MedShape Presents Smaller IM Nail Size at AAOS

MedShape Inc., an Atlanta, Ga.-based company that focuses on shape-memory orthopedic devices, has introduced a 10 mm version of its DynaNail ankle arthrodesis nail. This smaller DynaNail expands the use of the intramedullary (IM) nail to patients with narrow bone anatomies that require smaller fusion devices. MedShape will show samples of its 10 mm and older 12 mm DynaNail devices at the American Academy of Orthopaedic Surgeons 80th Annual Meeting in Chicago, Ill., held March 19-23.

Shape-memory alloys “remember” their original, cold-forged shape, returning to the pre-deformed shape when heated. Nitinol for orthopedic applications is manufactured to respond to body temperature.

According to the company, DynaNail is meant as an alternative to external fixators for performing tibiotalocalcaneal (TTC) arthrodesis procedures. The nail is made of nickel titanium (nitinol), which has shape-memory properties, and is designed to sustain compression across the joint on the level of an external fixator. Compression across the joint is important for ensuring the joint bones remain in close apposition and in promoting healing. Because DynaNail is supposed to eliminate the need for external fixators, the company claims that is reduced surgery time and minimizes the need for follow-up procedures. The method of insertion for DynaNail is the same as it is for traditional IM nails, so it does not require additional physician training.

“Surgeons have a number of product options when considering intramedullary rod fixation for treating complex ankle and rear-foot fusions,” said Randall Brower, M.D., D.P.M., of Desert Canyon Foot and Ankle in Phoenix, Ariz. “The DynaNail is the only ‘fourth generation’ rod to utilize new pseudoelastic nickel titanium technology. This has been a game changer with 100 percent fusion in all cases I’ve used it in to date.”

The insertion process requires surgeons to increase the size of the implant tunnel across the tibiotalocalcaneal (ankle) joint until they get “chatter” from the drill. Once the surgeon completes the tunnel drilling, either DynaNail size (10 mm or 12 mm) may be chosen depending on tunnel size. The new 10 mm size not only serves smaller bone anatomies, but is also a less invasive option while still retaining the compressive power provided by the Nitinol.

Jeremy Blair, team leader at DynaNail, said he and his colleagues are “enthusiastic about [the 10 mm DynaNail’s] efficacy in orthopedic surgery.”

Editor’s note: MedShape will be at AAOS booth number 4056 at the McCormick Place convention center.

Photo: Ken Gall (left) and Kurt Jacobus display MedShape’s DynaNail device, along with a lower-extremity skeleton that represents the surgical target. Photo courtesy of Georgia Institute of Technology / Gary Meek.