Patterns of tear progression for asymptomatic degenerative rotator cuff tears.

BACKGROUND: The purpose of this study was to examine patterns of rotator cuff tear size progression in degenerative rotator cuff tears and to compare tear progression risks for tears with and without anterior supraspinatus tendon disruption. METHODS: Asymptomatic full-thickness rotator cuff tears with minimum 2-year follow-up were examined with annual shoulder ultrasound examinations. Integrity of the anterior 3 mm of the supraspinatus tendon determined classification of cable-intact vs. cable-disrupted tears. Tear enlargement was defined as an increase of 5 mm or more in width. Tear propagation direction was calculated from measured changes in tear width in reference to the biceps tendon on serial ultrasound examinations. RESULTS: The cohort included 139 full-thickness tears with a mean subject age of 63.3 years and follow-up duration of 6.0 years. Ninety-six (69.1%) of the tears were considered cable intact. Cable-disrupted tears were larger at baseline (median, 19.0 mm vs. 10.0 mm; P < .0001) than cable-intact tears. There was no difference in the risk of enlargement (52.1% vs. 67.4%; P = .09) or time to enlargement (3.2 vs. 2.2 years; P = .37) for cable-intact compared with cable-disrupted tears. There was no difference in the magnitude of enlargement for cable-intact and cable-disrupted tears (median, 7.0 mm vs.9.0 mm; P = .18). Cable-intact tears propagated a median of 5 mm anteriorly and 4 mm posteriorly, whereas cable-disrupted tears propagated posteriorly. CONCLUSIONS: The majority of degenerative rotator cuff tears spare the anterior supraspinatus tendon. Although tears classified as cable disrupted are larger at baseline than cable-intact tears, tear enlargement risks are similar for each tear type.