Structural Evolution of Nonoperatively Treated High-Grade Partial-Thickness Tears of the Supraspinatus Tendon

Background: High-grade partial-thickness rotator cuff tears (hPTRCTs) are frequently encountered in the shoulder. However, little information is available on the prevalence or timing of tear progression. Purpose/Hypothesis: The purpose was to prospectively evaluate the structural progression of hPTRCTs with a minimum followup of 1 year using magnetic resonance imaging (MRI). The hypothesis was that a substantial portion of hPTRCT patients would experience tear progression or evolution to a full-thickness rotator cuff tear. Study Design: Case series; Level of evidence, 4. Methods: Between May 2010 and December 2015, 362 patients were diagnosed with hPTRCT (tear involvement >50% of the mediolateral length of the footprint) of the supraspinatus and were treated nonoperatively. Among these patients, 81 underwent follow-up MRI at least 1 year after initial presentation, and these patients were included in the final analysis. Initial and follow-up MRIs were used to determine whether tears had improved, had not changed, or had progressed. A change in tear involvement of >20% was defined as a significant change. Patients were categorized as follows: (1) a decrease in tear involvement of >20% (improved), (2) an increase or decrease of <= 20% (no change), or (3) an increase in tear involvement of >20% (progressed). Demographic data and morphologic data were analyzed to identify variables related to tear progression. Among them, severity of tendinosis was graded using MRIs: grade 1 (mild tendinosis), mild focal increase in tendon signal; grade 2 (moderate tendinosis), moderate focal increase in tendon signal; and grade 3 (marked tendinosis), marked generalized increase in tendon signal. Results: At initial diagnosis, 23 were articular-side (28%) and 58 were bursal-side (72%) hPTRCTs. The study cohort was composed of 51 women and 30 men, and the mean patient age was 62.3 years (range, 41-77 years). Follow-up MRI was performed at a mean 19.9 6 10.9 months (range, 12-52 months). A significant change in tear involvement was observed at follow-up. In 13 patients (16%, 2 articular-side and 11 bursal-side tears), tears were classified as progressed (the progressed group); in 48 patients (59%), tears exhibited no change (the unchanged group); and in 20 patients (25%, 9 articular-side and 11 bursal-side tears), tears were improved (the improved group). Univariate analysis showed initial tendinosis grade was significantly different in the 3 groups (grade 1, 2, and 3: 5, 4, and 4 in progressed; 36, 11, and 1 in unchanged; 10, 8, and 2 in improved group, respectively, P = .007). Conclusion: Although progression of hPTRCT in the long term is uncertain, after 1-year follow-up with MRI, tears progressed in 16% of the tears in this study. Furthermore, some tears were healed or reduced in size, which indicates that decisions to undertake surgical repair at time of presentation may be excessive.