title: Changes in axial alignment of the ipsilateral hip and knee after total hip arthroplasty.
abstract: OBJECTIVE
  We investigated changes in the axial alignment of the ipsilateral hip and knee after total hip arthroplasty (THA).
  
  
  METHODS
  We reviewed 152 patients undergoing primary THA (163 hips; 22 hips in men, 141 hips in women) without a pre-operative flexion contracture. The mean age was 64 years (30 to 88). The diagnosis was osteoarthritis (OA) in 151 hips (primary in 18 hips, and secondary to dysplasia in 133) and non-OA in 12 hips. A posterolateral approach with repair of the external rotators was used in 134 hips and an anterior approach in 29 hips. We measured changes in leg length and offset on radiographs, and femoral anteversion, internal rotation of the hip and lateral patellar tilt on CT scans, pre- and post-operatively.
  
  
  RESULTS
  The mean internal rotation increased by 11° (-15° to 46°) and was associated with underlying disease (OA), pre-operative range of internal rotation, gender, surgical approach, leg lengthening, and change of femoral anteversion (adjusted R(2) : 0.253, p < 0.001). The mean lateral patellar tilt increased by 4° (-5° to 14°) and was associated with age, leg lengthening, and increment of hip internal rotation (adjusted R(2): 0.193, p < 0.001).
  
  
  CONCLUSIONS
  Both internal rotation of the hip at rest and lateral patellar tilt are increased after THA. Changes in rotation after THA may affect gait, daily activities, the rate of dislocation of the hip, and ipsilateral knee pain.
  
  
  CONCLUSIONS
  Internal rotation of the hip at rest and lateral patellar tilt increase after THA.
authors.forename: K
authors.initials: K
authors.lastname: Akiyama
authors.affiliation: Japan Community Healthcare Organization Osaka Hospital, 4-2-78, Fukushima, Fukushima-ku, Osaka, 553-0003, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Nakata
authors.affiliation: Japan Community Healthcare Organization Osaka Hospital, 4-2-78, Fukushima, Fukushima-ku, Osaka, 553-0003, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kitada
authors.affiliation: Osaka Rosai Hospital, 1179-3, Nagasone-cho, Kita-ku, Sakai, 591-8025, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yamamura
authors.affiliation: Osaka University Graduate School of Medicine, 2-2, Yamadaoka, Suita, 565-0871, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ohori
authors.affiliation: Japan Community Healthcare Organization Osaka Hospital, 4-2-78, Fukushima, Fukushima-ku, Osaka, 553-0003, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Owaki
authors.affiliation: Japan Community Healthcare Organization Osaka Hospital, 4-2-78, Fukushima, Fukushima-ku, Osaka, 553-0003, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Fuji
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D007719:Knee Joint / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging / Q000601:surgery; D010329:Patella / Q000473:pathology; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
keywords: THA; axial alignment; hip; knee