J Korean Orthop Assoc.  1998 Dec;33(7):1928-1932.

Axial Stiffness of the Ilizarov Frame Using the Rancho Mounting Technique

• Oh JK
• Park JH

Abstract

The Ilizarov fixator allows significantly more axial motion at the fracture site than the conventional monofixators. But the transfixing wires have inevitable problems of soft tissue impalement. Therefore the Rancho mounting technique, replacing the transfixing wires with half pins, has become a common place. But the increment of the axial stiffness secondary to replacing transfixing wires with half pins has not been defined clearly yet. The authors measured the axial stiffness of the Ilizarov fixator and two different configurations of the Rancho frame. The group I frame was the Ilizarov fixator composed of four rings and two transfixing wires on each ring. The group II frame was the Rancho frame and it was constructed same as the Ilizarov frame but a transfixing wire was replaced with a half pin from two central rings respectively. The group III frame was another type of Rancho frame which was constructed same as the second group but the remaining transfixing wire was replaced with a half pin from the two central rings respectively. The axial stiffness of the Group I , II and Group III frames were 71.54+/-7.21N/mm, 89.65+/-6.42N/mm, 101.01+/-7.92N/mm respectively. The axial stiffness difference between the Group I frame and the Group II frame was statistically significant(p<0.01). Also the difference between the Group I frame and the Group III frame was statistically significant(p<0.01). This study shows that the replacement of two transfixing wires with two stainless half pins resulted in significant increment of the axial stiffness of the Ilizarov frame.

Keyword

Ilizarov fixator; Rancho mounting technique; Axial stiffness