I do "mini-open" procedures for rotator cuff surgery but keyhole surgery for stablisations. There are some short term benefits to keyhole surgery in the shoulder but in the longer term most studies show that open surgery for rotator cuff repairs remains the "gold standard". A mini-open procedure is where the cut on the shoulder is 5cm or less.
I am an experienced knee arthroscopist and the largest incision for my routine knee ligament (ACL) reconstructions is 4cm. This is to "harvest"/take the hamstring graft. The rest of the surgery is all keyhole.