Introduction
Rotator cuff tears can cause subacromial/subdeltoid bursal effusion. Bursal effusion may be associated with shoulder pain or symptoms due to increased inflammatory cytokine expression, but the influence of bursal effusion on patient reported outcome is unclear. In addition, factors associated with bursal effusion in individuals with rotator cuff tears has not been investigated. Therefore, this study aims to determine factors associated with bursal effusion and their effect on patient reported symptoms and function.
Methods
A total of 106 individuals (mean age, 60.2 ± 9.9 years; 50 female) who had a symptomatic isolated tear of more than 50% partial- or full-thickness of the supraspinatus tendon confirmed by ultrasound were prospectively enrolled. All individuals participated in a personalized 12-week exercise therapy program. Bursal effusion was evaluated at the time of enrollment and 1 year after the initiation of exercise therapy and was operationally defined as the presence of more than 2 mm of fluid thickness within the bursa as determined by ultrasound. Factors associated with the presence of bursal effusion included age, height, BMI, hand dominance, onset of shoulder pain, history of smoking, working status (current or retired), symptom duration (>3 months or <3 months), tear size and thickness (partial or full), and the Western Ontario Rotator Cuff Index (WORC) score at the time of enrollment. Variables were compared between individuals with vs without bursal effusion using the chi-square tests for categorical variables and the independent-samples t test or Mann-Whitney U tests for continuous variables. Additionally, multivariate analysis with a backwards stepwise technique was performed using variables with P < 0.10 during the univariate analysis. At 1 year follow up, ultrasound examination and WORC score were available in 85 individuals. WORC scores at 1 year were also compared between individuals with bursal effusion both at baseline and 1 year follow up and those without effusion both at baseline and 1 year follow up using the Mann-Whitney U test. Statistical significance was set at P < 0.05.
Results
More than 2 mm of thickness of fluid at bursa was found in 31 individuals at baseline. Older age, history of smoking, working status, and symptom duration were significantly associated with the presence of bursal effusion at baseline in the univariate analysis (p < 0.001, p = 0.002, p = 0.042, p = 0.039, respectively). Other variables including the WORC scores were not significantly associated with bursal effusion. The multivariate analysis demonstrated that age and history of smoking were significantly associated with the presence of bursal effusion (p = 0.003, p = 0.010, respectively). WORC scores at 1 year follow up was lower in 15 individuals who had bursal effusion both at baseline and 1 year follow up compared to 58 individuals who had no bursal effusion both at baseline and 1 year follow up (79.5 ± 24.9 vs 91.2 ± 12.3, p = 0.047).
Conclusion
Persistent bursal effusion was associated with inferior patient-reported symptoms and function as evidenced by worse WORC scores.