Benjamin Bockmann1,2, L Dankl3, G Kucinskaite4, A Kumar5, J J Timothy6, G Meschke7, A J Venjakob8, T L Schulte9. 1. Department of Orthopaedics and Trauma Surgery, St. Josef Hospital, Ruhr University, Bochum, Germany. Maik-Benjamin.Bockmann@ruhr-uni-bochum.de. 2. Department of Sports Orthopaedics, St. Vinzenz Hospital, Düsseldorf, Germany. Maik-Benjamin.Bockmann@ruhr-uni-bochum.de. 3. Department of Orthopaedics and Traumatology, Medical University of Innsbruck, Innsbruck, Austria. 4. Department of Diagnostic and Interventional Radiology and Nuclear Medicine, St. Josef Hospital, Ruhr University, Bochum, Germany. 5. Swiss Federal Institute of Technology, Zürich, Switzerland. 6. Chair of Materials Science and Testing, Technical University of Munich, Munich, Germany. 7. Institute for Structural Mechanics, Ruhr University, Bochum, Germany. 8. Department of Sports Orthopaedics, St. Vinzenz Hospital, Düsseldorf, Germany. 9. Department of Orthopaedics and Trauma Surgery, St. Josef Hospital, Ruhr University, Bochum, Germany.
Abstract
INTRODUCTION: Coracoid fractures after arthroscopic treatment of acromioclavicular (AC) joint separations lead to poor clinical outcomes. In this study, different configurations of bone tunnels in the lateral clavicle and coracoid were examined concerning the amount of stress induced in the coracoid. METHODS: An authentic 3D finite element model of an ac joint was established. Three 2.4 mm bone tunnels were inserted in the lateral clavicle, which were situated above, medially and laterally of the coracoid. Then, two 2.4 mm bone tunnels were inserted in the latter, each simulating a proximal and a distal suture button position. Von Mises stress analyses were performed to evaluate the amount of stress caused in the coracoid process by the different configurations. Then, a clinical series of radiographs was examined, the placement of the clavicle drill hole was analyzed and the number of dangerous configurations was recorded. RESULTS: The safest configuration was a proximal tunnel in the coracoid combined with a lateral bone tunnel in the clavicle, leading to an oblique traction at the coracoid. A distal bone tunnel in the coracoid and perpendicular traction as well as a proximal tunnel in the coracoid with medial traction caused the highest stresses. Anatomical placement of the clavicle drill hole does lead to configurations with smaller stresses. CONCLUSION: The bone tunnel placement with the smallest amount of shear stresses was found when the traction of the suture button was directed slightly lateral, towards the AC joint. Anatomical placement of the clavicle drill hole alone was not sufficient in preventing dangerous configurations. LEVEL OF EVIDENCE: Controlled laboratory study.
INTRODUCTION: Coracoid fractures after arthroscopic treatment of acromioclavicular (AC) joint separations lead to poor clinical outcomes. In this study, different configurations of bone tunnels in the lateral clavicle and coracoid were examined concerning the amount of stress induced in the coracoid. METHODS: An authentic 3D finite element model of an ac joint was established. Three 2.4 mm bone tunnels were inserted in the lateral clavicle, which were situated above, medially and laterally of the coracoid. Then, two 2.4 mm bone tunnels were inserted in the latter, each simulating a proximal and a distal suture button position. Von Mises stress analyses were performed to evaluate the amount of stress caused in the coracoid process by the different configurations. Then, a clinical series of radiographs was examined, the placement of the clavicle drill hole was analyzed and the number of dangerous configurations was recorded. RESULTS: The safest configuration was a proximal tunnel in the coracoid combined with a lateral bone tunnel in the clavicle, leading to an oblique traction at the coracoid. A distal bone tunnel in the coracoid and perpendicular traction as well as a proximal tunnel in the coracoid with medial traction caused the highest stresses. Anatomical placement of the clavicle drill hole does lead to configurations with smaller stresses. CONCLUSION: The bone tunnel placement with the smallest amount of shear stresses was found when the traction of the suture button was directed slightly lateral, towards the AC joint. Anatomical placement of the clavicle drill hole alone was not sufficient in preventing dangerous configurations. LEVEL OF EVIDENCE: Controlled laboratory study.
Authors: Matthew D Milewski; Marc Tompkins; Juan M Giugale; Eric W Carson; Mark D Miller; David R Diduch Journal: Am J Sports Med Date: 2012-05-02 Impact factor: 6.202
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Authors: Matthias A Zumstein; Philippe Schiessl; Benedikt Ambuehl; Lilianna Bolliger; Johannes Weihs; Martin H Maurer; Beat K Moor; Michael Schaer; Sumit Raniga Journal: Knee Surg Sports Traumatol Arthrosc Date: 2017-05-25 Impact factor: 4.342