Monday, October 24, 2016

Too tight stem -> too high head -> rocking horse glenoid loosening

A stem that is tight in the diaphysis can result in a too high humeral component that can, in turn, lead to rocking horse loosening of the glenoid component as shown by the x-rays of the right shoulder below (middle aged man who presented to us with a painful stiff shoulder).

We revised this shoulder by removal of the loose glenoid component, smoothing the bony glenoid surface without bone grafting or glenoid component reimplantation and by replacing the humeral component with a smaller stem inserted at the desired height and fixed with impaction allografting.

A three months after surgery he has a comfortable, functional shoulder with radiographic evidence of glenoid healing and a centered humeral head in both the AP
and axillary views.

Comment: Impaction grafting of a small stem allows proper positioning of the stem. The management of a loose glenoid does not require bone grafting to fill the defect or reimplantation of a new glenoid component.