title: Total hip arthroplasty in patients with ankylosing spondylitis: Midterm radiologic and functional results.
abstract: BACKGROUND
  The aim of this study was to evaluate the clinical and radiological outcomes of total hip arthroplasty (THA) in patients with Ankylosing Spondylitis (AS).
  
  
  METHODS
  One hundred five hips of 61 AS patients (mean age: 41.3 ± 10.2 years) who underwent THA between 1997 and 2012 were included into the study. Dorr's classification of proximal femoral geometry, acetabular protrusio, bone ankylosis, acetabular protrusion, Brooker classification of heterotopic ossification (HO), Gruen and Charnley classifications of implant loosening were used in radiographic assessments. Patients were called back to return for an additional long-term follow-up for functional assessment.
  
  
  RESULTS
  Cementless total hip arthroplasty was used in 83 hips (79%) and cemented TKA was used in 22 hips (21%). The overall rate of aseptic loosening was 7.6% at a mean follow-up of 5.4 years. Femoral loosening was statistically similar in cemented and cementless femoral components (14% vs. 8%, p = 0.089). Acetabular component loosening was statistically higher in patients with any degree of HO (p = 0.04). Regardless of the type of femoral implant (cemented or cementless), femoral component loosening was higher in Dorr's type C patients (p = 0.005). The average pre-operative HSS was 46.6 ± 16.3, and it improved to 80.7 ± 18.7 at last follow-up (p < 0.01).
  
  
  CONCLUSIONS
  Revision incidence was similar in between ankylosed and non-ankylosed hips. While complication rates are high, significant functional improvement can be achieved after THA in patients with AS.
authors: Biruni University Hospital, Orthopedics and Traumatology Department, Istanbul, Turkey. Electronic address: yavuz_saglam@hotmail.com.
authors: Yavuz
authors: Y
authors: Saglam
authors: Istanbul University, Istanbul Faculty of Medicine, Orthopedics and Traumatology Department, Istanbul, Turkey.
authors: Irfan
authors: I
authors: Ozturk
authors: Istanbul University, Istanbul Faculty of Medicine, Orthopedics and Traumatology Department, Istanbul, Turkey.
authors: Mehmet Fevzi
authors: MF
authors: Cakmak
authors: Istanbul University, Istanbul Faculty of Medicine, Orthopedics and Traumatology Department, Istanbul, Turkey.
authors: Mustafa
authors: M
authors: Ozdemir
authors: Istanbul University, Istanbul Faculty of Medicine, Orthopedics and Traumatology Department, Istanbul, Turkey.
authors: Onder
authors: O
authors: Yazicioglu
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging* / Q000601:surgery; D000328:Adult; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D006621:Hip Joint / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009999:Ossification, Heterotopic / Q000453:epidemiology*; D011183:Postoperative Complications / Q000453:epidemiology*; D011859:Radiography; D016059:Range of Motion, Articular; D012086:Reoperation; D013167:Spondylitis, Ankylosing / Q000601:surgery*
keywords: Acetabular protrusion; Ankylosing spondylitis (AS); Bath Ankylosing Spondylitis Disease Activity Index (BASDAI); Bone ankylosis; Total hip arthroplasty (THA)