title: Resurfacing knee arthroplasty in patients with allergic sensitivity to metals.
abstract: BACKGROUND
  The problem of metal sensitivity (Ni, Cr, and Co) in arthroplasty is still unsolved. To prevent the risk of allergy in cases with proved metal allergy in an epicutaneous test, a Natural Knee total knee arthroplasty, made totally from titanium (Ti-6Al-4V) and polyethylene, can be implanted. The results of this device have to be compared to the results of normal knee arthroplasty designed with a femoral component out of CrCoNi alloy. The mechanical resistance of this alloy is much higher than that of titanium, and therefore it is the standard for the femoral components of most knee-resurfacing devices.
  
  
  METHODS
  Thirty-five patients with a titanium Natural Knee were examined retrospectively after a mean follow-up of 2 years and 5 months (range 6 months to 5 years and 4 months). In comparison, 36 patients with a Genesis-I knee with a CrCoNi alloy femoral component were studied after a mean follow-up of 2 years and 4 months (range 8 months to 6 years and 2 months).
  
  
  RESULTS
  In spite of the lower mechanical resistance of titanium, the Natural Knee showed better results (knee score 84.1 points, function score 77.7 points, HSS score 80.1 points, 82.9% excellent and good results) than the Genesis-I knee (knee score 80.6 points, function score 76.4 points, HSS score 76.4 points, 68.5% excellent and good results), although these differences had no statistical significance.
  
  
  CONCLUSIONS
  The titanium Natural Knee prosthesis has proven to be a reliable knee joint replacement in the medium term.
authors.affiliation: Department of Orthopaedic Surgery, Klinikum Grosshadern, Ludwig Maximilians University Munich, Marchioninistrasse 15, 81377 Munich, Germany. c.pellengahr@surfeu.de
authors.forename: C
authors.initials: C
authors.lastname: Pellengahr
authors.forename: W
authors.initials: W
authors.lastname: Mayer
authors.forename: M
authors.initials: M
authors.lastname: Maier
authors.forename: P E
authors.initials: PE
authors.lastname: Müller
authors.forename: C
authors.initials: C
authors.lastname: Schulz
authors.forename: H R
authors.initials: HR
authors.lastname: Dürr
authors.forename: H
authors.initials: H
authors.lastname: Trouillier
authors.forename: M
authors.initials: M
authors.lastname: Steinborn
authors.forename: V
authors.initials: V
authors.lastname: Jansson
authors.forename: H J
authors.initials: HJ
authors.lastname: Refior
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006967:Hypersensitivity / Q000209:etiology* / Q000601:surgery*; D007720:Knee Prosthesis / Q000009:adverse effects*; D008297:Male; D008670:Metals / Q000009:adverse effects*; D008875:Middle Aged; D011183:Postoperative Complications / Q000601:surgery; D011474:Prosthesis Design; D020127:Recovery of Function; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D008670:Metals