Cannulated Implant Adds Compression And Stability To Hammertoe Fixation

As fixation for common podiatric surgery procedures continues to evolve, a new cannulated implant may represent an innovative solution for hammertoe procedures.

The HammerFUZE™ Hammertoe Compression System provides maximum compression and stability in hammertoe surgery, according to the manufacturer Vilex. As the company notes, the completely cannulated HammerFUZE system offers straight and 10-degree angled titanium implants.

John Dawson, DPM, FACFAS, has used the one-piece Vilex HammerFUZE for about a year. Despite not routinely using toe implants in the past, he has found the use of the HammerFUZE implant to be “quite straightforward.”

The majority of hammertoes that Dr. Dawson treats surgically have deformity both at the proximal interphalangeal joint as well as the metatarsophalangeal joint (MPJ). In the past, he had used K-wires to hold the deformity correction across both joints because non-cannulated hammertoe implants only allowed for internal fixation across the interphalangeal joint.

Cannulation of implants allows surgeons to place K-wires precisely in the intramedullary canal, according to Vilex. The company adds that cannulation also facilitates the optional insertion of a wire into the metatarsal to attain additional stabilization during healing. Vilex notes the implant’s stop drill, broach and driver are also cannulated. With the HammerFUZE system, surgeons also have the option of temporary fixation with a K-wire.

“With the advent of cannulated implants like the HammerFUZE (device), I can still use a K-wire to hold the soft tissue correction across the metatarsophalangeal joint but use a long-term and likely more stable form of fixation for the proximal interphalangeal joint arthrodesis,” says Dr. Dawson, a Fellow of the American College of Foot and Ankle Surgeons.

Vilex notes the Ti6Al4V titanium alloy provides the HammerFUZE with enhanced strength and biocompatibility. The implant’s specialized distal end includes a three-pronged, 3D cutting surface, which the company says facilitates increased surface area contact for stable fixation. Furthermore, the implant also uses the CompTWIST technique for extra intraoperative compression. As Vilex notes, this technique is possible via the aforementioned distal end’s appearance, which is similar to the helix of a screw or a barb. In addition, the company notes the proximal end of the HammerFUZE comes with hand-sharpened cutting tips and is self-drilling and self-tapping, similar to a cannulated Vilex screw.

Dr. Dawson notes the HammerFUZE is appropriate for almost any patient who needs a proximal interphalangeal joint arthrodesis. However, he feels the device’s potential compression and long-term stabilization make it more beneficial for patients with decreased bone density or those who are likely to have slow healing.

“There will probably always be a place for the simple K-wire stabilization of a hammertoe,” says Dr. Dawson, who is affiliated with Mercy Medical Group in Folsom, Calif. “However, with these newer cannulated implants, one can have long-term stabilization at the proximal interphalangeal joint arthrodesis as well as the temporary stabilization across the metatarsophalangeal joint.”