A SPECIALIZED SYSTEM FOR IN VITRO TEST OF ANATOMIC GLENOIDS BASED ON ASTM F2028-14

Glenoid loosening, primarily induced by the “rocking horse” phenomenon from humeral head load on the glenoid rim, is the foremost complication and cause of failure in anatomic total shoulder arthroplasty. The dynamic load exerted by universal fatigue testing machines significantly deviates from the standard ASTM F2028-14 in the rocking test. To accurately conduct the in vitro loosening test on anatomic glenoids, a specialized system and customized test methods are developed to achieve anatomic glenoid rocking and subluxation tests. The horizontal and vertical loading can be achieved synchronously or asynchronously by two self-developed high-performance electromagnetic linear motors. In addition, the subluxation tests on anatomic glenoids are verified by finite element simulation. The results show that the subluxation load and translation of anatomic glenoids in the subluxation tests are consistent with those in numerical simulations. The error of the applied axial force in the rocking tests is only 5[Formula: see text]N, strictly meeting the standard of ASTM F2028-14. During the rocking tests, the system runs smoothly and the software works well, indicating the feasibility of the in vitro shoulder joint test system. This study provides an approach to accurate dynamic evaluation of glenoid loosening or disassociation.