title: Weight patterns before and after total joint arthroplasty and characteristics associated with weight change.
abstract: BACKGROUND
  Although prevalence of obesity and incidence of total joint arthroplasty (TJA) have dramatically increased over the last two decades in the U.S., little is known of the preoperative and postoperative weight patterns of patients undergoing TJA.
  
  
  OBJECTIVE
  To describe the preoperative and postoperative weight patterns of patients undergoing TJA and evaluate characteristics associated with these patterns.
  
  
  METHODS
  Retrospective cohort study. A cohort of patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA) between January 1, 2008, and December 31, 2010, was identified. Using weight obtained at patient encounters, patients were categorized into gainers (increased weight by 5%), losers (decreased weight by 5%), or remained the same (changed < 5%) for the preoperative and postoperative periods. Patients were characterized by sex, age, and race.
  
  
  METHODS
  Weight change before and after TJA.
  
  
  RESULTS
  Of 30,632 patients with TJA identified, 34.5% underwent THA and 65.5% had TKA. Most patients remained the same weight during the year before (THA, 71.5%; TKA, 75.7%) and after the procedure (64.0% and 68.5%, respectively). Before and after THA, men were less likely to lose or gain weight than were women. Older patients were less likely to gain weight. Among patients undergoing TKA, men were less likely to lose weight preoperatively or postoperatively, or gain weight postoperatively, and older patients were less likely to gain weight before or after arthroplasty. Some racial associations with weight patterns were observed.
  
  
  CONCLUSIONS
  Specific groups are more susceptible to weight change and could benefit from weight management interventions.
authors.affiliation: Epidemiologist in Surgical Outcomes and Analysis at the San Diego Medical Center in CA. maria.cs.inacio@kp.org.
authors.forename: Maria Cs
authors.initials: MC
authors.lastname: Inacio
authors.affiliation: Associate Professor in the Department of Family and Preventive Medicine at the University of California San Diego School of Medicine in La Jolla. dsilverstein@ucsd.edu.
authors.forename: Donna Kritz
authors.initials: DK
authors.lastname: Silverstein
authors.affiliation: Associate Professor in the Department of Biostatistics at the University of California San Diego School of Medicine in La Jolla. reraman@ucsd.edu.
authors.forename: Rema
authors.initials: R
authors.lastname: Raman
authors.affiliation: Professor in the Graduate School of Public Health at San Diego State University in CA. cmacera@mail.sdsu.edu.
authors.forename: Caroline A
authors.initials: CA
authors.lastname: Macera
authors.affiliation: Professor Emeritus in the School of Exercise and Nutritional Sciences at San Diego State University in CA. jeannebernhard@cox.net.
authors.forename: Jeanne F
authors.initials: JF
authors.lastname: Nichols
authors.affiliation: Professor in the Graduate School of Public Health at San Diego State University in CA. rshaffer@mail.sdsu.edu.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Shaffer
authors.affiliation: Orthopaedic Surgeon in the Orthopedics Department, Kaiser Permanente in San Diego, CA. donald.c.fithian@kp.org.
authors.forename: Donald
authors.initials: D
authors.lastname: Fithian
mesh_terms: D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D019644:Arthroplasty, Replacement, Hip; D019645:Arthroplasty, Replacement, Knee; D002140:California; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D012189:Retrospective Studies; D012737:Sex Factors; D015430:Weight Gain; D015431:Weight Loss