One of the most common forms of arthritis is known as osteoarthritis, which affects over 30 million people in the United States alone. Also known as degenerative joint disease, it tends to affect people older in age or those with joint injuries. In most cases, it is the joints that are severely affected by osteoarthritis, including those in the hips, knees, fingers, and spine.
Osteoarthritis is a progressive disease that will lead to the overall deterioration of joint cartilage as well as the formation of bone spurs at the joint edges. Synovial fluid and cartilage are designed to create a low friction transition between the ending of the bones. However, once cartilage begins to lose its elasticity, the movement in the joints will become less fluid. In some cases, the cartilage will completely disappear, allowing the bone ends to rub together. This can lead to joint pain that is either chronic or intermittent throughout the day or night, as well as fragments of bone and cartilage in any remaining synovial fluid, which over time can lead to loss of coordination and mobility.
It is rare to see individuals under the age of 40 years old with osteoarthritis. More males than females will be diagnosed with osteoarthritis before the age of 45; however, it is more common in females after the age of 45. Regardless, it is typically more women, mainly elderly women, who will develop osteoarthritis. While it is believed that it is generally related to menopausal hormone loss, it is not yet fully understood why this is the case.
Also, athletes who have sustained multiple joint injuries over their career may be affected by osteoarthritis. The primary cause for this is purely mechanical in nature, due to joint damage that has been caused by excessive weight-bearing activities or running. An example of this would be how recreational runners are more prone to hip osteoarthritis, which tends to be the reverse for professional runners. It should be considered that any significant injury to ligaments, tendons, joints, or bones may lead to an increased risk of osteoarthritis. Also, specific heavy weight-bearing activities and repetitive motions throughout several occupations and leisurely activities may contribute to the development of osteoarthritis.
While it is a rare, osteoarthritis may be due to chemical, genetic, or metabolic variables. Specific studies have shown that 50% of all hip and hand cases were due to a positive family history of osteoarthritis. Also, anatomic misalignments and muscle weaknesses may lead to increased development of osteoarthritis.
Studies have shown that the expected number of cases may double in the year 2020 due to the general prevalence of obesity and the global population, as well as the increased lifespan. Individuals with an increased body weight live with significant stress on the knees, which leads to overbearing stress on the knee joints.
The overall goals of specific medical tests are to help distinguish osteoarthritis from other causes of joint pain as well as other forms of arthritis and monitor any side effects due to various treatments.
In many cases, blood testing is generally not useful in the diagnosis of osteoarthritis. Typically, physicians will diagnose an individual by getting their family history, performing x-rays, physical exams as well as an examination of synovial fluid from the affected joint. Other tests may be ordered to help rule out other conditions and evaluate the individual’s health, including:
- Cyclic citrullinated peptide antibody and Rheumatoid factor which are used in the diagnosis of rheumatoid arthritis and helps to differentiate it from osteoarthritis.
- Synovial fluid analysis is used to check for signs of joint infection as well as the detection of uric acid crystals that could indicate gout, which may contribute to joint damage in osteoarthritis.
- Erythrocyte sedimentation rate is a test that is used to detect the amount of inflammation in the body and may be increased in RA but not necessarily osteoarthritis.
- C-reactive protein can be used to test for the activity of the disease as well as inflammation. It can help distinguish between osteoarthritis and rheumatoid arthritis. An overall increased level of CRP occurs in rheumatoid arthritis but not osteoarthritis.
- The complete blood count is used to help evaluate white and red blood cells as well as hemoglobin and may be ordered by the physician to monitor the overall side effects of some osteoarthritis treatments.
- A comprehensive metabolic panel is used in the evaluation and monitoring of liver and kidney functions.