Ilizarov wire tensioning and holding methods: a biomechanical study.
OBJECTIVE
To investigate and compare two specific methods of Ilizarov wire tensioning and hold.


METHODS
This study utilised the vertical Hounsfield test machine H25KS, a stress/strain device with a load-cell linked to a computer program. Firstly, the department's present mechanical tensioners were assessed. Secondly, the method of twisting the three designs of wire holding bolts to achieve wire tension, as described by Ilizarov, was assessed. These bolts are described as "cannulated", "slotted" and "Russian" (which are hexagonal headed with a slot down one side).


RESULTS
The mechanical tensioners were found to be accurate, if inefficient, with a maximum producible tension of 1330N. The most effective bolts for creation of tension were the Russian, which produced mean wire tensions of 785N at 45 degrees; 1200N at 90 degrees; 1695N at 135 degrees. The cannulated and slotted bolts regularly broke the wires at 90 degrees twist.


CONCLUSIONS
The findings demonstrated two effective methods. The present tensioners were found to be inefficient when compared to the simple twisting of the wire holding bolts, which created equivalent tensions with ease and are capable of producing greater wire tensions. The Russian bolts are recommended for use when wire tension is created by bolt twisting.
Davidson
A W
AW
The Orthopaedic and Trauma Department, The Royal London Hospital, Whitechapel, London E1 1BB, UK. alastair_davidson@hotmail.com
Mullins
M
M
Goodier
David
D
Barry
M
M
D001696:Biomechanical Phenomena; D001864:Bone Wires / Q000592:standards*; D004867:Equipment Design; D006801:Humans; D018889:Ilizarov Technique; D013314:Stress, Mechanical; D013718:Tensile Strength