Masamitsu Ezoe, MD1, Masatoshi Naito, MD1 and Toshio Inoue, MD1
1 Department of Orthopaedic Surgery, Fukuoka University School of Medicine, 7-45-1, Nanakuma, Jyonan-ku, Fukuoka 814-0180, Japan. E-mail address for M. Ezoe: email@example.com
Investigation performed at the Department of Orthopaedic Surgery, Fukuoka University School of Medicine, Fukuoka, Japan
The authors did not receive grants or outside funding in support of their research for or preparation of this manuscript. They did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated. Background: Acetabular retroversion can result from posterior wall deficiency in an otherwise normally oriented acetabulum or from excessive anterior coverage secondary to a malpositioned acetabulum, or both. Theoretically, a retroverted acetabulum, which adversely affects load transmission across the hip, may occur more frequently in hips with degenerative arthritis. The aim of this study was to assess the prevalence of acetabular retroversion in normal hips and in hips with osteoarthritis, developmental dysplasia, osteonecrosis, and Legg-Calvé-Perthes disease.
Methods: We retrospectively examined anteroposterior radiographs of the pelvis of 250 patients (342 hips). Fifty-six patients (112 hips) had normal findings; sixty-six patients (seventy hips) had osteoarthritis; sixty-four (seventy-four hips), developmental dysplasia; thirty (thirty-six hips), osteonecrosis of the femoral head; and thirty-four (fifty hips), Legg-Calvé-Perthes disease. The sole criterion for a diagnosis of acetabular retroversion was the presence of a so-called cross-over sign on the anteroposterior radiograph of the pelvis.
Results: The prevalence of acetabular retroversion was 6% (seven of 112 hips) in the normal group, 20% (fourteen of seventy hips) in the osteoarthritis group, 18% (thirteen of seventy-four hips) in the developmental dysplasia group, 6% (two of thirty-six hips) in the group with osteonecrosis of the femoral head, and 42% (twenty-one of fifty hips) in the group with Legg-Calvé-Perthes disease. In patients with Legg-Calvé-Perthes disease, the prevalence of acetabular retroversion was 68% in twenty-five hips with Stulberg class-III, IV, or V involvement. In contrast, only four (16%) of twenty-five hips with Stulberg class-I or II involvement had acetabular retroversion. The difference was significant (p = 0.0002). Patients with osteoarthritis, developmental dysplasia, or Legg-Calvé-Perthes disease are significantly more likely to have acetabular retroversion than are normal subjects (p < 0.05).
Conclusions: Acetabular retroversion occurs more commonly in association with a variety of hip diseases, in which the prevalence of subsequent degenerative arthritis is increased, than has been previously noted.
The Journal of Bone and Joint Surgery (American). 2006;88:372-379.