title: Can acetabular orientation be restored by lumbar pedicle subtraction osteotomy in ankylosing spondylitis patients with thoracolumbar kyphosis?
abstract: To evaluate whether acetabular orientation (abduction and anteversion) can be restored by lumbar pedicle subtraction osteotomy (PSO) in ankylosing spondylitis (AS) patients with thoracolumbar kyphosis.
  
  
  
  A total of 33 consecutive AS patients with thoracolumbar kyphosis undergoing one-level lumbar PSO were retrospectively reviewed. Radiographical measurements included sagittal vertical axis, global kyphosis, thoracic kyphosis, local kyphosis, lumbar lordosis, pelvic incidence, sacral slope, and pelvic tilt. Acetabular abduction and anteversion were measured on CT scans of the pelvis before and after lumbar PSO. The preoperative and postoperative parameters were compared by the paired samples t test. Pearson's correlation analysis was conducted to determine the correlations between the changes in acetabular abduction and anteversion and the changes in sagittal spinopelvic parameters.
  
  
  
  After lumbar PSO, sagittal vertical axis, global kyphosis, and pelvic tilt were corrected from 15.7 ± 6.7 cm, 66.8° ± 17.5°, and 38.6° ± 9.0° to 2.9 ± 4.9 cm, 21.3° ± 8.2°, and 23.2° ± 8.2°, respectively (p < 0.001). Of note, acetabular abduction and anteversion decreased from 59.6° ± 4.6° to 31.4° ± 6.5° before surgery to 51.4° ± 6.5° and 20.2° ± 4.4° after surgery, respectively (p < 0.001). Moreover, the changes in acetabular abduction and anteversion were observed significantly correlated with the change in pelvic tilt (r = 0.527, p = 0.002; r = 0.586, p < 0.001).
  
  
  
  Abnormal acetabular abduction and anteversion could be corrected by lumbar PSO in AS patients with thoracolumbar kyphosis. Consequently, a relatively normal acetabular orientation could be achieved after lumbar PSO, which might decrease the potential risk of dislocation in AS patients with spine and hip deformities requiring subsequent THR surgery.
authors.affiliation: Spine Surgery, Drum Tower Hospital, Medical School of Nanjing University, Zhongshan Road 321, Nanjing, 210008, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Hu
authors.affiliation: Spine Surgery, Drum Tower Hospital, Medical School of Nanjing University, Zhongshan Road 321, Nanjing, 210008, China. qianbangping@163.com.
authors.forename: Bang-Ping
authors.initials: BP
authors.lastname: Qian
authors.affiliation: Spine Surgery, Drum Tower Hospital, Medical School of Nanjing University, Zhongshan Road 321, Nanjing, 210008, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Qiu
authors.affiliation: Spine Surgery, Drum Tower Hospital, Medical School of Nanjing University, Zhongshan Road 321, Nanjing, 210008, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.affiliation: Spine Surgery, Drum Tower Hospital, Medical School of Nanjing University, Zhongshan Road 321, Nanjing, 210008, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Spine Surgery, Drum Tower Hospital, Medical School of Nanjing University, Zhongshan Road 321, Nanjing, 210008, China.
authors.forename: Ze-Zhang
authors.initials: ZZ
authors.lastname: Zhu
authors.affiliation: Spine Surgery, Drum Tower Hospital, Medical School of Nanjing University, Zhongshan Road 321, Nanjing, 210008, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Spine Surgery, Drum Tower Hospital, Medical School of Nanjing University, Zhongshan Road 321, Nanjing, 210008, China.
authors.forename: Sai-Hu
authors.initials: SH
authors.lastname: Mao
authors.affiliation: Spine Surgery, Drum Tower Hospital, Medical School of Nanjing University, Zhongshan Road 321, Nanjing, 210008, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Qu
authors.affiliation: Spine Surgery, Drum Tower Hospital, Medical School of Nanjing University, Zhongshan Road 321, Nanjing, 210008, China.
authors.forename: Yun-Peng
authors.initials: YP
authors.lastname: Zhang
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging; D000293:Adolescent; D000328:Adult; D000368:Aged; D017760:Bone Malalignment / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007738:Kyphosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000379:methods*; D011859:Radiography; D012189:Retrospective Studies; D013167:Spondylitis, Ankylosing / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging; D055815:Young Adult
keywords: Acetabular orientation; Ankylosing spondylitis; Pedicle subtraction osteotomy; Thoracolumbar kyphosis