BACKGROUND: Prior rotator cuff disease natural history studies have focused on tear-related factors that predict disease progression within a given shoulder. The purpose of this study was to examine both patient- and tear-related characteristics of a painful rotator cuff tear that predict future pain development and functional impairment in a shoulder with a contralateral asymptomatic cuff tear.
METHODS: This was a prospective longitudinal cohort study of patients aged ≤65 years who underwent surgery for a painful degenerative rotator cuff tear and possessed an asymptomatic contralateral tear. Patients were followed up prospectively by shoulder ultrasound, physical examination, and functional score assessment. The primary outcome was change in the American Shoulder and Elbow Surgeons (ASES) score at 2 years. Secondary outcomes included the Western Ontario Rotator Cuff Index (WORC) score, Patient-Reported Outcomes Measurement Information System (PROMIS) score, Hospital Anxiety Depression Scale (HADS) depression and anxiety scores, and Veterans RAND-12 (VR-12) mental component score (MCS).
RESULTS: Sixty-five patients were included, with a mean follow-up period of 37 months (range, 24-42 months). In 17 patients (26%), contralateral shoulder pain developed at a median of 15.2 months (interquartile range [IQR], 10.5 months). No difference in age, sex, Charlson Comorbidity Index, or occupational demand was noted between patients in whom pain developed and those in whom pain did not develop. In the presenting painful shoulder, there was no difference in baseline tear size, muscle degeneration, or biceps pathology between groups. The mean baseline tear length (8.6 mm vs. 3.8 mm, P = .0008) and width (8.4 mm vs. 3.2 mm, P = .0004) were larger in asymptomatic shoulders in which pain subsequently developed compared with those in which pain did not develop. However, there was no difference in mean tear enlargement (P = .51 for length and P = .90 for width). There were no differences in baseline ASES, WORC, Patient-Reported Outcomes Measurement Information System (PROMIS), or HADS depression and anxiety scores between shoulders in which pain developed and those in which pain did not develop; however, patients in whom pain developed reported a lower baseline VR-12 MCS (53.3 vs. 57.6, P = .04). Shoulders in which pain developed had higher visual analog scale pain scores (2.9 [standard deviation (SD), 2.5] vs. 0.6 [SD, 1.0]; P = .016), lower ASES scores 75 [SD, 33] vs. 100 [SD, 11.6]; P = .001), and significant changes in all WORC scales with pain onset compared with those that remained asymptomatic. The study showed no significant difference in changes in the HADS anxiety and depression scores but found a significant increase in the VR-12 MCS in patients in whom pain developed (7.1 [interquartile range, 12.6] vs. -1.9 [interquartile range, 8.7]; P = .036).
CONCLUSION: In one-quarter of patients with painful cuff tears, pain developed in a contralateral asymptomatic cuff tear that resulted in a measurable decline in function within 3 years. Our analysis showed that only the baseline tear size of the asymptomatic shoulder was predictive of pain development. There were no tear-related features of the presenting painful rotator cuff tear or indices of mental health and physical function or occupational demand that were predictive of future pain development at short-term follow-up.