title: Does CT-based navigation improve the long-term survival in ceramic-on-ceramic THA?
abstract: BACKGROUND
  Although navigated THA provides improved precision in implant positioning and alignment, it is unclear whether these translate into long-term implant survival.
  
  
  OBJECTIVE
  We compared survivorship, dislocation rate, and incidence of radiographic failures such as loosening and bearing breakage after THA with and without navigation at a minimum 10-year followup.
  
  
  METHODS
  We retrospectively reviewed 46 patients (60 hips) and 97 patients (120 hips) receiving THA with or without a CT-based navigation system, respectively, using cementless THA ceramic-on-ceramic bearing couples. There were no differences in age, sex, diagnosis, height, weight, BMI, or preoperative clinical score between groups. We evaluated survivorship, mode of acetabular and femoral component fixation, osteolysis, and implant wear or breakage at a minimum followup of 10 years (average, 11 years; range, 10-13 years).
  
  
  RESULTS
  Survival at 13 years was 100% with navigation and 95.6% (95% CI, 88.4%-98.4%) without navigation. With navigation, all cups were placed within a zone of 40° (range, 30°-50°) of radiographic inclination and 15° (range, 5°-15°) of radiographic anteversion; without navigation, 31 cups (26%) were placed outside this zone. Hips treated without navigation had a higher rate of dislocation (8%) than the navigated cases (0%). Revision was performed in four nonnavigated cases, all of which showed evidence of neck impingement on the ceramic liner. Moreover, seven other cases without navigation showed posterior neck erosion on radiographs. These 11 impingement-related mechanical complications correlated with cup malorientation, and the incidence of impingement-related complications was higher in nonnavigated cases.
  
  
  CONCLUSIONS
  Navigation reduced the rates of dislocation and impingement-related mechanical complications leading to revision in cementless THA using ceramic-on-ceramic bearing couples over a minimum 10-year followup.
  
  
  METHODS
  Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
authors.affiliation: Department of Orthopaedic Medical Engineering, Osaka University Graduate School of Medicine, Yamadaoka 2-2, Suita, Osaka 565-0871, Japan. sugano@ort.med.osaka-u.ac.jp
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Sugano
authors.forename: Masaki
authors.initials: M
authors.lastname: Takao
authors.forename: Takashi
authors.initials: T
authors.lastname: Sakai
authors.forename: Takashi
authors.initials: T
authors.lastname: Nishii
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Miki
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D001672:Biocompatible Materials; D001843:Bone Cements; D002516:Ceramics; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011475:Prosthesis Failure; D012189:Retrospective Studies; D013238:Stereotaxic Techniques; D014057:Tomography, X-Ray Computed
chemical_list: D001672:Biocompatible Materials; D001843:Bone Cements