Intavent Orthofix

Contact: Sales Manager

Burney Court
Cordwallis Park
Maidenhead, Berks SL6 7BZ
UK

Phone: 01628 59450
Fax: 01628 78940

E-mail

Tapered Bone Screws

"Designed for Increased Holding Power"

The integrity of the pin-bone interface is vital to the success of external fixation; pin loosening must therefore be avoided.

The mechanisms of pin loosening are:

* Screw bending
* Unequal loading
* Pre-tensioning
* Pin track infection

This leads to. . .

. . . Lysis

Causing. . .

. . . Enlarged pin holes

Followed by. . .

Pin loosening

"What are the features of the Orthofix tapered screw that contribute to better purchase in the bone and stability of fixation?"

A Higher resistance to bending where it is most needed; at the near cortex

With a unilateral fixator, 60-70% of the load is exerted on the near cortex, (data on file). The greater screw diameter at the near cortex ensures a higher resistance to bending.

The Orthofix tapered screw

During insertion each screw thread cuts a new, slightly larger path in the bone.

Pre-drilling reduces the forces required for screw insertion and ensures an even load distribution.

The screw design thread geometry produces efficient radial purchase.

These design features combine to provide excellent bone purchase.

In addition, it has been shown that the act of dynamization itself - which is central to the Orthofix philosophy of fracture repair – reduces the stress on the screws and further enhances the security of screw fixation.

The 'Non-Orthofix' uniform diameter screw

During insertion each successive screw thread occupies the grooves cut in the bone by the previous threads.

This results in repeated and sustained erosion of the grooves.

The 'Non- Orthofix' uniform diameter self-drilling screw.

When the far cortex is encountered, difficulty may occur in penetrating the bone. The surgeon supplies additional force to insert the screw and the rapid insertion may cause the screw to advance into the bone like a wedge and rupture the cortex. Purchase may also be less than ideal, since continuity of the thread is interrupted by the flute.

At the near cortex, the force required for screw insertion may cause damage to the grooves already cut, and the screw entry hole is enlarged.

These design features may cause uneven load distribution and pin loosening.

Other benefits associated with the Orthofix tapered screws

They can be removed painlessly and easily in the out-patient department

Orthofix provides:

* The widest possible range of screw type and sized including cortical screws, cancellous screws and "cutting edge" screws for lengthening and bone transport procedures.
* Instrumentation designed to ensure a precise and standardised screw introduction technique with minimal trauma to associated soft tissue structures.
* A comprehensive postoperative pin-care protocol for the maintenance of trouble-free pin sites, an essential ingredient for the success of any external fixation procedure.