title: Two knees or not two knees? Patient costs and outcomes following bilateral and unilateral total knee joint replacement surgery for OA.
abstract: OBJECTIVE
  This study aims to address medical and non-medical direct costs and health outcomes of bilateral and unilateral total knee replacement from the patients' perspective during the first year post-surgery.
  
  
  METHODS
  Osteoarthritis patients undergoing primary unilateral total knee or bilateral total knee replacement (TKR) surgery at three Sydney hospitals were eligible. Patients completed questionnaires pre-operatively to record expenses during the previous three months and health status immediately prior to surgery. Patients then maintained detailed prospective cost diaries and completed SF-36 and WOMAC Index each three months for the first post-operative year.
  
  
  RESULTS
  Pre-operatively, no significant differences in health status were found between patients undergoing unilateral TKR and bilateral TKR. Both unilateral and bilateral TKR patients showed improvements in pain, stiffness and function from pre-surgery to 12 months post-surgery. Patients who had bilateral TKR spent an average of 12.3 days in acute hospital and patients who had unilateral TKR 13.6 days. Totally uncemented prostheses were used in 6% of unilateral replacements and 48% of bilateral replacements. In hospital, patients who had bilateral TKR experienced significantly more complications, mainly thromboembolic, than patients who had unilateral TKR. Regression analysis showed that for every one point increase in the pre-operative SF-36 physical score (i.e. improving physical status) out-of-pocket costs decreased by 94%. Out-of-pocket costs for female patients were 3.3 times greater than for males.
  
  
  CONCLUSIONS
  Patients undergoing bilateral TKR and unilateral TKR had a similar length of stay in hospital and similar out-of-pocket expenditures. Bilateral replacement patients reported better physical function and general health with fewer health care visits one year post procedure. Patients requiring bilateral TKR have some additional information to aid their decision making. While their risk of peri-operative complications is higher, they have an excellent chance of good health outcomes at 12 months and are not going to be doubly "out-of-pocket" for the experience.
authors.affiliation: Department of Rheumatology, Royal North Shore Hospital, University of Sydney, Sydney, St Leonards NSW 2065, Australia.
authors.forename: L M
authors.initials: LM
authors.lastname: March
authors.forename: M
authors.initials: M
authors.lastname: Cross
authors.forename: K L
authors.initials: KL
authors.lastname: Tribe
authors.forename: H M
authors.initials: HM
authors.lastname: Lapsley
authors.forename: B G
authors.initials: BG
authors.lastname: Courtenay
authors.forename: M J
authors.initials: MJ
authors.lastname: Cross
authors.forename: P M
authors.initials: PM
authors.lastname: Brooks
authors.forename: C
authors.initials: C
authors.lastname: Cass
authors.forename: M
authors.initials: M
authors.lastname: Coolican
authors.forename: M
authors.initials: M
authors.lastname: Neil
authors.forename: L
authors.initials: L
authors.lastname: Pinczewski
authors.forename: S
authors.initials: S
authors.lastname: Quain
authors.forename: F
authors.initials: F
authors.lastname: Robertson
authors.forename: S
authors.initials: S
authors.lastname: Ruff
authors.forename: W
authors.initials: W
authors.lastname: Walter
authors.forename: B
authors.initials: B
authors.lastname: Zicat
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000191:economics* / Q000592:standards*; D003365:Costs and Cost Analysis; D005260:Female; D006304:Health Status; D006801:Humans; D007902:Length of Stay / Q000191:economics; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000191:economics* / Q000601:surgery; D017060:Patient Satisfaction; D011788:Quality of Life; D011793:Queensland; D011795:Surveys and Questionnaires