Osteoarthritis: Clinical sciences

Osteoarthritis is a degenerative disease of the joints, characterized by mechanical wear and tear injury to articular cartilage, resulting in bony and synovial damage. This chronic inflammatory process is mediated by cytokines, such as interleukin-1 and tumor necrosis factor-ɑ, and can affect any joint, but it most commonly affects the knees, hips, hands, and feet! Important risk factors for osteoarthritis include age, being biologically female, obesity, and joint injury. Now, in most cases, osteoarthritis is a clinical diagnosis, but sometimes, imaging with X-ray might be needed if the diagnosis is not clear.

Now, if your patient presents with signs and symptoms suggestive of osteoarthritis, first you should perform a focused history and physical examination. The patient will typically have a history of joint pain that began in an isolated joint, such as the knee; hand, like the interphalangeal joints; wrist; or feet, like the metatarsophalangeal joints. Also, your patient may describe joint pain that is worse with activity and have limited joint range of motion. They may also have minimal morning stiffness that typically lasts less than 30 minutes before improving.

Now, here’s a clinical pearl to keep in mind! If your patient has morning stiffness that lasts longer than 30 minutes, then consider inflammatory arthritis, such as rheumatoid arthritis instead. Another way to distinguish between the two is by the pattern of affected joints. Rheumatoid arthritis tends to be symmetric, meaning that joints on both sides of the body are equally affected, whereas patients with osteoarthritis are more likely to have asymmetric joint involvement.

On the other hand, the physical exam may reveal tenderness along the joint line, and crepitus, which is a grating sound or sensation when the joint moves. Your patient may also have pain with range of motion testing of the joint, a limited range of motion, as well as bony enlargement of the interphalangeal joints. Bony enlargement at the distal interphalangeal or DIP joints, is called Heberden nodes, whereas enlargement at the proximal interphalangeal PIP joints, is called Bouchard nodes.

If the history and physical exam findings are consistent with osteoarthritis, then no further testing is needed and you can diagnose osteoarthritis. But if the diagnosis is not clear, you should order an x-ray of the affected joint. If the X-ray findings are not consistent with osteoarthritis, you should consider an alternative diagnosis. But if the x-ray shows joint space narrowing, osteophytes, and subchondral sclerosis, you can diagnose the patient with osteoarthritis.