Dr. Kenneth Brandt, clinical professor of medicine at the Kansas University Medical Center and professor of medicine at New York University has written this article on osteoarthritis as one section of a three-part series. The focus of this second article is diagnosis of this all too common disease.
Part one covered an update on new information about what is (and isn’t) osteoarthritis. The third part hasn’t been published yet. It will review current evidence on effective treatment for this condition.
It’s easy to assume as we get older that any joint pain must be osteoarthritis, often jokingly referred to as “Uncle Arthur” or “Arthur Itis”. But, in fact, there are many other possible causes of joint pain such as tumors, metabolic bone disease, osteomyelitis (infection), neurologic problems, and ligament instability.
How does the physician make the diagnosis? It’s a multi-step process from taking your history to performing a physical exam and then ordering appropriate tests. The physician knows to look for involvement of specific joints including the spine, hips, knees, thumbs, and middle joints of the fingers.
The most common symptoms reported by patients with osteoarthritis are joint pain, joint stiffness, and creaking, snapping, or cracking of the joints with movement, a phenomenon called crepitus. The pain and stiffness eventually cause loss of motion and function. Over time, joint deformity may occur as well. A noticeable limp may develop.
But no one wants a delayed diagnosis when deformities and loss of function could be prevented with early intervention. So the physician looks for other well-known tell-tale clues. For example, pain will full knee flexion (squat position) or with hip internal rotation point to arthritis. With osteoarthritis of the thumb and/or fingers, the patient may report difficulty opening jars, using a pinch grasp to hold a key, or grasping objects in general.
Morning stiffness that gradually gets better with movement in the first 20 to 30 minutes after getting out of bed or after sitting for too long is another red flag. In fact, so many patients experience this symptom, it has been given a name: the gelling effect or sensation.
Although osteoarthritis often affects both joints at the same time (e.g., both knees, both hips), it can develop in a single joint as a result of an accident or trauma some time in the past. The involved joint will start to get tender and the bones enlarge until the joint is clearly bigger looking than the uninvolved joint.
The physician will broaden his or her search for answers by ordering radiographs (X-rays) and lab tests. Blood values can offer information about the level of components in blood normally linked with inflammation.
Erythrocyte sedimentation rate, commonly referred to as ESR will be elevated with inflammation. C-reactive protein (CRP) is also increased. And antinuclear antibodies (ANAs) may rise. But the wise physician also knows these values increase with age or obesity. Careful interpretation of lab values is advised in older adults with joint pain. The presence of any or all of these lab values doesn’t immediately confirm a diagnosis of osteoarthritis.
Dr. Brandt cautions physicians to avoid what he calls diagnostic pitfalls. It is easy to misinterpret patients’ pain, deformity, X-rays, and lab results. An accurate diagnosis depends on the physician having an understanding of similarities (and differences) between signs and symptoms of osteoarthritis and other possible causes of joint pain.
A careful history and examination will aid the physician in making a differential diagnosis — in other words, recognizing osteoarthritis from neurologic conditions, other orthopedic problems (e.g., Dupuytrens disease, psoriatic arthritis or some other form of arthritis), and lung disease accompanied by bone or joint changes.
Joint pain or stiffness as a single symptom isn’t enough to know the patient has osteoarthritis. There is usually a collection of three or more of the common signs and symptoms described in this article along with joint changes seen on X-rays.
Making a correct diagnosis and beginning appropriate treatment early can change the course of this disease for many people. The information in this three-part series (including this second part on diagnosis) will guide all physicians in making clinical decisions regarding osteoarthritis.