The Effect of Humeral Short Stem Positioning, Humeral Head Contact, and Head Positioning on Bone Stress Following Total Shoulder Arthroplasty

Uncemented humeral stems cause stress shielding which result in bone resorption when used in total shoulder arthroplasty (TSA). Shorter length stems show a decrease in stress shielding, however the effect of humeral short stem positioning and humeral head contact and positioning on bone stress is currently not known, hence CT-based tools and Finite Element (FE) methods are used to quantify the effects of the mentioned variables on bone stresses after TSA.

Eight male cadaveric humeri were virtually constructed from computed tomography (CT) data, with a generic short humeral short stem as the implant.

The results of this work show that central stem positioning is preferred, and that for humeral head contact, full contact with the humeral resection results in the smallest changes in bone stress and bone volume with resorption potential. For humeral head position, tradeoffs in terms of cortical and trabecular bone loading were observed for both positions investigated

Keywords: Total shoulder arthroplasty; Humeral component; Hemiarthroplasty; Short Stem Implants; Joint Reconstruction; Finite Element Analysis; Stress Shielding; Bone Resorption

Year	Entry
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Year

Entry

2006

Ramos A, Simões JA. Tetrahedral versus hexahedral finite elements in numerical modelling of the proximal femur. Med Eng Phys. November 2006;28(9):916.

1993

Rho JY, Ashman RB, Turner CH. Young's modulus of trabecular and cortical bone material: ultrasonic and microtensile measurements. J Biomech. February 1993;26(2):111-119.

2018

Synnott S. The Effect of Implant Girth and Implant Collar on the Degree of Bone to Implant Contact and Bone Stresses in the Proximal Humerus [Master's thesis]. University of Western Ontario; 2018.

1997

Prendergast PJ. Finite element models in tissue mechanics and orthopaedic implant design. Clin Biomech (Bristol, Avon). September 1997;12(6):343-366.

1986

Wolff J. The Law of Bone Remodelling. Maquet P, Furlong R, trans. New York, NY: Springer; 1986.