title: Effects of rotational acetabular osteotomy on the mechanical stress within the hip joint in patients with developmental dysplasia of the hip: a subject-specific finite element analysis.
abstract: In this study we used subject-specific finite element analysis to investigate the mechanical effects of rotational acetabular osteotomy (RAO) on the hip joint and analysed the correlation between various radiological measurements and mechanical stress in the hip joint. We evaluated 13 hips in 12 patients (two men and ten women, mean age at surgery 32.0 years; 19 to 46) with developmental dysplasia of the hip (DDH) who were treated by RAO. Subject-specific finite element models were constructed from CT data. The centre-edge (CE) angle, acetabular head index (AHI), acetabular angle and acetabular roof angle (ARA) were measured on anteroposterior pelvic radiographs taken before and after RAO. The relationship between equivalent stress in the hip joint and radiological measurements was analysed. The equivalent stress in the acetabulum decreased from 4.1 MPa (2.7 to 6.5) pre-operatively to 2.8 MPa (1.8 to 3.6) post-operatively (p < 0.01). There was a moderate correlation between equivalent stress in the acetabulum and the radiological measurements: CE angle (R = -0.645, p < 0.01); AHI (R = -0.603, p < 0.01); acetabular angle (R = 0.484, p = 0.02); and ARA (R = 0.572, p < 0.01). The equivalent stress in the acetabulum of patients with DDH decreased after RAO. Correction of the CE angle, AHI and ARA was considered to be important in reducing the mechanical stress in the hip joint.
authors.affiliation: Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ike
authors.affiliation: Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Inaba
authors.affiliation: Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Kobayashi
authors.affiliation: Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yukizawa
authors.affiliation: Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Hirata
authors.affiliation: Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Tomioka
authors.affiliation: Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Saito
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D000328:Adult; D005260:Female; D020342:Finite Element Analysis; D006618:Hip Dislocation, Congenital / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010027:Osteotomy; D012399:Rotation; D013314:Stress, Mechanical; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Biomechanics; Developmental dysplasia of the hip; Finite element analysis; Rotational acetabular osteotomy