title: Constraint choice in revision knee arthroplasty.
abstract: OBJECTIVE
  Along with the increase in primary total knee arthroplasty, there has been an increase in the number of revisions. The aim of this study was to propose a selection algorithm for the knee revision constraint according to the state of ligaments and to the bone defects Anderson Orthopaedic Research Institute Classification [AORI] classification. The hypothesis was that this algorithm would facilitate the appropriate choice of prosthesis constraint, thus providing stable components and a good long-term survivorship of the knee revisions.
  
  
  METHODS
  Sixty consecutive revision knee arthroplasties in 57 patients were prospectively evaluated. Prostheses implanted at revision included postero-stabilised, condylar constrained and rotating hinged, relative to the state of the ligaments and of the bone loss around the knee. The median follow-up was nine years (range, 4-12).
  
  
  RESULTS
  The median IKS knee and function scores and HSS score were 41 (15-62), 21.5 (12-43) and 34 (23-65) points, respectively, before the operation, and 81 (48-97), 79 (56-92) and 83.5 (62-98) points (p < 0.001) at the latest follow-up evaluation. The median ROM increased from 74° (29-110°) preoperatively to 121° (98-132°) (p < 0.01) at the final follow-up. Re-revision was necessary in five (8.3%) patients.
  
  
  CONCLUSIONS
  A selection algorithm for the revision implant constraint based on the state of ligaments and the bone loss AORI classification could provide stable knee reconstructions and long-term success of knee revisions.
authors.affiliation: Department of Medicine and Health Science, University of Molise, Via Francesco De Sanctis, Campobasso, Italy. vassomichele@gmail.com
authors.forename: Michele
authors.initials: M
authors.lastname: Vasso
authors.forename: Philippe
authors.initials: P
authors.lastname: Beaufils
authors.forename: Alfredo
authors.initials: A
authors.lastname: Schiavone Panni
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D005260:Female; D006801:Humans; D015994:Incidence; D007593:Joint Instability / Q000453:epidemiology; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D007720:Knee Prosthesis / Q000009:adverse effects; D008022:Ligaments / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010014:Osteolysis / Q000453:epidemiology; D011446:Prospective Studies; D011475:Prosthesis Failure / Q000009:adverse effects; D011859:Radiography; D012086:Reoperation / Q000379:methods*; D012189:Retrospective Studies