Shoulder Arthritis

 Shoulder arthritis can be classified as primary, which has no known/identifiable cause, or secondary to various pathologic processes including post-traumatic, post-dislocation, inflammatory or crystalline arthropathy, osteonecrosis, neuropathic (Charcot arthropathy) and rotator cuff arthropathy. More precisely, post-traumatic arthritis usually occurs as a result of articular surface incongruencies created by a fracture, while dislocation arthropathy results from the damage inflicted to the articular cartilage even after a single episode of dislocation. Cuff-tear arthropathy or rotator cuff arthropathy is attributed to progressive rotator cuff tendon insufficiency due to the presence of large or massive tears, which leads to proximal migration of the humeral head to the point where it abuts to the acromion, thus leading to articular wear. Osteonecrosis is the result of the blood supply to the humeral head being disrupted by a number of known traumatic (fractures, dislocations etc.) and non-traumatic causes (systemic corticosteroid therapy, alcohol, radiotherapy, bone marrow diseases etc.) thus leading to cell death, subchondral collapse and, finally, chondral damage and degeneration. Finally, in inflammatory or crystalline arthropathy the cause of joint degeneration and progressive arthritis is either a systemic autoimmune disease (e.g. rheumatoid arthritis) or the deposition of urate or other type of crystal complexes to the joint surfaces. 

Patients with shoulder arthritis often present with activity – related pain that subsides with rest and limitation to shoulder motion, especially external rotation. Some patients may even be unable to actively abduct their shoulder, a physical sign termed pseudoparalysis, which is the result of a grossly insufficient rotator cuff. Sleeping may also become increasingly difficult either due to the pain itself or due to the patient’s inability to find a comfortable position in which to sleep. Crepitus (i.e. audible sounds from the impingement of intra-articular structures) can alco occur when moving the joint. 

Imaging for shoulder arthritis comprises, firstly, a comprehensive set of common radiographs, which is usually enough to demonstrate the wear to the joint surfaces as well as any additional bony disturbances.  As an adjunct to radiographs, both computed tomography (CT) scans or magnetic resonance imaging (MRI) can be ordered, which in turn assist in evaluating preoperatively the morphology of the glenoid and the condition of the rotator cuff muscles and tendons, respectively. 

As far as the treatment of glenohumeral arthritis is concerned, this consists of both conservative as well as operative measures. The first line of treatment in the majority of cases is conservative and involves paracetamol and non-steroidal anti-inflammatory medications for pain control followed by physical therapy to improve shoulder range of motion and strength. These measures can also be complemented by intra-articular injections of a combination of local anesthetic agents and glucocorticoids, thus combining immediate with long-term pain control and regulation of the inflammatory process. Their effect, however, is temporary. In cases where the cause of the arthritis is an inflammatory arthropathy, rheumatologic consultation is essential, while available treatments can greatly modify the prognosis of the disease. 

Operative treatment of shoulder arthritis includes a variety of techniques which can be implemented after careful patient selection. In cases of mild to moderate arthritis with minimal bony changes, to which conservative measures have not proven to be helpful, arthroscopic joint debridement is a viable option which can “buy the patient time” before an arthroplasty procedure. In young patients, especially, this can be accompanied by the removal of hypertrophic synovium, osteophytes or intra-articular loose bodies and capsulotomies forming what is known as a comprehensive arthroscopic management (CAM) procedure. However, when advanced arthritic changes have already settled, arthroplasty is the indicated procedure. If the rotator cuff and deltoid muscles are intact and functioning, the preferred technique is the anatomic total shoulder arthroplasty (TSA), while in the event of a deficient rotator cuff, with a functioning deltoid nevertheless, the reverse shoulder arthroplasty (RSA) is preferred. In younger patients and select cases of osteonecrosis and rheumatoid arthritis with insufficient glenoid bone stock, a shoulder hemiarthroplasty can be performed. Finally, in the case of persistent/resistant infection, nerve paralysis, severe soft – tissue deficiency or recurrent instability after other treatments, the only viable solution is shoulder arthrodesis, a rarely used technique which effectively limits all shoulder motion and immobilizes the joint in an as functional as possible position for the patient to use the remainder of their arm’s joints. 

In conclusion, as is the case with the rest of the large joints of the human body, arthritis of the shoulder is a painful and function-limiting condition which affects many people. Although a variety of causes can lead to this disease, it is not as common as knee or hip osteoarthritis. When present, its diagnosis is fairly straightforward, while its treatment involves both non-operative as well as operative solutions, the most appropriate among which must be selected based on each patient’s individual characteristics.