rotator cuff disease and impingement

The shoulder trades stability for an enormous range of motion: the ball of the arm bone sits on a shallow, plate-like socket, held in place mostly by four wrap-around muscles whose tendons form a sleeve called the rotator cuff. Because the cuff is doing such delicate, constant work — centering the ball, lifting the arm overhead — it is one of the most common sources of shoulder pain, especially the dull ache that flares when you reach up, sleep on that side, or comb your hair.

Rotator cuff disease is an umbrella for the spectrum of problems with that tendon sleeve: irritation and tendinopathy, partial tears, and full-thickness tears, often alongside an inflamed bursa above it. 'Impingement' is the older idea that the cuff and bursa get pinched in the narrow space beneath the bony roof of the shoulder (the acromion) when the arm lifts — hence the painful arc in mid-range elevation. The current view is more about the cuff failing to keep the ball centered and the tissue degenerating with age and overload, so many clinicians now prefer the broader term 'subacromial pain syndrome'. Most cuff problems are not from a single dramatic injury but from years of use, and small partial tears are common and often painless in older shoulders.

This is why rehabilitation, not surgery, is the first-line treatment for most rotator cuff disease and impingement. A progressive exercise program that strengthens the cuff and the shoulder-blade muscles, and retrains how the shoulder moves, restores the centering and the painless space — and for many people works as well as surgery for symptoms. Surgery is reserved mainly for certain full-thickness tears, especially acute ones in younger, active people, or when a good rehabilitation trial fails.