I’m dealing with this such a condition right now.
I have at least 2 small, partial tears in my right rotator cuff. I’m in pain and have limited movement, although everything should heal over time and without surgery. I just need to follow a physical therapy program.
As for treatable conditions that were once death sentences, the anti-vaxxers would love to return to a time when people became gravely ill, perhaps died, from measles, mumps, rubella, polio, diptheria, tetanus, hepatitis A and B, pertussis, pneumococcal and meningococcal diseases, etc.