A rotator cuff tear is a common injury involving one or more of the four tendons and muscles that stabilize the shoulder joint. Patients with a full-thickness tear must decide between surgical repair and non-operative management. Choosing not to repair the tear initiates a cascade of biological and mechanical changes that severely limit future function and treatment options. These consequences extend beyond simple pain, affecting the tendon, muscle, and the entire joint structure over time.
The Progression of Tear Size and Retraction
Leaving a full-thickness rotator cuff tear unrepaired typically causes the tear to worsen. Unlike injuries that stabilize naturally, constant forces from gravity and muscle use cause the tear to progressively enlarge. Studies show that a significant percentage of full-thickness tears increase in size over a few years if managed non-surgically.
As the tear grows, the disconnected tendon end experiences retraction. The muscle belly pulls the detached tendon end further away from its natural attachment point on the humerus bone. This retraction shortens the remaining tendon-muscle unit, moving it closer to the shoulder blade. Greater retraction requires more tension to pull the tendon back for surgical repair, making late-stage surgery more difficult or sometimes impossible.
Muscle Atrophy and Fatty Degeneration
Leaving a tear untreated leads to the degeneration of the muscle tissue. When the tendon detaches from its bony insertion, the corresponding muscle cannot generate tension effectively, leading to disuse and atrophy. Atrophy is a reduction in muscle mass, often visible on imaging as a smaller size compared to the healthy side.
The loss of muscle mass is accompanied by fatty infiltration, or lipomatous degeneration. In this condition, functional muscle fibers are slowly replaced by deposits of fat and fibrous tissue. This process is detrimental because it is largely irreversible. Muscle tissue replaced by fat cannot regain its ability to contract, even if the tendon is successfully reattached years later.
The severity of fatty degeneration determines the viability of future surgical repair and the likelihood of a successful outcome. High grades of fatty infiltration are associated with poorer functional results and a higher risk of re-tearing. The longer a tear goes unrepaired, the greater the irreversible damage to muscle quality, potentially making surgical intervention ineffective.
Long-Term Consequences: Cuff Tear Arthropathy
The ultimate structural endpoint of a chronic, massive, unrepaired rotator cuff tear is cuff tear arthropathy (CTA), a severe form of degenerative joint disease. The rotator cuff muscles normally center the ball of the humerus within the glenoid socket. Without this stabilizing force, the unopposed deltoid muscle pulls the humeral head superiorly.
This superior migration causes the humeral head to rub against the underside of the acromion, the roof of the shoulder socket. The abnormal friction and joint mechanics progressively erode the smooth articular cartilage covering the humeral head and the glenoid. The resulting bone-on-bone contact causes chronic pain, grinding, and a profound loss of function, often resulting in pseudoparalysis (inability to lift the arm away from the side).
At this advanced stage, the damage is irreversible, and treatment options become more complex. A standard shoulder replacement relies on a functional rotator cuff, which is absent in CTA. Instead, patients often require a reverse total shoulder arthroplasty (RSA). This specialized procedure switches the traditional ball-and-socket configuration. The RSA re-establishes a stable center of rotation, allowing the deltoid muscle to take over the failed rotator cuff’s function, providing pain relief and restoring some movement.