Spine - 2026-03-26 - Journal Article
Differentiating Spinal Deformity Versus Leg Length Discrepancy in Patients With Pelvic Obliquity: Systematic Review of Diagnostic Methods, Imaging, and Clinical Management.
Truumees E, Akkihal K, Griffin J, Singh D, Geck M, Stokes J, Mayer R
Topics
Key Takeaway
Among 24 cohort studies, standing AP radiographs with block/lift correction tests were the most reliable discriminators of limb-origin versus spine-origin pelvic obliquity, though mixed-etiology cases remain diagnostically unresolved.
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Summary
This systematic review of 436 screened records (24 included cohort studies) sought an evidence-based algorithm to distinguish spinal deformity from leg length discrepancy as the primary driver of pelvic obliquity. Standing AP radiographs reliably quantified both LLD and pelvic obliquity, and block/lift correction tests served as the key functional discriminator: obliquity resolving with correction indicates limb origin, while persistent deformity indicates spinal etiology. Mixed-etiology patients remain the critical diagnostic gap, with no validated threshold or protocol to guide management in this subgroup.
Key Limitation
No patient-level data were pooled and no diagnostic accuracy statistics (sensitivity, specificity, AUC) were extractable, so the proposed stepwise algorithm lacks quantified discriminative performance.
Original Abstract
STUDY DESIGN
Systematic review,
PROSPERO ID
(CRD42023112392).
OBJECTIVE
We aim to provide physicians with an evidence-based stepwise approach to distinguishing the primary cause of plane pelvic obliquity (PO) to guide treatment.
SUMMARY OF BACKGROUND DATA
PO is a frequent clinical finding in both spinal deformity (SD) and leg length discrepancy (LLD) but distinguishing between these etiologies remains challenging due to overlapping clinical and radiographic features and potential multifactorial origins. Misdiagnosis may delay care and worsen patient outcomes.
METHODS
PubMed, Embase, Scopus, and Web of Science were searched from inception to July 2025 for English-language studies evaluating coronal PO in the context of LLD and/or SD that explicitly compared or differentiated limb-origin from spine-origin obliquity using radiographic, advanced imaging, or validated clinical assessments and reported diagnostic accuracy, discriminative features, or management impact. Two reviewers independently screened studies, extracted data, and performed ROBINS-I risk assessment and Newcastle-Ottawa Scale quality assessment. Owing to marked heterogeneity in populations, measurement protocols, and thresholds, findings were synthesized qualitatively with stratification by age group where possible.
RESULTS
Of 436 records, 24 cohort studies met inclusion criteria. Standing anteroposterior (AP) radiographs reliably quantified both LLD and PO, while advanced imaging provided high reproducibility for subtle or ambiguous cases. Radiographic block or shoe lift correction tests distinguished limb-origin and spine-origin PO via immediate postural correction. Key discriminators included a lumbar curve or PO resolving with block/lift correction suggesting LLD, versus persistent deformity despite correction suggesting spinal etiology. Difficulty remains in diagnosing and treating mixed etiology patients.
CONCLUSION
Accurate differentiation of spinal versus limb-driven PO begins with a structured diagnostic approach. AP radiographs, followed by functional block tests, and advanced imaging, may increase diagnostic confidence and decrease unnecessary interventions. Particularly in patients with both LLD and coronal plane SD, prospective studies are required to standardize measurement protocols and improve long-term outcomes.
LEVEL OF EVIDENCE
IV.