title: Mid-term clinical results of total hip arthroplasty using a Wagner standard cup for dysplastic hip.
abstract: BACKGROUND
  The outcome of cementless total hip arthroplasty depends on many factors. We must not forget fundamental things those are design of outer surface of the component, that leads bone ingrowth into the prosthesis, better initial stability, and better insertional techniques. The purpose of this study was to review our experience with metal-on-metal total hip arthroplasty with a Wagner standard cup for patients who had acetabular dysplasia.
  
  
  METHODS
  Fifty-four patients with 55 hips underwent primary metal-on-metal total hip arthroplasty (Metasul prosthesis) with a Wagner standard cup (44-48 mm in outer diameter) and were followed for a minimum of 10 years. All patients received the same type of cementless femoral component (Natural hip stem) and femoral head (28 mm in diameter).
  
  
  RESULTS
  Seventeen of the 55 Wagner standard cups (30.9%) showed aseptic loosening over a mean period of 3.6 years after surgery, and there were no bone anchors on the outer surface of the 16 retrieved cups.
  
  
  CONCLUSIONS
  From our experience, the small Wagner standard cup does not achieve sufficient osteointegration and we do not recommend the use of this cup, especially for patients with acetabular dysplasia and/or those with a small stature.
authors.affiliation: Department of Orthopaedic Surgery, Juntendo Urayasu Hospital, Urayasu City, Chiba 279-0021, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Maezawa
authors.affiliation: Department of Orthopaedic Surgery, Juntendo Nerima Hospital, Nerima-ku, Tokyo 177-8521, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Nozawa
authors.affiliation: Department of Orthopaedic Surgery, Juntendo University School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan.
authors.forename: Takahito
authors.initials: T
authors.lastname: Yuasa
authors.affiliation: Department of Orthopaedic Surgery, Juntendo University School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Aritomi
authors.affiliation: Department of Orthopaedic Surgery, Juntendo University School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan.
authors.forename: Seiki
authors.initials: S
authors.lastname: Ogawa
authors.affiliation: Department of Orthopaedic Surgery, Juntendo Urayasu Hospital, Urayasu City, Chiba 279-0021, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Maruyama
authors.affiliation: Department of Orthopaedic Surgery, Juntendo University School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kaneko
keywords: Aseptic loosening; Dysplastic hip; Metal-on-metal total hip arthroplasty; Wagner standard cup