It is possible for the rotator cuff tendons to become less healthy because tendons have relatively little blood supply and can degenerate with the passage of time.
As a result, the rotator cuff tendons can tear either part way through the thickness of the tendon (partial thickness tear) or all of the way through the tendon (full thickness tear). Sometimes the surface of the tendons will be uninjured, but there can be an area of tearing within the tendon (intra-substance tear). If one or more of the rotator cuff tendons become torn, this will result in reduced shoulder function and can cause pain.
A large number of individuals in the general population, especially those in late middle-age and the elderly, have rotator cuff tears which develop over time with little symptoms. However, younger patients and some older patients with cuff tears may suffer symptoms, for which there is usually treatment available.
Partial thickness tears are often less symptomatic than full thickness tears but will become full thickness tears with time. Full thickness tears themselves can enlarge in size over time. Very large rotator cuff tears can be difficult to repair and massive rotator cuff tears can be or will become irreparable.
There is a risk that a small rotator cuff tear may become larger with time and eventually be too large to repair. However, some tendon tears do not enlarge in size with time. It remains difficult to predict if any individual’s cuff tear will become larger or more symptomatic with time.