title: Lingering Risk: Bariatric Surgery Before Total Knee Arthroplasty.
abstract: Obesity continues to increase in the United States with an estimated 35% obesity and 8% bariatric (body mass index >40) rate in adults. Bariatric patients seek advice from arthroplasty surgeons regarding the temporality of bariatric surgery (BS), yet no consensus currently exists in the literature.
  
  
  
  A total of 39,014 patients were identified in a claim-based review of the entire Medicare database with International Classification of Diseases, Ninth Revision codes to identify patients in 3 groups. Patients who underwent BS before total knee arthroplasty (group I: 5914 experimental group) and 2 control groups that did not undergo BS but had either a body mass index >40 (group II: 6480 bariatric control) or <25 (group III: 26,616 normal weight control). International Classification of Diseases, Ninth Revision, Clinical Modification codes identified preoperative demographics or comorbidities and evaluated short-term medical (30 day) and long-term surgical (90 days and 2 years) complications.
  
  
  
  Group I had the greatest female predominance, youngest age, and highest incidence of: deficiency anemia, cardiovascular disease, pulmonary disease, liver disease, ulcer disease, polysubstance abuse, psychiatric disorders, and smoking. Medical and surgical complication incidences were greatest in group I including: 4.98% deep vein thrombosis; 5.31% pneumonia; 10.09% heart failure; and 2-year infection, revision, and manipulation rates of 5.8%, 7.38%, and 3.13%, respectively. These values were significant elevation compared to III and slightly greater than II.
  
  
  
  This study demonstrates that BS before total knee arthroplasty is associated with greater risk compared to both nonobese and obese patients. This is possibly due to a higher incidence of medical or psychiatric comorbidities determined in the Medicare BS patients, wound healing difficulties secondary to gastrointestinal malabsorption, malnourishment from prolonged catabolic state, rapid weight loss before surgery, and/or age.
authors.affiliation: Department of Orthopaedic Surgery, Duke University School of Medicine.
authors.forename: Brian T
authors.initials: BT
authors.lastname: Nickel
authors.affiliation: Department of Orthopaedic Surgery, Duke University School of Medicine.
authors.forename: Mitchell R
authors.initials: MR
authors.lastname: Klement
authors.affiliation: Department of Orthopaedic Surgery, Duke University School of Medicine.
authors.forename: Colin T
authors.initials: CT
authors.lastname: Penrose
authors.affiliation: Duke Department of Biostatistics & Bioinformatics.
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Green
authors.affiliation: Department of Orthopaedic Surgery, Duke University School of Medicine.
authors.forename: Thorsten M
authors.initials: TM
authors.lastname: Seyler
authors.affiliation: Department of Orthopaedic Surgery, Duke University School of Medicine.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Bolognesi
mesh_terms: D000328:Adult; D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000706:statistics & numerical data; D050110:Bariatric Surgery / Q000009:adverse effects* / Q000706:statistics & numerical data; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000601:surgery*; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
keywords: bariatric surgery; complications; gastric bypass; obesity; total knee arthroplasty