title: The risk of bearing dislocation in lateral unicompartmental knee arthroplasty using a mobile biconcave design.
abstract: OBJECTIVE
  A safety study was conducted on a cohort of 25 patients who underwent lateral unicompartmental arthroplasty with a biconcave mobile-bearing insert.
  
  
  METHODS
  The first 25 lateral mobile-bearing unicompartmental knee replacements, performed in a general hospital by one surgeon, were prospectively reviewed, with a minimum follow-up of 1 year.
  
  
  RESULTS
  One bearing dislocation occurred 4 months postsurgery. The Oxford knee score improved in all patients from a preoperative mean of 23.3 (range 8-40, SD 8.4) to a postoperative mean of 42.1 (range 23-48, SD 6.7). General patient satisfaction at a mean follow-up of 20 months was excellent in 84 %, good in 12 % and fair in 4 %. The mechanical axis as a measure on full-leg standing radiographs improved from 5.7° valgus (range 1°-16°, SD 4.1°) to 1.7° valgus (7° to -3°, SD 2.1°). Mechanical alignment correction averaged 4.0° (range -1° to 15°, SD 3.9°).
  
  
  CONCLUSIONS
  The mobile biconcave insert design in the lateral unicompartmental knee replacement seems appropriate as a innovative, anatomy imitating solution, resulting in a good clinical outcome. Still, bearing dislocation remains a concern, especially in extended indication.
authors.affiliation: General Hospital Sint-Lucas Bruges, Sint-Lucaslaan 29, 8310, Brugge, Belgium, sebastiaanschelfaut@msn.com.
authors.forename: Sebastiaan
authors.initials: S
authors.lastname: Schelfaut
authors.forename: Lucas
authors.initials: L
authors.lastname: Beckers
authors.forename: Peter
authors.initials: P
authors.lastname: Verdonk
authors.forename: Johan
authors.initials: J
authors.lastname: Bellemans
authors.forename: Jan
authors.initials: J
authors.lastname: Victor
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007719:Knee Joint; D007720:Knee Prosthesis / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000601:surgery*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D016059:Range of Motion, Articular; D012086:Reoperation; D016896:Treatment Outcome