Use Data, Guidelines, and Intuition to Manage Infection after Toe/Forefoot Amputation

The number of articles published each year in orthopaedics that evaluate infections seems to approach, if not exceed, 1,000. Yet, despite all of these publications, consensus statements, and guidelines, we seem to have very few concrete recommendations about which every surgeon will say, “This is what needs to be done.” So we send out samples, run cultures, sonicate implants, and sometimes even perform DNA sequencing, and then we mix the data with selected recommendations and intuition to make our final treatment decisions. Foolproof? No, but it is the best we can do in many situations.

The article by Mijuskovic et al. in the September 5, 2018 edition of The Journal helps simplify this type of decision making in the setting of residual osteomyelitis after toe or forefoot amputation. The authors evaluated 51 consecutive patients with gangrene and/or infection who underwent either digit or partial foot amputations. They found that, after surgery, 41% of the patients without histological evidence of osteomyelitis (which the authors considered the reference, “true positive” analysis) had a positive culture from the same sample.  In addition, only 12 patients (24%) had both positive histological findings and positive cultures, the criteria set forth by the Infectious Disease Society of America for the definitive diagnosis of osteomyelitis.

As interesting as the main findings of the study are, some of the “minor” results are even more curious.  The decision regarding which patients received antibiotics after amputation seemed largely arbitrary, with 10 of the 14 patients who had a positive histological result not receiving any postoperative antibiotics. (Five of those patients ended up needing a secondary procedure.) In addition, because of the need for decalcification prior to analysis, the median time to receiving histological results was almost a week. Based on the findings in this study, in many instances patients are sent home or to a rehabilitation facility with antibiotics based only on the results of a potentially “false-positive” culture.

The authors conclude that their results “cast doubt on the strategy of relying solely on culture of bone biopsy specimens when deciding whether antibiotic treatment for osteomyelitis is necessary after toe or forefoot amputation.” But this paper also highlights the fact that we are still looking for definitive answers about which data to use and which to disregard when it comes to the detection and treatment of post-amputation osteomyelitis. We surgeons decide on which side to err, and we need to appreciate all three facets—data, guidelines, and patient factors—when discussing treatment options with patients.

Chad A. Krueger, MD
JBJS Deputy Editor for Social Media