Tensioning Wires with a Dyna Wire Tensioner

by IMEX Veterinary

Proper wire tensioning of small diameter wires on circular and hybrid fixator frames is simple when using the semi-calibrated Dyna wire tensioner. Recommended tension levels vary according to ring diameter with 66 mm rings at approximately 57 kg, 84 mm at approximately 81 kg, and 118 mm rings at approximately 95 kg. The 50 mm rings in the standard size system and any rings used with the mini CESF system should not be tensioned.

Three rings on the Dyna wire tensioner body indicate approximate tension levels for the three ring diameters that are tensioned. These lines represent the maximum tension to apply to the corresponding ring diameter and surgeons should feel free to stop before reaching that level of tension if they determine adequate tension has been applied. In addition, some surgeons recommend tensioning wires placed across partial rings less than wires across complete rings. The guidelines outlined above are based on complete rings.

Figure 1 | Illustration of IMEX Dyna Wire Tensioner

Wire Tensioning Steps

1. It is important that the wire tensioner’s locking bolt (A) be toward the tip of the tensioner when ready to tension wires.
2. Before tensioning, verify that the wire fixation bolt (B) holding the fixed end of the wire to the ring is secure.
3. It is also important to use two-wrench technique to tighten the bolt and nut. If a single wrench is used to tighten the wire fixation bolt, the wire may be bent at the wire –bolt junction. This bending can result in displacement of the bone or wire damage.
4. With the opposite end of the wire secured, verify that the wire fixation bolt on the end to be tensioned (C) is not locked. Open the Dyna wire tensioner locking bolt (A) and pass the wire to be tensioned into the tip of the tensioning device. Push the tensioning device onto the ring surface and then use a single wrench to tighten the Dyna wire tensioner locking bolt (A) onto the wire.
5. Holding the wire tensioner body (D) in one hand, turn the larger butt cap (E) clockwise to tension the wire. Increased tension should be felt with every turn.
6. If tension does not increase rapidly and consistently, either the Dyna wire tensioner locking bolt (A) is loose, or the wire is loose on the opposite side of the ring (B).
7. At this level of tensioning, the axis of the tensioner wants to ride up due to the wire tension involved. It is important to keep the tensioner in line with the wire in order to not increase or decrease tension inadvertently.
8. Using a two-wrench technique, secure the tensioned wire to the ring by tightening the wire fixation bolt (C) adjacent to the tensioner
9. Once both ends of the wire fixation bolt are secure, rotate the tensioner butt cap (E) counter-clockwise to remove any residual tension in the device.
10. Then use a 10 mm wrench to loosen the Dyna wire tensioner locking bolt (A) and remove the wire tensioner from the wire.