• Main Author: Benjamin Bockmann
• Affiliation: Ruhr University Bochum
• Type: Research Project
• Co-Author: A. Kumar, J. J. Timothy, G. Meschke
• Date: 2023
• Journal: ARTHROSCOPY AND SPORTS MEDICINE

Project Overview

This study investigated how bone tunnel placement during coracoclavicular (CC) ligament reconstruction affects shear stresses on the coracoid process. Using a 3D finite element (FE) model combined with a radiological analysis of patient data, the project evaluated different bone tunnel configurations to identify safer surgical techniques that reduce the risk of coracoid fractures.

Problem & Motivation

Arthroscopically assisted AC joint reconstructions often involve drilling tunnels in the clavicle and coracoid. However, stress fractures at the coracoid are a known complication, leading to poor clinical outcomes. Cadaver studies offer limited insights due to variable bone quality, so there is a need for computational and clinical analyses to identify optimal bone tunnel configurations that minimize mechanical stress.

Key Contributions

• Built a 3D finite element model of the AC joint using CT imaging and virtual bone tunnels.
• Tested six different tunnel configurations for clavicle–coracoid reconstruction.
• Conducted a radiological review of 40 patient cases to validate tunnel placement in real surgeries.
• Identified that a proximal coracoid tunnel combined with a lateral clavicle tunnel minimized shear stresses.
• Showed that certain configurations increased stress by up to 23%, raising fracture risk.

Technical Highlights

• Tools & Platforms: CT-based 3D modeling, 3D Slicer, GiD pre/post-processing, Kratos FE solver.
• Methods: Finite Element Analysis (Von Mises stress evaluation), radiological measurement of clavicle drill holes, statistical analysis with SPSS.
• Model Details: 420,793 tetrahedral finite elements, applied surface loading, Dirichlet boundary conditions.
• Validation: Compared FE predictions with radiological evidence from post-surgical X-rays of AC joint reconstructions.

Results & Impact

The study demonstrated that bone tunnel placement strongly influences stress distribution at the coracoid. A lateral traction direction with a proximal tunnel significantly lowered stresses, while medial or distal placements increased fracture risk.

Publication Details

Journal: Archives of Orthopaedic and Trauma Surgery
Year: 2023
DOI: 10.1007/s00402-022-04382-9