Shoulder Arthritis
The notes on this page are written as a source of information to both patients and health professionals. It is a general overview and its content should not be seen as direct medical advice. Further information regarding diagnosis and treatment specific to your condition can be made via a consultation with Dr Amaranath.
Shoulder Anatomy
The shoulder joint is a ball and socket joint consisting of the head of the humerus and the glenoid. Both of these surfaces are lined with articular cartilage and lubricated with synovial fluid. This allows for a smooth, pain free range of motion of the shoulder. The joint is surrounded by soft tissue structures such capsule, ligaments (thickening of the capsule), tendons and muscles. Each play a role in providing stability and movement to the shoulder through different daily activities.
What is Shoulder Arthritis?
Shoulder Arthritis is a degenerative condition of the shoulder were the articular cartilage is worn away leading to bare bone on bone contact between the humeral head and the glenoid. This contact between the two surfaces leads to pain and stiffness seen in shoulder arthritis.
What are the common causes?
Age related changes – The so called ‘wear and tear’ of the shoulder related to repetitive use over time. This slowly thins the cartilage out leading to a bare bony surface.
Inflammatory conditions – These include rheumatoid, psoriatic and other conditions that stimulate an autoimmune response leading to an inflammatory reaction within the joint that causes destruction of the articular cartilage and subchondral wear and painful arthritic changes.
Post traumatic – This is the sequelae of a fracture to either the proximal humerus or glenoid which has healed in a non-anatomic position leading to asymmetrical wear on either side of the joint and eventual joint wear and arthritis.
Other – These include other treatments and conditions not listed above which can affect the bone underlying the articular cartilage leading to its collapse (e.g. avascular necrosis of humeral head). They include chemotherapy, prolonged steroid use, infections (septic arthritis), etc.
What are the preferred Investigations/Imaging?
All patients with suggested arthritic changes of the shoulder joint should get the following imaging:
Plain X-Ray of the shoulder - This should include an Anterior/Posterior, Lateral and Axillary view.
CT scan of the shoulder - This is commonly used to asses bone stock and help plan the positioning of the implants. In most cases Dr Amaranath will obtain a CT scan with a 3D reconstruction and digital images that can be formatted to help develop a patient specific implant for your shoulder.
MRI Shoulder – This helps to identify the integrity of the rotator cuff tendon quality and identify they’re functionality. The information here will guide the type of treatment required and if a shoulder replacement is suitable then whether an anatomic or reverse implant would provide a better functional outcome.
What are the treatment options?
Non-operative – Once a diagnosis has been obtained the first line of treatment would include non-operative measures such as analgesia, corticosteroid injections, physiotherapy and activity modification.
Shoulder Arthroscopy – In early stages of OA there may be other pain generators in the shoulder (such as an inflamed biceps tendon, bursitis, arthritic acromioclavicular joint, etc) that can be addressed with keyhole shoulder arthroscopic surgery.
Anatomic Total Shoulder Replacement (ATSR) – Once non-operative measures have been exhausted and shoulder arthroscopy may not be an option, ATSR should be considered. The best functional outcome of this treatment options relies on intact rotator cuff tendons and musculature.
Reverse Total Shoulder Replacement (RTSR) – This is the alternative option when the rotator cuff is insufficient or absent (torn).
What’s is an Anatomic or Reverse Total shoulder Replacement?
Anatomic Shoulder Replacement (ATSR) – This form of joint replacement involves replacing the glenoid surface with a polyethylene insert and the humeral head with a Cobalt chrome or ceramic implant. This aims to maintain the anatomic relationship of the shoulder joint while replacing the worn articular surface.
Reverse Total Shoulder Replacement (RTSR) – The RTSR is a form of joint replacement which is used when there is an inadequate rotator cuff. The implant reverses the position of the humeral head and the glenoid cup, so that the sphere (head) is placed on the glenoid side and the cup is seated with the proximal humerus. This geometric change helps to improve the biomechanical function of the deltoid muscle which becomes the primary muscle in initiating and maintaining shoulder movement.
Patient Specific Implantation of Shoulder Replacements - In most cases your ATSR or RTSR will be planned using a digital reconstruction of your CT images to build 3D modelled guides that are specific for your shoulder. This will enable greater accuracy in implant positioning, which aims to increase the longevity of your shoulder replacement and improve your outcome.
What does the rehabilitation/recovery involve?
To find out more about rehabilitation and recovery after shoulder surgery please see our Rehabilitation Protocols here.