Microfracture technique for full-thickness chondral defects: Technique and clinical results

Articular cartilage defects rarely heal spontaneously. The changes are progressive and they become irreversible if no intervention is applied. Many techniques have been used in the past to include abrasion, drilling, tissue autografts, allografts, and cell transplantation. Physicians have taken a greater interest in treating chondral defects recently in part because of our better understanding of cartilage biology and pathology, and because of advances in imaging and arthroscopy. The senior author has developed a procedure referred to as the "microfracture" technique to enhance chondral resurfacing by providing a suitable environment for tissue regeneration. This technique has now been used in more than 1,200 patients. An arthroscopic awl is used to make multiple holes, or "microfractures," in the subchondral bone plate of full-thickness chondral defects. The holes are made as close together as necessary, but not so close that one breaks into another, thus damaging the subchondral plate between them. This technique usually results in microfracture holes that are approximately 3 to 4 millimeters apart (or 3 to 4 holes per square centimeter). The arthroscopic awls produce much less thermal necrosis of the bone than would a hand-driven or motorized drill. The released marrow elements form a "super clot" which provides an enriched environment for tissue regeneration. Long-term results, with follow-up covering more than 8 years, have been and continue to be very positive.