Risk Factors of Early Complications, Readmission, and Reoperation After Below Knee Amputation

Abstract

Category: Diabetes, Hindfoot, Trauma, Limb Salvage Introduction/Purpose: The number of below knee amputation (BKA) patients experiencing complications requiring readmission and reoperation remains significant despite improvements in BKA technique and identification of potential hazards. Analysis of this population is critical due to increased risk of mortality following amputation and the economic burden placed on the healthcare system. With the introduction of Hospital Readmission Reduction Program, prevention of early complication and readmission has become an area of interest for both policy makers and clinicians. The purpose of this study is to investigate risk factors and comorbidities associated with early occurrences of complication, unexpected readmission, and unplanned reoperations after BKA. Methods: Current Procedural Terminology (CPT) code 27880 was used to retrospectively identify 4,631 below knee amputation patients between the years 2012 and 2014 from the National Surgical Quality Improvement Program (NSQIP) database, a nationally collected clinical database. Primary outcomes of unplanned reoperation or readmission were investigated, with independent predictors evaluated using multivariate logistic regression. Secondary outcomes of interest were mortality and major or minor complications within 30 days of index procedure. Major complications included deep surgical site infection (SSI), unplanned intubation, pulmonary embolism, failure to wean, acute renal failure, cerebrovascular accident, cardiac arrest, myocardial infarction, deep vein thrombosis, sepsis, shock, wound dehiscence, and renal insufficiency. Minor complications included superficial SSI, pneumonia, and urinary tract infection. Results: Within 30 days of the 4,631 BKAs, one or more complications occurred in 858 (18.5%) patients; 12.8% major and 8.7% minor (Table 1). Unplanned readmission occurred in 405 (8.75%) patients with SSI being the leading cause. Patients with significantly increased risk of readmission included age greater than 79 years old, transfer from another facility, smoking, and bleeding disorder. A total of 446 (9.63%) patients underwent unplanned reoperations. The 30-day mortality rate was 5.14% (n = 238). The most common procedures for unplanned reoperation were above knee amputation (n = 128, 28.7%), debridement/secondary closure (n = 114, 25.6%), and revision BKA (n = 46, 10.32%). Variables resulting in a significantly increased risk of reoperation included transport from another facility, smoking, bleeding disorder, and preoperative ventilator use. Conclusion: This study represents the largest multicenter cohort examining BKA complications, readmission, and reoperation. Patients that required transport from another facility, were smokers, or had diagnosed bleeding disorders experienced the highest risk of reoperation or readmission. Statistically significant risk factors for reoperation and readmission also included preoperative ventilator use and age, respectively. Surgical site complications were the leading reason for readmission. Complication rates may be improved with more stringent surgical planning of BKA including smoking cessation and coagulation or vascular evaluations. Facility transfer, age, and preoperative ventilator use should play a role in considerations for surgical intervention and patient counseling.