title: An Analysis of Risk Factors for Short-Term Complication Rates and Increased Length of Stay Following Unicompartmental Knee Arthroplasty.
abstract: BACKGROUND
  Unicompartmental knee arthroplasty (UKA) is an increasingly popular procedure, with excellent long-term outcomes. However, there are only a limited number of reports reporting its short-term morbidity and mortality.
  
  
  OBJECTIVE
  We sought to analyze the reported 30-day morbidity, mortality, and risk factors for complications and prolonged length of stay (>4 days) following UKA.
  
  
  METHODS
  Utilizing the National Surgical Quality Improvement Program (NSQIP) database, including patients (n = 2316) from 2005-2012, we correlated the reported 30-day complications and prolonged length of stay with patient demographics and risk factors.
  
  
  RESULTS
  The overall rate of complications was low (3.2%). The distribution of complications demonstrated 0.5% major systemic, 1.4% minor systemic, 0.7% major local, and 0.9% minor local complications, with a 2.1% readmission rate. Multivariate regression demonstrated increased BMI and a history of chronic obstructive pulmonary disease (COPD) as independent risk factors for complications. Furthermore, multivariate regression demonstrated increased BMI, ASA ≥ 3, history of COPD, recent operation, and postoperative transfusion as independent risk factors for prolonged length of hospitalization.
  
  
  CONCLUSIONS
  Utilizing the NSQIP, we present one of the largest studies to date evaluating complications following UKA. Our multivariate model demonstrated obesity and COPD to be the risk factors for complications while obesity, ASA ≥ 3, COPD, recent operation, and blood transfusion to be the risk factors for prolonged length of stay.
authors.affiliation: Rush University, Department of Orthopaedic Surgery, 1611 W. Harrison Blvd, Suite 200, Chicago, IL 60612 USA.
authors.forename: Bryan D
authors.initials: BD
authors.lastname: Haughom
authors.affiliation: Hospital for Special Surgery, Department of Orthopaedic Surgery, 535 East 70th St, New York, NY 10021 USA.
authors.forename: William W
authors.initials: WW
authors.lastname: Schairer
authors.affiliation: Rush University, Department of Orthopaedic Surgery, 1611 W. Harrison Blvd, Suite 200, Chicago, IL 60612 USA.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Hellman
authors.affiliation: Hospital for Special Surgery, Department of Orthopaedic Surgery, 535 East 70th St, New York, NY 10021 USA.
authors.forename: Benedict U
authors.initials: BU
authors.lastname: Nwachukwu
authors.affiliation: Rush University, Department of Orthopaedic Surgery, 1611 W. Harrison Blvd, Suite 200, Chicago, IL 60612 USA.
authors.forename: Brett R
authors.initials: BR
authors.lastname: Levine
keywords: COPD; Complications; NSQIP; Obesity; Short-Term; Transfusion; Unicompartmental Knee Arthroplasty