I am scheduled for Reverse Shoulder Surgery on March 3. I am on my 3rd surgeon. The first two well-experienced refused to do my left shoulder which is very bad. The final surgeon is about 35 years old, not as much experience. However, he had one year of additional training and studying at Cleveland Clinic under the supervision of the country's 2 top surgeons for Reverse Shoulder.
You do a CT scan, which then the software will find the exact fit for your new shoulder parts. There is a guide made so the surgeon knows where to drill the holes. The guide is just for this person, from a medical manufacturer. From an engineering point of view, this gives the optimal opportunity to have the best way for success. As a retired engineer, I would not think of doing this type of operation any other way.
The other two only used X-ray and MRI scans, The second surgeon referred me to this surgeon and both never suggested a CT scan to place the parts. My surgeon said my shoulder was the worst shoulder he has seen. I feel more confident having him do it. If you need the ball and rotator cup
replaced, don't do it without a guide from the results of a CT scan.