title: Pseudoarthrosis of the ilium after periacetabular osteotomy that was treated by cemented total hip arthroplasty: a case report.
abstract: BACKGROUND
  Preserving the hip joint to delay arthroplasty for patients with acetabular dysplasia-associated early-stage osteoarthritis has become more common, and several surgical procedures have demonstrated pain relief and improved hip joint function. Periacetabular osteotomy, one of the joint-preserving surgical procedures of the hip, provides favorable outcomes, although there are no reports of total hip arthroplasty being used to treat pseudoarthrosis of the periacetabular osteotomy segment. Therefore, we report a case of pseudoarthrosis in the osteotomy segment after periacetabular osteotomy. The patient was treated using modified total hip arthroplasty and achieved a favorable short-term outcome.
  
  
  METHODS
  A 62-year-old Japanese woman was diagnosed with bilateral acetabular dysplasia at the age of 50 years, and underwent right and left periacetabular osteotomy at the ages of 52 and 55 years, respectively. When she was 61-years old, she experienced repeated episodes of left coxalgia during walking, with increasing pain at rest, and subsequently visited our department. Plain radiography and computed tomography of her left hip joint confirmed pseudoarthrosis of the periacetabular osteotomy segment. In addition, narrowing of her left hip joint space was observed, which indicated advanced osteoarthritis of the hip. Therefore, she underwent left total hip arthroplasty when she was 62-years old. During the surgery, fibrous fusion of the periacetabular osteotomy segment was confirmed via fluoroscopy, although no abnormal mobility was observed. Thus, the osteotomy segment was fixed with one absorbable screw and two bone pegs (which were prepared using allogeneic bone), and the acetabular cup was fixed using cement. Her postoperative course was generally favorable and bone fusion of the periacetabular osteotomy segment was confirmed at 3 years and 6 months after surgery. Her modified Harris hip score was 43 before the surgery and had improved to 90 at the final follow-up.
  
  
  CONCLUSIONS
  Modified total hip arthroplasty was successfully used to treat osteoarthritis of the hip and pseudoarthrosis of the periacetabular osteotomy segment. This procedure achieved pseudoarthrosis region bone fusion and a favorable postoperative outcome.
authors.affiliation: Department of Orthopaedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan. hikokanaji@gmail.com.
authors.forename: Arihiko
authors.initials: A
authors.lastname: Kanaji
authors.affiliation: Department of Orthopaedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Nishiwaki
authors.affiliation: Department of Orthopaedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan.
authors.forename: Akihito
authors.initials: A
authors.lastname: Oya
authors.affiliation: Department of Orthopaedic Surgery, Fujita Health University, 1-98 Dengakugakubo, Kutsukake, Toyoake, Aichi, 470-1192, Japan.|Maehara Surgery, Orthopedic Surgery, Pediatrics, 16-1 Nishinokaido, Ano-cho, Toyoake, Aichi, 470-1144, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Maehara
authors.affiliation: Maehara Surgery, Orthopedic Surgery, Pediatrics, 16-1 Nishinokaido, Ano-cho, Toyoake, Aichi, 470-1144, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Maehara
authors.affiliation: Department of Orthopaedic Surgery, Fujita Health University, 1-98 Dengakugakubo, Kutsukake, Toyoake, Aichi, 470-1192, Japan.
authors.forename: Teruyo
authors.initials: T
authors.lastname: Oishi
authors.affiliation: Department of Orthopaedic Surgery, Fujita Health University, 1-98 Dengakugakubo, Kutsukake, Toyoake, Aichi, 470-1192, Japan.
authors.forename: Harumoto
authors.initials: H
authors.lastname: Yamada
authors.affiliation: Department of Orthopaedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Suda
authors.affiliation: Department of Orthopaedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Nakamura
authors.affiliation: Department of Orthopaedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan.
authors.forename: Morio
authors.initials: M
authors.lastname: Matsumoto
mesh_terms: D019644:Arthroplasty, Replacement, Hip; D005260:Female; D006618:Hip Dislocation, Congenital / Q000601:surgery*; D006801:Humans; D007085:Ilium / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D059351:Organ Sparing Treatments; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging / Q000601:surgery*; D010027:Osteotomy; D011542:Pseudarthrosis / Q000000981:diagnostic imaging / Q000601:surgery*; D011859:Radiography; D012086:Reoperation; D014057:Tomography, X-Ray Computed
keywords: Periacetabular osteotomy; Pseudoarthrosis; Total hip arthroplasty