Full-Thickness Rotator Cuff Tears Can Magnify Injury

Patients with a full-thickness shoulder tears had a greater risk for tear enlargement and progression of muscle degeneration, and a greater risk of pain development was associated with tear enlargement across all tear types, according to study results.

Researchers followed 224 patients with an asymptomatic rotator cuff tear in one shoulder and pain due to rotator cuff disease in the contralateral shoulder for a median of 5.1 years. Overall, 118 patients presented with initial full-thickness tears, 56 presented with initial partial-thickness tears and 50 were controls. The researchers calculated validated functional shoulder scores, as well as annual shoulder ultrasonography and clinical evaluations.

Results showed 49 percent of shoulders had tear enlargement, with a median time to enlargement of 2.8 years. Severity of the final tear type influenced the occurrence of tear-enlargement events, with 61 percent of full-thickness tears, 44 percent of partial-thickness tears and 14 percent of controls experiencing enlargement, according to the data. No relationships were observed between sex or patient age with tear enlargement.

Forty-six percent of patients developed new pain, with a greater risk of pain development associated with final tear type and onset of new pain associated with the presence of tear enlargement. New pain development occurred in 28 percent of controls, 46 percent of shoulders with partial-thickness tears and 50 percent of shoulders with full-thickness tears.

Tear enlargement was associated with progressive degenerative changes of the supraspinatus muscle, the researchers said. Supraspinatus muscle degeneration increased in 4 percent of the shxoulders with a stable tear compared with 30 percent of the shoulders with tear enlargement.

The researchers also found increase infraspinatus muscle degeneration in 9 percent of the shoulders with a stable tear vs. 28 percent of shoulders where the tear had enlarged.