title: Total ankle replacement with use of a new three-component implant.
abstract: BACKGROUND
  Total ankle arthroplasty has evolved over the past decade, and newer three-component implants have demonstrated favorable clinical results and improved survivorship. The present study analyzed the clinical and radiographic results of the first 240 total ankle arthroplasties performed by the authors with one of these new three-component prostheses.
  
  
  METHODS
  Two hundred and forty consecutive primary total ankle arthroplasties were performed in 233 patients (115 women and 118 men; mean age, 61.6 years) between November 2003 and October 2007 with the Mobility prosthesis. Intraoperative and postoperative complications, reoperations, and failures were recorded. The American Orthopaedic Foot & Ankle Society hindfoot score and a visual analog scale score assessment of pain were determined at each follow-up visit. Range of ankle motion was measured on functional radiographs, and the radiographs were studied to assess component positioning, radiolucencies, new bone formation, and periprosthetic bone cysts.
  
  
  RESULTS
  Two hundred and thirty-three of the arthroplasties were available for follow-up at least one year after surgery. The mean duration of follow-up was 32.8 ± 15.3 months. There were ten intraoperative complications (4.2%) and twenty postoperative complications (8.6%). A reoperation was necessary in eighteen ankles (7.7%). Five arthroplasties (2.1%) failed at a mean of twenty-seven months after surgery. The mean American Orthopaedic Foot & Ankle Society hindfoot score improved from 48.2 to 84.1 points (p < 0.001). The mean pain level decreased from 7.7 to 1.7 points (p < 0.001). The mean total range of ankle motion improved from 19.8° to 21.9° (p < 0.001). The tibial component had a mean of 2.1° of varus and a mean posterior slope of 6.0° relative to the tibial axis. The prevalence of nonprogressive radiolucency ranged from 1.8% to 37.3% in the ten zones surrounding the tibial component, and from 0 to 2.2% in the three zones surrounding the talar component.
  
  
  CONCLUSIONS
  The short-term clinical and radiographic results after Mobility total ankle arthroplasty are encouraging and are at least comparable with those associated with other modern three-component implants. The minimum duration of follow-up of one year is short, and studies with longer follow-up are needed to confirm our findings.
authors.affiliation: Department of Orthopaedic Surgery, Foot and Ankle Center, Schulthess Clinic, Zurich, Switzerland. pascal.rippstein@kws.ch
authors.forename: Pascal F
authors.initials: PF
authors.lastname: Rippstein
authors.forename: Martin
authors.initials: M
authors.lastname: Huber
authors.forename: J Chris
authors.initials: JC
authors.lastname: Coetzee
authors.forename: Florian D
authors.initials: FD
authors.lastname: Naal
mesh_terms: D058737:Arthroplasty, Replacement, Ankle / Q000379:methods*; D005260:Female; D006801:Humans; D007595:Joint Prosthesis; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology; D016896:Treatment Outcome