Biomechanical evaluation of a novel glenoid design in total shoulder arthroplasty

Wang, Vincent M.; Krishnan, Ramaswamy; Ugwonali, Obinwanne F.C.; Flatow, Evan L.; Bigliani, Louis U.; Ateshian, Gerard A.

doi:10.1016/j.jse.2004.09.029

« Previous Next »Journal of Shoulder and Elbow Surgery
Volume 14, Issue 1, Supplement , Pages S129-S140, January 2005

Biomechanical evaluation of a novel glenoid design in total shoulder arthroplasty

Vincent M. Wang, PhD
- Leni and Peter W. May Department of Orthopaedics, Mount Sinai School of Medicine, New York, NY, USA
Ramaswamy Krishnan, MS
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
Obinwanne F.C. Ugwonali, MD
- Department of Orthopaedic Surgery and the Shoulder Service, Columbia-Presbyterian Medical Center, New York, NY, USA
Evan L. Flatow, MD
- Leni and Peter W. May Department of Orthopaedics, Mount Sinai School of Medicine, New York, NY, USA
Louis U. Bigliani, MD
- Department of Orthopaedic Surgery and the Shoulder Service, Columbia-Presbyterian Medical Center, New York, NY, USA
Gerard A. Ateshian, PhD
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
- Reprint requests: Gerard A. Ateshian, PhD, Professor of Mechanical Engineering and Biomedical Engineering, Columbia University, Department of Mechanical Engineering, 500 West 120th St, 220 SW Mudd, MC 4703, New York, NY 10027-6699

The amount of articular curvature mismatch providing optimal performance in total shoulder arthroplasty (TSA) is unknown. The objectives of this study were to quantify glenohumeral joint mechanics before and after TSA and to compare the performance of 3 glenoid components: (1) nonconforming, (2) conforming, and (3) a novel design featuring a conforming center extending into a nonconforming periphery. Six fresh-frozen cadaveric shoulders (mean age, 43 years) were mechanically tested on a custom apparatus by use of simulated muscle forces and a coordinate-measuring machine to determine joint kinematics. B-spline models of the natural and prosthetic articular surfaces were generated, and joint contact was computed by use of a proximity criterion. During both centered (P = .02) and eccentric (P = .05) loading protocols, glenoid contact migrated posteriorly in conforming implants. No statistical differences in kinematics and contact were found among the nonconforming design, the new design, and the natural joint. Therefore, adding a central region of conformity does not compromise the ability of nonconforming TSA components to reduce rim loading.