Preoperative Anteroposterior and Lateral Assessment of Sagittal Spinopelvic Parameters Show High Positional Correlation and Measurement Reliability Preceding Both Hip Preservation and Reconstruction Surgery
Author(s): Kuhns BD, McCarroll TR, Quesada-Jimenez R, Kahana-Rojkind AH, Sikligar D, Cohen MF, Domb BG.
DOI Link: 10.1016/j.asmr.2025.101146
Background
Spinopelvic alignment is increasingly recognized as an important factor in both hip preservation and arthroplasty planning. However, variability in measurement reliability and the relationship between anteroposterior (AP) and lateral radiographic parameters remains a limitation. This study evaluated reliability and correlation of sagittal spinopelvic measures across imaging positions.
Methods
This retrospective reliability study included patients undergoing hip surgery with complete AP and lateral pelvic radiographs in standing, supine, and sitting positions. Four independent reviewers assessed sagittal spinopelvic parameters, including sacral slope, spinopelvic tilt, pelvic incidence, anterior pelvic plane, pelvic inclination, and AP-derived proxies such as sacrococcygeal-to-pubis (SC) distance. Interobserver reliability was assessed using ICC, and correlations between AP and lateral measures were analyzed.
Key Findings
- 60 patients included with multi-position imaging
- Excellent reliability (ICC > 0.90): sacral slope, SC distance
- Good reliability (ICC > 0.85): most parameters in standing and supine positions
- Lower reliability in sitting position for APP, SPT, pelvic inclination (ICC 0.76–0.79)
- Strongest AP–lateral correlation:
- SC distance vs sacral slope
- Standing: r = 0.70 (P < .001)
- Supine: r = 0.72 (P < .001)
- Overall, AP radiographic measures showed meaningful correlation with lateral spinopelvic parameters
Conclusion
Spinopelvic parameters demonstrate strong reliability in standing and supine positions, with consistent correlations between AP and lateral imaging—particularly for SC distance and sacral slope. These findings support routine preoperative assessment of spinopelvic alignment in both hip preservation and arthroplasty patients.
What Does This Mean for Providers?
AP radiographs may provide clinically meaningful surrogate information for sagittal spinopelvic alignment when lateral imaging is limited, especially using SC distance. However, position-specific variability (particularly sitting views) reinforces the need for standardized imaging protocols when planning hip surgery.