Homans’ sign is a diagnostic marker for deep vein thrombosis (DVT) where the doctor flexes the patient’s knee and foot to check for pain. It is not highly specific for DVT and can also be present in other conditions. Diagnosis of DVT relies on other tests such as venography and ultrasound. DVT can lead to life-threatening pulmonary embolism.
Homans’ sign is a diagnostic marker suggesting the presence of a clot in the deep veins of a lower limb. When evaluating a patient for the possibility of a deep vein thrombosis (DVT) or blood clot, the doctor flexes the patient’s knee and flexes the foot forcefully so that the toes point up. This maneuver applies traction to the main vein in the calf region, the posterior tibial vein. If the patient experiences pain in the calf muscle or behind the knee with this maneuver — a positive Homans sign — the doctor will proceed with further tests, such as venography, to confirm the diagnosis. This sign was first described in an article in 1938 by a surgeon, John Homans, in which he advanced his theory that early DVT produces congestion and irritability of the calf muscles, leading to the pain elicited with the sign.
In addition to deep vein thrombosis, Homans’ sign can be present in other conditions of the lower extremity. Widespread swelling of the lower extremities due to infection or muscle injury may also contribute to pain during knee flexion with foot flip. Patients with ruptured discs in the lumbar spine with nerve root compression may also have Homans’ sign. Additionally, women who chronically wear high heels may notice a positive sign of Homan when they switch to flat shoes. This sign is present in approximately 33% of patients with DVT and 20% of patients without DVT, indicating that it is not highly specific for DVT.
Because the clinical signs of DVT can be unreliable, the diagnosis of DVT depends primarily on confirmation by other diagnostic tests, including impedance plethysmography, venography, and ultrasonography. Impedance plethysmography measures the extent to which tissue in the leg prevents the flow of electrical current in the leg with a lower impedance pointing to a clot. Venography uses a radiopaque dye that will show a blockage in blood flow. Ultrasound measures the amount of compressibility of the leg veins, with reduced compressibility indicating a clot. Most clinicians will use both the clinical presentation, including the presence of Homan’s sign, and ancillary diagnostic tests to assess the likelihood that a patient has DVT.
Deep vein thrombosis occurs when blood clots in one of the deep leg veins that carry blood to the heart. Many patients have no symptoms. If the patient does not receive any treatment, however, the clot can break apart, dislodge and travel up to the lung, blocking an artery to lung tissue. This condition, called a pulmonary embolism, can be life-threatening.
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