PC162. Outcomes of Below-Knee Amputation for Lower Extremity Infection: One-Stage versus Two-Stage Operative Approach

Below-knee amputation (BKA) for lower extremity infection may be performed as a single operation, or as a two-stage procedure with guillotine amputation and subsequent formalization. BKA failure owing to recurrent infection or necrosis is associated with significant morbidity; however, it is unclear whether the potential benefits of staging outweigh the risk of an additional operation. Here, we compare the effectiveness of two-stage BKA to single-stage BKA for lower extremity infection. A retrospective review was performed of all patients who underwent BKA for lower extremity infection at our urban limb salvage center from 2011 to 2016. The study population was divided into those who underwent two-stage BKA versus those who underwent single-stage BKA. The primary end point was failure of the BKA surgery, defined as need for surgical revision, unplanned conversion to above-knee amputation (AKA), or mortality within six weeks. Secondary end points included postoperative complications and time to discharge. Of 205 limbs among 198 patients in the study, 100 (48.8%) underwent single-stage BKA and 105 (51.2%) underwent two-stage BKA. There was no significant difference in age, Charleston Comorbidity Index, or American Society of Anesthesiologists score between groups. Two-stage operations had higher rates of leukocytosis (P < .001), and diabetes (P < .001) with perioperative hyperglycemia (P < .001). Of the 19 BKAs that failed (9.3%), 12 occurred after single-stage amputation (16.6%) versus 7 after two-stage amputation (8.4%); this was not significant (P = .18). There was no difference in the incidence of perioperative mortality or major complications (7.6% two-stage vs 7.0% one-stage; P = .86). In the subset of patients with systemic infection as evidenced by perioperative leukocytosis (155 limbs, 75.6%), a significant reduction in failure was associated with two-stage amputation (4.8% two-stage vs 13.8% one-stage; P = .048), but this was not preserved in the absence of leukocytosis (7% one-stage vs 13.6% two-stage; P = .69). Two-stage BKA was associated with longer hospital stays (17.5 vs 13.7 days; P = .006), greater transfusion need (P = .045) and higher rates of acute kidney injury (P = .045). In this retrospective study, two-stage below-knee amputation was not associated with lower rates of BKA failure compared with single-stage operation, and was associated with higher rates of certain complications and a longer hospital stay. Although two-stage BKA seems to be the operation of choice in the setting of systemic infection, this benefit was not seen for only local infection. Further prospective research will help to more clearly identify the subset of patients with foot infections that may safely undergo a single-stage BKA.