title: Diabetes is associated with persistent pain after hip and knee replacement.
abstract: OBJECTIVE
  In some patients, for unknown reasons pain persists after joint replacement, especially in the knee. We determined the prevalence of persistent pain following primary hip or knee replacement and its association with disorders of glucose metabolism, metabolic syndrome (MetS), and obesity.
  
  
  METHODS
  The incidence of pain in the operated joint was surveyed 1-2 years after primary hip replacement (74 patients (4 bilateral)) or primary knee replacement (119 patients (19 bilateral)) in 193 osteoarthritis patients who had participated in a prospective study on perioperative hyperglycemia. Of the 155 patients who completed the survey, 21 had undergone further joint replacement surgery during the follow-up and were excluded, leaving 134 patients for analysis. Persistent pain was defined as daily pain in the operated joint that had lasted over 3 months. Factors associated with persistent pain were evaluated using binary logistic regression with adjustment for age, sex, and operated joint.
  
  
  RESULTS
  49 of the 134 patients (37%) had a painful joint and 18 of them (14%) had persistent pain. A greater proportion of knee patients than hip patients had a painful joint (46% vs. 24%; p = 0.01) and persistent pain (20% vs. 4%; p = 0.007). Previously diagnosed diabetes was strongly associated with persistent pain (5/19 vs. 13/115 in those without; adjusted OR = 8, 95% CI: 2-38) whereas MetS and obesity were not. However, severely obese patients (BMI ≥ 35) had a painful joint (but not persistent pain) more often than patients with BMI < 30 (14/21 vs. 18/71; adjusted OR = 5, 95% CI: 2-15).
  
  
  CONCLUSIONS
  Previously diagnosed diabetes is a risk factor for persistent pain in the operated joint 1-2 years after primary hip or knee replacement.
authors.affiliation: a 1School of Medicine, University of Tampere.
authors.forename: Tuomas J
authors.initials: TJ
authors.lastname: Rajamäki
authors.affiliation: b 2 Coxa, Hospital for Joint Replacement.
authors.forename: Esa
authors.initials: E
authors.lastname: Jämsen
authors.affiliation: c 3 Department of Surgery and Anaesthesia.
authors.forename: Pia A
authors.initials: PA
authors.lastname: Puolakka
authors.affiliation: a 1School of Medicine, University of Tampere.|d 4 Department of Internal Medicine , Tampere University Hospital, Tampere, Finland.
authors.forename: Pasi I
authors.initials: PI
authors.lastname: Nevalainen
authors.affiliation: b 2 Coxa, Hospital for Joint Replacement.
authors.forename: Teemu
authors.initials: T
authors.lastname: Moilanen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018771:Arthralgia / Q000453:epidemiology*; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D003920:Diabetes Mellitus / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000601:surgery*; D020370:Osteoarthritis, Knee / Q000601:surgery*; D010149:Postoperative Pain / Q000453:epidemiology; D011183:Postoperative Complications / Q000453:epidemiology; D011446:Prospective Studies; D012307:Risk Factors; D016896:Treatment Outcome