The term arthritis literally means inflammation of a joint, but is generally used to describe any condition in which there is damage to the cartilage. Damage of the cartilage in the shoulder joint causes shoulder arthritis. Inflammation is the body’s natural response to injury. The warning signs that inflammation presents are redness, swelling, heat and pain.
The cartilage is a padding that absorbs stress. The proportion of cartilage damage and synovial inflammation varies with the type and stage of arthritis. Usually, the pain early on is due to inflammation. In the later stages, when the cartilage is worn away, most of the pain comes from the mechanical friction of raw bones rubbing on each other.
Types of Arthritis
There are over 100 different types of rheumatic diseases. The most common causes of arthritis are osteoarthritis and rheumatoid arthritis.
Osteoarthritis: Osteoarthritis is also called degenerative joint disease. This is the most common type of arthritis, which occurs often in older people. This disease affects cartilage, the tissue that cushions and protects the ends of bones in a joint. With osteoarthritis, the cartilage starts to wear away over time. In extreme cases, the cartilage can completely wear away, leaving nothing to protect the bones in a joint, causing bone-on-bone contact. Bones may also bulge, or stick out at the end of a joint, and this is called a bone spur.
Osteoarthritis causes joint pain and can limit a person’s normal range of motion (the ability to freely move and bend a joint). When severe, the shoulder joint may lose all movement, making a person very disabled.
Rheumatoid Arthritis: This is an auto-immune disease in which the body’s immune system (the body’s way of fighting infection) attacks healthy joints, tissues, and organs. Occurring most often in women of childbearing age (15-50), this disease inflames the lining (or synovium) of joints. It can cause pain, stiffness, swelling, and loss of function in joints. When severe, rheumatoid arthritis can deform, or change, a joint.
Rheumatoid arthritis affects mostly joints of the hands and feet and tends to be symmetrical. This means the disease affects the same joints on both sides of the body (both the hands or both feet) at the same time and with the same symptoms. About two to three times as many women as men have this disease
Post traumatic arthritis: Any injury to the shoulder that may or may not be associated with a fracture or dislocation can predispose the shoulder to subsequent arthritis. The risk is highest with a fracture actually involving the articulating surfaces of the ball or socket of the shoulder joint. In some fractures of the upper end of the arm bone that are fractured into many pieces the blood supply to this portion of the bone may be affected leading to bone cell death. This condition is called Avascular necrosis of the humeral head and can be a cause of rapidly progressive post traumatic shoulder arthritis.
Cuff tear arthropathy:A tear of one or more of the tendons of the shoulder joint called the rotator cuff can cause a mechanical imbalance of the forces around the shoulder. This can lead to eccentric loading of the ball and socket joint and early wear and tear of the shoulder joint. This type of arthritis typically involves the upper back portion of the socket and the ball impinging onto the shoulder blade.
Instability Arthritis: A tear of one or more of the ligaments of shoulder joint or of the rim of tissue around the socket (labrum) following repeated shoulder dislocations or failed surgery for shoulder instability, can lead to a mechanical imbalance of the forces around the shoulder. This can lead to eccentric loading of the ball and socket joint and early wear and tear of the shoulder joint. This type of arthritis typically involves the centre or front of the socket.
Osteoarthritis is caused by the wearing out of the cartilage covering the bone ends in a joint. This may be due to excessive strain over prolonged periods of time, or due to other joint diseases, injury or deformity. Primary osteoarthritis is commonly associated with ageing and general degeneration of joints.
Secondary osteoarthritis is generally the consequence of another disease or condition, such as repeated trauma or surgery to the affected joint, or abnormal joint structures from the time of birth.
Rheumatoid arthritis is often caused when the genes responsible for the disease are triggered by infection or environmental factors. With this trigger the body produces antibodies, the defence mechanism of the body, against the joint and may cause rheumatoid arthritis.
There are several forms of arthritis and the symptoms vary according to the form of arthritis. Each form affects the body differently. Arthritic symptoms generally include swelling and pain or tenderness in joints for more than two weeks, redness or heat in a joint, limitation of motion of a joint, and early morning joint stiffness.
In an arthritic shoulder
- The cartilage lining is thinner than normal or completely absent. The degree of cartilage damage and inflammation varies with the type and stage of arthritis
- The capsule of the arthritic shoulder is swollen
- The joint space is narrowed and irregular in outline; this can be seen in an X-ray image.
- Bone spurs or excessive bone can also build up around the edges of the joint
Dr Bala will diagnose arthritis with a medical history, physical exam and X-rays of the affected part. Computed tomography (CT) scans and magnetic resonance imaging (MRI) scans are also performed to diagnose arthritis.
Dr Bala may prescribe anti-inflammatory medicine. He may recommend physiotherapy, which includes exercises and heat treatment. In some cases, a steroid injection into the joint can help.
In severe cases surgery may be suggested. The type of surgery will depend on your age and severity of the disease. In the elderly with severe arthritis, joint replacement usually gives good results. This is usually an excision of the damaged joint surface, and implantation of a partial shoulder replacement (shoulder hemicap), total shoulder replacement or a reverse shoulder replacement (joint replacement) depending on whether the rotator cuff tendons are intact or not, the age and physical demand of the patient and the dominance of the limb.
In cases of severe arthritis where there is bone loss at the back of the socket of the shoulder joint special techniques are needed for reverse shoulder replacement. These include 3D printing of the shoulder socket using a special CT scan to help design guides to help in the accurate placement of the shoulder replacement. Dr Bala is trained in the use of such Patient Specific Instrumentation (PSI). In other cases of severe arthritis, the CT scan is used to design a custom-made socket (Custom prosthesis for reverse shoulder replacement).
Dr Bala has been part of teams designing instrumentation for the use of computers in joint replacement surgery (navigated joint replacement) and his publication was presented at the Annual meeting of American Academy of Orthopaedic Surgeons (AAOS) in 2016. Dr Bala was part of one of the first few robotic joint replacements in the Asia pacific region in 2015.
Some of Dr Bala’s interests lie in complex shoulder replacements for tumours, fractures around shoulder replacements and revision shoulder replacements.
Dr Bala has also designed a novel technique to mould a cement spacer during surgery when treating infected shoulder replacements.
In rare cases where the shoulder arthritis is due to a nerve injury in the base of the neck, the only option for a painless shoulder is shoulder fusion (shoulder arthrodesis). This can be achieved with 2 perpendicular plates and bone graft taken from the waist.