Diagnosis and Tests for Knee Pain

Doctors aim to find the cause and the extent of the problem.

History

The doctor asks when the pain started, where it is, whether there was an injury or twist, morning stiffness, swelling, locking, giving way, fever, other joints, medicines and other illnesses.

Examination

They look for swelling, warmth, deformity and muscle wasting, check movement and walking, and test the ligaments, meniscus and kneecap. They also check the hip and the back.

Imaging

• X-ray: shows joint space narrowing, bone spurs and fractures. It is often the first test for osteoarthritis.
• Ultrasound: shows fluid, bursitis and tendon problems
• MRI: shows ligaments, meniscus, cartilage and bone bruising. It is used for injuries and unclear pain.
• CT scan: for complex fractures

Blood tests

• ESR, CRP and blood count for inflammation or infection
• Uric acid for gout
• Rheumatoid factor and anti-CCP for rheumatoid arthritis
• Vitamin D and others as needed

Joint fluid test

Fluid taken from a swollen knee can show crystals in gout or bacteria in infection. This is urgent for a hot knee.

Arthroscopy

A keyhole look inside the knee, used for both diagnosis and treatment in selected cases.

Key point

Many knee problems are diagnosed from history and examination, with X-ray or MRI used when needed.

Before your appointment

Note when the knee pain began, where it hurts, and whether there was a fall or twist. Describe swelling, stiffness, locking, giving way, clicking and what makes it better or worse. List all medicines, painkillers, supplements and herbal products. Mention fever, other joint pain, gout and past knee problems. Bring earlier X-rays or reports and your usual shoes. Ask about tests, exercise, safe pain relief and when surgery is considered. Seek urgent care for a hot swollen knee with fever or inability to bear weight, or call 112 for severe symptoms.