We reviewed 28 knees with osteoarthritis (femoro-tibial joint) who had undergone high tibial osteotomy (interlocking osteotomy). They were evaluated by arthroscopy before and after surgery. We graded the arthroscopic cartilage and meniscal findings according to Fujisawa's classification. We observed fibrous tissue growing over the ulcer of the medial cartilage. Several knees had fibrillation at the lateral cartilage, but had no symptoms. One medial and lateral meniscus had fibrillation.
