Evidence map›Paper›PMID 42852555›Full record

ArticleBone & joint open2026

Estimating within-patient sagittal pelvic tilt change from routine anteroposterior hip radiographs in patients undergoing total hip arthroplasty : development and temporal validation.

Kyosuke Kobayashi, Kenichi Kidera, Syuta Yamada, Tatsuya Fukushima, Akira Hozumi

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Article in Bone & joint open, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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5 · Who and what money

Authors and funding

5 authors.

Kyosuke KobayashiDepartment of Orthopaedic Surgery, Nijigaoka Hospital, Nagasaki, Japan.ORCID 0000-0003-4112-4782
Kenichi KideraDepartment of Orthopaedic Surgery, Nijigaoka Hospital, Nagasaki, Japan.ORCID 0009-0002-9756-9860
Syuta YamadaDepartment of Orthopaedic Surgery, Nijigaoka Hospital, Nagasaki, Japan.
Tatsuya FukushimaDepartment of Orthopaedic Surgery, Nijigaoka Hospital, Nagasaki, Japan.
Akira HozumiDepartment of Orthopaedic Surgery, Nijigaoka Hospital, Nagasaki, Japan.ORCID 0000-0003-2539-5945

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Aims: Changes in sagittal pelvic tilt influence functional cup orientation in total hip arthroplasty (THA). Although lateral spinopelvic radiographs are the reference standard, they are not routinely obtained, whereas anteroposterior (AP) hip radiographs are widely used. This study evaluated whether within-patient pelvic tilt changes can be accurately estimated using AP radiographs. Methods: This retrospective observational study included 116 patients who underwent primary THA (derivation cohort). Supine and standing AP radiographs and CT data were acquired preoperatively. CT-derived synthetic radiographs were generated and adjusted to match the pelvic foramen ratio (PFR) measured on AP radiographs, yielding adjusted synthetic (AS) radiographs. For the supine-to-standing transition, the change in anterior pelvic plane tilt (ΔAPPt) measured on AS radiographs was used as the reference outcome, and the change in pubic symphysis-to-transischial line distance (ΔPSTI, mm) on AP radiographs was used as the predictor. A linear regression model was developed to estimate ΔAPPt from ΔPSTI. Internal validation was performed using fivefold cross-validation. Independent temporal validation was performed in a separate cohort (n = 80). Results: The derived equation was (ΔAPPt = -0.74 × ΔPSTI + 1.2). Fivefold cross-validation showed a mean error of 0.01° (root mean square error (RMSE) 1.4°, mean absolute error (MAE) 1.0°; 95% limits of agreement (LoA) -2.6° to 2.7°). Absolute error was ≤ 3° in 112 out of 116 (96.6%) cases and ≤ 5° in 116 out of 116 (100%). Independent temporal validation showed a mean error of 0.2° (RMSE 1.3°, MAE 0.9°; 95% LoA -2.4° to 2.8°). Absolute error was ≤ 3° in 75 out of 80 cases (93.8%) and ≤ 5° in 80 out of 80 (100%), within an observed ΔAPPt range of -15.3° to 8.0°. Conclusion: A regression equation based on ΔPSTI estimated supine-to-standing within-patient ΔAPPt from routine AP hip radiographs with a clinically acceptable agreement (95% LoA approximately ± 3°).

Identifiers

PMID42852555
PMCPMC13645462

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.