Bioceram Types 1, 2, 4, 5 (Kyocera)

In the 1970s, the use of hip prostheses spread from Europe to Japan, and two major factions were formed, the Charnley and Müller factions. Both sides advocated the excellence of their concepts and awaited the long-term results. Shikita, who was the first to use Charnley’s metallic head-on-polyethylene cup hip prosthesis in Japan in 1968, became the leader of the Müller faction. He emphasized the wear problem in Charnley’s prosthesis owing to the increased surface pressure of the small 22 mm-diameter head. He researched crosslinked polyethylene using γ-ray irradiation, as polyethylene wear affects the life span of artificial hip joints [1]. In 1971, Shikita was the first to use a crosslinked polyethylene artificial hip joint with a stem fabricated from COP steel (Mizuho Medical Industry) [2]. In contrast, ceramic sliding parts gained attention in Europe for wear resistance [3]. Shikita and Kyocera held an orthopedic colloquium in 1975 and worked on the development of a ceramic hip prosthesis in Japan [4]. To reduce polyethylene cup wear by alumina ceramic heads, 32 mm and 28 mm heads were fabricated with mono- and poly-crystalline alumina. Two types of stem designs were fabricated: KC-1 (Bioceram type 1) and KC-2 (Bioceram type 2) [4]. Subsequently, based on experience with KC-2, modified Type 4 and Type 5 designs were developed to facilitate stem insertion, even in dysplastic hips [5, 6].