Establishing Normative Values for Acromion Anatomy: A Comprehensive MRI-Based Study in a Healthy Population of 996 Participants

Abstract

Shoulder pain is a common issue often linked to conditions such as subacromial impingement or rotator cuff lesions. The role of the acromion in these symptoms remains a subject of debate. This study aims to establish standardized values for commonly used acromion dimensions based on whole-body MRI scans of a large and healthy population and to investigate potential correlations between acromion shape and influencing factors such as sex, age, BMI, dominant hand, and shoulder pain. The study used whole-body MRI scans from the Study of Health in Pomerania, a German population-based study. Acromion index, acromion tilt, and acromion slope were measured. Interrater variability was tested with two independent, trained viewers on 100 MRI sequences before actual measurements started. Descriptive statistics and logistic regression were used to evaluate the results. We could define reference values based on a shoulder-healthy population for each acromion parameter within the 2.5 to 97.5 percentile. No significant differences were found in acromion slope, tilt, and index between male and female participants. No significant correlations were observed between acromion morphology and anthropometric parameters such as height, weight, or BMI. No significant differences were observed in acromion parameters between dominant and non-dominant hands or stated pain intensity. This study provides valuable reference values for acromion-related parameters, offering insight into the anatomy of a healthy shoulder. The findings indicate no significant differences in acromion morphology based on sex, weight, BMI, or dominant hand. Further research is necessary to ascertain the clinical implications of these reference values. The establishment of standardized reference values opens new possibilities for enhancing clinical decision making regarding surgical interventions, such as acromioplasty.

Normative Values for Sternoclavicular Joint and Clavicle Anatomy Based on MR Imaging: A Comprehensive Analysis of 1591 Healthy Participants

“…Transversal layers were initially created, supplemented by an additional 3D frontal layer generated by the study authors using HORUS PACS. The plug-in was used in a similar way before [ 26 ].…”

“…To assess reliability, n = 106 images were measured twice by two readers, demonstrating interreader variability within acceptable limits. Bland and Altman plots and interclass correlation coefficients were applied to evaluate intra- and interreader variabilities ( Figure 8 and Table 1 ) [ 26 ].…”

“…To assess reliability, n = 106 images were measured twice by two readers, demonstrating interreader variability within acceptable limits. Bland and Altman plots and interclass correlation coefficients were applied to evaluate intra-and interreader variabilities (Figure 8 and Table 1) [26]. To assess reliability, n = 106 images were measured twice by two readers, demo strating interreader variability within acceptable limits.…”

“…To assess reliability, n = 106 images were measured twice by two readers, demo strating interreader variability within acceptable limits. Bland and Altman plots and i terclass correlation coefficients were applied to evaluate intra-and interreader variabi ties (Figure 8 and Table 1) [26]. Statistical analysis involved calculating medians (p50) and quartiles (p25 and p75), establishing median-based regression models for age and sex relationships, and Pearson coefficients for inter-side and variable relationships with height, weight, and BMI.…”

“…Thi plug-in facilitated distance and angle measurements between various anatomical points Transversal layers were initially created, supplemented by an additional 3D frontal laye generated by the study authors using HORUS PACS. The plug-in was used in a simila way before [26].…”