Lesions exceeding 150 mm² require OATS mosaicplasty: marrow stimulation produces fibrocartilage that breaks down within two to three years, whilst transplanted hyaline cartilage lasts decades.Lesions exceeding 150 mm² require OATS mosaicplasty: marrow stimulation produces fibrocartilage that breaks down within two to three years, whilst transplanted hyaline cartilage lasts decades.