPM) machine for several weeks, which gently moves the knee to promote healing and prevent stiffness. Rehabilitation progresses through phases, focusing initially on pain control, swelling reduction, and regaining range of motion, then moving towards strengthening exercises, balance training, and eventually a gradual return to higher-impact activities, which can take anywhere from four to twelve months.
Assessing Treatment Outcomes
Outcomes of microfracture surgery are subject to several factors, including patient age, lesion size, and rehabilitation adherence. The tissue formed after microfracture is predominantly fibrocartilage, differing from the original articular (hyaline) cartilage found in healthy joints. Fibrocartilage is durable scar tissue, but it lacks the smooth, resilient, and shock-absorbing properties of hyaline cartilage.
While many patients experience significant pain reduction and functional improvement in the short to medium term, the long-term durability of the fibrocartilage can vary. Studies indicate that positive results may begin to decline after a few years, particularly in older patients or those with larger lesions, due to the breakdown of the repair tissue. While initial improvements are seen, a notable percentage of patients may experience a decline in function after two to five years post-surgery. Larger defect sizes, such as those over 3.6 square centimeters, and prior knee surgeries have been identified as risk factors for needing additional interventions after microfracture.
Considering Other Treatments for Cartilage Damage
Microfracture surgery is one of several approaches for managing cartilage damage. Non-surgical options are often considered first, especially for mild to moderate injuries. These include physical therapy to strengthen muscles and improve joint mechanics, anti-inflammatory medications, and injections such as corticosteroids, hyaluronic acid, or platelet-rich plasma (PRP). Stem cell therapies are also an emerging non-surgical treatment.
For surgical alternatives, other procedures aim to repair or replace damaged cartilage. Osteochondral autograft transplantation (OATs), also known as mosaicplasty, transfers healthy cartilage and bone plugs from a less weight-bearing area of the patient’s own joint to the damaged site. Another option is autologous chondrocyte implantation (ACI), a two-stage procedure where a patient’s own cartilage cells are harvested, grown in a lab, and then reimplanted into the defect, aiming to create a more hyaline-like repair tissue. These varied treatment strategies highlight the importance of personalized medical advice to determine the most suitable course of action.