title: Annual revision rates of partial versus total knee arthroplasty: A comparative meta-analysis.
abstract: BACKGROUND
  Utilization of unicompartmental knee arthroplasty (UKA) and patellofemoral arthroplasty (PFA) as alternatives to total knee arthroplasty (TKA) for unicompartmental knee osteoarthritis (OA) has increased. However, no single resource consolidates survivorship data between TKA and partial resurfacing options for each variant of unicompartmental OA. This meta-analysis compared survivorship between TKA and medial UKA (MUKA), lateral UKA (LUKA) and PFA using annual revision rate as a standardized metric.
  
  
  METHODS
  A systematic literature search was performed for studies quantifying TKA, MUKA, LUKA and/or PFA implant survivorship. Studies were classified by evidence level and assessed for bias using the MINORS and PEDro instruments. Annual revision rates were calculated for each arthroplasty procedure as percentages/observed component-year, based on a Poisson-normal model with random effects using the R-statistical software package.
  
  
  RESULTS
  One hundred and twenty-four studies (113 cohort and 11 registry-based studies) met inclusion/exclusion criteria, providing data for 374,934 arthroplasties and 14,991 revisions. The overall evidence level was low, with 96.7% of studies classified as level III-IV. Annual revision rates were lowest for TKA (0.49%, CI 0.41 to 0.58), followed by MUKA (1.07%, CI 0.87 to 1.31), LUKA (1.13%, CI 0.69 to 1.83) and PFA (1.75%, CI 1.19 to 2.57). No difference was detected between revision rates for MUKA and LUKA (p=0.222).
  
  
  CONCLUSIONS
  Revisions of MUKA, LUKA and PFA occur at an annual rate of 2.18, 2.31 and 3.57-fold that of TKA, respectively. These estimates may be used to inform clinical decision-making, guide patient expectations and evaluate the cost-effectiveness of total versus partial knee replacement in the setting of unicompartmental OA.
authors.affiliation: Computer Assisted Surgery Center, Department of Orthopaedic Surgery, Hospital for Special Surgery, Weill Cornell Medical College, New York, NY, United States; Icahn School of Medicine at Mount Sinai, New York, NY, United States. Electronic address: chawlah@hss.edu.
authors.forename: Harshvardhan
authors.initials: H
authors.lastname: Chawla
authors.affiliation: Computer Assisted Surgery Center, Department of Orthopaedic Surgery, Hospital for Special Surgery, Weill Cornell Medical College, New York, NY, United States. Electronic address: vanderlistj@hss.edu.
authors.forename: Jelle P
authors.initials: JP
authors.lastname: van der List
authors.affiliation: Computer Assisted Surgery Center, Department of Orthopaedic Surgery, Hospital for Special Surgery, Weill Cornell Medical College, New York, NY, United States. Electronic address: christa@hss.edu.
authors.forename: Alexander B
authors.initials: AB
authors.lastname: Christ
authors.affiliation: Computer Assisted Surgery Center, Department of Orthopaedic Surgery, Hospital for Special Surgery, Weill Cornell Medical College, New York, NY, United States; Icahn School of Medicine at Mount Sinai, New York, NY, United States. Electronic address: maximiliano.sobrero@icahn.mssm.edu.
authors.forename: Maximiliano R
authors.initials: MR
authors.lastname: Sobrero
authors.affiliation: Computer Assisted Surgery Center, Department of Orthopaedic Surgery, Hospital for Special Surgery, Weill Cornell Medical College, New York, NY, United States; Department of Orthopaedic Surgery, Spaarne Hospital, Hoofddorp, The Netherlands. Electronic address: hazuiderbaanmd@gmail.com.
authors.forename: Hendrik A
authors.initials: HA
authors.lastname: Zuiderbaan
authors.affiliation: Computer Assisted Surgery Center, Department of Orthopaedic Surgery, Hospital for Special Surgery, Weill Cornell Medical College, New York, NY, United States. Electronic address: pearlea@hss.edu.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Pearle
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D006801:Humans; D020370:Osteoarthritis, Knee / Q000601:surgery*; D012086:Reoperation
keywords: Annual revision rate; Lateral unicompartmental knee arthroplasty; Medial unicompartmental knee arthroplasty; Patellofemoral arthroplasty; Total knee arthroplasty