25dkou579 10.3205/25dkou579 urn:nbn:de:0183-25dkou5795 Meeting Abstract Wangler Wangler Sebastian S

Department of Orthopaedic Surgery and Traumatology, Inselspital, Bern University Hospital, University of Bern, Bern, Schweiz

author Kohlprath Kohlprath Raphael R

Department of Orthopaedic Surgery and Traumatology, Inselspital, Bern University Hospital, University of Bern, Bern, Schweiz

author Erdbrink Erdbrink Stephanie S

Department of Orthopaedic Surgery and Traumatology, Inselspital, Bern University Hospital, University of Bern, Bern, Schweiz

author Künzler Künzler Michael M

Department of Orthopaedic Surgery and Traumatology, Inselspital, Bern University Hospital, University of Bern, Bern, Schweiz

author Moser Moser Helen H

Department of Orthopaedic Surgery and Traumatology, Inselspital, Bern University Hospital, University of Bern, Bern, Schweiz

author Schär Schär Michael M

Department of Orthopaedic Surgery and Traumatology, Inselspital, Bern University Hospital, University of Bern, Bern, Schweiz

author German Medical Science GMS Publishing House

Düsseldorf

610 20251031 engl This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. Dieser Artikel ist ein Open-Access-Artikel und steht unter den Lizenzbedingungen der Creative Commons Attribution 4.0 License (Namensnennung). M0634 579 Deutsche Gesellschaft für Orthopädie und Unfallchirurgie Deutsche Gesellschaft für Orthopädie und Orthopädische Chirurgie Deutsche Gesellschaft für Unfallchirurgie Berufsverband für Orthopädie und Unfallchirurgie Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2025) Abstracts | Schulter Trauma Berlin 20251028 20251031 AB92-4675 TextObjectives and questions: Isolated fractures of the greater tuberosity represent up to 20% of all proximal humeral fractures. Conservative and surgical treatment strategies are reported. Fracture displacement on radiographs is a key factor in treatment decisions, but the accuracy of measurement methods can limit this process. This study aimed to (Aim I) assess the inter- and intraobserver reliability of established radiographic measurements of fracture displacement and (Aims II/III) determine if these measurements can predict superior, posterior, or combined superior + posterior fracture displacement quantified on CT scans in a patient cohort.Material and methods: Forty-nine cases of isolated greater tuberosity fractures with complete radiographs and CT scans were analyzed. (Aim I) Displacement was measured on radiographs in millimeters as superior (‘sup’) and lateral (‘lat’) displacement, along with Mutch's superior ratio (‘sGT’), anterior/posterior ratio (‘apGT’), and Nyffeler’s impingement index (‘I-Ind’). Reliability was assessed by three independent observers. (Aim II) A humerus saw-bone model with predefined superior, posterior, and combined fracture displacements was used to validate a CT-based measurement technique. (Aim III) This CT-based method was applied to patient CT scans, and linear regression was used to test if radiographic measurements predicted the CT-measured displacements.Results: (Aim I) Inter- and intraobserver reliability was excellent for ‘I-Ind’ (inter 0.98/intra 0.94), good-excellent for ‘lat’ (0.82/0.76) and ‘sGT’ (0.75/0.94), and moderate for ‘sup’ (0.73/0.66) and ‘apGT’ (0.64/0.49). (Aim II) The CT-based technique accurately measured superior (R2=0.99), posterior (R2=0.99), and combined (R2=0.99) displacement. (Aim III) Patient CT scans showed mean displacement of 3.3±2.5 mm superior, 8.4±5.6 mm posterior, and 11.6±7 mm combined. Superior displacement correlated with ‘sup’ (p<0.001), posterior with ‘lat’ (p<0.001), ‘apGT’ (p=0.004), ‘I-Ind’ (p=0.048), and combined displacement with ‘lat’ (p<0.001) and ‘apGT’ (p=0.006). In fractures displaced ≥5 mm, ‘sup’ (p=0.002) correlated with superior, ‘lat’ (p=0.003) and ‘I-Ind’ (p=0.049) with posterior, and ‘lat’ (p<0.001) with combined displacement.Discussion and conclusions: The CT-based technique accurately measured fragment displacement in the saw-bone model. For fractures with ≥5 mm displacement, ‘lat’ was the best predictor of combined displacement (interobserver reliability: 0.82–0.94). However, in the reported cohort, 'lat' underestimated the “true” fragment displacement. Therefore, in ‘lat’ measurements ≥ 3mm, a CT scan for quantification of fragment displacement should be considered. However, these findings must be confirmed in bigger patient populations before clinical translation. 0 0 0 0