title: High-flexion total knee arthroplasty: survivorship and prevalence of osteolysis: results after a minimum of ten years of follow-up.
abstract: BACKGROUND
  We are aware of no information about the mid-term performance of the high-flexion total knee arthroplasty, although early results have been reported. The purpose of this study was to evaluate the mid-term results of high-flexion and conventional knee prostheses.
  
  
  METHODS
  We prospectively compared the results of 100 patients with osteoarthritis who had received a NexGen Legacy Posterior Stabilized (NexGen LPS) prosthesis in one knee and a NexGen Legacy Posterior Stabilized-Flex (NexGen LPS-Flex) prosthesis in the other. Seventy-five patients (150 knees) were women and twenty-five (fifty knees) were men. The mean age was sixty-five years (range, forty-eight to eighty-five years) at the time of the index procedure. The mean duration of follow-up was 10.3 years (range, ten to 10.6 years). The patients were assessed with radiographs, with the rating system of the Knee Society, and with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score at three months, one year, and annually thereafter.
  
  
  RESULTS
  Total knee scores, knee function scores, pain scores, WOMAC scores, knee motion, and activity scores did not differ significantly between the two designs of the implants, on the basis of the numbers studied, either preoperatively or at the time of final follow-up. One knee in the NexGen LPS-Flex group was revised because of recurrent infection. No knee in either group had aseptic loosening of the components. The Kaplan-Meier survivorship at ten years postoperatively, with revision defined as the end point, was 100% (95% confidence interval, 94 to 100) for the NexGen LPS prosthesis and 99% (95% confidence interval, 93 to 100) for the NexGen LPS-Flex prosthesis.
  
  
  CONCLUSIONS
  After a minimum duration of follow-up of ten years, there were no significant differences between the two groups with regard to implant survivorship, functional outcome, knee motion, or prevalence of osteolysis.
authors.affiliation: The Joint Replacement Center, Ewha Womans University MokDong Hospital, 911-1, MokDong, YangChun-Ku, Seoul, South Korea. younghookim@ewha.ac.kr
authors.forename: Young-Hoo
authors.initials: YH
authors.lastname: Kim
authors.forename: Jang-Won
authors.initials: JW
authors.lastname: Park
authors.forename: Jun-Shik
authors.initials: JS
authors.lastname: Kim
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D004185:Disability Evaluation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000601:surgery*; D010014:Osteolysis / Q000453:epidemiology*; D010147:Pain Measurement; D011183:Postoperative Complications / Q000453:epidemiology*; D015995:Prevalence; D011446:Prospective Studies; D011859:Radiography; D016059:Range of Motion, Articular; D012086:Reoperation / Q000706:statistics & numerical data; D013530:Surgical Wound Infection / Q000453:epidemiology; D015996:Survival Rate