Practice Perfect 831
Making Practice Perfect Decisions
Part 8 - Use Enough Fixation Properly
Making Practice Perfect Decisions
Part 8 - Use Enough Fixation Properly
Today’s Practice Perfect brings us exactly 80% of the way through our journey of making clinical and surgical decisions. Today comes Principle 8:
With any foot and ankle procedure that requires fixation, it is very important to think carefully about the best way to utilize that fixation. I’ve been in the position more than once in my career, looking back on a case and thinking, “I should have done X fixation instead of Y.” In reality, there are usually several reasonable fixation options for most procedures. For example, when performing a first metatarsophalangeal joint arthrodesis, several research studies have demonstrated crossed screws, screw-plate combinations, and even crossed Kirschner wires can achieve successful fusions. Similarly, crossed screw fixation has been shown to be equally effective as screw-plate combinations for the Lapidus bunionectomy.
On the other hand, a relatively recent and somewhat robust literature points toward greater amounts of fixation for Charcot reconstruction. The superconstruct principle even goes beyond simply “using more fixation,” instructing us to fuse nearby otherwise normal joints to achieve greater stability in these highly unstable deformities.
Here are some important characteristics to consider when choosing fixation:
- Stability
- Number of devices
- Compression
- Neutralization of or resistance to deforming forces
- In which direction will it fail?
Consider the radiograph in Figure 1, which was a patient of mine that underwent a first MTP joint fusion. Prior research has shown that a screw for compression and a plate for stability lead to successful fusions, and for most of my patients, I prefer that construct. But consider the last two bullets in our list. Does a dorsal plate neutralize forces? Since ground reactive forces push upward, the dorsal side is the compression rather than distraction side, so optimally the plate would be on the plantar surface (the distraction side) of the fusion site – obviously impossible for this procedure. What about considering the direction in which it would fail? Presumably things would fail in a dorsal and lateral direction (especially if the fusion were performed for a hallux valgus deformity), but lateral placement of a plate is also impossible. Luckily for us, even though the dorsal positioning is not optimal, the plate is strong enough to resist those forces that might lead to failure. Thus, utilizing hardware that is strong enough to resist deforming forces is important.
As another thought experiment, look at the images in Figure 2. This is a patient with diabetes and peripheral neuropathy who sustained a bimalleolar ankle fracture (no posterior malleolar fracture). Before scrolling down and seeing what I did, ask yourself two questions. First, “what fixation would I use?” and second, “on what principles am I basing my choice for fixation?”
Boiling fracture treatment down to the simplest level, there are two goals: putting the bone in the anatomical position and then keeping it there to allow the fracture to heal. With those goals in mind, think in terms of the characteristics listed above. The distal aspect of the ankle fracture (lateral malleolus, medial malleolus, and talus) has displaced laterally, so if the fixation were to fail, it would fail in the lateral direction. Our fixation, then, should resist laterally directed forces, so the plate can be placed laterally. In reality, the failure would be in the posterolateral direction, so one can also argue for a posterolateral (or antiglide) plate. Next, compressing the fracture surfaces together is important when possible, and it would have been optimal to have a compression screw in the fibula, but the fracture was actually more comminuted than the radiographs show, preventing the use of an interfragmentary screw.
Figure 2. Completed ankle fracture reduction and fixation.
Choosing the number of devices is a twofold decision in this patient. For the medial malleolar fracture, we chose one screw for compression and the other to prevent rotation, the stability principle. We also considered the patient when deciding to use two syndesmotic screws. The patient’s syndesmosis was, in fact, not damaged, as determined by a dorsiflexion and external rotation test intraop. This extra fixation was used to add increased construct strength because the patient was osteopenic and was a diabetic with neuropathy with increased risk of Charcot arthropathy. Consider the patient actually refers back to Principle 4 in our series, Consider the Patient.
What fixation is ultimately used is up to the surgeon, but the point in this entire exercise is to consciously consider universal principles to rationally make decisions. In practice, you can’t make decisions based simply on “what I learned in residency” or what some supposed “expert” says but rather on fundamental principles aimed at providing patients the optimal chance to successfully heal and function. Making thoughtful choices is what this entire series is all about.
Best wishes.
Jarrod Shapiro, DPM
PRESENT Practice Perfect Editor
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