Before my dad was disabled (unrelated to this story, it was a car wreck), he worked at a factory doing a job (operating a huge industrial die-cutting machine) that required really repetative movement in his upper body (loading a stack of large, heavy plastic stock into the die cutter, then removing it once it's been cut, repeat x10,000) Had trouble with both of his shoulders, tendonitis and all that junk. Started out with cortisone shots and other non-invasive methods, which didn't really work. He had big-time surgery on the first shoulder, with a huge Frankenstein-style scar that looked like they sewed his entire arm back on there. The second shoulder, a few years later, was done using arthroscopic surgery -- meaning it was done through three small incisions (less than an inch)...those few years made a huge difference back in the late 80s/early 90s, so I'm sure yours will be way more high-tech.
Best of luck...hopefully you will feel decent afterwards and you can just chill and enjoy daytime TV, pain pills, maybe a stack of car (or other) magazines to read...enjoying your time off knowing you will be better than before soon. Both of my knees make a very loud grinding noise when I bend them, especially while I'm putting my weight on them. Who knows, I might go under the knife for some similar work on my knee.
Again, good luck, I hope everything goes smoothly!