Twenty-six hips (19 patients) with osteonecrosis of the femoral head with stage I or II of the disease, according to the Ficat and Arlet classification, underwent core decompression. Osteonecrosis was confirmed histologically in all 26 hips. Of 19 patients, 7 had prognostic factors traditionally associated with poor outcome including collagen vascular disease and continued use of steroids. The follow-up period averaged 7 years 10 months (range: 2 years 5 months-13 years 8 months) for 17 patients with 24 hips. Two patients died secondary to systemic illness. Seventeen hips (65.4%) had very good or good results using the Ficat criteria. Eight hips (30.8%) needed further operation [total hip arthroplasty (THA) for 7 hips, osteotomy for 1 hip]. Of the 12 hips in patients who had used steroids, 6 hips (50%) were converted to THA. Four hips in patients with systemic lupus erythematosus (SLE) needed THA (100%). We conclude that core decompression provides an effective treatment for steroid-associated osteonecrosis other than in cases with SLE, as well as providing effective treatment for non-steroid-associated osteonecrosis in the early stages of the disease.

To determine the role of the periosteal flap in chondrocyte transplantation for the treatment of articular cartilage defects, a cartilage defect was created on the patellar groove of the rabbit knee. The defect was filled with chondrocytes cultured in collagen gel, and was covered with a periosteal flap the cambial layer of which was facing the patella (P group), or facing down against the bone marrow (M group). The same defect was covered with a periosteal flap that was frozen and thawed three times (F group), and an artificial collagen film (C group). At 3 and 6 months, the defects were filled with reparative tissues that showed a smooth surface and resembled hyaline cartilage in the P, M, and F groups. There were no significant differences between the reparative tissues in the three groups histologically, immunohistochemically, biochemically, and biomechanically, although the collagen film fell down into the defect and the reparative tissue had a fibrous tissue-like appearance. These results showed that the periosteal flap does not have a beneficial humoral or cellular effect on the formation of reparative tissue, suggesting that the periosteal flap might act as a mechanical barrier to prevent leakage of grafted chondrocytes.

Forty-eight mature male Japanese white rabbits were subjected to unilateral resection of a segment of the gluteal muscles at the sacral origin and a section of infrapatellar ligament. Animals were killed at 1, 2, 4, and 8 weeks postoperatively, and the articular cartilage of the femoral heads was evaluated. The collagen fibrillar network of the articular surface was observed by scanning electron microscopy (SEM) using microdissection by ultrasonication. Cationized ferritin (CF) was used for the labeling of negative charges on the articular surfaces and the thickness of CF layers was observed under the transmission electron microscope. Metachromasia of the matrix decreased remarkably at 4 weeks postoperatively, and fibrillation of the articular surface was evident at 8 weeks postoperatively. Derangement and rupture of the collagen network developed as early as 1 week after surgery. The thickness of the CF layer significantly decreased at 4 weeks postoperatively. This study confirms that alterations of the articular surface, such as derangement of the collagen network and loss of the negative charge, are some of the earliest changes in osteoarthritis. In addition, application of ultrasonication with proper frequencies to the articular cartilage effects an optimal removal of mucus, with the consequent exposure of a well-preserved articular surface for SEM study.

We report herein the successful treatment of a patient with an osteochondral defect extending to the edge of the lateral femoral condyle by transplantation of tissue-engineered cartilage made ex vivo using atelocollagen gel covered by periosteum with a bone block to reconstruct the normal contour of the femoral condyle.