The diagnosis of a torn rotator cuff—the group of four tendons and muscles surrounding the shoulder joint—begins with a structured approach that progresses from a clinical evaluation to advanced imaging. A tear often causes significant pain, especially at night or with overhead movement, and noticeable weakness that can limit daily activities. Since many other shoulder conditions mimic these symptoms, the diagnostic process involves combining a detailed patient history with specific physical tests and is then confirmed by imaging technology.
Initial Clinical Assessment
The diagnostic journey starts with the medical history, where the healthcare provider gathers information about the mechanism of injury, such as a specific fall or chronic overuse from repetitive activities. Details regarding the duration, location, and nature of the pain are recorded, including whether it is worse with certain movements or at rest. The provider also checks for referred pain originating from the neck, which can mimic shoulder pain, by checking for cervical spine involvement.
The preliminary physical examination involves observing the shoulder for muscle atrophy, particularly in the supraspinatus and infraspinatus muscles. The provider checks both active and passive range of motion (ROM) to determine how far the patient can move the arm independently versus how far the provider can move it. Tenderness is evaluated by gently pressing on different parts of the shoulder to pinpoint the source of discomfort. These initial steps establish suspicion for a rotator cuff tear and direct specialized testing.
Specific Physical Examination Maneuvers
Following the initial assessment, the healthcare provider uses specific maneuvers to isolate and test the strength and integrity of the individual rotator cuff tendons.
Tests for Specific Tendons
- The Empty Can Test (Jobe’s Test) assesses the supraspinatus tendon, the most commonly torn. The patient resists a downward force with the arm elevated to 90 degrees and internally rotated; pain or significant weakness indicates a positive result.
- The Drop Arm Test, also for the supraspinatus, suggests a full-thickness tear if the patient cannot slowly lower their arm from a 90-degree abducted position.
- The Lift-Off Test or the Belly Press Test assesses the subscapularis tendon (primary internal rotator). The Lift-Off Test requires the patient to place the hand behind the back and attempt to lift it away, with an inability to do so suggesting a tear.
- If internal rotation is limited, the Belly Press Test is used, noting weakness if the patient cannot maintain pressure while pressing the palm into the abdomen.
- The External Rotation Lag Sign evaluates the infraspinatus and teres minor (primary external rotators). The provider passively rotates the arm outward and then asks the patient to hold the position, with the arm drifting back toward the body indicating weakness.
Finally, tests like the Neer’s Test and Hawkins-Kennedy Test are performed to check for impingement, a common finding where the tendons are squeezed in the joint space, causing pain.
Confirmatory Diagnostic Imaging
While the physical examination suggests a tear, diagnostic imaging is necessary to confirm the diagnosis, determine the tear’s size, and plan for treatment.
X-rays are typically the first imaging test ordered, but they cannot show the soft tissues of the rotator cuff. The main purpose of the X-ray is to rule out other problems, such as arthritis, fractures, or bone spurs, which can narrow the space available for the tendons.
Ultrasound is an inexpensive, convenient, and accurate screening tool, especially for identifying full-thickness tears. This imaging uses sound waves to create real-time images of the tendon structure, allowing dynamic assessment during movement. However, the accuracy of the ultrasound depends on the skill and experience of the technician.
Magnetic Resonance Imaging (MRI) is considered the gold standard for soft tissue evaluation because it provides the most detailed images of the tendons, muscles, and surrounding structures. An MRI accurately shows the size and location of a tear, differentiates between partial and full-thickness tears, and evaluates the condition of the muscle tissue. For enhanced detail, an MR Arthrogram (MRA) may be used, which involves injecting a contrast dye into the joint space before the scan to highlight smaller tears.
Understanding Tear Severity and Classification
Once imaging confirms the injury, the rotator cuff tear is classified based on its severity and extent of damage. A partial-thickness tear means the tendon is damaged or frayed but remains partially attached to the bone. These tears are classified by location—articular (undersurface) or bursal (upper surface)—and the percentage of tendon thickness involved, often categorized as less than or greater than 50%.
A full-thickness tear involves the complete separation of the tendon from its attachment to the bone, creating a gap in the tissue. Full-thickness tears are classified by size: small (less than 1 cm), medium (1 to 3 cm), large (3 to 5 cm), or massive (greater than 5 cm or involving multiple tendons). Classification also considers the degree of tendon retraction and the amount of fatty infiltration or atrophy in the associated muscle, which is visible on the MRI and affects the chance of a successful repair.