title: [A new intramedullary nailing system for long bone fractures--biomechanical evaluation and animal study of a new intramedullary nail].
abstract: Interlocking intramedullary nails have expanded their application to the fixation of long bones especially for unstable or comminuted fractures. However, there are certain drawbacks in this method: prolongation of operative time and increased radiation hazard to the patient as well as to the surgical staff, the latter of which is especially a problem in the distal interlocking under fluoroscopic control. In order to solve the problem a new intramedullary nail (J-type) was developed and tested in vitro with Hiprox femur models as well as in vivo using canine models. The nail made of Ti-6Al-4V alloy is composed of an inner nail and an outer cylinder. The proximal portion is transversely fixed with two screws, while the distal portion is fixed into the cancellous bone with four expandable blades. The strength of fixation with this nail was compared to those with four other commercially available interlocking nails as to bending, tortional and compression stiffness as well as to the durability against repeated compression. In the present in vitro and in vivo experiments, a newly developed intramedullary nail (J-type) provides evidence for satisfactory mechanical strength. The use of J-type nail also contributes to shorter operative time and reduction of radiation hazard.
authors.affiliation: Department of Orthopaedic Surgery, Juntendo University, School of Medicine, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Uta
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001858:Bone Nails / Q000592:standards*; D004285:Dogs; D005069:Evaluation Studies as Topic; D005260:Female; D005264:Femoral Fractures / Q000601:surgery*; D007432:Intraoperative Period; D008297:Male; D011833:Radiation Injuries, Experimental / Q000517:prevention & control; D013314:Stress, Mechanical; D013997:Time Factors