| Objective: Our team designed a drilling guide for K-wire in Tension-band And the double hollow sleeves, a new internal fixation of patella fracture with kirschner wire. The purpose of this study was to compare the biomechanical properties of tension bands made up with wires and k-wires or double hollow sleeves in internal fixation of patella fractures and to provide a new choice of the treatment for patellar fracture. The clinic study was to clarify whether the drilling guide could advance the function of Tension-band in internal fixation for patella fracture by improve accuracy of the location of K-wires.Methods: The study included the biomechanical and clinical studies. Biomechanical was divided into two sections.(1)transverse fractures at the equator of the patella were simulated in 8 adult cadaver knees and fixed successively with 3 steel-wire sizes and 4 configurations of tension bands in combination with K-wires. Biomechanical stability were tested by fracture gaps under cyclic loading and interfragmentary compression.(2)In this section, sixteen cadaveric knees were allocated to 2 transverse patella fracture fixation groups: tension bands of wires combined with Kirschner wires or double hollow sleeves. Biomechanical stability were tested by the biggest loads and interfragmentary compression as well as fracture gaps after the repetitive testing of 200 th cycles knee motion from 90°flexion to full extension.(3)In the clinical study, between October 2010 and October 2013,fifty-twe patients with displacement patella fracture were treated with AO modified tension-band wiring. The aiming guide was used during the surgery for twenty-nine patients of experimental group while it was not allowed to use during the surgery for patients of control group.Results:(1)fractures fixed with two wires around each K-wire respectively were more stable than fixed with single wire around two K-wires; and The interfragmentary compression were bigger until the wire break when the fractures fixed with 1.2mmdiameter wires, but fracture gaps were narrower when the fractures fixed with1.0mm diameter wires.(2)The results of the biomechanical study showed Interfragmentary compression and the biggest loads of double hollow sleeves group were bigger than the Kirschner wires group. Fracture gaps of double hollow sleeves group were smaller too except the vertical displacements when knees full extended after the 200 th cycles movement.(3)There were no significant difference in bleed volume whether the drilling guide for K-wire was used or not. Meanwhile,when the drilling guide for K-wire was used,the surgery time and using time of tourniquet were significantly shorter as well as the time to bony union of the fractures. Times of k-wires, drilling were significantly fewer, and placement of k-wires was more standard. The Bostman scores were graded as excellent and good in 92 % for patients with either a transverse or comminuted fracture when the drilling guide for K-wire was used.Conclusion:(1)Patella fractures could been fixed more stably with Tension-band wiring by adjusting size,figure and site of wire twists of stainless steel wire.(2)In contrast to modified anterior tension wiring with Kirschner wires, tension bands of wires combined with double hollow sleeves was a better fixation device to stabilize transverse patella fractures securely and sustainably.( 3) The drilling guide is reasonable in design and convenient in use. Moreover, it could improve the accuracy and quality of inserting K-wire in Tension-band wiring of patellar fracture. |
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