Osteoarthritis
Pathoanatomy: (The Problem)
The cartilage is a remarkable substance made up of complex molecules in combination with water arranged in a very specific pattern. As it ages it begins to dehydrate and this causes it to lose some of its important organization. This causes fibrilation and weakening such that it can no longer resist repetitive forces and friction as well. Eventually, it wears thin and becomes rough, with small particles breaking off and causing inflammation within the joint. In an attempt to deal with the damage the body forms bone spurs or osteophytes and the joint capsule often thickens. In the shoulder joint both of these secondary responses can be harmful, causing further damage and limitations.
Symptoms and Signs: (What it feels like)
Aching pain within the joint, especially with changes in the weather, is how many people describe the initial symptoms of osteoarthritis of the shoulder. At first the discomfort occurs predominantly with activities, but eventually it will be present even at rest or at night. Crepitance or a grating/grinding sensation may be present. Because of the anatomy of the muscles around the shoulder joint, swelling may not be appreciated as much as in other joints such as the knee. Some patients feel as if their shoulder is warm or hot–probably a result of the inflammation. There may be associated symptoms such as a rotator cuff tear causing weakness and a limited range of motion.
Natural History: (What happens with no treatment)
Like osteoarthritis in other areas of the body, this is a progressive problem. It slowly but progressively worsens, causing an increase in symptoms. Eventually the patient’s activities may become so limited that the pain actually decreases for a time due to inactivity. Occasionally we will see patients who note very little pain despite relatively severe arthritis, though this is the exception to the rule.
Treatment and Options:
Initial treatment includes rest, therapy to avoid stiffness, and if tolerated, anti-inflammatory medication to decrease inflammation and pain. Occasionally anti-inflammatory medicine is injected into the joint to more aggressively control inflammation.
Debridement using an arthroscope can, in some cases, improve function and decrease pain, especially if their is a mechanical problem like a rotator cuff tear or a “loose body” such as a broken off bone spur which is catching in the joint. Arthroscopy will not, however, reverse the osteoarthritic process.
Eventually, when the symptoms and progression can not be otherwise controlled, consideration can be made for joint replacement. This is a more extensive procedure, but it can have dramatic effects on improvement of function and symptoms.
Surgical Intervention:
Arthroscopy has been discussed elsewhere. Replacement of the shoulder joint requires removing the humeral head and replacing it with an internal prosthesis. The glenoid, or cup, is resurfaced with a plastic liner. An incision is made in front of the shoulder and the osteoarthritic bone is removed, allowing placement of the components. Some of the components are cemented in place.
After the surgery the patient remains in the hospital for 2 to 3 days. Immediately motion is started with the assistance of a therapist. Certain strength requiring activities must be avoided for 8 to 10 weeks. Some of the risks of shoulder replacement include infection, bleeding, nerve or blood vessel damage, fracture, loosening of the components, and need for re-operation. The long-term outlook is quite good in successful shoulder replacement. Most patients find dramatic decrease in their pain and a significant increase in their ability to do things requiring shoulder motion.