title: The incidence of implant fractures after knee arthroplasty.
abstract: OBJECTIVE
  This study aimed to evaluate the incidence of "implant" fractures after knee arthroplasty using clinical literature and worldwide arthroplasty registers. The hypothesis was that register datasets report higher rates of these rare complications than clinical studies.
  
  
  METHODS
  Calculations were based on the pooled incidence of revision operations after fractures of knee arthroplasties, comparing clinical studies published in MEDLINE-listed journals and annual reports from worldwide arthroplasty registers in a structured literature analysis based on a standardized methodology.
  
  
  RESULTS
  Twelve clinical studies and datasets from six worldwide registers were included. Rates of fractures of knee arthroplasties were reported from 0.2 to 2.5 % in clinical studies versus 0.02-0.17 % in worldwide arthroplasty registers.
  
  
  CONCLUSIONS
  Fractures of knee arthroplasty systems are rare complications, with clinical studies showing higher incidence rates than worldwide arthroplasty registries. Unicompartmental knee arthroplasty (UKA) implanted before 2000, constrained primary or revision constrained total knee arthroplasties, and patellar replacements showed the highest incidence of implant fracture. The results of this analysis can help clinicians to counsel patients on potential complications following knee arthroplasty.
  
  
  METHODS
  III.
authors.affiliation: Department of Orthopedic Surgery, Medical University of Graz, Auenbruggerplatz 5, 8036, Graz, Austria.
authors.forename: Magdalena M
authors.initials: MM
authors.lastname: Gilg
authors.affiliation: Department of Trauma Surgery, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93042, Regensburg, Germany.
authors.forename: Christian W
authors.initials: CW
authors.lastname: Zeller
authors.affiliation: Department of Orthopedic Surgery, Medical University of Graz, Auenbruggerplatz 5, 8036, Graz, Austria.
authors.forename: Lukas
authors.initials: L
authors.lastname: Leitner
authors.affiliation: Department of Orthopedic Surgery, Medical University of Graz, Auenbruggerplatz 5, 8036, Graz, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Leithner
authors.affiliation: Department of Orthopedic Surgery, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria.
authors.forename: Gerold
authors.initials: G
authors.lastname: Labek
authors.affiliation: Department of Orthopedic Surgery, Medical University of Graz, Auenbruggerplatz 5, 8036, Graz, Austria. patrick.sadoghi@medunigraz.at.
authors.forename: Patrick
authors.initials: P
authors.lastname: Sadoghi
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D006801:Humans; D015994:Incidence; D007720:Knee Prosthesis; D010329:Patella / Q000601:surgery; D057068:Periprosthetic Fractures / Q000453:epidemiology*; D011183:Postoperative Complications / Q000453:epidemiology*; D012042:Registries; D012086:Reoperation
keywords: Arthroplasty; Breakage; Fracture; Implant; Knee; Replacement; TKA; TKR