Imaging of shoulder arthropathies, p. 35-55 HR VOLUME 6 | ISSUE 1 J Musculoskeletal Imaging Pictorial Essay Imaging of shoulder arthropathies Maria Douka1, Evangelia E. Vassalou2, Athena P. Plagou3, Apostolos H. Karantanas4, 5 1 Department of Radiology, Athens Naval Hospital, Athens, Greece 2 Department of Medical Imaging, General Hospital of Sitia, Greece 3Ultrasound Unit, Private Radiological Institution, Athens, Greece 4 Departments of Radiology, Medical School - University of Crete and Medical Imaging, University Hospital, Heraklion, Greece 5 Advanced Hybrid Imaging Systems, Institute of Computer Science, Foundation for Research and Technology (FORTH), Herak- lion, Greece SUBMISSION: 7/5/2020 - ACCEPTANCE: 27/8/2020 Abstract The glenohumeral joint is a complex anatomical struc- patients without previous trauma or infection, radiol- ture characterised by hypermobility and large synovi- ogists should explore other underlying causes such as al and articular surfaces. Shoulder pain is a common crystal-induced arthropathy and Charcot’s neuropath- clinical complaint in adults, related to a wide spectrum ic arthropathy. Young adults may show early-onset os- of disorders, including synovial disorders such as in- teoarthritis as a complication of previous trauma and flammatory and crystal-induced arthropathies, rotator long-standing synovial osteochondromatosis. This pic- cuff disease and osteonecrosis. Primary degenerative torial review presents the pathophysiology, important osteoarthritis is rarely seen because the glenohumer- clinical aspects and the main imaging findings which al joint is non-weight-bearing. In the presence of ad- allow an accurate diagnosis of glenohumeral joint ar- vanced osteoarthritis of the glenohumeral joint in thritis. Key words Shoulder Joint/diagnostic imaging; Shoulder Joint/pathology; Magnetic Resonance Imaging; Joint Diseases/diagnosis; Radiography; Osteoarthritis/diagnostic imaging Corresponding Apostolos H. Karantanas, Medical School, University of Crete, Voutes, Heraklion Author, 71110, Greece, Email: [email protected] Guarantor 35 HR Imaging of shoulder arthropathies, p. 35-55 J VOLUME 6 | ISSUE 1 Introduction Shoulder pain is one of the commonest symptoms af- fecting the general population, with a prevalence of up to 30% [1]. Pain-generating sources are both the gle- nohumeral (GHj) and acromioclavicular (ACj) joints, as well as the rotator cuff (RC) and the capsuloligamentous structures [2]. Although radiologists maintain a high index of suspicion regarding RC disease and labral pa- thology, arthropathies are often overlooked, especially in the context of limited or lacking specific clinical in- formation. a A wide spectrum of differential diagnoses is described under the umbrella of shoulder arthropathy (Table 1) [3]. Although history and clinical examination have a vital role in the diagnostic algorithm, imaging is a cru- cial part of the diagnostic approach. Patients with GHj or ACj arthritis usually present with a gradually wors- ening pain. The ACj arthritis has typically localised pain which is exacerbated upon pressure over the joint. GHj arthritis on the other hand has a vague pain location, which typically worsens on active and passive motion b [1]. In shoulder arthritis, plain radiographs (PR) are the Fig. 1. Ultrasonography in rheumatoid arthritis. a) Posterior imaging modality of first choice. A standard antero- approach showing the glenohumeral joint effusion (thin ar- posterior (external rotation of the hand) view allows row) and the synovitis with the presence of “rice bodies” (open visualisation of the AC joint. The “Grashey” or posterior arrows). b) Posterior approach in another patient showing oblique anteroposterior view assesses the GHj. When PR synovitis with positive Doppler signal (arrow). HH: Humeral are inconclusive, MRI, due to its superb contrast reso- head; Gl: Glenoid. lution, allows for synchronous assessment of the osse- ous, cartilaginous and soft-tissue structures of the joint [4]. Despite the high prevalence of GHj arthritis, there 1a. Rheumatoid arthritis is scarce literature regarding the systemic description Early diagnosis of RA, which has a prevalence of about of the entities related to this condition [5, 6]. In this 1% in adults, is a challenge with huge potential bene- pictorial essay, we focus on arthropathies affecting the fit, before permanent disability is established [5]. RA is GHj which is a commonly underestimated topic among the commonest inflammatory arthropathy affecting the radiologists. Important pathophysiological and clinical GHj, showing no specific clinical symptoms and signs [5, aspects as well as key imaging findings, with emphasis 7]. The GHj is involved in one third of patients with RA on MRI, will be presented in an attempt to increase the at the time of diagnosis [2]. Pathophysiologically, GHj awareness of radiologists for early diagnosis and proper involvement shares the same pattern with peripheral patient management. small joints. Synovial hypertrophy represents the car- dinal feature which may harm the articular cartilage, 1. Inflammatory arthritis subchondral and bare bone and periarticular soft tis- Imaging modalities such as PR, MRI and ultrasound (US) sues [6]. have an integral role in diagnosing and monitoring of Radiographic abnormalities may be absent in 28% of inflammatory disorders of the GHj, including rheuma- patients with RA. However, they are usually evident in toid arthritis (RA) and seronegative spondylarthropa- 45% and 64% of patients at 5 and 19 years from the on- thies (SpA) [7]. set of symptoms [8, 9]. In addition, RC symptomatology, 36 Imaging of shoulder arthropathies, p. 35-55 HR VOLUME 6 | ISSUE 1 J Table 1. Causes of common and uncommon glenohumeral arthropathies Rheumatoid arthritis Inflammatory Seronegative arthropathies Infectious Septic arthritis HADD Crystalline CPPD arthropathies Gout Syringomyelia Neurological Erb’s disease Parkinson Toxic (corticosteroids, alcohol abuse or radiation) Avascular necrosis Haemoglobinopathies Metabolic diseases (Gaucher’s etc) PVNS Amyloid arthropathy Miscellaneous Synovial osteochondromatosis Haemophilic arthropathy Trauma leading to macroinstability Traumatic Overuse leading to microinstability Post-traumatic osteonecrosis of the humeral head Material failure or malposition Postsurgical Chondrolysis Altered biomechanics after capsulorrhaphy Arthropathy caused by displacement of the humeral head after a rotator cuff Degenerative tear with or without a tendon tear, is present in up to 75% relative to subcutaneous fat intraarticular tissue that of patients with GHj RA [9]. The earliest PR findings in- is non-displaceable and poorly compressible with po- clude soft tissue swelling and periarticular osteopaenia. tentially concomitant effusion (Fig. 1a) [17]. Presence Evolution of marginal erosions on the superolateral sur- of synovitis should prompt the use of power or colour face of the humeral head and in the medial aspect of the Doppler US to establish vascularity and, hence, inflam- surgical neck of the humerus typically develop within mation of the tissue (FIg. 1b). Bursitis and tenosynovitis 1-2 years from the onset of symptoms. Erosions of the of the long head of biceps tendon, being present in a articular surfaces and joint space narrowing (JSN) rep- significant percentage of patients, can also be depicted resent common end-stage findings [6, 8, 10-13]. by US. Hypoechoic or anechoic thickened tissue with/ The reported sensitivity of US, being similar to MRI, is out fluid within the tendon sheath, which is seen in two better than PR regarding the detection of early erosions perpendicular planes and which may exhibit Doppler in the humeral head [8, 10-15]. In this context, US is su- signal, defines tenosynovitis on US [17]. Distention of perb in detecting early cortical erosions located at the the subacromial-subdeltoid bursa due to synovial thick- superolateral aspect of the humeral head whereas MRI ening (>3 mm) with/out effusion represent US findings can better assess lesions located at the posterolateral suggestive of bursitis [16]. cortex [13, 14]. Regarding synovitis, it can be accessed Computed tomography (CT) has a limited role in RA of via US mainly by examining two locations, namely the the shoulder. The method is utilised mainly for assessing posterior and axillary recess [16]. Synovitis is depicted the osseous structures for the presence of large erosions as hypoechoic (infrequently isoechoic or hyperechoic) and JSN, when operative treatment is concerned [12]. 37 HR Imaging of shoulder arthropathies, p. 35-55 J VOLUME 6 | ISSUE 1 Fig. 2. A 49-year-old female patient with known rheumatoid arthritis of the wrists for 8 years and the left shoulder for 6 years. The oblique fat suppressed T2-w coronal (a) and fat suppressed contrast enhanced T1-w (b) MR images of the right shoulder show the joint effusion (thin arrows), the rice bodies (open thin arrows), the supraspinatus tendon tear with proximal retrac- tion (arrowhead) and the extensive synovitis within the subacromial-subdeltoid bursa (open arrows). Bone marrow hyperplasia is the result of known iron deficiency anaemia. Early rheumatoid arthritis in the right shoulder of a 60-year-old female patient. The oblique sagittal fat suppressed T2-w (c) and fat suppressed contrast enhanced T1-w (d) MR images show the joint effusion (thin arrows), the synovial thickening with rice bodies (thin open arrows), and the extensive synovitis (open arrows). MRI is the gold standard for the evaluation of in-