title: Early aseptic loosening of cementless monoblock acetabular components.
abstract: Early aseptic loosening of cementless monoblock acetabular components is a rare complication of total hip arthroplasty (THA) and hip resurfacing arthroplasty (HRA). The purpose of this study was to evaluate the incidence and risk factors for early aseptic loosening of the cementless monoblock acetabular components.
  
  
  
  This retrospective analysis consisted of 4,043 cementless hip devices (3,209 THAs and 834 HRAs). We identified 41 patients with early aseptic loosening of the acetabular component. A control group of 123 patients without acetabular component loosening was randomly selected. The demographic data and risk factors for loosening of the acetabular component were evaluated. The mean follow-up time was 4.6 years (range, 1.7-7.8). The end-point was acetabular revision.
  
  
  
  The incidence of early acetabular component loosening was 1.0 %. Mean time to revision was 1.2 years (SD 1.6, range 0.0-5.4). There was significantly more Dorr type A and C acetabular morphology in patients with early loosening (P = 0.014). The loosened components were implanted to more vertical (P < 0.001) and less anteverted (P = 0.001) position than those of the control group. Presence of acetabular dysplasia or acetabular component type did not associate to early loosening.
  
  
  
  Acetabular morphology (Dorr type A and C) and component positioning vertically and less anteverted were more common in patients with early aseptic loosening of cementless acetabular components. Suboptimal cup position most likely reflects challenges to obtain sufficient stability during surgery. We hypothesize that errors in surgical technique are the main reason for early loosening of monoblock acetabular components.
authors: Department of Orthopaedics, Traumatology and Hand Surgery, Kuopio University Hospital, Kuopio, Finland.
authors: Simo S A
authors: SS
authors: Miettinen
authors: Department of Orthopaedics and Traumatology, Helsinki University Hospital and University of Helsinki, Sairaalakatu 1, 01400, Vantaa, Finland. tatu.makinen@hus.fi.
authors: Tatu J
authors: TJ
authors: Mäkinen
authors: Department of Orthopaedics and Traumatology, Turku University Central Hospital, Turku, Finland.
authors: Inari
authors: I
authors: Laaksonen
authors: Department of Orthopaedics and Traumatology, Turku University Central Hospital, Turku, Finland.
authors: Keijo
authors: K
authors: Mäkelä
authors: School of Health Sciences, University of Tampere, Tampere, Finland.
authors: Heini
authors: H
authors: Huhtala
authors: Department of Orthopaedics, Traumatology and Hand Surgery, Kuopio University Hospital, Kuopio, Finland.
authors: Jukka
authors: J
authors: Kettunen
authors: Department of Orthopaedics and Traumatology, Helsinki University Hospital and University of Helsinki, Sairaalakatu 1, 01400, Vantaa, Finland.|Pihlajalinna Oy, Helsinki, Finland.
authors: Ville
authors: V
authors: Remes
mesh_terms: D000077:Acetabulum / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000379:methods; D016022:Case-Control Studies; D005260:Female; D005500:Follow-Up Studies; D006617:Hip Dislocation / Q000601:surgery; D006621:Hip Joint / Q000601:surgery; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011183:Postoperative Complications / Q000453:epidemiology; D011475:Prosthesis Failure / Q000009:adverse effects*; D012086:Reoperation / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012307:Risk Factors
keywords: Acetabular morphology; Aseptic loosening; Case–control study; Cup positioning; Hip arthroplasty