Microfracture significantly improved knee function in patients with isolated full-thickness cartilage defects of the femur, Kai Mithoefer, M.D., reported at the annual meeting of the American Academy of Orthopaedic Surgeons.
His prospective evaluation of the common technique, which involves clearing out defective cartilage and creating a series of holes in the subchondral bone to stimulate growth of fibrocartilaginous repair tissue, showed that best results were obtained in patients who had good repair tissue fill (as opposed to moderate or poor fill), low body mass index (BMI), and symptom duration less than 12 months.
In the study, 48 patients were evaluated, with a minimum 2-year follow-up, using a combination of validated outcomes scores—including the SF-36 and Activities of Daily Living scores—cartilage-sensitive MRI, and a subjective rating. Most patients were male; they averaged 21 years of age.
Patients with good fill grade “had significantly more improvement in all the scores than patients with moderate fill grade,” reported Dr. Mithoefer, of Massachusetts General Hospital, Cambridge. Lower BMI was associated with better functional outcomes. Poor fill grade was associated with limited improvement and decreasing functional scores after 24 months. Patients with poor fill grade also had higher BMI and a longer duration of symptoms, he reported.
In another study of osteoarticular transplantation surgery for large full-thickness cartilage defects of the knee, investigators found that 80% of 58 patients who underwent the procedure demonstrated significant improvement at an average of 36 months, reported Albert W. Pearsall IV, M.D., of the University of South Alabama Knollwood Park Hospital in Mobile.