Reliability and Validity Analysis of Pelvic Sagittal Inclination Calculated by Inverse Cosine Function Method on Pelvic Anteroposterior Radiographs.
Orthop Surg
; 14(10): 2721-2729, 2022 Oct.
Article
in En
| MEDLINE
| ID: mdl-36102214
ABSTRACT
OBJECTIVE:
Evaluation of sagittal pelvic tilt is significant for hip surgeons. However, the accurate measurement of pelvic sagittal inclination (PSI) is still a challenge. The objective of this study is to propose a new method for measurement of PSI from pelvic anteroposterior radiograph based on the inverse cosine function obtained from individualized pelvic model.METHODS:
Collecting the imaging data of 30 patients with both pelvic CT and full-length spine radiographs. Establishing pelvic model by customized 3D reconstruction software. The length of three groups of longitudinal and transverse line segments (A'p and B') were measured from full-length spine anteroposterior radiographs. The corresponding anatomical parameters, including A, B, b, â α, â γ, were measured and calculated on the same patient's pelvic model. The estimated PSI (ePSI) based on three groups of anatomical landmarks, including ePSI-1, ePSI-2, and ePSI-3, were calculated by equation, ePSI = arccos A ' p b * B ' - â α , and compared with the actual PSI (aPSI) measured by Surgamap software. For the reliability and validation evaluation, three observers measured these parameters in two rounds. Intra-class correlation and inter-class correlation were both calculated. Bland-Altman method was used to evaluate the consistency between the estimated PSI (ePSI) and the actual PSI (aPSI).RESULTS:
ePSI-1 and ePSI-2 showed excellent intra-observer reliability (0.921-0.997, p < 0.001) and inter-observer reliability (0.801-0.977, p < 0.001). ePSI-3 had a fair inter-observer reliability (0.239-0.823, p < 0.001). ePSI-1 showed the strongest correlation with aPSI (r = 0.917, p < 0.001). Mean (maximum) absolute difference of ePSI-1, ePSI-2, and ePSI-3 is 2.62° (7.42°), 4.23° (13.78°), and 7.74° (31.47°), respectively. The proportion of cases with absolute difference less than 5° in three groups were 86.7% (ePSI-1), 66.7% (ePSI-2), 56.7% (ePSI-3).CONCLUSION:
This new method based on inverse cosine function has good reliability and validity when used in the evaluation of PSI on pelvic anteroposterior radiographs.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Pelvis
/
Posture
Type of study:
Diagnostic_studies
/
Prognostic_studies
Limits:
Humans
Language:
En
Journal:
Orthop Surg
Year:
2022
Document type:
Article
Affiliation country:
China