title: Early migration of the tibial component of the buechel-pappas total ankle prosthesis.
abstract: Interest in mobile-bearing total ankle arthroplasty has increased in recent years. Clinical studies show favorable but varying results, with survival rates between 70% and 90% at 10-year followup. Design-specific differences in early migration patterns might explain variations in the results and modes of failure. Using radiostereometric analysis (RSA) we prospectively followed 15 RA patients with a cementless mobile-bearing total ankle arthroplasty. The American Orthopaedic Foot and Ankle Society ankle score and radiostereometric radiographs were evaluated immediately postoperatively, 6 weeks postoperatively, 3 months, 6 months, and 12 months postoperatively and yearly thereafter. The postoperative clinical results improved. We observed increased migration of the tibial component during the first 3 months, but this stabilized by the 6 month followup. The mean lateral-medial migration was 0.8 mm, distal-proximal migration was 0.9 mm, and posteroanterior migration was -0.5 mm. The latter implies the total resultant migration was in anterior and valgus tilting of this tibial component. However, migration stabilized at 6 months postoperatively. We believe the surgical technique (anterior cortical window for placement) and the method of tibial fixation likely explain this migration.
  
  
  METHODS
  Therapeutic, Level IV. See Guidelines for Authors for a complete description of levels of evidence.
authors.affiliation: Department of Orthopaedics, Leiden University Medical Center, The Netherlands. r.g.h.h.nelissen@lumc.nl
authors.forename: Rob G H H
authors.initials: RG
authors.lastname: Nelissen
authors.forename: H Cornelis
authors.initials: HC
authors.lastname: Doets
authors.forename: Edward R
authors.initials: ER
authors.lastname: Valstar
mesh_terms: D000843:Ankle Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D001175:Arthrography; D019643:Arthroplasty, Replacement / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000209:etiology* / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D011475:Prosthesis Failure; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery*; D013997:Time Factors