September 10, 2018
Kinamed Sales & Marketing Competitive Product Update on:
FiberTape® Cerclage System by Arthrex®
Introduction
Arthrex recently introduced an FDA-cleared all polymer “cerclage” product called the FiberTape Suture Cerclage System. It is made from gel-spun polyethylene, the same material used in the outer sheath of SuperCable®. However, this Arthrex® product has very different mechanical properties than SuperCable in that it does not contain an inner core of Nylon and it is not elastic to any appreciable degree. It also has no locking clasp and relies on a complex knot tying process to secure. Arthrex seems to be targeting their device to applications in the shoulder based on the information they provide on their website. Let’s take a closer look at the key differences between SuperCable and this Arthrex product.
Iso-Elastic™ Property of SuperCable
Gel-spun polyethylene fibers are by themselves extremely inelastic (they don’t stretch). The “Iso-elastic” property built into SuperCable is a key feature of the product and is produced by the interaction of the internal nylon core and the woven gel-spun polyethylene sheath. As you are already well aware, this Iso-Elastic property provides the following critical benefits that make SuperCable a truly revolutionary cerclage device:
- Elasticity stores energy such that the tensioned and stretched SuperCable applies a great deal of interfragmentary compression across bone fragments, yielding greatly increased stability of the bone construct;
- Repaired bone constructs often remodel and settle a little during the healing process and the Iso-Elastic property inherent in SuperCable allows it to take up this “slack” and remain tight around the bone to preserve stability;
- The cable elasticity absorbs energy from cyclic functional loads that are applied to the healing construct, such that the cable has much less tendency to saw or cut its way into the bone;
- With an inelastic cerclage device like FiberTape, the smallest amount of construct settling or penetration of the strands into the bone, as discussed above, can result in a significant loss of construct stability that negatively affects healing.
In short, the FiberTape may look good going onto the bone but we believe that during healing, the initial fixation will rapidly degrade. The Iso-Elastic property of SuperCable on the other hand tends to make the fixation not only very solid initially but also very durable throughout the healing phase of the fracture or osteotomy.
The locking clasp versus a knot tying exercise
The entire process of passing, tensioning, and tying of the FiberTape appears very complex based on the Arthrex’s own video demonstration of the product; and we can safely assume they did their best to make it look as easy as possible. A complex double pass around the bone is required, followed by threading of various strands to create an initial knot. A tensioning instrument is then applied and the FiberTape is tightened, followed by removal of the instrument and application of an additional knot, followed again by reapplication of the tensioning instrument and tightening, followed by additional knot tying to finally secure the device – phew! The whole process of passing of the FiberTape and then tensioning and tying it in place appears to be significantly more time consuming and cumbersome than applying and locking SuperCable. And importantly, once the FiberTape is tied, one cannot go back and add additional tension to the construct. The SuperCable locking clasp offers the great benefit of allowing the surgeon to easily go back later to bump up the cable tension after initial application and locking.
Here are Arthrex videos showing their rather involved surgical technique:
https://www.arthrex.com/sv/resources/animation/WpVjyJFfKU6nCgFhlPpaQw/fibertape-cerclage-system
Study on Related Arthrex FiberWire® Product Versus Metal Wire
A study by Renner, et al, on laboratory tests comparing the related Arthrex FiberWire product to plain metal wire showed that the Arthrex product was comparable to wire in some measures but was deemed inferior to plain metal wire in others:
“Conclusions: FiberWire Cerclages appear, in vitro, equally suitable to steel wires to stabilize nondisplaced periprosthetic humeral fractures. To actively reduce a displaced fracture, steel wires may still be the first choice.”
https://www.ncbi.nlm.nih.gov/pubmed/24810079
Summary
- FiberTape is not Iso-Elastic so it is unlikely to provide strong, durable compression over time;
- The FiberTape surgical technique appears to be cumbersome and time-consuming;
- FiberTape cannot be provisionally tensioned and re-tensioned later;
- A related Arthrex product was found in a study to be only equivalent to or less useful than mono-filament wire on various metrics (SuperCable has consistently been shown to perform better than wire).
Let us know if you come across pricing or additional competitive information about the FiberTape product. Please feel free to contact me (rbruce@kinamed.com) if you have questions.
Wishing you a strong finish to 2018!
Bob Bruce, VP, Global Marketing and Product Strategy