Department of Orthopedic Surgery and Traumatology

Inselspital Bern

Through top-level university medicine, the clinic ensures that every patient receives optimal treatment and has access to the latest developments, methods, and possibilities in medicine. As a university clinic, we aim to combine research, teaching, and service. Scientific activity has a high priority, and the knowledge gained is implemented in daily clinical practice.

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Director

Prof. Moritz Tannast

Profile

  • Hip research focuses on pre-arthritic deformities like femoroacetabular impingement or hip dysplasia. The goal is to improve preoperative MR imaging and surgical decision-making using artificial intelligence.
  • Spine research focuses on disc de- and regeneration, biological approaches for augmentation of spinal fusion, management of spinal trauma, spinal infection, spinal tumor/metastatic disease, and clinical performance analysis of spinal implants.
  • Research on the Shoulder joint focusses on the study of diagnostic and prognostic factors for RCT and anterior shoulder instability using AI based image processing, biomechanical modelling and dynamic biplanar radiography.
  • The main focus of the knee research group lies in the establishment of 3-dimensional templating for fracture repair and ligament reconstructions and on-site 3D printing of surgical guides. Further research activities include clinical studies on ligamentous injuries of the knee and complex knee arthroplasty.
  • Foot and ankle research mainly focuses on arthrosis of the ankle joint, innovative treatment of ankle fractures and AMIC plastic in osteochondral lesions.
  • Orthogeriatrics investigates the impact of orthogeriatric pathways and rehabilitation protocols on the clinical outcome in geriatric patients, while incorporating AI based 3D CT diagnostics to advance fracture classification and decision-making.
     
  • The orthopaedic research in collaboration with the Department for BioMedical Sciences (DBMR) concentrates on three main aspects: 1) Improved spinal fusion for the elderly using a combination of add-ons to the clinically approved bone morphogenic-2 (BMP-2). 2). The second line of research investigates into regenerative approaches to maintain or repair the intervertebral discs by investigation into silk-fiber reinforced hyaluronic acid-collagen type 2 cross-linked hydrogels for intervertebral disc with or without progenitor cells. 3) The third line of research is focuses on tendon and ligaments such as the enthesis of the rotator-cuff joint of the shoulder, where a mechanobiological of ovine ex-vivo bioreactor model has been developed.

External Partners

Aalborg University, AnyBody Technology, AO Research Institute, Davos, Brisbane Hand and Upper Limb Research Institute, CABMM at the University of Zurich, Clinica Santa Maria Providencia Chile, CustomSurg AG, DBMR University of Bern, Department of Small Animals, Division of Magnetic Resonance Spectroscopy and Methodology (AMSM), Dynamic Imaging Center, EMPA, ETHZ, Hôpital de La Tour, Meyrin, Kantonsspital St Gallen, Macquarie University, Sydney, Australia, Medacta AG, RMS Foundation, Bettlach; SUVA, sitem Center, Sonnenhof, Stiftungsfonds swiss orthopaedics, Swiss national science foundation SNF, the University of Queensland, Schulthess Klinik, TU Delft, University Hospital Basel, University of Geneva, ZHAW, Evoleen AG, AO Research Institute, Davos, CABMM at the University of Zurich, DBMR University of Bern, Zürcher Hochschule für angewandte Wissenschaften (ZHAW), Hochschule Luzern (HSLU), Space Biology Group, Universidad Pompeu Fabra (UPF) Barcelona, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands, Center of Experimental Rheumatology, Department of Rheumatology, University Hospital Zurich 

Grants

  • Age-Stiftung: Geriatrische Rehabilitation – daheim, digital, selbstbestimmt (GRIMSEL) (PD A. Eggimann)
  • Filmed: Filmed-Projekt: Reframing aging – an educational intervention on communication for future healthcare professionals (PD A. Eggimann)
  • Innosuisse: Automatic segmentation of complex bone fractures from CT images (Dr. N. Gerber)
  • Innosuisse, Medacta: 3D Pre-Operative Planning based on MRI for Shoulder Arthroplasty (PD K. Gerber K, PD M. Schär, Prof. M. Zumstein)
  • Johnson & Johnson Depuy Synthes, Fellowship (Prof. M. Deml)
  • sitem-insel Support Fund (SISF): Dynamic Biplanar Radiographic analysis of anterior shoulder instability and the effect of physical therapy (Prof. M. Schär, PD K. Gerber)
  • Stipendienfonds swiss orthopaedics:
    • Validation of Dynamic Biplanar Radiographie lmaging for Accurate Hip Joint Kinematic Analysis Using 3D Printed Models and Cadaveric Specimens (J. Hirt Julien, Prof. M. Tannast)
    • A Novel, Cartilage-Seated 3D-Printed Guide for accurate Open Acetabular Rim Trimming – A Cadaveric Feasibility and Validation Stud (Dr. S. Schaible, Prof. M. Tannast)
    • Cohort Study: Multicenter Fatty Infiltration Assessment (MFIA) (PD S. Wanger, PD M. Schär)
    • The perfect pelvic radiograph: An AI based technique for digital reconstructive radiograpy from 3D MRI with automatic landmark detection and correction for pelvic malorientation (Dr. J. Roshardt, Prof. S. Steppacher)
    • Sexual function in female and male patients after Anterior Lumbar Interbody Fusion (ALIF): a prospective, multicentric, controlled study (Dr. Ch. Tinner)
  • Sutter Stöttner Foundation: Biomimetic Microgel-Based Cell and Cell-free Delivery Systems for Regeneration of the Intervertebral Disc (MimeDisK)
  • (T. Rahvar, Prof. B. Gantenbein)
  • SUVA: Outcome of Surgical versus Primary Non-Surgical Treatment of Incomplete Burst Fractures of the Thoracolumbar Spine in Patients without Neurological Symptoms: A Randomized Controlled Clinical Trial (Prof. Albers)
  • Swiss National Science Foundation:
    • Expanding acetabular fracture classification using 3D CT analysis and deep learning techniques (Dr. N. Gerber N, Prof. JD Bastian)
    • The role of bone loss in recurrent anterior shoulder instability – three-dimensional image based analysis (PD K. Gerber, PD M. Schär)
    • Implant-Free Spinal Fusion for the Elderly – Enhanced Biologics Using BMP-2 Analog L51P and Prostaglandin Receptor EP4 Modulation (PD S. Häckel)
  • UniBE Venture Fellowship 2025 grant: Deep-learning based diagnosis for rotator cuff tear patients (H. Hess, PD K. Gerber)

Highlights 2025

Rehabio: Successful Development of a Digital Rehabilitation Prototype with successful Acquisition of Four Competitive Grants

In 2025, Professor Bastian and his research team, in partnership with Evoleen AG, a Swiss innovator in health solutions, successfully developed the first prototype of Rehabio, a digital rehabilitation solution for patients recovering from fragility fractures. Rehabio focuses on supporting post-acute care following surgical treatment of non-traditional hip fractures with postoperative weight-bearing restrictions.

The prototype was created through the integration of clinical expertise, physiotherapy research, rehabilitation science, and digital innovation, with financial support from the BFH CARE@HOME Call. Initial user testing with patients and physiotherapists demonstrated high usability, strong acceptability, and clear potential to address a critical gap in transitional care.

Building on this milestone, the Rehabio project team led by Professor Bastian secured three additional competitive grants, enabling the transition from prototype to Rehabio Version 1.0 and supporting its forthcoming scientific evaluation. This exceptional funding success reflects the team’s combined clinical, rehabilitative, scientific, and technological expertise and positions the Bern medical hub as a national pioneer in digital, patient-centered orthogeriatric care.

Figure 1. A) Longitudinal Fast Field Echo (FFE) MRI scans of bovine coccygeal intervertebral disc (IVD) explants on day 0 (left panel) and after 7 days of organ culture (right panel) dynamic loading with 10 ng/mL IL-1β added to the medium (top raw) under static loading and 10 ng/mL IL-1β (second raw) or under dynamic loading and IL-1β Receptor antagonist (RA) (third raw) (B) Scale bars show 5mm length B) Mechano-transport finite element (FE) simulation results. B) The subject-personalized FE models of the static control, IL-1β-, and IL-1Ra- treated bovine IVDs. D) The predicted maximum principal stress (MPa) in the nucleus pulposus of each IVD. C) The predicted glucose concentration (mM) within the NP for each IVDs in organ culture.

“Disc4all” Marie Skłodowska Curie International Training Network (ITN) successfully completed

The Tissue Engineering for Orthopaedics & Mechanobioloy Group (TOM-lab.com) has contributed in a Marie Skłodowska Curie International Training Network (ITN) “disc4all” on the possible therapeutic usage of Il-4 and IL-10 for the combined therapeutic treatment to fight discogenic low back pain. The project main achievement was the creation of simulation platforms that integrates models and datasets, enabling simulations (Figure 1), analyses, biomarker identification, and pathway integration, that will have an impact for researchers, healthcare professionals, regulators, and industry in the spine, and in general, orthopedics field.

Bermudez-Lekerika et al., JOR Spine. 2025

Figure 2. Bone homeostasis and osteoporosis-related challenges in spinal fusion in the vertebrae. This figure illustrates the key biological and mechanical challenges affecting spinal fusion in elderly patients. In normal vertebrae, mesenchymal stromal cells (MSCs) within the bone marrow differentiate into osteoblasts, which mature into osteocytes and maintain bone formation. Concurrently, hematopoietic stem cells (HSCs) differentiate into osteoclasts (OCs), which mediate bone resorption.

Improved Spinal Fusion by addition of biologics

Spinal fusion is the standard-of-care in clinics and is routinely operated on patients about 15,000 times every year in Switzerland. Discectomy followed by spinal fusion is for many patients the only way their low back pain can be managed by stabilization. However, there are factors that are hampering a successful osteosynthesis of the two adjacent vertebrae, which leads to preuso-arthrosis and severe pain for many patients. Clinically, approved is bone morphogenic protein -2 (BMP-2), however, this cytocine is applied in rather supraphysiological doses and with known off-target side-effects such as ectopic bone formation or even cancer. Our research has identified potential molecules, which might reduce of the dosage of BMP-2 considerably (Figure 2).

Chen et al., JOR Spine. 2025

Figure 3. AI-driven shoulder modelling pipeline showing CT-based 3D reconstructions of the humerus and scapula (left), AI-based native glenoid prediction for bone loss quantification (middle), and a biomechanical shoulder model driven by bi-planar dynamic imaging (right).

Three-dimensional dynamic study of shoulder instability

In collaboration with Dr. Michael Schär and PD DR. Kate Gerber, the AI in Orthopaedic Surgery research group has commenced the first study on humans at the Dynamic Imaging Center at sitem-insel (Prof. Ameet Aiyangar). The study leverages state-of-the-art dynamic bi-planar imaging to perform high accuracy 3D analysis of patients with anterior shoulder instability, providing critical insights into in vivo joint kinematics and the biomechanical mechanisms underlying shoulder instability and its treatment. Funded by the Swiss National Science Foundation (Grant No. 10.000.342) and the sitem-Insel support fund, the project investigates the role of bone loss and muscle activation on shoulder stability. By integrating AI-based anatomical analysis from medical imaging, the study aims to enable more accurate 3D biomechanical modelling of the shoulder, automate 3D diagnosis, and ultimately improve clinical outcomes for patients with shoulder instability. Beyond the shoulder, this imaging and analysis framework establishes a foundation for future dynamic studies of other joints.

Kamradt S. et al., ‘AI-Based 3D Analysis of Glenoid Bone Loss’, in 30th Congress of the European Society of Biomechanics (ESB), Zürich, Switzerland, July 6–9 (2025) (pdf)