A rotary powered surgical tissue cutting instrument comprising an elongate tubular outer member including an open proximal end, a distal end, an internal passage, an opening in said distal end in communication with said internal passage, a main body length section having an external surface with an outer diameter, a proximal length section having an external surface with an outer diameter smaller than said outer diameter of said main body length section, an abutment surface between said external surface of said main body length section and said external surface of said proximal length section, said proximal length section extending proximally from said abutment surface to said proximal end of said outer member, said main body length section extending distally from said abutment surface to said distal end of said outer member; an elongate inner member rotatably disposed within said internal passage of said outer member, said inner member including a proximal end, a distal end, a cutting element at said distal end of said inner member exposed from said opening in said outer member to cut anatomical tissue when said inner member is rotated within said outer member; a powered surgical handpiece mounted to said proximal end of said outer member to maintain said outer member in a stationary position on said handpiece and mounted to said proximal end of said inner member to effectuate rotation of said inner member within said outer member, said handpiece including a housing having a front end with a front end surface and a chamber within said housing having an access opening on said front end surface, said proximal length section of said outer member extending through said access opening into said chamber of said housing with said abutment surface in abutment with said front end surface of said housing, said proximal end of said inner member extending proximally from said proximal end of said outer member to be rotatably driven within said handpiece; and an irrigation system including a first irrigation passage in said handpiece having an inlet port connectible with a source of irrigation fluid and having an exit opening on said front end surface, a second irrigation passage in said outer member including a groove in said external surface of said main body length section extending longitudinally along said main body length section from an entry opening of said groove on said abutment surface to an outlet opening of said groove near said distal end of said outer member, said entry opening of said groove being aligned with said exit opening to form an irrigation channel for the flow of irrigation fluid extending from said inlet port of said first irrigation passage to said outlet opening of said second irrigation passage, and a sleeve disposed over said main body length section of said outer member, said sleeve extending longitudinally from a rearward end of said sleeve to a forward end of said sleeve disposed adjacent said outlet opening of said groove, said sleeve being disposed over said main body length section with a snug fit while allowing communication through said outlet opening of said groove for discharge of irrigation fluid from said irrigation channel, whereby said irrigation channel is enclosed and sealed between said inlet port of said first irrigation passage and said outlet opening of said second irrigation passage.