The Gilbert Biomaterials and Regenerative Medicine Laboratory

RESEARCH: MODULAR DEVICE TESTING AND TEST METHOD DEVELOPMENT

Medical Device Testing and Test Method Development

Modular taper testing methods

Modular tapers in orthopedic implants are an important design element that assists surgeons in providing the best implant construct for the patient, eases revision and allows optimal materials to be used for different aspects of the implant design. These modular tapers have experienced significant concerns in the past related to Mechanically Assisted Crevice Corrosion (Gilbert et al, J Biomed Mat Res, 1993). Current bench-top testing of modular taper junctions have been changing significantly due to increased concern about the effects of surgeon, patient and implant design and materials on the taper fretting corrosion performance. As a result, the Gilbert lab has developed a number of novel test methods to evaluate modular taper mechanics and corrosion behavior. These tests include taper seating mechanics tests (Ouellette, et al., JOR, 2017) as well as incremental cyclic fretting corrosion tests (Mali and Gilbert, ASTM STP, 2016)

Figure: Seating mechanics analysis of head-beck modular taper locking.


Figure: Seating mechanics analysis of head-beck modular taper locking.





References:
Goldberg JR, Gilbert JL, “In-Vitro Corrosion Testing of Modular Hip Tapers”, Applied Biomaterials, 2003: 64B(2); 78-93.

Gilbert JL, Mehta M, Pinder B, “In-vitro Fretting Crevice Corrosion of Stainless Steel-Cobalt Chrome Modular Hip Stems: Effect of Material, Assembly and Offset”, J Biomed Mat Res (B), 2009 Jan: 88B (1);162-173.

Mali S, Gilbert JL, “Correlating Fretting Corrosion and Micromotions in Modular Tapers: Test Method Development and Assessment”, ASTM Special Technical Publication 1591 on Implant Modularity, Eds. Greenwald, Kurtz, Lemons, Mihalko, ASTM International, W. Conshohocken, PA, 2015, pp.259-282.

Mali SA, Singh V, Gilbert JL,”Effect of Mixed Alloy Combinations on Fretting Corrosion Performance of Spinal Screw and Rod Implants”, J Biomed Mat Res – Part B: Applied Biomat, Vol. 105, No. 5, July 2017, pp 1169-1177.

Ouellette E, Shenoy A, Gilbert JL, “The seating mechanics of head-neck modular tapers in vitro: Load-displacement measurements, design, moisture and rate effects”, conditionally accepted, J Ortho Res, August 2017, DOI: 10.1002/jor.23725.

Singh V, Shorez J, Mali S, Hallab N, Gilbert JL, “Materials dependent fretting corrosion in spinal fusion devices: Evaluation of onset and long term response”, in revision, JBMR-B.

Pierre D, Swaminathan V, Scholl L, TenHuisen K, Gilbert JL, “Effects of Seating Load Magnitude on Incremental Cyclic Fretting Corrosion in 12/14 Modular Taper Junctions” J Arthroplasty, in press.