Jo et al. BMC Musculoskeletal Disorders (2015) 16:272 DOI 10.1186/s12891-015-0740-x RESEARCHARTICLE Open Access Macroscopic and microscopic assessments of the glenohumeral and subacromial synovitis in rotator cuff disease Chris H. Jo1*, Ji Sun Shin1, Ji Eun Kim2 and Sohee Oh3 Abstract Background: Whereas synovitis is one of most common findings during arthroscopic surgery in patients with rotator cuff diseases, no study has investigated its characteristics. We propose a macroscopic assessment system for investigating the characteristics of synovitis. Methods: Fifty-four patients with a full-thickness rotator cuff tear undergoing arthroscopic rotator cuff repair with an average age of 62.5 ± 7.0 years were included. For the macroscopic assessment, 3 parameters, villous hypertrophy, hyperemia, and density, were measured and translated into grades in 3 regions-of-interest (ROI) in the glenohumeral joint and 4 ROIs in the subacromial space. For the microscopic assessments, 4 commonly used microscopic assessment systems were used. The reliability and association between the macroscopic and microscopic assessments were investigated. Results: The inter- and intra-observer reliability of all of the macroscopic and microscopic assessments were excellent. The severity of synovitis was significantly greater in the glenohumeral joint than that in the subacromial space, 1.54 ± 0.61 versus 0.94 ± 0.56 (p < 0.001). Synovitis varied with respect to location, and was generally more severe near the tear with the macroscopic assessment system. Meanwhile, none of the microscopic assessment systems demonstrated differences between different ROIs in both the glenohumeral joint and the subacromial space. Conclusions: The macroscopic assessment system for synovitis in rotator cuff disease in this study showed excellent reliability. It critically described characteristics of synovitis that microscopic assessment systems could not. Therefore, this system could be a useful tool for investigating synovitis in rotator cuff disease. Background United States, rotator cuff diseases lead to more than 4.5 Shoulder pain is reported to be the third most common million yearly physician visits, and over 300,000 rotator musculoskeletal disorder (16 %), after back (23 %) and cuff repairs per year are performed annually costing knee pain (19 %) [1–3], and it poses a substantial socio- more than $3 billion [11, 12]. economic burden of up to $7 billion in the United States Rotator cuff disease, or syndrome, represents a [4]. Approximately 40–50 % of patients will still have spectrum of rotator cuff pathologies from subacromial persistent pain even after 1 year of conservative treat- bursitis or tendinopathy, partial- and full-thickness tear, ment [5, 6]. Rotator cuff disease is the most common and rotator cuff arthropathy [13]. Subacromial bursitis cause of shoulder pain [7–9]. The prevalence of symp- and tendinopathy are also called as impingement syn- tomatic rotator cuff disease increases with age, occurring drome [14]. Meanwhile, it is well known that rotator cuff in approximately 2.8 % of those older than 30 years and disease involves not only the rotator cuff tendon but also in 15 % of those older than 70 years [7, 10]. In the rotator cuff muscles proximally [15], tissues of the glenohumeral joint and subacromial space, including * Correspondence: [email protected] synovium, ligaments, labrum and bursa in the middle 1 Department of Orthopedic Surgery, SMG-SNU Boramae Medical Center, [16, 17]; and the proximal humerus distally [18]. There- Seoul National University College of Medicine, Seoul, Korea Full list of author information is available at the end of the article fore, the authors suggest that rotator cuff disease needs © 2015 Jo et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Jo et al. BMC Musculoskeletal Disorders (2015) 16:272 Page 2 of 9 be regarded and treated as a “pan-joint disease” of the For validation of the macroscopic assessment system, in- shoulder similar to osteoarthritis [19]. ter- and intra-observer reliability tests were conducted Among the pathologic changes observed during rota- and associations with 4 commonly used microscopic as- tor cuff surgery, synovitis in the glenohumeral joint and sessment systems were analyzed. subacromial space is one of most frequently observed findings. As evidences in rheumatoid arthritis and osteo- ROI in the glenohumeral joint and subacromial space arthritis have shown that synovitis is associated with ex- The macroscopic and microscopic assessments were acerbated symptoms such as pain and degree of joint performed in the 3 ROIs of the glenohumeral joint (an- dysfunction [20, 21], and that it may promote cartilage terior, inferior, and posterior), and in the 4 ROIs of the degeneration, it is not difficult to assume that synovitis subacromial space (anterior, posterior, medial, lateral) may also have certain roles in rotator cuff disease. The for each patient (Fig. 1). first step in the management of synovitis in rotator cuff disease should be the establishment of a reliable method Macroscopic assessment of synovitis with arthroscopy for describing characteristics and monitoring the severity All procedures were performed in the lateral decubitus of synovitis. Except for some laboratory studies reported position under general anesthesia as previously described on synovial inflammation in the subacromial bursa as a [34]. After systematic exploration of the glenohumeral pain source [22–29], and as a factor for rotator cuff de- joint, the macroscopic assessment of synovitis in the an- generation [30], few studies have reported the character- terior, posterior and inferior ROIs was performed. Syn- istics of synovitis in rotator cuff disease [29, 31, 32]. ovial tissue was harvested from each ROI using a basket Microscopic assessment is usually considered the gold forceps. Then, the arthroscope was removed and redir- standard for analysis of synovitis in osteoarthritis [33]. ected to the subacromial space. A lateral working portal However, microscopic assessments might not be feasible and a posterolateral viewing portal were also established. in some clinics, would be hard to cover different regions Exploration of the subacromial space and the assessment in the joint and subacromial space, could not provide of synovitis were performed in the anterior, posterior direct information at the time of surgery, and has been medial and lateral ROIs, followed by harvesting of the reported to fail to detect a relationship between that and synovial tissues from each ROI. pain or disability in osteoarthritis [33]. In this sense, Macroscopic assessment of synovitis were performed whereas a macroscopic assessment system of the charac- with three complementary parameters with respect to teristics of synovitis in rotator cuff disease would be synovial villi in each ROI; hypertrophy, hyperemia, and helpful, no study has suggested any tool for macroscopic density. Only villi groups with 5 or more villi were evaluation of the characteristics of synovitis in rotator considered, and any isolated group with fewer than 5 cuff disease. villi was excluded. If arthroscopically different-looking Therefore, the purposes of the study were to propose groups of villi were simultaneously observed in the same and validate a macroscopic assessment system for syno- ROI, each was graded and the worse grade was selected. vitis in the glenohumeral joint and subacromial space in Hypertrophy was scored based on the size of the rotator cuff disease and to investigate the characteristics synovial villi; 0, < 2 mm; 1, 2 ~ 5 mm; 2, > 5 mm. of synovitis according to this system. Hyperemia represents the vascularity of synovial villi and was evaluated based on the redness of the villi; 0, Methods pale and transparent; 1, slightly reddish; 2, definitely red. Study design and patients If not apparent, hyperemia was determined with the har- This prospective cohort study was approved by our insti- vested synovial tissue. Density was assessed by the cover- tutional review board (SMG-SNU Boramae Medical age of synovial villi in each ROI; 0, < 1/3; 1, 1/3 ≤. After Center Institutional Review Board), and all patients pro- adding the scores for each parameter, the macroscopic vided informed consent. Eligible patients were those grade of synovitis was defined as follows; grade 0, 0; with a full-thickness rotator cuff tear and available tissue grade 1, 1–2; grade 2, 3; grade 3, 4. Macroscopic assess- samples from both glenohumeral and subacromial syno- ment of synovitis was conducted by two fellowship- vium harvested at the time of surgery. We excluded trained orthopedic surgeons independently. patients if they had impingement disease, a partial- thickness tear, rotator cuff arthropathy, infection, iso- Microscopic assessment of synovitis lated subscapularis tear, calcific tendinitis, retear, or no Biopsy specimens were immediately fixed in neutral available tissue samples. buffered 10 % formalin. Subsequently, the specimens We