[Aging process of the acetabulum with special reference to the osteophyte formation (author's transl)].

Osteophyte formation at the acetabulum was investigated in connection with aging and osteoarthritis. The materials consisted of 39 specimens of the acetabula obtained from fresh cadavers ranging from 14 to 89 years of age. Of those two of the specimens were in the second decade, two in the third, and others were over 40. Osteophyte appeared at three parts of the acetabula; the peripheral part, the foveal area and the lower portion at the ligamentous attachment. Two types of the peripheral osteophytes were distinguished from their growth direction, and in some sections both types were observed together. Foveal osteophytes were recognized at the rim of the semilunar cartilage in the advanced age group and a double acetabular floor was formed by both the osteophytic projection and the existing foveal trabeculae. In some cases there were small osteophytes formed in the ligamentous tissue at the lower ends of the acetabula. As distribution and growth of the osteophytes in the aging process were in accord with those in osteoarthritis, it would be reasonable to assume that the osteophyte formation in aging might be one of the initial changes of the development of osteoarthritis.