title: Modular fixed-bearing total knee arthroplasty with retention of the posterior cruciate ligament. A study of patients followed for a minimum of fifteen years.
abstract: BACKGROUND
  There have been a limited number of studies of total knee arthroplasties with durations of follow-up of fifteen years, but we are not aware of any involving modular fixed-bearing posterior cruciate-retaining prostheses.
  
  
  METHODS
  A consecutive series of 139 total knee arthroplasties in 109 patients (average age, sixty-seven years), performed by one surgeon using a nonconforming posterior cruciate-retaining prosthesis, was followed for fifteen years or longer. Forty-five patients (fifty-nine knees) were examined at a minimum of fifteen years postoperatively, fifty-seven patients (seventy knees) had died, five patients (eight knees) were too ill to return for assessment, and two patients (two knees) were considered lost to follow-up. The patients were assessed clinically with use of the Knee Society clinical rating system, and the knees were assessed radiographically. Survivorship analysis was performed with use of worst-case-scenario analysis and with failure defined as a reoperation for any reason.
  
  
  RESULTS
  There were five reoperations, four of which were performed because of wear of the polyethylene insert. In addition, one loose cemented femoral component was revised at fifteen years. The survival rate without revision or a need for any reoperation was 92.6% at fifteen years. The mean Knee Society score and functional score at fifteen years were 96 and 78 points, respectively. The prevalence of radiolucent lines was 13%, with 2% around the femur, 11% around the tibia, and none around the patella. None of these lines were clinically relevant. There was no evidence of progressive radiolucent lines, and there was one case of asymptomatic femoral osteolysis.
  
  
  CONCLUSIONS
  In this single-surgeon series, modular fixed-bearing posterior cruciate-retaining total knee arthroplasties had good clinical and radiographic results with excellent survivorship for up to fifteen years. These results are comparable with those in long-term studies of posterior stabilized implants and of prostheses with mobile-bearing and nonmodular tibial inserts.
authors.affiliation: Department of Orthopaedic Surgery, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Dixon
authors.forename: Richard R
authors.initials: RR
authors.lastname: Brown
authors.forename: Dominik
authors.initials: D
authors.lastname: Parsch
authors.forename: Richard D
authors.initials: RD
authors.lastname: Scott
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020959:Polyethylene; D016119:Posterior Cruciate Ligament; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation
chemical_list: D020959:Polyethylene