Trends in Hammertoe Surgery

Traditional fixation methods for Hammertoe Correction include cerclage wire and external k-wire fixation for the past 40 years. As of recently though, these traditional methods have been challenged by new fixation options such as screws (BioPro Digital Compression Screw, Vilex Digital Fusion Toe Implant), staples (SBI StaFix Staples), and suture anchors (Core Essence ReNOVO). Additionally, a new breed of hammertoe implants has become increasingly popular including Nitinol shape memory implants, (BME Hammerlock, Stryker (MMI) Smart Toe), peg and hole implants (Wright Medical Pro-Toe VO, Tornier StayFuse), and now Arrow Tipped Implants (Arrowhead ARROW-LOK).

But does it all make a difference? Do these new techniques have an advantage over the standard k-wire? In most cases, the external k-wire is fast, technically straightforward, and inexpensive. Unfortunately with this technique, patients have the added morbidity of a pin protruding out the end of their toe(s), the possibility of a pin tract infection and the anxiety and discomfort involved with removing the pins. There’s a saying that you can’t teach an old dog new tricks, but this may be one worth trying, as newer fixation methods for hammertoe correction can offer some patients a better option.

Specifically in regards to hammertoe implants, three different types have evolved and are now available on the market. First, the memory shape metal implants have taken off in recent years and have become popularized as one of the go to standards in internal options. The BME Hammerlock and the MMI Smart Toe are two Nitinol implants available that have received the most attention and have really opened the door for similar implants to follow. The drawback to these implants is the specific temperature requirement needed to store the implant prior to insertion along with the time sensitive nature of the implant once it is removed from its cryo-preserved state. If the implant is not inserted in a timely manner, the arms of the device can open, hindering the implant’s insertion. Additionally, the implant does have the ability to break over time if stressed above and beyond its modulus of elasticity. In most instances, this does not lead to problematic symptoms and can be monitored over time. Take a look at the new BME Speed as it has eliminated the need for temperature regulation while still utilizing the benefits of the nitinol.

Next up are the peg and hole type implants such as the Tornier StayFuse implant and the Wright Medical Pro-Toe VO. Rather than inserting a time sensitive implant whose legs expand with body temperature, these implants are directly inserted into both ends of the fusion site. From there, the two independent pieces are joined together, creating a stable construct. Lastly and the most recent implant to come to the table is the Arrow-LOK implant. A variation from a buried k-wire, this implant is the most straightforward and simple implant on the market. Even so, initially it is technically demanding and takes a few reps before it becomes second nature (which it does). The 3-dimensional arrow tipped implant is available in both straight and angled options.

So in the end there are a variety of options that surgeons can choose from when correcting hammertoes. The gold standard has been the external k-wire, however, newer implants (at a cost) have demonstrated predictable results with added patient benefits. These new generation implants offer patients the option of internal fixation and potentially less morbidity.