title: Porous-ingrowth revision acetabular implants secured with peripheral screws. A minimum twelve-year follow-up.
abstract: BACKGROUND
  During revision total hip arthroplasty, the acetabular component is often secured with screws to ensure initial press-fit stability. The purpose of the present study was to assess a series of acetabular revisions involving the use of a porous-coated acetabular component that was stabilized with peripheral screws and to evaluate the results in relation to the acetabular bone deficiencies that were present at the time of the revision procedure.
  
  
  METHODS
  From 1987 to 1991, 203 consecutive acetabular revisions were performed. In 142 hips, a severe acetabular bone deficiency that did not require an allograft was reconstructed with a porous-coated acetabular cup that was secured with a minimum of two peripheral screws. After an average duration of follow-up of 13.2 years, 134 hips were reviewed clinically and radiographically. The procedure was considered to be a clinical failure if the component was revised or if the postoperative clinical scores were poorer than the preoperative scores.
  
  
  RESULTS
  At the time of the most recent follow-up, 127 (95%) of the 134 hips were stable and clinically successful. The other seven hips (5%) were considered to have failed. Five of these seven hips failed because of an infection, and two failed because of aseptic loosening. Five (19%) of the twenty-seven hips with a Paprosky type-3A defect (a defect in which 30% to 50% of the host acetabulum is missing) failed.
  
  
  CONCLUSIONS
  Revision total hip arthroplasty with use of a porous-coated acetabular component that is fixed with peripheral screws can provide long-term durability in hips with severe acetabular defects that do not require the use of an allograft (Paprosky type-1 and type-2 defects). We recommend that when an acetabular implant with peripheral screws is used for the treatment of a more severe (type-3) defect, the cup should be augmented with structural allograft to improve initial stability, or other implants should be utilized.
authors.affiliation: Rush Medical College and the Central DuPage Hospital Adult Reconstruction Fellowship Program, Chicago, Illinois, USA. steveweeden@hotmail.com
authors.forename: Steven H
authors.initials: SH
authors.lastname: Weeden
authors.forename: Wayne G
authors.initials: WG
authors.lastname: Paprosky
mesh_terms: D000077:Acetabulum / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D001863:Bone Screws; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010014:Osteolysis / Q000601:surgery*; D016062:Porosity; D011474:Prosthesis Design; D012086:Reoperation; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome