The correct prosthesis head size can be measured on the retrieved humeral head. In cases of comminution an x-ray of the contralateral humeral head will be used to determine the appropriate size.
Note: The humeral head is not spherical. Measure the smallest diameter.
Note: If an x-ray is used to determine the size of the humeral head use a marker ball in order to compensate for any radiological magnification.
The correct size of the humeral head can also be assessed by direct comparison with a trial head.
Determine the posteromedial metaphyseal extension
The posteromedial metaphyseal extension (h) determines the implantation height of the prosthesis. It can be measured easily with a ruler.