Vilex offers a broad range of Dual-Thread™ compression screws, known in the trade as F-series. The smallest has thread OD of 2.0 mm and overall length of 6.0 mm and the largest is 14.o mm OD and length 250 mm.
The F-series are primarily titanium, although certain sizes will be
available in stainless. As with all Vilex implants and accessories, they are manufactured in the US and are FDA approved. Like all other Vilex screws, the F-series are cannulated, self-drilling and tapping, and possess a triple hand-sharpened cutting tip. The dual thread screws require the same instrumentation as conventional Vilex lag screws. The screw head is threaded and is also self-tapping. Depending on the screw size, countersinking may or not be necessary.
The F-series produce bone compression by virtue of the difference in pitch between the head thread and the screw thread. Depending on the intended application, the pitch of the head thread can be as little as 1/2 the pitch of the thread.
Indications
Vilex screws are intended solely for upper and lower extremities and are not intended for spinal use. The Dual-Thread compression screws are ideal for fractures in articular surfaces such as femur ball or metatarsal head because the screw head can be buried flush with the bone surface. However, because of their versatility, many surgeons employ these screws in virtually any situation requiring bone screws. Because the screw head is threaded and can be imbedded into the proximal cortex, the Vilex Dual-ThreadTM screws result in less tissue irritation and are less likely to back out even in poor bone quality.
