title: Causes of failure after total knee arthroplasty in osteoarthritis patients 55 years of age or younger.
abstract: OBJECTIVE
  To identify the modes of failure after total knee arthroplasty (TKA) in patients >55 years of age and to compare with those >55 years of age in patients who underwent revision TKA.
  
  
  METHODS
  We retrospectively reviewed 256 revision TKAs among patients who underwent TKA for knee osteoarthritis between January 1992 and December 2012. The causes of TKA failure were analyzed and compared between the groups.
  
  
  RESULTS
  Thirty-one revision TKAs were performed in patients ≤55 years of age at the time of primary TKA, whereas 225 cases were in those >55 years of age at primary TKA. In the ≤55 years of age group, the most common cause of TKA failure was polyethylene wear (45%) followed by infection (26%) and loosening (17%). The interval from primary TKA to revision was 8.6 years (range, 1 to 17 years). There were relatively lower infection rate and higher loosening rate in patients ≤55 years of age, but the difference was not statistically significant.
  
  
  CONCLUSIONS
  The main causes of failure after TKA in patients ≤55 years of age were polyethylene wear, infection and loosening, and there was no significant difference in the modes of failure after TKA between the two groups.
authors.affiliation: Department of Orthopedic Surgery, Seoul Sacred Heart General Hospital, Seoul, Korea.
authors.forename: Kyung Tae
authors.initials: KT
authors.lastname: Kim
authors.affiliation: Department of Orthopedic Surgery, Seoul Sacred Heart General Hospital, Seoul, Korea.
authors.forename: Song
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Orthopedic Surgery, Seoul Sacred Heart General Hospital, Seoul, Korea.
authors.forename: Dong Oh
authors.initials: DO
authors.lastname: Ko
authors.affiliation: Department of Orthopedic Surgery, Seoul Sacred Heart General Hospital, Seoul, Korea.
authors.forename: Bong Soo
authors.initials: BS
authors.lastname: Seo
authors.affiliation: Department of Orthopedic Surgery, Seoul Sacred Heart General Hospital, Seoul, Korea.
authors.forename: Woo Shik
authors.initials: WS
authors.lastname: Jung
authors.affiliation: Department of Orthopedic Surgery, Seoul Sacred Heart General Hospital, Seoul, Korea.
authors.forename: Byung Kwon
authors.initials: BK
authors.lastname: Chang
keywords: Arthroplasty; Failure; Knee; Revision; Younger age