When a patient complains of pain in a joint, the arthritis specialist needs to figure out the exact location of the pain source. Is it due to something happening within the joint itself or is it due to adjacent structures such as the bone, ligaments, tendon, or bursa. Another possibility is that the pain could be referred meaning that the site that is causing the pain is not where the pain is.
An example of this latter situation is osteoarthritis of the hip that often causes pain in the knee. Also, a pinched nerve in the low back can also cause pain in the leg.
Arthritis pain is often accompanied by stiffness in the joint, pain with use, reduced range of motion, and occasionally swelling due to inflammation or fluid accumulation. The joint can be stiff after inactivity. For example, patients with osteoarthritis or rheumatoid arthritis will often get stiff if they sit for a long time. They can then loosen up by moving around.
Patients with an arthritic condition involving a joint have the "quartet" of arthritis: swelling, heat, redness, and pain.
The presence of fluid inside the joint (called an "effusion") can help establish the diagnosis.
Bone pain is most often due to fracture but may also occur due to infection (this is called "osteomyelitis"), or irritation of the bone surface, the periosteum. Periosteal problems can occur as a result of malignancy or conditions such as Paget's disease of bone, an unusual metabolic disease that causes bone deformity as well as bone pain.
Patients with tendonitis or bursitis usually have localized pain. Pain is aggravated by activity and relieved by rest. Getting a detailed history can provide clues to recent overuse that could be the trigger for the problem. Knowledge of anatomy can often pinpoint the source. Physical examination is critical because certain maneuvers can provoke or reproduce the pain thereby narrowing the diagnostic focus.
With bursitis, if there is significant inflammation, there will be swelling as well as pain and redness localized to the affected bursa.
Sometimes, though, it is difficult to separate a tendon issue from a bursal issue because the structures lie in such close proximity. Examples would be tendonitis/bursitis involving the shoulder or hip where this problem can be a difficult one to differentiate. Occasionally both the tendons and bursae can be affected.
Ligament problems are almost always due to trauma and the history as well as physical examination can establish the diagnosis. Confirmatory imaging studies such as magnetic resonance imaging and diagnostic ultrasound can be helpful here.