title: [Implantation of a non-cemented acetabulum with the use of a navigation system].
abstract: OBJECTIVE
  To compare, on the basis of clinical and radiographic findings, the results of non-cemented acetabulum implantation involving the use of a CT-free navigation system with those of implantation without its use.
  
  
  METHODS
  A total of 50 patients undergoing implantation of a non-cemented acetabulum in the period from April 2002 to September 2003 were evaluated. Twenty-five patients operated on without the navigation system were included in group 1 on a random basis and 25 patients treated with the use of the system constituted group 2.
  
  
  METHODS
  Both groups were evaluated on the basis of clinical and X-ray findings. The radiographic measurement of acetabulular inclination was based on anteroposterior projection of both hips made on films on films equal in size. Anteversion of the acetabulum was assessed according to the Ackland system. The Merle d'Aubigne and Postel scores were used for clinical evaluation. The results were compared statistically.
  
  
  RESULTS
  In group 1, the average inclination was 50.6 degrees (range, 38-62) and the average anteversion was 9.4 degrees (range, 3-18). In group 2, the values were 43.0 degrees (32-55) and 10.4 degrees (8-16) for the average inclination and anteversion, respectively. The difference in acetabular inclination between the two groups was statistically significant. When accuracy was evaluated, the difference in acetabular anteversion was statistically significant.
  
  
  CONCLUSIONS
  The achievement of an optimal position of the acetabular component is one of the important factors for good, long-term outcomes of hip replacement. The optimal position that, as suggested by many authors, involves an inclination of 45 +/- 10 degrees and an anteversion of 15 +/- 10 degrees provides sufficient stability, low wear and a satisfactory range of motion in the hip joint. The results close to these values were achieved in the patients included in group 2.
  
  
  CONCLUSIONS
  A comparison of the groups showed that the computer-assisted navigation system used in implantation resulted in an optimal position of the acetabular component.
authors.affiliation: Ortopedické oddĕlení Nemocnice Znojmo.
authors.forename: V
authors.initials: V
authors.lastname: Stipcák
authors.forename: J
authors.initials: J
authors.lastname: Stoklas
authors.forename: R
authors.initials: R
authors.lastname: Hart
authors.forename: M
authors.initials: M
authors.lastname: Janecek
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging; D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography; D025321:Surgery, Computer-Assisted; D014584:User-Computer Interface