title: The femoral head/neck offset and hip resurfacing.
abstract: Because the femoral head/neck junction is preserved in hip resurfacing, patients may be at greater risk of impingement, leading to abnormal wear patterns and pain. We assessed femoral head/neck offset in 63 hips undergoing metal-on-metal hip resurfacing and in 56 hips presenting with non-arthritic pain secondary to femoroacetabular impingement. Most hips undergoing resurfacing (57%; 36) had an offset ratio <or= 0.15 pre-operatively and required greater correction of offset at operation than the rest of the group. In the non-arthritic hips the mean offset ratio was 0.137 (0.04 to 0.23), with the offset ratio correlating negatively to an increasing alpha angle. An offset ratio <or= 0.15 had a 9.5-fold increased relative risk of having an alpha angle >or= 50.5 degrees. Most hips undergoing resurfacing have an abnormal femoral head/neck offset, which is best assessed in the sagittal plane.
authors.affiliation: Department of Orthopaedic Surgery, University of Ottawa, The Ottawa Hospital, Ottawa, Ontario, Canada. pbeaule@Ottawahospital.on.ca
authors.forename: P E
authors.initials: PE
authors.lastname: Beaulé
authors.forename: N
authors.initials: N
authors.lastname: Harvey
authors.forename: E
authors.initials: E
authors.lastname: Zaragoza
authors.forename: M J
authors.initials: MJ
authors.lastname: Le Duff
authors.forename: F J
authors.initials: FJ
authors.lastname: Dorey
mesh_terms: D000077:Acetabulum / Q000473:pathology; D000328:Adult; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D005260:Female; D005270:Femur Head / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D005272:Femur Neck / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D016916:Joint Deformities, Acquired / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D010384:Pelvic Bones / Q000000981:diagnostic imaging; D016059:Range of Motion, Articular; D014057:Tomography, X-Ray Computed