Knee Pain Overview
Getting a Knee Pain Diagnosis
History: Even in today's world of technology, doctors rely on a detailed history and physical exam more than any single test.
The doctor will typically want to know the exact nature of the pain.
- Where in the knee is your pain?
- What does the pain feel like?
- How long has the pain been present?
- Has it happened before?
- Describe any injuries to the knee.
- What makes it better or worse?
- Does the knee pain wake you up at night?
- Does the knee feel unstable?
- Have you been limping?
The doctor will also want to know a bit about you.
- Do you have any major medical problems?
- How active is your lifestyle?
- What are the names of the medications you are taking?
The doctor will want to know about any related symptoms.
- Do you still have normal sensation in your foot and lower leg?
- Have you been having fevers?
- The doctor will likely have you disrobe to completely expose the knee. If possible, wear shorts to your appointment.
- The doctor will then inspect the knee and press around the knee to see exactly where it is tender.
- In addition, the doctor may perform a number of maneuvers to stress the ligaments, tendons, and menisci of the knee and evaluate the integrity of each of these.
X-rays, CT scans, and other tests
- Depending on your particular history and exam, the doctor may suggest X-rays of the knee. X-rays show fractures (broken bones) and dislocations of bones in the knee as well as arthritis and abnormally large or small joint spaces.
- Rarely, the doctor may order a CT scan (a 3-dimensional X-ray) of the knee to precisely define a fracture or deformity.
- Both X-rays and CT scans are excellent for diagnosing fractures. They both are also poor, however, at evaluating soft tissue structures of the knee such as ligaments, tendons, and the menisci.
- Magnetic resonance imaging (MRI) uses large magnets to create a 3-dimensional image of the knee.
- In contrast to CT scans, MRIs do not image bones and fractures as well.
- Also in contrast to CT scans, MRIs are excellent for evaluating ligaments and tendons for injuries.
- The knee and all bursae of the knee are filled with fluid.
- If your symptoms suggest infection or crystalline arthritis, such as gout, your physician may remove fluid, with a needle, from the knee.
- This fluid will then be analyzed to better clarify the diagnosis.
- Crystals, which suggest crystalline arthritis, often can be seen under the microscope. Infection may also be detected under a microscope by finding bacteria and pus in the fluid.
- Blood tests: The doctor may also elect to perform certain blood tests to evaluate for signs of infection or diseases such as rheumatoid arthritis, lupus, and diabetes.
- The orthopedic surgeon may elect to perform arthroscopy if you have chronic knee pain.
- This is a surgical procedure where the doctor will place a fiber optic telescope within the knee joint. The arthroscope is attached to a camera that relays real-time images to a video monitor.
- By doing so, the surgeon may be able to see small particles in the knee or to look more closely at damaged menisci or cartilage.
- The doctor may also be able to repair damage by shaving down torn cartilage or removing particles from the knee while looking at the inside of your knee on a video monitor.
Types of Knee Pain
The nerves that provide sensation to the knee come from the lower back and also provide hip, leg, and ankle sensation. Pain from a deeper injury (called referred pain) can be passed along the nerve to be felt on the surface. Knee pain, therefore, can arise from the knee itself or be referred from conditions of the hip, ankle, or lower back. All of the following sources of knee pain arise from the knee joint itself.
In general, knee pain is either immediate (acute) or long-term (chronic). Acute knee pains can be caused by an acute injury or infection. Chronic knee pain is often from injuries or inflammation (such as arthritis) but can also be caused by infection.