1. Development of longer lasting artificial joints:

  Professor Kazuhiko Ishihara of Material Engineering and we developed a nanometer scaled surface modification technique to graft a phospholipid polymer, 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer, onto the surface of polyethylene (PE) with carbon covalent bonding. This treatment changes the character of the PE surface from hydrophobic to hydrophilic. Due to a newly formed water layer, the frictional force between joint surfaces decreases drastically. We also proved that wear debris barely induces osteolysis in tests involving animals. Japan Medical Materials Corporation has performed a clinical trial of a total hip with an MPC polymer grafted PE liner and is preparing application for a marketing authorization.

2. Three dimensional assessments of joints:

  Each joint has unique and complex structures. Moreover, injuries and diseases add a wide variety of changes. Thus, it is not easy for surgeons to understand the detailed anatomy of individual joints. We are studying the practical utility of three-dimensional bone models constructed by the lamination layer technique in consort with Dr. Tatsuro Karita. These models are useful not only to plan difficult operations, but also for training less-experienced doctors.

3. Strategic studies on long-range joint reconstruction:

  Joint reconstruction should be planned with a long-range prospect, especially for young individuals with some anatomical burden. For example, acetabular dysplasia is a comparatively common hip disorder in Japan. Young adults sometimes suffer sharp hip pain because of this disorder. The late Dr. Hiroshi Tagawa had developed a new surgery for these individuals, a rotational acetabular osteotomy (RAO), in 1968. Later, the late Dr. Setsuo Ninomiya modified the surgical technique and taught his procedure to many surgeons. We are studying the long-term results of RAO in cooperation with Dr. Yurie Koyama, a researcher in the field of nursing science. We are also studying the best setting of an artificial hip joint in individuals who had undergone RAO, utilizing a three-dimensional bone model. These studies will provide an empirical basis for a rational decision-making in clinical settings.