Had both of them done. Both injuries resulted from falls. Complete tear on the left, partial but nearly complete on the right. Also had to have right bicep reattached surgically.

The first step is probably imaging just to be sure what you're dealing with. The joint may need some general cleanup as well...mine did. After that, the surgery is no big deal. It's the rehab. Like has been mentioned your shoulder will likely be immobilized for several weeks. Then it's PT and rehab. Do it religiously. Ultimately, both my shoulders are as good as new post surgery. I had issues with scar tissue in both after surgery. I hit a wall in PT and both times it was scar tissue build up. Doc said I was just prone to it. The left shoulder required a 2nd surgery to remove it. The right required a 'manipulation'. The put you under and move your shoulder to it's limits to break/tear up the scar tissue. After I woke up from the manipulation I literally walked across the clinic parking lot to the PT place and did my PT. It took 19 months after surgery to get back to work after the first injury. It 'only' took a year the second time. It's a long process but was definitely worth it to me.