We achieved good short-term results with osteochondral grafts for cartilage defects using the following three approaches: (1) plugs were implanted at about 3-mm intervals for large lesions, (2) surviving cartilage was used for bone grafts in osteonecrosis of the knee, (3) lesions with exposed subchondral bone in the tibia did not undergo grafting if the lesion was small or moderate in size.
We performed osteochondral grafting in 243 patients (257 joints) from May 1997 to July 2009. In 53 patients (57 knees), lesions were larger than 400 mm2 and follow-up was done after more than 1 year. Among these, according to the International Knee Documentation Committee (IKDC) objective score, 14 knees in 13 patients (24.5%) were abnormal or severely abnormal.
We developed an ultrasonic measurement system to measure cartilage stiffness, surface roughness, and thickness. We evaluated the mechanical properties of the grafted cartilage (P), the surrounding normal-like cartilage (N), the gap (G), and the donor sites (D) on follow-up after osteochondral grafting using our ultrasonic device. P (106.2%) was significantly stiffer than G (49.3%) and D (65.1%), and P (93.2%) was significantly less rough than G (113.8%) and D (107.9%). In terms of cartilage thickness, there were no significant differences between the four sites. At follow-up, the grafted plugs had similar mechanical properties to that of normal cartilage after 1 year.
