title: What are the causes of revision total knee arthroplasty in Japan?
abstract: BACKGROUND
  There is limited information regarding the cause of revision TKA in Asia, especially Japan. Owing to differences in patient backgrounds and lifestyles, the modes of TKA failures in Asia may differ from those in Western countries.
  
  
  OBJECTIVE
  We therefore determined (1) causes of revision TKA in a cohort of Japanese patients with revision TKA and (2) whether patient demographic features and underlying diagnosis of primary TKA are associated with the causes of revision TKA.
  
  
  METHODS
  We assessed all revision TKA procedures performed at five major centers in Hokkaido from 2006 to 2011 for the causes of failures. Demographic data and underlying diagnosis for index primary TKA of the revision cases were compared to those of randomly selected primary TKAs during the same period.
  
  
  RESULTS
  One hundred forty revision TKAs and 4047 primary TKAs were performed at the five centers, indicating a revision burden of 3.3%. The most common cause of revision TKA was mechanical loosening (40%) followed by infection (24%), wear/osteolysis (9%), instability (9%), implant failure (6%), periprosthetic fracture (4%), and other reasons (8%). The mean age of patients with periprosthetic fracture was older (77 versus 72 years) and the male proportion in patients with infection was higher (33% versus 19%) than those of patients in the primary TKA group. There was no difference in BMI between primary TKAs and any type of revision TKA except other causes.
  
  
  CONCLUSIONS
  The revision burden at the five referral centers in Hokkaido was 3.3%, and the most common cause of revision TKA was mechanical loosening followed by infection. Demographic data such as age and sex might be associated with particular causes of revision TKA.
authors: Department of Orthopaedic Surgery, Hokkaido University Graduate School of Medicine, Kita-Ku, Sapporo, Japan.
authors: Yasuhiko
authors: Y
authors: Kasahara
authors: Tokifumi
authors: T
authors: Majima
authors: Shoichi
authors: S
authors: Kimura
authors: Osamu
authors: O
authors: Nishiike
authors: Jun
authors: J
authors: Uchida
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000295:instrumentation*; D044466:Asian People; D001696:Biomechanical Phenomena; D016009:Chi-Square Distribution; D005260:Female; D050723:Fractures, Bone / Q000208:ethnology / Q000601:surgery; D006801:Humans; D007564:Japan / Q000453:epidemiology; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D007720:Knee Prosthesis; D008019:Life Style / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D010014:Osteolysis / Q000208:ethnology / Q000601:surgery; D011183:Postoperative Complications / Q000208:ethnology / Q000601:surgery*; D011475:Prosthesis Failure; D016459:Prosthesis-Related Infections / Q000208:ethnology / Q000601:surgery; D011859:Radiography; D012086:Reoperation; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome
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