Trauma in ortho is some of the best surgery. Long bones typically do very well, but can be complicated, especailly with open fractures - infections, non-unions, malunions being some of the hardest to deal with. Periarticular fractures are a fun challenge, and many do reasonably well. Early post-traumatic arthritis can be a real problem.
Though a "trained chimp" (please refer to pot-hole's insight above) could probably figure out how to assemble a scope, or how to put together the modular pieces of a major total joint - the real fun of these cases is found in the subtle differences each case offers. I suppose that any trained monkey would agree that all total knee replacements are the same; right?
Fianlly, it is true that orthopedists do the coolest procedures. Get into a good general practice, and your day in the OR could consist of scoping a few shoulders or knees, replacing a joint or two, fix a fracture, release a carpal tunnel or trigger finger, and still be home early in the day. Sure beats sewing valves and vessels into sick hearts, or looking at the poop-shoot from the inside through the back door...