Functional pelvic tilt frequently differs from the anterior pelvic plane in non-arthritic hip disorders: implications for 3D motion analysis

Aims: Hip preservation surgeons are increasingly using commercially available 3D motion analysis software to investigate areas of impingement and quantify femoral head coverage. Variations in functional pelvic tilt will affect the position of the acetabular rim and projected femoral head coverage,...

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Main Authors: Mark R. J. Jenkinson, Calvin Cheung, Alastair G Dick, Johan Witt, Jonathan Hutt
Format: Article
Language:English
Published: The British Editorial Society of Bone & Joint Surgery 2025-06-01
Series:Bone & Joint Open
Subjects:
Online Access:https://online.boneandjoint.org.uk/doi/epdf/10.1302/2633-1462.66.BJO-2024-0265.R1
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author Mark R. J. Jenkinson
Calvin Cheung
Alastair G Dick
Johan Witt
Jonathan Hutt
author_facet Mark R. J. Jenkinson
Calvin Cheung
Alastair G Dick
Johan Witt
Jonathan Hutt
author_sort Mark R. J. Jenkinson
collection DOAJ
description Aims: Hip preservation surgeons are increasingly using commercially available 3D motion analysis software to investigate areas of impingement and quantify femoral head coverage. Variations in functional pelvic tilt will affect the position of the acetabular rim and projected femoral head coverage, but currently the majority of available software standardizes sagittal rotation to the anterior pelvic plane (APP). The study hypothesis was that the APP does not correlate well with patient-specific pelvic position. Methods: In total, 60 patients were selected from an institutional database: 20 with acetabular retroversion (AR), 20 with developmental dysplasia of the hip (DDH), and 20 with cam-type femoroacetabular impingement (FAI). Multiplanar CT reformats were created and the sagittal rotation was aligned to the APP. The sagittal pelvic orientation was then corrected until the anteroposterior (AP) projection mirrored that of their preoperative supine and standing plain radiographs. The change in sagittal pelvic tilt angle required was measured. Results: The mean deviation from the APP in the AR group was 11.55° (SD 4.96°) for supine radiographs and 3.28° (SD 8.66°) for standing radiographs. The mean deviation from the APP in the DDH group was 12.2° (SD 4.26°) for supine radiographs and 6.96° (SD 3.43°) for standing radiographs. The main deviation from the APP in the FAI group was 8.63° (SD 5.21°) for supine radiographs and -1.28° (SD 7.31°) for standing. Conclusion: There is a wide variation in patients’ functional pelvic positioning in both supine and standing radiographs, in all different subgroups, which rarely correlates with the APP. Commercial 3D motion analysis may therefore give misleading results for both the extent and location of hip impingement as well as femoral head coverage, which may affect surgical decision-making. Consideration should be given to incorporating this into the software algorithms. Cite this article: Bone Jt Open 2025;6(6):651–657.
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spelling doaj-art-cc778dae7b4a49f796191a9984a6f3f42025-08-20T03:46:00ZengThe British Editorial Society of Bone & Joint SurgeryBone & Joint Open2633-14622025-06-016665165710.1302/2633-1462.66.BJO-2024-0265.R1Functional pelvic tilt frequently differs from the anterior pelvic plane in non-arthritic hip disorders: implications for 3D motion analysisMark R. J. Jenkinson0Calvin Cheung1Alastair G Dick2Johan Witt3Jonathan Hutt4 Queen Elizabeth University Hospital, Glasgow, UK University College London, London, UK University College London Hospital, London, UK University College London Hospital, London, UK University College London Hospital, London, UK Aims: Hip preservation surgeons are increasingly using commercially available 3D motion analysis software to investigate areas of impingement and quantify femoral head coverage. Variations in functional pelvic tilt will affect the position of the acetabular rim and projected femoral head coverage, but currently the majority of available software standardizes sagittal rotation to the anterior pelvic plane (APP). The study hypothesis was that the APP does not correlate well with patient-specific pelvic position. Methods: In total, 60 patients were selected from an institutional database: 20 with acetabular retroversion (AR), 20 with developmental dysplasia of the hip (DDH), and 20 with cam-type femoroacetabular impingement (FAI). Multiplanar CT reformats were created and the sagittal rotation was aligned to the APP. The sagittal pelvic orientation was then corrected until the anteroposterior (AP) projection mirrored that of their preoperative supine and standing plain radiographs. The change in sagittal pelvic tilt angle required was measured. Results: The mean deviation from the APP in the AR group was 11.55° (SD 4.96°) for supine radiographs and 3.28° (SD 8.66°) for standing radiographs. The mean deviation from the APP in the DDH group was 12.2° (SD 4.26°) for supine radiographs and 6.96° (SD 3.43°) for standing radiographs. The main deviation from the APP in the FAI group was 8.63° (SD 5.21°) for supine radiographs and -1.28° (SD 7.31°) for standing. Conclusion: There is a wide variation in patients’ functional pelvic positioning in both supine and standing radiographs, in all different subgroups, which rarely correlates with the APP. Commercial 3D motion analysis may therefore give misleading results for both the extent and location of hip impingement as well as femoral head coverage, which may affect surgical decision-making. Consideration should be given to incorporating this into the software algorithms. Cite this article: Bone Jt Open 2025;6(6):651–657.https://online.boneandjoint.org.uk/doi/epdf/10.1302/2633-1462.66.BJO-2024-0265.R1hip3d motionpelvic tiltpelvic tiltarthritic hipfemoroacetabular impingementdevelopmental dysplasia of the hip (ddh)femoral headradiographsacetabular retroversionmean deviationsagittal pelvic tiltsagittal rotation
spellingShingle Mark R. J. Jenkinson
Calvin Cheung
Alastair G Dick
Johan Witt
Jonathan Hutt
Functional pelvic tilt frequently differs from the anterior pelvic plane in non-arthritic hip disorders: implications for 3D motion analysis
Bone & Joint Open
hip
3d motion
pelvic tilt
pelvic tilt
arthritic hip
femoroacetabular impingement
developmental dysplasia of the hip (ddh)
femoral head
radiographs
acetabular retroversion
mean deviation
sagittal pelvic tilt
sagittal rotation
title Functional pelvic tilt frequently differs from the anterior pelvic plane in non-arthritic hip disorders: implications for 3D motion analysis
title_full Functional pelvic tilt frequently differs from the anterior pelvic plane in non-arthritic hip disorders: implications for 3D motion analysis
title_fullStr Functional pelvic tilt frequently differs from the anterior pelvic plane in non-arthritic hip disorders: implications for 3D motion analysis
title_full_unstemmed Functional pelvic tilt frequently differs from the anterior pelvic plane in non-arthritic hip disorders: implications for 3D motion analysis
title_short Functional pelvic tilt frequently differs from the anterior pelvic plane in non-arthritic hip disorders: implications for 3D motion analysis
title_sort functional pelvic tilt frequently differs from the anterior pelvic plane in non arthritic hip disorders implications for 3d motion analysis
topic hip
3d motion
pelvic tilt
pelvic tilt
arthritic hip
femoroacetabular impingement
developmental dysplasia of the hip (ddh)
femoral head
radiographs
acetabular retroversion
mean deviation
sagittal pelvic tilt
sagittal rotation
url https://online.boneandjoint.org.uk/doi/epdf/10.1302/2633-1462.66.BJO-2024-0265.R1
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