A New Approach For Correcting Hammertoe Deformities

Author(s): 
By Gerald W. Paul, DPM
You must also confirm the threads of the two component system will engage some cortical bone internally. If not, you will get a “pistoning” effect of the implant in the soft medullary bone. This is very similar to what you could see with an internally buried threaded K-wire technique. This pistoning will not set things up well for an arthrodesis. Obviously, you would want to resect as little off the base of the middle phalanx as possible as this bone is already short. You also do not want to disrupt an abundant amount of intrinsic tendon attachments. You also don’t need to perform an aggressive resection of the head of the proximal phalanx. Resection of the head can be at, or just proximal to, the surgical neck of the bone. You only need to resect enough bone in order to distract the middle and proximal phalanx. This will give you clearance for the two component system to “snap” parallel into each other, as well as fully reduce the deformity at this joint level. Excessive shortening of the toes is discouraged. When implanting the two components in bone, be aware that forceful manipulation is unnecessary. The soft medullary canal is very receptive to gentle drilling and implantation. I personally have not needed the power attachment bit and feel the risk is too high for a split bone cortex. I have found it very useful to slightly countersink the hex components on either side of the arthrodesis site. The male and female components will still engage and this does create some excellent bony apposition. It is highly recommended to insert the proximal (female) component first for obvious reasons. The “mid” or male portion is difficult to work around if you are still drilling and inserting the proximal portion at the joint. When You Are Snapping The Device Together The final step of snapping the device together is one of the most critical to the success of the procedure. I recommend using sterile gauze during this step to avoid slippage of your fingers on the toe. You should distract the middle phalanx gently in order to align the two components axially. If the two components are not in alignment, you not only risk a poor apposition, but damage to the implant itself. You also need to be very persistent when applying significant pressure to get the device to engage. Strive for bone-to-bone contact. You will encounter several “alarming” ratcheting noises when compressing the components but this is normal. When the process is complete, you’ll hear a more “pronounced” snap but this just indicates that the components have completely seated themselves. Sometimes, you’ll need to slightly rotate the phalanges in order to obtain the full engagement of the “prox” and “mid” implant components. As your familiarity with the device increases, recognizing the final engagement of the implant becomes easier. You should confirm good bony apposition via visualization, probing and fluoroscopy. Final Thoughts Using the StayFuse implant gives you several advantages in comparison to other procedures. The three-step technique for implantation is very simple to perform, with minimal instrumentation. A range of diameters and lengths are available, depending on bone size. There is no disruption of the joints, proximal or distal, to the PIPJ. Employing the device enables you to provide a more stable union with added rotational stability. This improved fixation enhances the healing process. There is no post-op implant exposure, which eliminates pin tract infections. Without an external wire and when you compare it to traditional K-wire fixation, the implant improves patient comfort as well as patient perception and can reduce the prolonged need of a post-op shoe. If the situation arises, you do have the option of removing the device later via a “windowing” technique through the middle phalanx. The only real disadvantage I see with the device is the inability to concurrently stabilize across the metatarsophalangeal joint with pinning, if this was so desired for mechanical or structural reasons. In comparison to the other digital arthrodesis procedures performed, I have found the StayFuse implant to be an excellent device. It is coupled to a relatively simple implantation procedure and has had reproducible results. I have addressed digits two through four using the implant. (The fifth toe usually is best addressed with a simple arthroplasty at the PIPJ.) It is up to your discretion whether adjunctive soft tissue procedures (i.e.

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