Macroscopic aspects of glenohumeral synovitis are related to rotator cuff tear severity

Background: The microscopic pattern of inflammatory mediators associated with rotator cuff pathology is well documented; however, little is known regarding the contemporary presence of macroscopic inflammatory joint involvement. Our aim was to investigate shoulder synovitis in a large group of patients with different sized rotator cuff tears (RCTs) and to correlate the degree of macroscopic inflammatory changes of the glenohumeral joint with RCT severity. Materials and methods: A total of 296 consecutive patients (169 F, 127 M; mean age ± standard deviation: 60.75 ± 7.91) submitted to arthroscopic RCT repair were enrolled. RCT was classified intraoperatively. Glenohumeral synovitis was investigated according to 4 parameters (Davis classification 2017: capsule color, villous projections, capillaries, and axillary recess). A total score was calculated, and a 3-grade severity scale was introduced. Statistics was performed. Results: Intraclass correlation coefficient (ICC) results show good to excellent reliability: capsule color (ICC: 0.95; 95% confidence interval [CI]: 0.89-0.99), villous projections (ICC: 0.90; 95% CI: 0.85-0.95), capillaries (ICC: 0.91; 95% CI: 0.86-0.95), and axillary recess (ICC: 0.55; 95% CI: 0.80-0.89).The synovitis total score was found to be 1.47 ± 1.16, 2.86 ± 1.84, and 3.99 ± 1.64 in patients with type I, II, and III RCTs, respectively. A significant difference was found between groups (P < .001). The prevalence of all the examined parameters was found to be significantly different between the different sized RCT groups (capsule color: P < .001; villous projections: P < .001; capillaries: P < .001; and axillary recess: P < .001). According to a 3-grade severity scale, the prevalence of absent, mild, and severe glenohumeral synovitis significantly differed between the RCT severity groups (P < .001). Conclusions: The present study demonstrated that synovitis is a constant finding of rotator cuff pathology; it is present in 75% of patients with RCTs and correlates with tear severity. Whether synovitis is the cause or effect of RCT is still questionable. Further studies are also needed to better understand its role as a pain generator, as documented in other diseases.