2025 ISAKOS Congress in Munich, Germany

2025 ISAKOS Biennial Congress Paper


Anterolateral and Posterolateral Phenotypes of Hip Dysplasia: The Paradox of Lumbopelvic Alignment

Marco Haertlé, MD, Hannover, Lower Saxony GERMANY
Christian Konrads, MD, Prof., Stralsund GERMANY
Sufian S. Ahmad, MD, Hannover GERMANY

Department of Orthopaedics, Hannover, GERMANY

FDA Status Not Applicable

Summary

Regarding the hip-spine association in patients with acetabular dysplasia, pelvic tilt constitutes a component of the corresponding phenotype of dysplasia, rather than a compensatory tilt.

Abstract

Purpose

The relationship between sagittal lumbopelvic alignment and the dysplastic hip joint is currently at the forefront of scientific interest. The intention of this study was to analyze whether there is association between the morphology of the acetabulum in dysplastic hip joints and the sagittal lumbopelvic alignment.

Methods

From September 2022 to March 2024, a total of 206 patients with hip dysplasia were examined. The hip joints of the patients were classified into anterolateral and posterolateral dysplasia morphologies. Additionally, the lumbopelvic sagittal alignment of those patients was analyzed and correlated with the phenotype of dysplasia. Furthermore, a multivariable linear regression analysis was conducted to assess the association of lumbopelvic sagittal alignment with additional independent factors.

Results

It was demonstrated that the pelvic tilt (PT) significantly differs between anterolateral and posterolateral hip dysplasia phenotypes (16.84° ± 8.75° vs. 11.51° ± 6.63°, p = 0.0002). Similar findings were shown for pelvic incidence (PI) (57.19° ± 12.96° vs. 50.75° ± 13.1°, p = 0.0031). However, sacral slope (SS) appeared independent of the morphology of hip joint dysplasia (39.95° ± 11.27° vs. 39.13° ± 11.88°, p = 0.3441). The association between a PT of >14.5° and anterolateral dysplasia was identified as the most significant factor within the linear regression analysis.

Conclusion

The results of this study underline a prevailing paradox in the dysplastic hip-spine association. Contrary to previous theories, pelvic tilt constitutes a component of the corresponding phenotype of dysplasia, rather than a compensatory tilt.