Implant Offers Unique Benefits For Intramedullary Fixation

Whether one is repairing a hammertoe deformity or seeking a better fixation option for a hallux interphalangeal joint fusion, podiatric surgeons may want to consider an implant that offers a two-piece locking design, a larger diameter and a viable alternative to K-wire fixation.

   The StayFuse Intramedullary Fusion Device offers an interlocking two-piece titanium screw that snaps together for intramedullary fusions of small bones, according to Tornier, the manufacturer of the device. The company notes that podiatric surgeons can use the StayFuse for fusions or fracture fixation of toes and small bones.

   Charles Zelen, DPM, has put in over 1,000 StayFuse implants over the past nine years. He credits the locking mechanism of the implant for facilitating enhanced stability.

    “(The implant) locks into place for unparalleled stability during the healing process,” explains Dr. Zelen, a past President of the Virginia Podiatric Medical Association.

   Kurt Massey, DPM, also praises the two-piece locking design of the StayFuse implant and the availability of multiple proximal and middle phalanx implant size configurations.

    “Other intramedullary fixation devices are one-piece designs, which do not give the option of mixing different proximal and distal implant sizes to match specific bone geometries,” notes Dr. Massey, who is board certified in foot surgery and reconstructive rearfoot and ankle surgery.

   Dr. Massey says another key difference between the StayFuse device and other implants is a larger diameter.

    “The StayFuse device has a relatively larger diameter than competitive implants where it actually crosses the arthrodesis site and is therefore more resistant to fatigue failure during the cyclic loading experienced during gait,” maintains Dr. Massey, who has performed approximately 60 procedures with the StayFuse implant. “ … An implant with a smaller diameter at the actual arthrodesis site is more prone to mechanical failure during the time the patient is weightbearing prior to osseous fusion.”

   Podiatric surgeons can perform the StayFuse implant procedure through a “very small incision” and can achieve accuracy with toe length on the operating room table “for a great cosmetic result,” according to Dr. Zelen, a Fellow of the American College of Foot and Ankle Surgeons.

   Dr. Massey says the relative strength of the StayFuse implant also gives surgeons the option of slightly lengthening an iatrogenically shortened digit in a more sedentary patient.

    “We often face revisions of failed arthrodesis/arthroplasty procedures in which the iatrogenically shortened toe is a problem both cosmetically and functionally,” notes Dr. Massey. “It is possible to create a ‘gap’ between the proximal and middle phalanx by not completely inserting the proximal implant into the proximal phalanx. This, in effect, lengthens the toe at the expense of forfeiting osseous fusion at the site. … While intramedullary devices are load sharing by design, the StayFuse device is unique in its ability to support load bearing in a more sedentary patient due to the larger diameter of the implant where it crosses the gap created at the arthrodesis site.”

   Dr. Zelen says the StayFuse device would be contraindicated in the presence of active infection, malignancy or when the bone stock will not support the threaded components of the device. Other contraindications include peripheral vascular disease, peripheral neuropathy and sensitivity to titanium, according to Dr. Massey.