Stress shielding of the proximal humerus

Last revised by Henry Knipe on 22 Mar 2023

Stress shielding of the proximal humerus after total shoulder arthroplasty (TSA) is a bone resorption around the proximal prosthesis stem.

According to Wolff's Law, bone remodels in response to stress. After a TSA or shoulder hemiarthroplasty, intact bone previously responsible for bearing mechanical load is replaced with a metallic humeral implant more rigid than intact cortical bone, which causes a change in the distribution of loading that leads to remodeling with resorption of bone in the affected regions. This bone volume reduction after arthroplasties leads to implant loosening and periprosthetic fracture.

Polyether-ether-ketone (PEEK) is an excellent alternative to titanium alloys. The stiffness of PEEK closely matches that of cortical bone and acts as a load sharing device, as opposed to a weight bearing device with the advantage that in dynamic areas of the body, such as the hands and feet, it prevents stress shielding after fracture fixation.

Radiographic signs of stress shielding are more present with press-fit components associated with increasing relative stem diameter.

The postoperative assessment is usually done using AP, Grashey and axillary views. The transition from good bone stock postoperatively, to osteopenia, and eventually collapse of the bone down to the prosthesis requires careful comparison with serial x-rays.

ADVERTISEMENT: Supporters see fewer/no ads

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.