I have had the great fortune to start my Pilates career in a physical therapy practice. We had clients with Repetitive Stress Injuries (reporters injured from the work on the computer), back, knee and shoulder injuries. Pilates works on the entire body, not just the injured place on the body.
As with the journalists, Pilates worked on improving their posture and the foundations of support. When you have poor posture, it changes how you use your shoulders and arms. Try it. Slump and lift your arms up. Stand tall and feel how different your arms feel.