A rotator cuff tear occurs when one or more of the four tendons that stabilize the shoulder joint detach from the humerus (upper arm bone). The rotator cuff enables a wide range of motion, including lifting and rotating the arm. While a standard full-thickness tear is a complete separation, a retracted rotator cuff tear is a more severe injury where the torn tendon edge has pulled significantly away from its original attachment site.
Defining Retraction: What Makes This Tear Different
Retraction refers to the displacement of the torn tendon end away from the humerus, moving inward toward the shoulder socket (glenoid). This displacement happens because the muscle belly, which remains connected to the tendon, is no longer opposed by the bone attachment. The muscle’s natural elastic tension causes it to shorten and pull the detached tendon stump back, similar to a rubber band snapping or recoiling when cut.
The degree of retraction is a primary factor determining the difficulty of surgical repair. This displacement is measured in millimeters or centimeters, quantifying the distance between the torn tendon edge and its footprint on the bone. Greater retraction requires the surgeon to stretch the tendon a longer distance to reattach it, which increases tension at the repair site and can compromise healing. Severe retraction can make the tissue entirely inelastic, making a traditional, tension-free repair impossible.
Immediate and Long-Term Consequences of Retraction
Tendon retraction initiates biological changes within the muscle that affect the shoulder’s long-term health and function. One immediate consequence is muscle atrophy, a reduction in the size and volume of the detached muscle. This wasting occurs because the muscle is no longer functioning across the joint or under normal load.
A long-term consequence is fatty infiltration, also known as lipomatous changes. This process involves the replacement of healthy, contractile muscle fibers with non-functional fat and fibrous tissue. Once a muscle undergoes significant fatty infiltration, the change is considered largely irreversible, meaning the tissue cannot be restored to its original quality, even if the tendon is physically reattached.
These degenerative changes make retraction a poor prognostic factor for a successful surgical outcome. If the muscle is too atrophied and infiltrated with fat, the reattached tendon may retear because the compromised muscle lacks the necessary strength and elasticity. Furthermore, severe retraction can lead to superior migration of the humeral head, where the ball of the joint shifts upward due to the loss of the rotator cuff’s stabilizing force.
Diagnosis and Classification of Retracted Tears
To accurately assess a retracted tear, medical professionals rely heavily on imaging techniques, especially Magnetic Resonance Imaging (MRI). While X-rays can indicate a long-standing tear by showing superior migration of the humeral head, MRI provides the detailed soft tissue visualization necessary to confirm the tear and evaluate muscle quality. The severity of retraction and degeneration is graded using standardized classification systems.
The Patte classification system describes the extent of tendon retraction, dividing it into stages based on how far the tendon stump has pulled back relative to the humeral head and glenoid. The Goutallier classification system grades the extent of fatty infiltration within the muscle belly. This classification ranges from Grade 0 (normal muscle) to Grade 4 (more fat than muscle), with higher grades correlating with reduced surgical success and higher retear rates.
Specialized Treatment Approaches
Treating a severely retracted tear is more challenging than repairing a non-retracted tear because the tissue is often under high tension and degraded. The primary goal is often arthroscopic repair, which involves specialized mobilization techniques to gently release scar tissue and stretch the tendon back toward its insertion site on the bone. If the tendon can be brought back without undue tension, it is reattached using strong sutures anchored into the humerus.
When retraction and muscle degeneration are too advanced for a direct repair, the surgeon must consider alternative, complex surgical options. One option is a tendon transfer, where a healthy tendon (such as the Latissimus Dorsi) is rerouted to take over the function of the torn rotator cuff muscle. Another approach involves augmentation, using biological or synthetic patches to bridge the gap between the torn tendon and the bone.
For chronic, irreparable tears involving significant joint damage or dysfunction, the final option is often a Reverse Total Shoulder Arthroplasty (RTSA). This procedure is a complete shoulder replacement that reverses the ball-and-socket anatomy of the joint. Reversing the anatomy allows the deltoid muscle to compensate for the loss of the damaged rotator cuff, restoring the patient’s ability to lift their arm.