Can Hertel Criteria Reliably Predict Avascular Necrosis After Intracapsular Proximal Humerus Fractures in the...

Background/Objectives: Avascular necrosis (AVN) of the humeral head is a severe complication after intracapsular proximal humerus fractures in the elderly. Hertel's radiographic classification is widely used to estimate ischemic risk, yet its real-world accuracy remains debated. Methods: We retrospectively analyzed 204 patients aged ≥65 years treated between 2019 and 2022 for intracapsular proximal humerus fractures. Fractures were classified according to Hertel's criteria and the LEGO system. The incidence of AVN and its association with radiographic predictors were assessed. Diagnostic performance metrics (sensitivity, specificity, predictive values, accuracy) were calculated for Hertel's classification. Results: AVN developed in 22 patients (10.8%). High-risk fractures according to Hertel's criteria showed a 24.7% AVN rate versus 0.8% in low-risk fractures (p < 0.001; OR = 38.7). Hertel's model demonstrated high sensitivity (95.5%) and negative predictive value (99.2%) but low positive predictive value (24.7%). Medial hinge disruption and calcar extension < 8 mm were the strongest radiographic predictors (p < 0.001). Conclusions: Hertel's classification effectively identifies elderly patients at low risk for AVN, given its high sensitivity and NPV. However, its limited positive predictive value highlights the need for integrative models combining radiographic and clinical parameters to improve ischemic risk stratification.