Prospects for bone fixation—development of new cerclage fixation techniques

Abstract

The principles for the fixation and treatment of bone fractures have been well established based on the multidisciplinary studies performed by the Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of Internal Fixation (AO/ASIF group). As the basis for modern internal fixation of fractures, these principles are presently supported by the majority of orthopedic surgeons. However, with recent advances in bioengineering and biomaterials, it has become necessary to reconsider these principles. We focused our attention on cerclage fixation, which is not considered so important by the AO group, and developed two new cerclage materials. One is a nylon strap that is in wide industrial use. In the field of orthopedics, Partridge first employed the nylon strap for internal fixation and demonstrated its efficacy in 1976. However, its use was thereafter discontinued because of various complications. We developed a nylon strap for temporary fracture fixation and demonstrated its efficacy in clinical studies. We also developed a bioabsorbable thread for the tight tying of bones. Bone fixation with a thread is sometimes used clinically, but adequate fixation often cannot be obtained because of loosening of the knot. Therefore, we prepared a blended thread by mixing poly- l-lactic acid (PLLA) and ε-polycaprolactone (PCL) fiber, so that it could be fixed tightly by melting. The fatigue strength of this thread was higher than that of a stainless-steel wire with the same cross-sectional area. We are aiming to establish more effective and convenient methods of treatment by developing new bone fixation materials and examining their efficacy. In the future treatment of fractures, it will be important to develop new instruments and bone fixation materials for the purpose of standardizing the procedures used by surgeons.