Determining the Cause of Knee Pain

What your doctor is looking for when examining your knee

When you see you doctor about knee pain, he will discuss the nature of the problem with you and conduct an examination. What he finds can tip him off to what's causing your knee pain. Here are some of the common features of the knee your doctor will check during an exam. Determining the cause of the pain is key to recommending proper treatment.

Skin
Your doctor will check the skin for signs of injury or infection. Inspection for cuts, scrapes, bruising, redness, or other abnormalities is standard. You doctor will also inspect any previous surgical incisions. Signs of infection or trauma can tell your doctor a lot, and these findings may help direct the rest of your examination.

Fluid
Excess fluid can be found either around the knee or inside the knee joint itself. Around-the-knee fluid can collect as a result of a contusion (bruise) or bursitis. Within the knee, fluid can collect inside the joint after cartilage and ligament injuries, and is also commonly associated with knee arthritis.

Motion
Patients should be able to fully extend the knee. You can check for the ability to do this by sitting on the floor and resting your leg out straight. Place one hand behind the knee. You should be able to push your hand against the floor with the back of you knee; inability to do so indicates decreased knee motion. Most people without knee problems can bend their knee to place their heel against their buttocks. Inability to do this can also be the sign of knee problems. Your doctor may ask you to move the joint so that he can see if motion is being hindered in any way.

Tenderness
Tenderness to pressure can help your physician locate the cause of a problem. Common areas of tenderness include the joint line (the top of the shin bone). This area is often tender with meniscus tears, cartilage damage, and knee arthritis. Tenderness around the kneecap is often a sign of kneecap problems. The collateral ligaments and the patellar tendon can also be tested for tenderness.

Stability
Your doctor can perform several specific tests to check the stability of your knee. The four major ligaments of the knee can all be easily tested. These ligaments are:

• Anterior Cruciate Ligament
• Posterior Cruciate Ligament
• Medial Collateral Ligament
• Lateral Collateral Ligament

Each of these ligaments can be tested with specific maneuvers to check to see if stressing them causes pain or instability of the knee.

Tests
Specific tests can be performed, depending on signs of possible problems. Specific tests are often used to diagnose meniscus tears, kneecap problems, and other conditions in the knee.

Related Problems Causing Knee Symptoms
Your doctor will also consider other conditions that could be causing pain around the knee. Not all problems that cause knee pain are due to a problem within the knee joint itself. Sometimes, patients with hip conditions and spine problems can experience knee pain. These problems may be further investigated if there is a possibility that the cause of pain could be coming from another body part.

_Source:

O'Shea KJ, "The Diagnostic Accuracy of History, Physical Examination, and Radiographs in the Evaluation of Traumatic Knee Disorders" Am. J. Sports Med., Mar 1996; 24: 164 - 167.