Reverse shoulder arthroplasty (RSA) is an
effective treatment for rotator cuff tears. Despite its advantages,
complications occur at a high rate. Complications requiring revision include a
high rate of base plate failure, 38% of which are due to instability. The
primary stability the base plate ensures is a crucial factor and, thus, is the
subject of much debate in clinical studies and biomechanical research. This
study is aimed to provide data that will contribute to the base plate¡¯s
pri-mary stability and glenoid longevity by clarifying the stresses at the
scapular fossa and base plate interface associated with elevation after RSA. A
3D finite element model was created from the DICOM data for the scapulohumeral
joint and SMR shoulder system. For loading conditions, 30 N was applied for
each posi-tion with abduction angles of 0, 45, 90, and 135 degrees. A
three-dimensional fi-nite element analysis was performed using the static
implicit method with LS-DYNA. The von Mises stresses in the scapular fossa were
found not to exceed the yield stress on the bone even after elevation to an
abduction angle of 135 de-grees after RSA. It is rough to uniformly compare the
yield stress and the von Mises stress, but it was inferred that the possibility
of fracture is low unless a large external force is applied. A maximum von
Mises stress showed 0 degrees of abduction, suggesting that the lowered
position is in a more severe condition than the elevated position. If better
improvement is desired, it may be necessary to devise ways to reduce the stress
on the upper screw.
%K Reverse Shoulder Arthroplasty %K Finite Element Analysis %K Yield Stress %K Glenoid %U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=131078