title: All-polyethylene tibial components in obese patients are associated with low failure at midterm followup.
abstract: BACKGROUND
  In the United States, the obese population has increased markedly over the last four decades, and this trend continues. High patient weight places additional stress on TKA components, which may lead to increased polyethylene wear, osteolysis, radiolucencies, and clinical failure. Metal-backed tibial components and all-polyethylene tibial components in the general population have comparable osteolysis and failure, but it is unclear whether these components yield similar osteolysis and failure in obese patients.
  
  
  OBJECTIVE
  We therefore determined the (1) function, (2) occurrence of osteolysis, and (3) complications in a cohort of obese patients receiving all-polyethylene tibial components.
  
  
  METHODS
  Between September 17, 1996, and December 19, 2002, we implanted all-polyethylene tibial components in 90 obese patients (125 knees); 24 patients (33 knees) died and 13 patients (17 knees) were lost to followup, leaving 53 patients (59%) with 75 knees. All surgeries were cruciate-retaining, tricompartmental TKAs. We evaluated patients with Knee Society Scores and serial radiographs. Minimum followup was 7 years (mean, 10.4 years; range, 7-14 years).
  
  
  RESULTS
  At latest followup, mean Knee Society Score was 92 points. There were five tibial radiolucencies, all less than 1 mm and characterized as nonprogressive. We observed minimal, nonprogressive osteolysis in one knee. One patient required reoperation after a traumatic event. There were no implant-related failures and no implants at risk of failure.
  
  
  CONCLUSIONS
  At an average 10-year followup, all-polyethylene tibial components were functioning well in this obese group. These findings confirm the effectiveness of all-polyethylene tibial components in obese patients.
authors: Towson Orthopaedic Associates, LLC, Towson, MD, USA. ehenze1@jhmi.edu
authors: David F
authors: DF
authors: Dalury
authors: Kimberly K
authors: KK
authors: Tucker
authors: Todd C
authors: TC
authors: Kelley
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000379:methods*; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000175:diagnosis*; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000601:surgery; D010149:Postoperative Pain / Q000503:physiopathology; D020959:Polyethylene / Q000737:chemistry*; D011474:Prosthesis Design / Q000379:methods*; D011475:Prosthesis Failure; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology; D020127:Recovery of Function; D012189:Retrospective Studies; D018570:Risk Assessment; D012737:Sex Factors; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D020959:Polyethylene