Changes in acetabular orientation during total hip arthroplasty. Bone Joint J 2019 Jun;101-B(6_Supple_B):45-50
Date
05/31/2019Pubmed ID
31146568DOI
10.1302/0301-620X.101B6.BJJ-2018-1335.R1Scopus ID
2-s2.0-85067294644 (requires institutional sign-in at Scopus site) 18 CitationsAbstract
AIMS: The aims of this study were to determine the change in pelvic sagittal alignment before, during, and after total hip arthroplasty (THA) undertaken with the patient in the lateral decubitus position, and to determine the impact of these changes on acetabular component position.
PATIENTS AND METHODS: We retrospectively compared the radiological pelvic ratio among 91 patients undergoing THA. In total, 41 patients (46%) were female. The mean age was 61.6 years (sd 10.7) and the mean body mass index (BMI) was 20.0 kg/m2 (sd 5.5). Anteroposterior radiographs were obtained: in the standing position preoperatively and at six weeks postoperatively; in the lateral decubitus position after trial reduction intraoperatively; and in the supine position in the post-anaesthesia care unit. Pelvic ratio was defined as the ratio between the vertical distance from the inferior aspect of the sacroiliac (SI) joints to the superior pubic symphysis and the horizontal distance between the inferior aspect of the SI joints. Changes in the apparent component position based on changes in pelvic ratio were determined, with a change of > 5° considered clinically significant. Analyses were performed using Wilcoxon's signed-rank test, with p < 0.05 considered significant.
RESULTS: Intraoperatively, in the lateral decubitus position, the pelvic ratio increased (anterior tilt) in 69.4% of cases, did not change significantly in 20.4%, and decreased (posterior tilt) in 10.2% of cases. When six-week postoperative radiographs were compared with preoperative radiographs, the pelvic ratio decreased in 44.9% of cases, did not change significantly in 42.3%, and increased in 12.8% of cases. This change in alignment correlated with a change in acetabular component version of > 5° in 79.6% of cases intraoperatively and 57.7% of cases at six weeks postoperatively.
CONCLUSION: Changes in pelvic sagittal pelvic position occur throughout THA that, if unaccounted for, introduce errors in acetabular component placement. The use of intraoperative imaging may help the appropriate placement of the acetabular component. Cite this article: Bone Joint J 2019;101-B(6 Supple B):45-50.
Author List
Schloemann DT, Edelstein AI, Barrack RLMESH terms used to index this publication - Major topics in bold
AcetabulumArthritis
Arthroplasty, Replacement, Hip
Female
Femur Head Necrosis
Hip Dislocation
Humans
Male
Middle Aged
Osteoarthritis, Hip
Patient Positioning
Postoperative Care
Preoperative Care
Radiography
Retrospective Studies
Rotation
