This blog is dedicated to the ultimate podiatry oxymoron: a simple hammertoe surgery of the fifth toe.
When it comes to foot surgery, we all got our start working on toes. In school, we all learned the three etiologies of hammertoes: extensor substitution, flexor substitution and flexor stabilization. Based on those theories, we learned a surgical algorithm. Once we got into residency, we learned that nobody really used the "textbook" for making a decision on what to do surgically.
So it came down to “arthroplasty versus arthrodesis.” You quickly learned that some of your attendings were arthroplasty guys and some were fusion guys. When it comes to the fifth toe, we all learned that you never do an arthrodesis (with the rare exception in a neurologic foot). This is where people fall into a trap with the fifth toe.
Let me elaborate. Let us say you have a patient with hammertoe and corn on the fifth toe, and you recommend surgery. What are you going to do? We have already established the fact that you are not going to do an arthrodesis. Therefore, you are going to do an arthroplasty, right? So you go and do an arthroplasty and it works most of the time. What about the times when the surgery does not work? Why does the corn remain or move to a slightly different location?
I think we can all agree that the most difficult hammertoe to correct is the crossover second toe. There is a lot of intra-operative decision making. There is a stepwise approach to correcting the transverse plane deformity after the “hammertoe” is fixed. To that end, I have always believed the fifth toe closely rivals the second toe in complexity and for surgical planning.
Key Preoperative Considerations
So how many times do you book that patient for a hammertoe repair on the fifth toe and you go through the motions, do an arthroplasty and call it a day? I am going to share with you some of the critical checkpoints that I go through when planning a fifth toe surgery.
1. What is the position of the toe/nail when weightbearing and non-weightbearing? Does the toe need to be derotated?
2. Does the toe purchase the ground on weightbearing? If it is floating, then doing an arthroplasty alone will most likely fail to resolve the patient's symptomatology.
3. Consider the location of the corn. Is it located dorsally, dorsolaterally or mostly laterally? A corn located due north on the toe is most likely a digit with only a sagittal plane deformity. A lateral lesion is usually present in a toe with adductovarus deformity.
4. As far as X-ray evaluation goes, is there symphalangism of the middle and distal phalanges? Is the middle phalanx wide and irregularly shaped (spool/spindle shaped), or does it have a prominent lateral condyle? Toes with symphalangism are more rigid and more likely to have distal corns over the middle and distal phalanges.
Certainly, there are probably infinite combinations of possibilities when evaluating each fifth toe. When it comes to bone work, I will consider doing a lateral hemiphalangectomy of the middle and distal phalanges along with the head resection of the proximal phalanx if the corn is mostly lateral and oblong encompassing both the proximal and middle phalanges. If there is a "double" corn, then two bone segments are involved. When there is symphalangism, there is a greater likelihood of a Lister's corn in addition to the run of the mill proximal interphalangeal joint (PIPJ) corn.
A lot of decision making comes into play when considering soft tissues. If the toes are not purchasing the ground, then you will need to consider at the very least an extensor hood recession of the extensor tendon and a dorsal capsulotomy of the metatarsophalangeal joint (MPJ). If you are doing a revision in a patient with a longstanding deformity, you may have to consider skin lengthening techniques.
In the more severe deformity, I will also consider taking a plantar skin wedge resection in the sulcus to keep the toe down. There are times when you may consider using a K-wire in the fifth toe, especially when you are dealing with a floating hammertoe. I prefer not to do a flexor digitorum longus tendon transfer but it is always in the back of my mind for the most severe deformity.
Adductovarus influence on the fifth toe can be very strong. In this case, more often than not, one would perform a derotational skin plasty. I have found that a more aggressive skin wedge design is best.
So the next time you are going to book your simple fifth toe hammertoe surgery, take the time to do a thorough exam. Look at the position of the toe when weightbearing, when the foot is relaxed and the location of the corn. Study the X-rays to get clues as to the “bone(s)” causing the problem.