Schulterinfo.ch - Glenohumeral Joint - Synovitis
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Abstract
Glenohumeral synovitis can have various causes.
Clinically, the diagnosis of glenohumeral synovitis is almost impossible because the joint is virtually impalpable. Patients usually report deep-seated pain and there is a limitation of movement for both external rotation and internal rotation. Synovitis occurs frequently along systemic diseases.
In order to verify synovitis, synovial fluid analysis, rarely histopathological assessment, or imaging technologies are used.
Synovitis is treated with e.g. NSAIDs, corticosteroids and treatment of the underlying disease. Concomitant pathologies need to be addressed and treated accordingly.
Synovitis, or Synovialitis, is an inflammation of the lining of the joint capsule in synovial joints. The main characteristic of these joints is the presence of a joint cavity, in which synovial cells secrete the so-called synovial fluid. Macroscopically, synovitis impresses as a local synovial inflammation with hyperaemia and hypertrophy of the synovial villi [1].
Synovitides are an expression of inflammatory processes in the joint. Therefore, most inflammatory arthritides may be responsible in developing synovitis. However, certain diseases are accompanied by synovial inflammation more often such as:
- Rheumatoid arthritis (RA)
- Crystal arthropathies
- Frozen shoulder
- Infection
A compilation of underlying inflammatory diseases can be found in the table below. Practically all of these diseases can lead to inflammation in the glenohumeral joint.
Inflammation also occurs in the joint in the case of underlying degenerative diseases or in the context of a chronic or acute rupture of the rotator cuff. Analysis of the synovial fluid helps to differentiate between inflammatory and mechanical affection of the joint.
To this day, unclarity remains, whether synovitis is a process that further progresses chronic shoulder pathologies or is a result of chronic shoulder diseases [1]. However, studying pathological processes in RA has led to the discovery of increased inflammatory mediator production in inflamed synovial cells such as prostaglandins, bradykinin, TNF-α, interleukin-1, and interleukin-6 [2]. Hence, direct activation of afferent nerves and their sensitisation led to increased pain levels and lowered thresholds for otherwise harmless stimuli [2]. These and other mediators were also found in higher quantities in other chronic diseases mentioned above and were shown to recruit leukocytes [3]. Therefore, inactivation of these mediators depicts a potential target for treatment to prevent progression of synovitis. Specific treatment of the underlying disease, or synovitis, also prevents joint damage or cartilage damage and later secondary arthrosis.
As synovitis is widely regarded as an epiphenomenon rather than its own entity, literature about prevalence of synovitis is scarce. In a study with 167 patients suffering from different chronic shoulder diseases, 87.6% showed signs of microscopic synovitis [1].
Symptoms of synovitis are rather unspecific. However, affected joints show the two cardinal signs of synovitis: pain and restricted movement.
As a whole range of different diagnosis may coincide with synovitis, so that a comprehensive internal and rheumatological anamnesis is necessary.
Clinically, the diagnosis of glenohumeral synovitis is almost impossible because the joint is virtually impalpable. Patients usually report deep-seated pain and there is a limitation of movement for both external rotation and internal rotation. Although recently, a macroscopic assessment system has been proposed, where 3 parameters including villous hypertrophy, hyperaemia, and density were graded during arthroscopy [4]. Other authors attempted to further optimise criteria, yet some objectivity remains [5]. In rheumatoid arthritis, additional symptoms may include proliferation of the synovial membrane, imposing as an almost pathognomonic pannus [6].
Gold standard in verifying synovitis is a histopathological assessment [1]. In order to verify synovitis, synovial fluid analysis, rarely histopathological assessment, or imaging technologies are used.
Ultrasonography is used in questionable synovitis [6]. Particularly useful is the Doppler signal in the detection of synovial hyperaemia [6]. MRI with intravenous gadolinium-based contrast is used in a similar matter, where it can help identify and characterise synovitis with high sensitivity [6].
- Enthesitis
- Tendinitis
- Other glenohumeral diseases
As synovial inflammation may represent a circulus vitiosus by releasing pro-inflammatory mediators, which trigger the release of even more cytokines, it is important to combat an inflamed joint as early as possible [2]. In case of rheumatoid arthritis, several drugs were discovered which decrease the levels of inflammatory mediatiors [2].
Non-steroidal anti-inflammatory drugs as well as administration of corticosteroids seem to be beneficial in most cases of synovitis [2]. The focus is on the treatment of the underlying disease in addition to a glenohumeral local infiltration after relieving paracentesis.
Prognosis and progressive course of disease
The prognosis and further course depends on the underlying disease or the response to the specific therapy.
- Stahnke, Katharina, Lars Morawietz, Philipp Moroder, and Markus Scheibel. 2019. "Synovitis As A Concomitant Disease In Shoulder Pathologies". Archives Of Orthopaedic And Trauma Surgery 139 (8): 1111-1116. doi:10.1007/s00402-019-03152-4.
- Walsh, David A., and Daniel F. McWilliams. 2012. "Pain In Rheumatoid Arthritis". Current Pain And Headache Reports 16 (6): 509-517. doi:10.1007/s11916-012-0303-x.
- Scanzello, Carla R. 2011. "Pathologic And Pathogenic Processes In Osteoarthritis: The Effects Of Synovitis". HSS Journal 8 (1): 20-22. doi:10.1007/s11420-011-9228-x.
- Jo, Chris H., Ji Sun Shin, Ji Eun Kim, and Sohee Oh. 2015. "Macroscopic And Microscopic Assessments Of The Glenohumeral And Subacromial Synovitis In Rotator Cuff Disease". BMC Musculoskeletal Disorders 16 (1). doi:10.1186/s12891-015-0740-x.
- Davis, Daniel E., Mitchell Maltenfort, Joseph A. Abboud, and Charles Getz. 2017. "Classifying Glenohumeral Synovitis: A Novel Intraoperative Scoring System". Journal Of Shoulder And Elbow Surgery 26 (11): 2047-2053. doi:10.1016/j.jse.2017.06.003.
- Littlejohn, Emily A., and Seetha U. Monrad. 2018. "Early Diagnosis And Treatment Of Rheumatoid Arthritis". Primary Care: Clinics In Office Practice 45 (2): 237-255. doi:10.1016/j.pop.2018.02.010
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