Structural Characteristics Are Not Associated With Pain and Function in Rotator Cuff Tears: The ROW Cohort Study

BACKGROUND: Structural characteristics of rotator cuff tears are used in surgical decision making. However, data on the association of tear size with patient-reported pain and function are sparse. PURPOSE: To assess the association of tear size, fatty infiltration, and muscle atrophy with shoulder pain/function in patients with cuff tears undergoing operative and nonoperative treatment. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 67 patients with rotator cuff tears were recruited for this longitudinal cohort study. Patients were determined to have a cuff tear using clinical assessment and blinded magnetic resonance imaging review. The Shoulder Pain and Disability Index (SPADI) was used as a measure of shoulder pain and function. RESULTS: Tear size and thickness were not significantly associated with pain (SPADI pain score, 60.6 [95% CI, 49.8-71.5] for partial-thickness tear; 56.8 [95% CI, 42.8-70.7] for <2 cm full-thickness tear; 60.4 [95% CI, 51.7-69.0] for ≥2 cm full-thickness tear). Tear size and thickness were not associated with function (SPADI disability score, 42.7 [95% CI, 29.8-55.6] for partial-thickness tear; 37.6 [95% CI, 23.9-51.4] for <2 cm full-thickness tear; 45.1 [95% CI, 35.4-54.8] for ≥2 cm full-thickness tear). Fatty infiltration, muscle atrophy, and tendon retraction were also not significantly associated with SPADI pain and disability scores. A Mental Health Index score of <68 as well as age ≥60 years were significantly associated with a higher SPADI pain score. Female sex, increased number of comorbidities, Mental Health Index score of <68, and age <60 years were significantly associated with a higher SPADI disability score. CONCLUSION: In patients with rotator cuff tears undergoing operative and nonoperative treatment, pain and functional status were not associated with tear size and thickness, fatty infiltration, and muscle atrophy. Conversely, factors unrelated to cuff anatomy such as mental health, comorbidities, age, and sex were associated with pain/function. These findings have clinical implications during surgical decision making and suggest that pain and functional disability in patients with rotator cuff tears is multifactorial and should not solely be attributed to structural characteristics.