In my January blog, I wrote about the use of the flexor digitorum longus tendon transfer for the flexible or semi-rigid hammertoe/claw toe deformities (see http://www.podiatrytoday.com/blogged/why-flexor-digitorum-longus-transfe...  ). I would like to take a look at the other approach to the rigid hammertoe deformity and specifically arthroplasty vs. arthrodesis.
We often consider hammertoe surgery a “basic” surgery or “simple” surgery, but it can be fraught with complications. I have both seen and had my share over the years. I once heard the late Gerard Yu, DPM, lecture about hammertoe surgery, saying he disliked it so much, he would “manually reduce” (i.e. fracture) the hammertoe under anesthesia and percutaneously fixate it. He went on to discuss his frustration with hammertoe surgery. I can certainly relate to Dr. Yu’s comments with 24 years of hammertoe surgery under my belt.
The potential complications are well known for hammertoe surgery and these complications include: flail toe, swelling, pain, stiffness, loss of correction, lack of purchase, non-union, and the list goes on. The thing that is so frustrating about hammertoe surgery is the lack of reproducibility of what seems to be a fairly simple procedure. As I mentioned in my prior blog, the use of the flexor digitorum longus transfer when possible produces more consistent results in my opinion.
There are a couple of considerations for surgical correction of the rigid hammertoe deformity.
1. Arthrodesis versus arthroplasty
2. Fixation versus no fixation
3. Type of fixation
4. Soft tissue rebalancing
With any surgical deformity correction, the key to success is correction at all levels of deformity. I prefer to work proximal to distal with all multi-level surgical deformity reduction. In this case, I would address proximal soft tissue rebalancing first. The metatarsophalangeal joint (MPJ) is loaded but pushing upwards at the plantar aspect of the MPJ to see if the proximal phalanx reduces to a neutral position. If it does not reduce, I do an extensor tenotomy and, if necessary, a MPJ release. Then I reload the forefoot and check to see if the proximal phalanx is fully corrected. If not, I will use a McGlamry elevator to release the plantar aspect of the metatarsal head. This typically will correct more severe deformities that step one did not correct but there are those cases that still do not have full correction after this step. In those cases, I will either do a Weil osteotomy of the metatarsal head or a plantar plate repair. In my opinion, these procedures are infrequently required.
One would address the proximal interphalangeal joint with either an arthroplasty or an arthrodesis. I have done both over my career. Without a doubt, my preference is arthrodesis. It is the more predictable of the two procedures. I use a simple end-to-end arthrodesis using a #32 sagittal saw blade with minimal bone resection. It is important to resect enough bone to correct the deformity without shortening too much. I grab the head of the proximal phalanx with a one-two pick-up just behind the articular cartilage and then resect the head just proximal to the pick-up. For the base of the middle phalanx, I essentially shave it off just past the subchondral bone plate. I then feather the fusion site with the joint in complete reduction to ensure flush surfaces.
Fixation is another very interesting topic worthy of its own discussion. I have evolved from leaving in 0.062-inch K-wires for six weeks to using internal fixation hammertoe devices. I have pretty much used all the internal fixation options on the market, both 0-degree and 10-degree implants. I have also used internal threaded 0.062-inch K-wires. Which is my favorite? I do not like the angle options of any of the implants. I do not think any of the implants provide true compression. Many of the implants are too fragile and can easily fracture. The insertion technique for several of the implants can also be cumbersome.
Fingers and toes have a natural resting flexion. Therefore, fusion at 0 degrees results in a non-purchasing digit that acts like a “dead stick.” A stiff and straight toe typically produces poor patient satisfaction. The 10-degree implants can also result in poor patient satisfaction due to the toe still appearing to be contracted. K-wires, both external and internal, produce the same results as a 0-degree implant. I can’t recommend one implant over another at this time. Therefore, I recommend that you use the implant that produces the most reliable results for you.
Patients may progress from a cast boot or surgical shoe into a gym shoe after three weeks for internal fixation or six weeks for external fixation. Utilize buddy splinting with 1-inch Coban for approximately eight weeks.
Hammertoe surgery, although technically simple, can prove to be frustrating for both surgeon and patient. Correcting each level of deformity, performing arthrodesis instead of arthroplasty and ensuring adequate fixation and postoperative care can reduce frustration and improve consistency. A better hammertoe implant down the pike would also help.