The predictive value of individual anatomical measurement of scapula in the diagnosis of rotator cuff injury

Background: Rotator cuff injuries, which cause health problems especially in athletes and older adults, may be linked to factors like age, overuse, muscle imbalance, and potentially, certain shoulder joint shapes, though the impacts of the Critical Shoulder Angle (CSA) and the Lateral Acromion Angle (LAA) are still unclear. The aim of this study was to explore the correlation between the individual anatomical structure of the scapula and rotator cuff injuries. Methods: A total of 71 patients suffering from shoulder ailments were examined, with 40 individuals having rotator cuff injuries and the remaining 31 not. Both groups were evaluated based on gender, age, critical shoulder angle (CSA), and lateral acromion angle (LAA). Multivariate logistic regression was used to analyze the factors influencing rotator cuff injury, and the ROC curve was plotted to assess the diagnostic efficiency of LAA and CSA for this injury. Results: The age [(54.8 ± 11.5) years] and CSA [(40.6 ± 4.7) °] of the rotator cuff injury group were considerably higher than those without [(47.7 ± 11.4) years and (36.8 ± 5.5) °] (P<0.05), whereas the LAA [(70.9 ± 7.0) °] was lower (P<0.05). Age (OR=0.952, 95% CI: 0.911 ～ 0.994, P=0.027), LAA (OR=1.114, 95% CI: 1.034 ～ 1.199, P=0.004), and CSA (OR=0.844, 95% CI: 0.752 ～ 0.947, P=0.004) emerged as significant factors of rotator cuff injury. The study established optimal cutoff values of age, LAA, and CSA at 55.50 years, 72.67°, and 37.10°respectively, and the AUC predicting rotator cuff injury was 0.680 (95% CI: 0.554 ～ 0.805, P=0.010), 0.719 (95% CI: 0.597 ～ 0.840, P=0.002) 0.737 (95% CI: 0.612 ～ 0.862, P=0.001). LAA and CSA showed decent predictive value for rotator cuff injury (AUC>0.7), but age was a poor predictor. Conclusion: Both CSA and LAA are influential factors of rotator cuff injury. An increase in the CSA of the shoulder joint and a decrease in LAA could indicate the presence of a rotator cuff injury. Trial registration Retrospectively registered