title: The role of surgeon volume on patient outcome in total knee arthroplasty: a systematic review of the literature.
abstract: BACKGROUND
  A number of factors have been identified as influencing total knee arthroplasty outcomes, including patient factors such as gender and medical comorbidity, technical factors such as alignment of the prosthesis, and provider factors such as hospital and surgeon procedure volumes. Recently, strategies aimed at optimizing provider factors have been proposed, including regionalization of total joint arthroplasty to higher volume centers, and adoption of volume standards. To contribute to the discussions concerning the optimization of provider factors and proposals to regionalize total knee arthroplasty practices, we undertook a systematic review to investigate the association between surgeon volume and primary total knee arthroplasty outcomes.
  
  
  METHODS
  We performed a systematic review examining the association between surgeon volume and primary knee arthroplasty outcomes. To be included in the review, the study population had to include patients undergoing primary total knee arthroplasty. Studies had to report on the association between surgeon volume and primary total knee arthroplasty outcomes, including perioperative mortality and morbidity, patient-reported outcomes, or total knee arthroplasty implant survivorship. There were no restrictions placed on study design or language.
  
  
  RESULTS
  Studies were variable in defining surgeon volume ('low': <3 to <52 total knee arthroplasty per year; 'high': >5 to >70 total knee arthroplasty per year). Mortality rate, survivorship and thromboembolic events were not found to be associated with surgeon volume. We found a significant association between low surgeon volume and higher rate of infection (0.26% - 2.8% higher), procedure time (165 min versus 135 min), longer length of stay (0.4 - 2.13 days longer), transfusion rate (13% versus 4%), and worse patient reported outcomes.
  
  
  CONCLUSIONS
  Findings suggest a trend towards better outcomes for higher volume surgeons, but results must be interpreted with caution.
authors.affiliation: Division of Orthopaedics, Department of Surgery Kingston General Hospital, Queen's University, 76 Stuart St, Nickle 3, Rm 9-309, Kingston, ON K7L 2V7, Canada. rick.lau3@gmail.com
authors.forename: Rick L
authors.initials: RL
authors.lastname: Lau
authors.forename: Anthony V
authors.initials: AV
authors.lastname: Perruccio
authors.forename: Rajiv
authors.initials: R
authors.lastname: Gandhi
authors.forename: Nizar N
authors.initials: NN
authors.lastname: Mahomed
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000295:instrumentation / Q000401:mortality / Q000639:trends*; D015897:Comorbidity; D061847:Hospitals, High-Volume / Q000639:trends*; D061846:Hospitals, Low-Volume / Q000639:trends*; D006801:Humans; D007720:Knee Prosthesis; D007902:Length of Stay; D015999:Multivariate Analysis; D016017:Odds Ratio; D011475:Prosthesis Failure; D018570:Risk Assessment; D012307:Risk Factors; D013530:Surgical Wound Infection / Q000209:etiology; D013923:Thromboembolism / Q000209:etiology; D013997:Time Factors; D065227:Transfusion Reaction; D016896:Treatment Outcome