Practice Perfect 952
Should We Use Prophylactic Antibiotics to Prevent Pin Tract Infections?

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The use of Kirschner wires for foot surgery is highly common. Despite the many new interesting internal fixation techniques for hammer toe surgery, I still find myself falling back on K wires for fixation of digital hammer toe repairs. These relatively simple fixation techniques seem to stand the test of time.

Recently, a colleague and I were discussing our personal preferences for taking care of patients with percutaneous K wires. We approached our patient care quite differently from each other. I tend to apply dry dressings to cover the K wires and I never prescribe postoperative antibiotics for prophylaxis against possible infections until I see clinical signs of infection. My partner does the opposite, applying a moist dressing to the pin-skin interface and prescribes prophylactic antibiotics after the surgery. Do we need to prescribe antibiotics for patients in whom we leave percutaneous wires after surgery? Let's see if the medical literature can help us answer this question.

In 2019, McKenzie et al. retrospectively reviewed the results of 2017 K wire placements in 1237 patients. Of these patients, they reported 35 pin site infections (a rate of 1.74%). They found some factors that increased the risk of pin tract infections, including male sex, elevated BMI, current smoking, and an increased number of pins. These results indicate that the rate of infection associated with K wires is very low with some specific risk factors that we should keep in mind.

In 2015, Kramer et al. retrospectively reviewed the outcomes of a single surgeon’s 1115 hammertoe procedures (2698 hammertoes in 876 patients). That’s a lot of hammertoes! The patients were not given prophylactic antibiotics and no specific pin care or protection was performed. Amongst other findings, there were 9 pin tract infections (0.3%). However, it’s important to state that 24 patients were given postoperative antibiotics if slight drainage or erythema was noted. For some unstated reason, the 24 patients weren’t counted as pin tract infections (no actual criteria were used to diagnose a pin tract infection), so let’s add them to the number of pin tract infections. This makes the infection rate rise to 0.9%. It’s still a very low number.

If that’s not enough to convince us that antibiotics aren’t necessary, a study by Mangwani and colleagues from 2017 is tailor-made to answer the question. In this prospective study, 100 patients undergoing digital surgery with K wires left in for 4-6 weeks were randomly assigned to either receiving prophylactic antibiotics after surgery or not. The overall infection rate was 4%. Three patients in the prophylactic antibiotic group and one patient in the no antibiotic group had an infection. This study was a bit underpowered, but the overall methodology provides us the best quality evidence yet.

From these studies, it’s safe to infer that prophylactic antibiotics are not necessary for patients undergoing surgery leaving exposed pins with an infection prevalence between 0.9% and 4%. Given the rising incidence of antibiotic-resistant bacteria, and the challenges they pose, my suggestion is to avoid the use of postoperative prophylactic antibiotics, maintain clean pin care with soap and water (not antimicrobial solutions), and prescribe antibiotics when signs of infection are noted. Similarly, pins can be removed early when deemed necessary by the surgeon.

Best wishes on your next hammertoe repair.

Jarrod Shapiro, DPM
PRESENT Practice Perfect Editor
[email protected]