Clinical depression can exacerbate the symptoms of knee arthritis beyond what is evident on X-rays, according to a new study from the Journal of Bone and Joint Surgery (JBJS). Patients with mild to moderate knee arthritis are especially affected by depression, the study notes.
"Knee osteoarthritis is a common cause of pain and impairment in older adults," said Tae Kyun Kim, MD, study author and director of the Division of Knee Surgery and Sports Medicine at Seoul National University Bundang Hospital's Joint Reconstruction Center. "Often, the level of arthritic symptoms reported by patients is much more severe than what is represented by X-rays, which can make it difficult for the doctor to treat.
"The results of this study indicate that depression can play a major role in the way patients experience the symptoms of knee arthritis, and that even when X-rays show the arthritis is not severe, patients with depression may report significant pain," Dr. Kim said. "The relationship between pain and depression suggests that both should be considered by physicians when treating patients with knee osteoarthritis, particularly in those with X-rays not indicating severe damage to the joint."
The study included 660 men and women aged 65 years or older who were evaluated for the severity of their knee arthritis on X-rays, as well as symptom severity. Patient interviews and questionnaires were used to assess coincident depressive disorders. The study was conducted as a part of the Korean Longitudinal Study on Health and Aging (KLoSHA).
As expected, the researchers found the levels of pain attributed to knee arthritis were higher in patients whose X-rays indicated greater joint damage; however, they also found depressive disorders were associated with an increase in pain in patients with mild to moderate knee arthritis, even when X-rays did not show significant joint damage.
"When evaluating the results of this study, the contribution of depression to knee osteoarthritis symptoms was almost as important as the damage indicated on X-rays," Dr. Kim noted.
Knee arthritis typically affects men and women over 50 years of age, and occurs most frequently in people who are overweight. Common symptoms include:
- pain or stiffness in or around the knee;
- swelling of the knee;
- limited range of motion when walking or moving the knee; or
- knee weakness or a feeling of instability.
In more severe cases, the knee joint may appear deformed, such as bowlegged or knock-kneed appearance, either bulging outward or toward the side of the leg. Knee replacement surgery is often performed in patients with severe symptoms.
Although studies have indicated depression is not uncommon among older adults, it remains largely underdiagnosed. According to the National Institute of Mental Health (NIMH):
- The risk of depression increases with other illnesses and when ability to function becomes limited.
- Estimates of major depression in older people range from 1 percent to 5 percent among those living in the community, to as high as 11.5 percent in hospital patients and 13.5 percent in those who require home healthcare.
- An estimated 5 million older adults have mild depression, which is often undiagnosed. Symptoms of depression may include:
- feelings of sadness or hopelessness;
- loss of interest in activities that were once enjoyed;
- change in appetite or sleep patterns;
- difficulty thinking and remembering; or
- frequent thoughts of death or dying.
"Despite the reported satisfactory outcomes of knee replacement surgery a percentage of patients still experience knee pain and impaired movement," said Dr. Kim said. "Sometimes pain and disability after surgery is medically unexplained, so in these patients screening for depression might be a very good option."
Disclosure: In support of their research for or preparation of this work, one or more of the authors received, in any one year, outside funding or grants in excess of $10,000 from Pfizer Global Pharmaceuticals (Grant No. 06-05-039) and Seongnam City Government in Korea (Grant No. 800-20050211). Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity.