- Discussion:
- interfragmentary screw fixation can be easily and securely combined w/ the
use of an anterior tension band which provides resistance to fracture
displacement from anterior distraction when knee is in extension as
well as resistance to displacement as the knee moves into flexion;
- this method is most appropriate for simple, non-comminuted transverse frxs;
- screw types:
-
3.5-mm cortical screws are best suited for this;
- technique uses 4.0 to 4.5-millimeter cannulated screws;
- 4.0 or 4.5-mm screws to be the most appropriate;
- provisional fixation can be achieved w/ cannulated-screw guide-wires
or with reduction forceps;
- screws are placed across the fracture in lag fashion, w/ threads
engaging only the far side of the fracture;
- screws are best left 4-5 mm short of measured length;
- of tension-band wire is placed through one of the cannulated screws;
- then placed over the anterior surface of the patella
- then thru center of other cannulated screw
- then back over anterior surface of patella, where it is twisted to other
end of wire;
- two twists in the wire can be used to tighten each limb of the
tension band symmetrically;
-
cautions:
- it is essential the screw threads cross the fracture site w/o protruding thru the far cortex;
- in the case of a proximal fracture, the screws should be inserted from superior to inferior (instead
of the usual inferior to superior);
