How much can you move your arm following rotator cuff surgery done?

Rest. This is an answer best asked of your surgeon. Every surgeon has different protocols and different philosophies about motion after rotator cuff repairs. The rotator cuff pulls against the repair even when you sit in a sling/immobilizer completely braced. So it will never be completely protected. Some surgeons want physical therapy right away to keep motion. Others will wait 6-12 weeks.