title: Routine Postoperative Laboratory Tests Are Unnecessary After Partial Knee Arthroplasty.
abstract: While partial knee arthroplasty (PKA) is increasingly performed on an outpatient basis, many surgeons still admit patients overnight and obtain laboratory studies on the first postoperative day. The purpose of this study was to investigate the utility and cost effectiveness of routine postoperative laboratory studies after PKA.
  
  
  
  This is a retrospective review of 322 consecutive unilateral or bilateral simultaneous PKAs (unicompartmental, patellofemoral, and modular bicompartmental knee arthroplasty) performed by a single surgeon. There were 408 complete blood counts and basic metabolic panels ordered.
  
  
  
  Despite a large number of laboratory studies ordered and abnormalities detected, there was a 1.6% rate of laboratory-associated interventions (for either hypokalemia or hyperglycemia in 5 patients) and no red blood cell transfusions. Hospital charges associated with laboratory studies totaled $85,413. There were no 90-day postoperative hospital readmissions or emergency department evaluations related to abnormal postoperative laboratory values.
  
  
  
  With an increasing emphasis placed on cost containment, the low rate of laboratory-associated interventions after PKA suggests that routinely obtaining laboratory studies are neither necessary nor cost effective.
authors.affiliation: Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Julie L
authors.initials: JL
authors.lastname: Shaner
authors.affiliation: Department of Orthopaedic Surgery, Rowan University School of Osteopathic Medicine, Stratford, New Jersey.
authors.forename: Ammar R
authors.initials: AR
authors.lastname: Karim
authors.affiliation: Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: David S
authors.initials: DS
authors.lastname: Casper
authors.affiliation: Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Ball
authors.affiliation: Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Padegimas
authors.affiliation: Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania; Rothman Institute, Philadelphia, Pennsylvania.
authors.forename: Jess H
authors.initials: JH
authors.lastname: Lonner
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D064790:Clinical Laboratory Services / Q000191:economics / Q000706:statistics & numerical data*; D003362:Cost-Benefit Analysis; D005260:Female; D017722:Hospital Charges; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D012189:Retrospective Studies; D019564:Unnecessary Procedures / Q000191:economics / Q000706:statistics & numerical data*
keywords: Medicare charges; bicompartmental; laboratory studies; partial knee arthroplasty; patellofemoral; unicompartmental