Macroscopically normal cartilage from the human osteoarthritic femoral head. II. Measurement of cartilage thickness and cell density.

Cell density and thickness of macroscopically "normal" cartilage from 32 osteoarthritic (OA) femoral heads removed surgically have been studied by using histomorphometry. The results have been interpreted with special reference to qualitative aspects of regions analyzed at a microscopic level. OA cartilage with a microscopically normal appearance have a normal cell content and thickness except for the region adjacent to the zone of cartilage cleavage where a significant reduction in superficial cell density was found. OA cartilage showing middle tissue layer lesions such as unmasked fibers was characterized by an almost normal cellularity but a significantly increased tissue thickness.