Can a torn shoulder tendon (rotator cuff) get better with exercise?

Short answer

For pain and function, yes. With tears that wore through slowly, nearly 3 in 4 people went 10 years on exercise alone without surgery, and scores at 1 and 6 years did not differ from surgery. But the torn tendon did not reattach, and for tears up to 3 cm, surgery came out ahead after 15 years.

Can a torn shoulder tendon (rotator cuff) get better with exercise?
'Torn tendon → only surgery fixes it' — does this formula hold?
When people hear that the deep tendons of the shoulder (the rotator cuff) are torn, surgery is often the first thing on their mind. We checked studies that compared exercise alone with surgery at 1, 6 and 15 years.
452 people started with exercise
3 in 4 got by without surgery
452 people with a full tear but no injury behind it did 6-12 weeks of exercise therapy. Their scores improved at 6 and 12 weeks, and fewer than 25% chose surgery within 2 years. After 10 years, 27% had had surgery, and scores in those who did not have surgery did not drop over the 10 years.
Head to head with surgery
No difference in scores at 1 and 6 years
180 shoulders with a tear were split into exercise only, exercise plus bone-shaving surgery, and exercise plus tendon repair. At 1 year, shoulder scores rose 17.0, 17.5 and 19.8 points, with no difference. After an average of 6.2 years, they were 18.5, 17.9 and 20.0, still with no difference.
Pooled studies say the same
Surgery cut pain by just 0.87 more points out of 10
In an analysis that pooled 9 trials, the 3 trials (258 people) comparing surgery directly with exercise showed pain at 1 year (out of 10) of 1.6 with exercise, and 0.87 points lower with surgery. 87.3% of the exercise group and 94.3% of the surgery group said they were better.
But the torn tendon did not reattach
Over 15 years the tear doubled in length
103 people with tears of 3 cm or less were followed for 15 years. In the 26 who only exercised, the tear grew from 16.2 mm to 31.6 mm. At 15 years, surgery was ahead by 11.8 points on the shoulder score and 1.8 points out of 10 on pain. 15 of the 51 people in the exercise group later had surgery.
Size and time made the difference
1 cm tears showed no difference up to 6 years
The study of tears averaging 1 cm found no difference between surgery and exercise even after 6 years. The study of tears up to 3 cm found surgery pulling further ahead at 5, 10 and 15 years. Most of these studies covered small tears that wore through slowly, without an injury.
Bottom line: exercise fixed the pain
It did not reattach the torn tendon
With tears that wore through slowly, nearly 3 in 4 people went 10 years on exercise alone without surgery, and scores at 1 and 6 years did not differ from surgery. But exercise did not reattach the tendon, and for tears up to 3 cm, surgery was ahead after 15 years. Tendons torn suddenly in an injury were not what these studies mainly covered.