Apparatus and method for treating a body joint wound subsequent to surgical intervention. Before delivering requested media, the media service provider may determines whether the media rendering client device that requested the media is the type of device that is authorized to receive the request media. If loading succeeds, then signature data included in this program is read out. A printhead subassembly according to the present teachings can have a reduced number of parts and cost, simplified manufacture, and increased yields and lifetime compared to some other printhead subassemblies.