Homan Sign

The Homan sign is a clinical finding of pain behind the knee upon forced dorsiflexion of the foot. This sign was initially described by the American surgeon John Homans in 1994 and has been traditionally performed as part of the physical examination in individuals with suspected deep vein thrombosis (DVT) of the lower extremity. It is thought that the mechanism underlying the Homan sign is that flexion of the knee and forced dorsiflexion of the ankle causes traction on the posterior tibial vein, resulting in pain behind the knee.  

When evaluating for the Homan sign, the individual’s knee should be in a flexed position. The examiner will then forcibly and abruptly dorsiflex the individual’s ankle and observe for pain behind the knee, which constitutes a positive Homan sign. If the dorsiflexion is not forceful enough, an accurate result may not be obtained. 

For many years, a positive Homan sign was thought to be a clinical sign of deep vein thrombosis of the lower extremity; however, evidence shows that not all individuals with DVT exhibit a positive Homan sign at evaluation. Therefore, the Homan sign is considered insensitive and nonspecific for DVT. 

Some conditions that may result in a positive Homan sign include intervertebral disc herniation, a ruptured Baker cyst, neurogenic claudication, calf muscle spasms, and cellulitis of the lower leg. Interestingly, individuals with a short Achilles tendon who usually wears high heels may experience a positive Homan sign when they start wearing flat shoes.

Because of the unreliability of the Homan sign and clinical evaluation in diagnosing DVT, additional diagnostic procedures are typically performed if DVT is suspected. Current guidelines support clinical predictive scores (e.g., Wells score) for diagnosing DVT and non-invasive methods like a compression ultrasound with a doppler and a D-dimer blood test. If the diagnosis is inconclusive, more invasive venography can be performed, where a dye is injected into the veins. An X-ray is obtained to identify blockages.