This narrative review covers press-fit humeral fixation in anatomic total shoulder arthroplasty and why the proximal humerus remodels after implantation. It compares standard, short, and stemless designs for stress shielding. It proposes a standardized way to describe implants and grade radiographic changes so future studies can be compared.
When you plan a press-fit anatomic TSA, remember that some stress shielding is unavoidable. Metal and bone have different elastic moduli, so by Wolff's Law the offloaded proximal humerus remodels in every press-fit case.
The variable you control is the canal-filling ratio. A larger-diameter stem grabs the diaphysis, offloads the proximal bone, and drives more shielding, so pick the smallest width stem that is stable.
Short and stemless designs keep load in the metaphysis and reduce proximal shielding, which matters for bone stock at future revision. Long-term survivorship data still exist mainly for standard stems, so this is a trade-off, not a settled win.
Do not overcall loosening on film. A symmetric radiolucent halo may be exposure artifact, and osteolysis usually signals polyethylene wear from the glenoid rather than the stem itself. Assess only by comparing immediate postop and current films taken with identical technique.
This narrative review covers press-fit humeral fixation in anatomic total shoulder arthroplasty and why the proximal humerus remodels after implantation. It compares standard, short, and stemless designs for stress shielding. It proposes a standardized way to describe implants and grade radiographic changes so future studies can be compared.
When you plan a press-fit anatomic TSA, remember that some stress shielding is unavoidable. Metal and bone have different elastic moduli, so by Wolff's Law the offloaded proximal humerus remodels in every press-fit case.
The variable you control is the canal-filling ratio. A larger-diameter stem grabs the diaphysis, offloads the proximal bone, and drives more shielding, so pick the smallest width stem that is stable.
Short and stemless designs keep load in the metaphysis and reduce proximal shielding, which matters for bone stock at future revision. Long-term survivorship data still exist mainly for standard stems, so this is a trade-off, not a settled win.
Do not overcall loosening on film. A symmetric radiolucent halo may be exposure artifact, and osteolysis usually signals polyethylene wear from the glenoid rather than the stem itself. Assess only by comparing immediate postop and current films taken with identical technique.