Title : Evaluation of proximal ulnar morphology: A systematic review of Varus Angulation (VA) of proximal ulnar
Abstract:
Background: Varus angulation (VA) of the proximal ulna is a key morphological feature influencing fracture reduction, implant design, and elbow biomechanics. Despite its clinical significance, reported values and measurement techniques vary widely.
Objective: To systematically review and synthesize the existing literature on proximal ulnar VA in adults, establishing normative values, evaluating methodological variation, and recommending standardized assessment approaches.
Methods: Following PRISMA guidelines, electronic databases (MEDLINE, Embase, Cochrane Library) were searched from January 2000 to November 2024. Eligible studies reported quantitative measurements of VA in adults without pathology. Data on study design, measurement technique, imaging modality, and risk of bias (assessed with the AQUA Tool) were extracted and analyzed.
Results: Seventeen studies were included, spanning CT imaging, X-ray, and cadaveric analyses. Reported VA means ranged from 6.6° to 17.7°, with a pooled mean of 12.39°?±?2.90°. Tip to Varus Apex Distance ranged from 47.8?mm to 99.7?mm (pooled mean 81.74?±?4.16?mm). Significant methodological heterogeneity was observed, particularly in anatomical landmarks (e.g., olecranon tip, posterior cortex, triceps insertion) and measurement lines (axis-based vs. vertical). ANOVA revealed significant differences in VA across modalities (p?<?0.0001).
Conclusions: Substantial variability exists in VA measurement definitions and techniques, complicating direct comparisons. Standardized, anatomically consistent protocols—preferably using advanced imaging—are needed to improve reproducibility, inform implant design, and enhance surgical planning.
