26dkou205 10.3205/26dkou205 urn:nbn:de:0183-26dkou2059 Meeting Abstract Schaible Schaible Samuel S

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

author Roshardt Roshardt Jose J

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

author Hirt Hirt Julien J

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

author Fankhauser Fankhauser Fabio F

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

author Steppacher Steppacher Simon Damian SD

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

author Tannast Tannast Moritz M

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

author German Medical Science GMS Publishing House

Düsseldorf

610 20261020 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). M0659 205 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 2026) Abstracts | Impingement Berlin 20261020 20261023 DKOU26_Abs_2489 TextObjectives and questions: Over- and undertrimming in open acetabular rim trimming can compromise stability or leave residual impingement, increasing revision risk. The objective of this study was to verify the accuracy of a novel personalized 3D-printed guide on patient-specific 3D-printed bone models and on cadaveric hips.Material and methods: We conducted a prospectively planned experimental accuracy study on 24 hips: 20 patient-specific 3D-printed hip models based on computed tomography (CT) scans from our database (deformities: acetabular protrusion, acetabular retroversion, posterior overcoverage) and 4 cadaveric hips. Guides were designed in CAD software and manufactured using stereolithography (SLA), while the patient-specific pelves were produced using fused deposition modeling (FDM). A CT-based 3D plan defined the target postoperative lateral center-edge angle (LCEA), lunate surface area change, sectoral center-edge angles, and trim depth. The planned resection geometry was transferred into the guide design. After open guide-assisted rim trimming, deviations from the plan were calculated as postoperative minus planned values; negative deviations indicate over-trimming. LCEA and lunate surface area were measured once per hip; sectoral angles and trim depth were measured at each of 12 clock-face positions per hip. Accuracy was assessed using Bland-Altman analysis, reporting mean deviation (bias) and 95% limits of agreement (LoA). Group differences (3D-printed models vs cadavers) were compared using Mann-Whitney U tests for LCEA and lunate surface area and mixed-effects models for sectoral angles and trim depth. Data are reported as mean ± SD; α=0.05.Results: LCEA deviation was −0.2° ± 2.2° on 3D-printed models (n=20 hips; LoA −4.5° to +4.0°), with 13/20 (65%) within ±2°; cadavers showed +2.0° ± 1.4° (n=4 hips; p=0.03). Lunate surface area deviation was −8 ± 81 mm² on 3D-printed models versus +89 ± 110 mm² on cadavers (p=0.13). Sectoral angle deviation was −0.3° ± 1.5° on 3D-printed models (n=100 positions; LoA −3.3° to +2.7°), with 94/100 (94%) within ±2°; cadavers showed −4.0° ± 4.3° (n=29 positions; p<0.001). Trim depth deviation was +0.1 ± 0.6 mm on 3D-printed models (LoA −1.1 to +1.3 mm), with 96% within ±1 mm; cadavers showed +1.5 ± 2.1 mm (p<0.001).Discussion and conclusions: The personalized 3D-printed guide reproduced the planned rim resection with near-zero mean deviations for LCEA, lunate surface area, sectoral angles, and trim depth on patient-specific 3D-printed bone models. Accuracy decreased on cadaveric hips with cartilage-seated guides, suggesting guide seating on cartilage as the key translational challenge. Clinical validation and design optimization are warranted. 0 0 0 0