Since osteoarthritis is the main cause of knee pain and the most common in people aged above 50 years, the first disease to be considered should be osteoarthritis of the knee.
A typical history of osteoarthritis knee followed by examination and X-ray finding can confirm the diagnosis of osteoarthritis knee (OA knee in medical language).
On examination of knee joint, there may be some swelling of the knee joint. Tenderness does not occur usually if the knee joint is moved and the patient says the pain occurs only when she/he walks (because of the pressure). In extreme cases, there may be severe pain with swelling and redness of the joint.
We should now exclude the possibility of Rheumatoid Arthritis, Injury, and Fracture also before finalizing the diagnosis. Rheumatoid factor in the blood and serum uric acid must be tested to exclude Rheumatoid Arthritis and Gout.
X-ray of the knee: X-ray of the knee joint AP and lateral view is the most commonly advised test to confirm osteoarthritis knee. The findings are:
- Reduction of joint space
- Sub-periosteal sclerosis
- Cyst formation
In this disease the joint space becomes very less and there may be erosions on the joints surfaces
CT scan and MRI Scan: If there are doubts, further investigations with CT scan or MRI scan of the knee joints can be done. These tests can help to exclude diseases like fractures, infection (tendenitis), meniscus injury, and ligament injury.
Arthroscopy: this is the latest test to diagnose knee pain. In this test, the knee joint is punched with an arthroscope and examined. An arthroscope is a device, which carries a camera at its tip. With the help of this camera, the inside of the knee joint can be seen.
Nature of the pain
Knee pain generally occurs during walking, running, sitting for long time and this is because of rubbing of the eroded bone surface of the joint. This pain often comes on getting up from sitting position or climbing staircase. Patient avoids Indian style commodes because of pain in the knees.
Overweight also aggravates knee pain as the joint space between the knee bones further reduces due to the weight of the body.
In young people there may be a history of knee injury leading to osteoarthritis of the knee.