FiberWire is superior in strength to stainless steel wire for tension band fixation of transverse patellar fractures.

BACKGROUND: The metal implants used to achieve fixation of displaced transverse patellar fractures are associated with implant failure, postoperative pain and a significant re-operation rate. Recent studies have examined braided suture as a possible alternative to stainless steel wire to increase patient satisfaction and decrease re-operation rates, but suture has not demonstrated clearly superior fixation strength. FiberWire is a reinforced braided polyblend suture that has demonstrated superior characteristics to the previous sutures studied and has not to our knowledge been examined as a material for tension band fixation of transverse patellar fractures. METHODS: Materials testing was performed on repeated samples of No. 5 FiberWire suture and 18-gauge stainless steel wire. The strength and stiffness of each material was measured. The two materials were then used for tension band fixation on a novel transverse patellar fracture model and tested to failure by three-point bending. The constructs included a single stainless steel wire, a single-strand FiberWire tied with a sliding knot, double-strand FiberWire tied with sliding knots and double-strand FiberWire tied with a Wagoner's Hitch. The fixation strength and stiffness of the constructs were measured. FINDINGS: Unlike stainless steel, FiberWire maintained its initial stiffness until failure. Furthermore, during three-point-bend testing, double-strand FiberWire was found to have a significantly higher failure load than stainless steel wire when the suture was tied and locked under the tension produced by a modified Wagoner's Hitch. INTERPRETATION: FiberWire is a potentially superior alternative to stainless steel wire in tension band fixation of transverse patellar fractures.

Direct measurement of the electrogyratory effect in bismuth silicon oxide.

A direct measurement of the electrogyratory effect in bismuth silicon oxide is performed at wavelengths of 633, 543, and 442 nm. We experimentally measured the electrogyratory effect separately from the electro-optic effect. For externally applied electric fields ranging from 0 to 60 kV/cm, the contribution due to the electrogyratory effect is found to be negligible with respect to the contribution due to the electro-optic effect. Since devices employing bismuth silicon oxide typically require applied electric fields in this range, the electric field dependence of the rotary power is shown not to perturb the desired operation.