Power operated rotary knife with disposable blade support assembly

A method of debriding tissue utilizing a power operated rotary knife, the steps of the method comprising:

• a) providing a power operated rotary knife having a handle assembly and a blade support assembly coupled to the handle assembly, the blade support assembly including:
• a head portion;
• a blade housing portion extending from a distal end of the head portion, the blade housing portion including an annular ring and defining an annular groove in a bottom surface of the annular ring;
• an annular rotary knife blade permanently supported for rotation within the annular groove of the blade housing portion, the annular rotary knife blade having first and second axially spaced apart ends and an annular body extending therebetween, the annular body including a plurality of gear teeth at the first end and an annular blade section adjacent the second end;
• a drive gear mechanism rotatably supported within the head portion and including a plurality of gear teeth that mesh with the plurality of gear teeth of the annular body support section to rotate the annular rotary knife blade;
• and a retainer structure including a retainer rotatably supporting the annular body of the annular rotary knife blade within the annular groove, the retainer permanently affixed within the annular groove, wherein the retainer includes an upper wall, a first plurality of tabs and a second plurality of tabs, wherein the first plurality of tabs extend from the upper wall and contact a wall of the annular groove to affix the retainer within the annular groove and wherein the second plurality of tabs extend from the upper wall and define a bearing race to rotatably support the annular body of the annular rotary knife blade;
• b) using the power operated rotary knife to trim a layer of tissue;
• and
• c) removing the trimmed layer of tissue.