Christoph Engelhardt1, Alain Farron2, Fabio Becce3, Nicolas Place4, Dominique P Pioletti1, Alexandre Terrier5. 1. Laboratory of Biomechanical Orthopedics, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland. 2. Service of Orthopedics and Traumatology, Lausanne University Hospital, Lausanne, Switzerland. 3. Department of Diagnostic and Interventional Radiology, Lausanne University Hospital, Lausanne, Switzerland. 4. Institute of Sports Sciences, Faculty of Biology Medicine, University of Lausanne, Lausanne, Switzerland; Department of Physiology, Faculty of Biology Medicine, University of Lausanne, Lausanne, Switzerland. 5. Laboratory of Biomechanical Orthopedics, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland. Electronic address: alexandre.terrier@epfl.ch.
Abstract
BACKGROUND: Previous clinical studies have reported associations between glenoid inclination (GI), the acromion index (AI), and the critical shoulder angle (CSA) on the one hand and the occurrence of glenohumeral osteoarthritis and supraspinatus tendon tears on the other hand. The objective of this work was to analyze the correlations and relative importance of these different anatomic parameters. METHODS: Using a musculoskeletal shoulder model developed from magnetic resonance imaging scans of 1 healthy volunteer, we varied independently GI from 0° to 15° and AI from 0.5 to 0.8. The corresponding CSA varied from 20.9° to 44.1°. We then evaluated humeral head translation and critical strain volume in the glenoid articular cartilage at 60° of abduction in the scapular plane. These values were correlated with GI, AI, and CSA. RESULTS: Humeral head translation was positively correlated with GI (R = 0.828, P < .0001), AI (R = 0.539, P < .0001), and CSA (R = 0.964, P < .0001). Glenoid articular cartilage strain was also positively correlated with GI (R = 0.489, P = .0004) but negatively with AI (R = -0.860, P < .0001) and CSA (R = -0.285, P < .0473). CONCLUSIONS: The biomechanical shoulder model is consistent with clinical observations. The prediction strength of CSA is confirmed for humeral head translation and thus presumably for rotator cuff tendon tears, whereas the AI seems more appropriate to evaluate the risk of glenohumeral osteoarthritis caused by excessive articular cartilage strain. As a next step, we should corroborate these theoretical findings with clinical data.
BACKGROUND: Previous clinical studies have reported associations between glenoid inclination (GI), the acromion index (AI), and the critical shoulder angle (CSA) on the one hand and the occurrence of glenohumeral osteoarthritis and supraspinatus tendon tears on the other hand. The objective of this work was to analyze the correlations and relative importance of these different anatomic parameters. METHODS: Using a musculoskeletal shoulder model developed from magnetic resonance imaging scans of 1 healthy volunteer, we varied independently GI from 0° to 15° and AI from 0.5 to 0.8. The corresponding CSA varied from 20.9° to 44.1°. We then evaluated humeral head translation and critical strain volume in the glenoid articular cartilage at 60° of abduction in the scapular plane. These values were correlated with GI, AI, and CSA. RESULTS: Humeral head translation was positively correlated with GI (R = 0.828, P < .0001), AI (R = 0.539, P < .0001), and CSA (R = 0.964, P < .0001). Glenoid articular cartilage strain was also positively correlated with GI (R = 0.489, P = .0004) but negatively with AI (R = -0.860, P < .0001) and CSA (R = -0.285, P < .0473). CONCLUSIONS: The biomechanical shoulder model is consistent with clinical observations. The prediction strength of CSA is confirmed for humeral head translation and thus presumably for rotator cuff tendon tears, whereas the AI seems more appropriate to evaluate the risk of glenohumeral osteoarthritis caused by excessive articular cartilage strain. As a next step, we should corroborate these theoretical findings with clinical data.
Authors: Peter N Chalmers; Anthony A Romeo; Gregory P Nicholson; Pascal Boileau; Jay D Keener; James M Gregory; Dane H Salazar; Robert Z Tashjian Journal: Clin Orthop Relat Res Date: 2019-02 Impact factor: 4.176
Authors: Peter N Chalmers; Thomas Suter; Matthijs Jacxsens; Yue Zhang; Chong Zhang; Robert Z Tashjian; Heath B Henninger Journal: J Shoulder Elb Arthroplast Date: 2019-06-06