title: Risk of total knee arthroplasty after operatively treated tibial plateau fracture: a matched-population-based cohort study.
abstract: BACKGROUND
  The aims of operative treatment of displaced tibial plateau fractures are to stabilize the injured knee to restore optimal function and to minimize the risk of posttraumatic arthritis and the eventual need for total knee arthroplasty. The purpose of our study was to define the rate of subsequent total knee arthroplasty after tibial plateau fractures in a large cohort and to compare that rate with the rate in the general population.
  
  
  METHODS
  All patients sixteen years of age or older who had undergone surgical treatment of a tibial plateau fracture from 1996 to 2009 in the province of Ontario, Canada, were identified from administrative health databases with use of surgeon fee codes. Each member of the tibial plateau fracture cohort was matched to four individuals from the general population according to age, sex, income, and urban/rural residence. The rates of total knee arthroplasty at two, five, and ten years were compared by using time-to-event analysis. A separate Cox proportional hazards model was used to explore the influence of patient, provider, and surgical factors on the time to total knee arthroplasty.
  
  
  RESULTS
  We identified 8426 patients (48.5% female; median age, 48.9 years) who had undergone fixation of a tibial plateau fracture and matched them to 33,698 controls. The two, five, and ten-year rates of total knee arthroplasty in the plateau fracture and control cohorts were 0.32% versus 0.29%, 5.3% versus 0.82%, and 7.3% versus 1.8%, respectively (p < 0.0001). After adjustment for comorbidity, plateau fracture surgery was found to significantly increase the likelihood of total knee arthroplasty (hazard ratio [HR], 5.29 [95% confidence interval, 4.58, 6.11]; p < 0.0001). Higher rates of total knee arthroplasty were also associated with increasing age (HR, 1.03 [1.03, 1.04] per year over the age of forty-eight; p < 0.0001), bicondylar fracture (HR, 1.53 [1.26, 1.84]; p < 0.0001), and greater comorbidity (HR, 2.17 [1.70, 2.77]; p < 0.001).
  
  
  CONCLUSIONS
  Ten years after tibial plateau fracture surgery, 7.3% of the patients had had a total knee arthroplasty. This corresponds to a 5.3 times increase in likelihood compared with a matched group from the general population. Older patients and those with more severe fractures are also more likely to need total knee arthroplasty after repair of a tibial plateau fracture.
authors.affiliation: Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, MG-314, Toronto, ON M4N 3M5, Canada. E-mail address for D. Wasserstein: david.wasserstein@mail.utoronto.ca.
authors.forename: David
authors.initials: D
authors.lastname: Wasserstein
authors.affiliation: Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, MG-314, Toronto, ON M4N 3M5, Canada. E-mail address for D. Wasserstein: david.wasserstein@mail.utoronto.ca.
authors.forename: Patrick
authors.initials: P
authors.lastname: Henry
authors.affiliation: Institute for Clinical Evaluative Sciences, 2075 Bayview Avenue, G1-06, Toronto, ON M4N 3M5, Canada.
authors.forename: J Michael
authors.initials: JM
authors.lastname: Paterson
authors.affiliation: Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, MG-314, Toronto, ON M4N 3M5, Canada. E-mail address for D. Wasserstein: david.wasserstein@mail.utoronto.ca.
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Kreder
authors.affiliation: Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, MG-317, Toronto, ON M4N 3M5, Canada.
authors.forename: Richard
authors.initials: R
authors.lastname: Jenkinson
mesh_terms: D000328:Adult; D019645:Arthroplasty, Replacement, Knee / Q000379:methods* / Q000706:statistics & numerical data; D016022:Case-Control Studies; D005260:Female; D005500:Follow-Up Studies; D005593:Fracture Fixation, Internal / Q000009:adverse effects* / Q000379:methods; D017102:Fracture Healing / Q000502:physiology; D006801:Humans; D015994:Incidence; D015601:Injury Severity Score; D057072:Intra-Articular Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D007718:Knee Injuries / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008592:Menisci, Tibial / Q000601:surgery; D008875:Middle Aged; D009864:Ontario; D020370:Osteoarthritis, Knee / Q000209:etiology / Q000503:physiopathology / Q000601:surgery; D011183:Postoperative Complications / Q000503:physiopathology / Q000601:surgery; D016016:Proportional Hazards Models; D011859:Radiography; D020127:Recovery of Function; D012189:Retrospective Studies; D018570:Risk Assessment; D013978:Tibial Fractures / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery; D000070600:Tibial Meniscus Injuries; D016896:Treatment Outcome