title: Minimum Lateral Bone Coverage Required for Securing Fixation of Cementless Acetabular Components in Hip Dysplasia.
abstract: Objectives.To determine the minimum lateral bone coverage required for securing stable fixation of the porous-coated acetabular components (cups) in hip dysplasia.Methods.In total, 215 primary total hip arthroplasties in 199 patients were reviewed. The average follow-up period was 49 months (range: 24-77 months). The lateral bone coverage of the cups was assessed by determining the cup center-edge (cup-CE) angle and the bone coverage index (BCI) from anteroposterior pelvic radiographs. Further, cup fixation was determined using the modified DeLee and Charnley classification system.Results.All cups were judged to show stable fixation by bone ingrowth. The cup-CE angle was less than 0° in 7 hips (3.3%) and the minimum cup-CE angle was -9.2° (BCI: 48.8%). Thin radiolucent lines were observed in 5 hips (2.3%), which were not associated with decreased lateral bone coverage. Loosening, osteolysis, dislocation, or revision was not observed in any of the cases during the follow-up period.Conclusion.A cup-CE angle greater than -10° (BCI > 50%) was acceptable for stable bony fixation of the cup. Considering possible errors in manual implantation, we recommend that the cup position be planned such that the cup-CE angle is greater than 0° (BCI > 60%).
authors.affiliation: Department of Orthopaedic Surgery, Japan Community Health Care Organization (JCHO), Kyushu Hospital, 1-8-1 Kishinoura, Yahatanishi-ku, Kitakyushu 806-8501, Japan.
authors.forename: Masanori
authors.identifier: 0000-0002-0219-3147
authors.initials: M
authors.lastname: Fujii
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Nakashima
authors.affiliation: Department of Orthopaedic Surgery, Japan Community Health Care Organization (JCHO), Kyushu Hospital, 1-8-1 Kishinoura, Yahatanishi-ku, Kitakyushu 806-8501, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Nakamura
authors.affiliation: Department of Orthopaedic Surgery, Japan Community Health Care Organization (JCHO), Kyushu Hospital, 1-8-1 Kishinoura, Yahatanishi-ku, Kitakyushu 806-8501, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Ito
authors.affiliation: Department of Orthopaedic Surgery, Japan Community Health Care Organization (JCHO), Kyushu Hospital, 1-8-1 Kishinoura, Yahatanishi-ku, Kitakyushu 806-8501, Japan.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Hara
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000601:surgery*; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006617:Hip Dislocation / Q000000981:diagnostic imaging / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D016062:Porosity; D011474:Prosthesis Design; D012086:Reoperation