title: Early migration of tibial components is associated with late revision: a systematic review and meta-analysis of 21,000 knee arthroplasties.
abstract: OBJECTIVE
  We performed two parallel systematic reviews and meta-analyses to determine the association between early migration of tibial components and late aseptic revision.
  
  
  METHODS
  One review comprised early migration data from radiostereometric analysis (RSA) studies, while the other focused on revision rates for aseptic loosening from long-term survival studies. Thresholds for acceptable and unacceptable migration were determined according to that of several national joint registries: < 5% revision at 10 years.
  
  
  RESULTS
  Following an elaborate literature search, 50 studies (involving 847 total knee prostheses (TKPs)) were included in the RSA review and 56 studies (20,599 TKPs) were included in the survival review. The results showed that for every mm increase in migration there was an 8% increase in revision rate, which remained after correction for age, sex, diagnosis, hospital type, continent, and study quality. Consequently, migration up to 0.5 mm was considered acceptable during the first postoperative year, while migration of 1.6 mm or more was unacceptable. TKPs with migration of between 0.5 and 1.6 mm were considered to be at risk of having revision rates higher than 5% at 10 years.
  
  
  CONCLUSIONS
  There was a clinically relevant association between early migration of TKPs and late revision for loosening. The proposed migration thresholds can be implemented in a phased, evidence-based introduction of new types of knee prostheses, since they allow early detection of high-risk TKPs while exposing only a small number of patients.
authors.affiliation: Department of Orthopaedics, Bio Imaging Group, Leiden University Medical Center, Leiden, the Netherlands. b.g.c.w.pijls@lumc.nl
authors.forename: Bart G
authors.initials: BG
authors.lastname: Pijls
authors.forename: Edward R
authors.initials: ER
authors.lastname: Valstar
authors.forename: Klaas-Auke
authors.initials: KA
authors.lastname: Nouta
authors.forename: Josepha Wm
authors.initials: JW
authors.lastname: Plevier
authors.forename: Marta
authors.initials: M
authors.lastname: Fiocco
authors.forename: Saskia
authors.initials: S
authors.lastname: Middeldorp
authors.forename: Rob Ghh
authors.initials: RG
authors.lastname: Nelissen
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation / Q000379:methods; D018570:Risk Assessment; D013997:Time Factors; D016896:Treatment Outcome