Are K-wires still the standard of care for hammertoe proximal interphalangeal joint (PIPJ) fusion? Coughlin and coworkers found an 81 percent successful rate of PIPJ fusion in 118 toes using K-wire fixation.1 Lamm and colleagues similarly showed a 20 percent nonunion rate with PIPJ fusion and K-wire fixation.2 It seems that we should not be satisfied with any operation yielding a 20 percent failure rate. There are benefits to this technique. K-wires are inexpensive and easy to use. There are, however, many downsides to K-wires, including wire failure (breakage/bending), greater risk of infection, patient anxiety with removal, lack of compression and lack of rotational stability. I don’t believe we, as a community of foot and ankle surgeons, are done with K-wires altogether. In fact, we may come full circle in the coming years and crown K-wires as the “best” option for hammertoe success. Although it is a possibility, I doubt K-wires will continue to be the standard of care for hammertoe fusion. We do have ever increasing diversity in options for management of this common issue. Newer options, including stainless, titanium, nitinol, silicone, bioabsorbable, screw fit, press fit, adjustable, removable, large, small, straight and angled fixation devices, are expanding our hammertoe management strategies and surgical technique. So how do we choose? Cost is one important deciding factor in any medical situation, especially with the current healthcare environment. Surgeons often correct hammertoes at a surgical or outpatient clinic that does not get favorable reimbursement (at least in my area) for the implant, which makes it economically challenging. One option for cost containment is to examine the revenue of one toe with an implant versus multiple toes with implants. Perhaps an isolated toe with implant adds revenue for the center whereas multiple toes and implants may not. Also, if one performs adjunctive procedures, such as metatarsal osteotomies or a bunionectomy, the increased charges may allow hammertoe implant use and still allow for positive revenue. If one operates on multiple hammertoes, however, a PIPJ arthroplasty without implant or fusion with K-wire makes the most sense from a cost conscious perspective. Hopefully in the future, the reimbursement rules might change in favor of the surgical centers in years to come. Surgeon familiarity is another factor in choosing hammertoe equipment and technique. We do not yet have the literature to demonstrate the superiority of one implant over the others. It is likely that all of the implants have the ability to facilitate union and successful patient outcomes. The deciding factors may be surgeon confidence and technique with a particular implant. It may be best to choose a favorite implant or a few implants, “master” their use and recognize the best indications for each. If one is getting undesirable results with a given implant, fortunately he or she can exchange it out of the surgical tool belt for another option. Finally, implant availability is an important factor in the choice of technique. Some implants are lacking representation. Some implants are so new to the market that they aren’t available in one's home region. After considering cost, comfort level and implant availability, consider adding a newer generation hammertoe implant to your surgical repertoire, especially if you have had failures with K-wires in the past. My own personal strategy is to always have K-wires available as a backup but I am enjoying success with some newer toe implant technology. References 1. Coughlin MJ, Dorris J, Polk E. Operative repair of the fixed hammertoe deformity. Foot Ankle Int. 2000; 21(2):94-104. 2. Lamm BM, Riberio CE, Vlahovic TC, Fiorilli A, Bauer GR, Hillstrom HJ. Lesser proximal interphalangeal joint arthrodesis: a retrospective analysis of the peg-an-hole and end-to-end procedures. J Am Podiatr Med Assoc. 2001;91(7):331-6.
Choice of fixation in hammertoe surgery needs to take into consideration the focus of deformity. There are a number of options, including implants, available when the primary focus is at the PIP joint. Significant contracture at the MTP joint is not addressed by PIP joint implants and may benefit from the use of k-wires. Claw toe type deformity in which a k-wire traverses both IP joints and the MTP joints may be superior. There are new PIP joint implant designs that allow placement of a k-wire through the implant.
There is a distinct paucity of literature to support the use of digital implants for digital arthrodesis. The sparse literature which does exist to support the use of digital implants is almost entirely corporate-sponsored. Generally, in the few head-to-head studies available, K wires have been demonstrated as not being inferior to the utilization of digital implants. The significant cost of digital implants can only be justified by the demonstration of significantly superior outcome when compared to Kirschner wires. Another factor to consider is our complications. Almost all Kirschner wire associated complications can be addressed simply by removal of the Kirschner wire. Removal of failed digital implant arthrodesis is frequently complex, requires a good deal of bone destruction, and leaves the patient with permanent swelling and associated local symptoms. At the present time, I do not believe there are any compelling reasons to prefer a digital implant over the use of Kirschner wires for digital arthrodesis. Certainly, the use of digital implants is not the standard of care.