title: Wear and lysis is the problem in modular TKA in the young OA patient at 10 years.
abstract: BACKGROUND
  Most long-term followup studies of younger patients who underwent TKA include a relatively high percentage of rheumatoid patients, whose function and implant durability may differ from those with osteoarthritis (OA).
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the minimum 10 year followup of TKA performed in more active patients with OA, using modular tibial components, to determine the durability of that construct. Specifically, we determined (1) survivorship; (2) revision rates; (3) functional scores; and (4) rates of radiographic failure at a minimum 10 year followup.
  
  
  METHODS
  We retrospectively reviewed 59 patients (67 knees) with OA who underwent primary total knee arthroplasty with posterior cruciate retaining (27%) or posterior cruciate substituting (73%) components which had modular tibial trays. Patients were evaluated clinically for need of revision and Knee Society, SF-36 and WOMAC scores as well as UCLA and Tegner activity scores. Radiographs were evaluated for loosening and osteolysis. The minimum followup of living patients was 10 years (mean, 12.4 years; range, 10 to 18.4 years). Ten patients (11 knees) died; two patients (2 knees) were lost to followup.
  
  
  RESULTS
  Ten patients (11 knees; 16%) had revisions for aseptic loosening and/or osteolysis. Thirty-one patients (65%) were still performing moderate labor or sports activities. The average UCLA score was 5.5 (range, 2-9). No nonrevised knee demonstrated radiographic loosening.
  
  
  CONCLUSIONS
  Most patients in this active patient population continued to have acceptable function although 16% underwent revision for wear and/or osteolysis. Isolated tibial insert exchange alone was performed in four of the 11 (36%) revised knees. These data should provide comparison for total knee arthroplasties performed in younger patients with newer designs and newer bearing materials.
  
  
  METHODS
  Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
authors.affiliation: University of Iowa, 200 Hawkins Dr, UIHC, 01029 JPP, Iowa City, IA 52242, USA.
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Odland
authors.forename: John J
authors.initials: JJ
authors.lastname: Callaghan
authors.forename: Steve S
authors.initials: SS
authors.lastname: Liu
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Wells
mesh_terms: D000328:Adult; D000367:Age Factors; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000295:instrumentation*; D005260:Female; D006801:Humans; D007484:Iowa; D053208:Kaplan-Meier Estimate; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000601:surgery*; D010014:Osteolysis / Q000209:etiology / Q000601:surgery; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D012086:Reoperation; D012189:Retrospective Studies; D013314:Stress, Mechanical; D013997:Time Factors; D016896:Treatment Outcome