Injury is the principle reason a doctor might have to perform a valgus stress test on a patient. Used to gauge the integrity of ligaments primarily in the knees and elbows, this test is typically performed in two ways as the patient lies flat, with the legs straight and then spread about 30-degrees apart. While supporting the upper arm or thigh, the forearm or calf is forced sideways as far as possible to see if any tears or strains may have weakened the joint.
The valgus stress test is closely related to the varus stress test of the same joints. A valgus test gauges lateral ligament damage on the inside of the joint, which could lead to an extended look at the elbows or knees. By contrast, the varus test determines if damage has been sustained to the other side of those joints, creating a bow-legged stance. This would be indicated by strain or deformity when stress is placed in the opposite direction as in the valgus test.
To perform a valgus stress test on the knee, for instance, the patient is advised to lay on a table. With the legs first straight and together, the doctor holds the thigh above the knee with one hand and the ankle with the other hand. Holding the thigh stable, the ankle hand pulls outward slightly to gauge how much resistance is provided by the ligaments. The doctor then often tells the patient to widen his or her legs about 30-degrees apart to perform the test again.
Doctors alter the valgus stress test just a little to perform it on the elbow. Standing or seated, the patient is asked to extend the arm down his or her side, with the palm facing outward to display the forearm. Holding the bicep, the doctor of clinician can then manipulate the joint for a varus or valgus stress test. Another test, called the lateral compression test, involves performing the valgus test on the elbow or knee, while the limb being tested is slowly bent and extended.
For both the elbow and the knee, doctors have a few other tests to test joint health. A Tinel sign test is performed on the elbow to determine if tingling or pain is felt when the median or ulnar nerves, running from the shoulder to the fingertips, are tapped. If so, this could indicate inflammation, injury, nerve damage or more serious disorders like osteoarthritis or even a cancerous tumor.