Microfracture is an arthroscopic procedure to stimulate the body to create new cartilage in an area of full-thickness cartilage loss in the knee. Small holes are made in the underlying bone to release stem cells that form a repair tissue.
Performed arthroscopically. The damaged cartilage is debrided to a stable rim. Using an awl (a sharp pick), multiple small holes (3–4 mm apart) are made in the exposed bone. This allows bone marrow blood and stem cells to fill the defect and form a fibrocartilage clot. The operation takes 30–45 minutes.
Microfracture is recommended for small to medium full-thickness cartilage defects (typically less than 2–3 cm²) in patients under 40–45 years, particularly for lesions on the femoral condyle.
Physiotherapy, activity modification, injections, weight management. OATS or ACI/MACI are alternatives for larger defects.
MRI to assess defect size. Day-case procedure.
Formation of fibrocartilage repair tissue. Good short-term results in approximately 75–85% of patients. However, fibrocartilage is less durable than native hyaline cartilage, and results may deteriorate over five to ten years.
Non-weight-bearing for six to eight weeks to protect the healing tissue.
Common during healing.
The repair tissue is less resilient than normal cartilage and may degrade over time.
The repair tissue may not form adequately.
Excessive fibrocartilage formation.
Joint infection.
Loss of knee flexion.
General or spinal anaesthesia.
Non-weight-bearing for six to eight weeks. CPM machine may be used. Progressive rehabilitation. Running at four to six months. Return to sport at six to nine months.
Reviews at two weeks, six weeks, three months, and six months.
Microfracture is the simplest technique but produces fibrocartilage (less durable). OATS transplants true hyaline cartilage plugs. ACI grows hyaline-like cartilage in a laboratory. For small defects, microfracture is a good first-line option.