Influence of joint kinematics on polyethylene wear in anatomic shoulder joint arthroplasty

• DOI: 10.1016/j.jse.2018.02.063
• Publication Date: 2018-04-23T13:16:38Z
• Authors: Steffen Braun; Stefan Schroeder; Ulrike Mueller; Robert Sonntag; Matthias Buelhoff; Jan Philippe Kretzer
• Keywords: Rotation; Shoulder Joint; Shoulder Prosthesis; Models, Biological; Prosthesis Failure; Weight-Bearing; Rotator Cuff; 03 medical and health sciences; 0302 clinical medicine; Arthroplasty, Replacement, Shoulder; Polyethylene; Humans; Range of Motion, Articular

Despite the positive results in total shoulder arthroplasties (TSAs), a higher revision rate is documented compared with total hip and knee replacements. Wear is the possible main cause of TSA failure in the long-term. This study investigated the effect of joint kinematics and the influence of the rotator cuff on the polyethylene wear performance in an anatomic TSA.Lifting a load of 2 kg with an abduction/adduction of 0° to 90° was simulated for 2 × 106 cycles as a primary motion using a fully kinematic joint simulator. A combined rotation in anteversion-retroversion of ±5° and ±10° was also simulated. The force in the superior-inferior direction and the axial joint compression were applied under force control based on in vivo data of the shoulder. A soft tissue restraint model was used to simulate an intact and an insufficient rotator cuff.The highest wear rate in the intact rotator cuff group was 58.90 ± 1.20 mg/106 cycles with a combined rotation of ±10°. When an insufficient rotator cuff was simulated, the highest polyethylene wear rate determined was 79.67 ± 4.18 mg/106 cycles.This study confirms a high dependency of the polyethylene wear behavior and dimension on the joint kinematics in total shoulder replacement. This can be explained by an increasing cross-shear stress on the polyethylene component. The results obtained indicate that additional combined kinematics are an indispensable part of wear tests on anatomic shoulder replacements.