It is an indicator of deep vein thrombosis.
The sign is present when calf pain is caused by passive dorsiflexion of the foot .
However, clinical signs and symptoms have been found to be of little help in the diagnosis of venous thrombosis of the legs because they lack sensitivity.
Homans sign, swelling, and erythema have sensitivities of 60-88% and specificities of 30-72% in well-designed studies for the diagnosis of deep vein thrombosis (using venography as the reference standard).
Studies of the Homans sign suggest that it is positive in between 8% and 56% of people with proven deep vein thrombosis (DVT), but also positive in more than 50% of symptomatic people without DVT.
Homans sign can be positive in both calf DVT and ruptured Baker’s cyst.
Deep vein thrombophlebitis (DVT) is a serious condition that can be asymptomatic and go unnoticed, which can lead to death due to a pulmonary embolism .
It is a partial or complete occlusion of a vein by a thrombus with a secondary inflammatory reaction in the wall of the vein.
An individual is at risk for thrombus formation if they have some degree of venous stasis, have blood that is hypercoagulable, and have sustained injury to the venous walls.
Other risk factors for a DVT also include:
- Age over 40 years.
- History of previous DVT or pulmonary embolism.
- Major surgery (particularly of the pelvis or lower extremities).
- Obesity .
- Trauma to the pelvis or lower extremities.
- Congestive heart failure
- Prolonged immobilization (injury to the spinal nucleus in particular).
- Use of estrogen replacement therapies or oral contraceptives.
It is imperative that these risk factors are recognized in our patients and we are aware of a clinical test such as the Homans test.
Physical therapy : To evaluate the Homans sign, the patient’s knee is in an extended position and the examiner forcefully dorsiflexes the patient’s ankle
A positive sign is indicated when pain in the popliteal region and calf occurs when the foot is dorsiflexed. However, some people seem to have a different opinion on how this test should be applied.
These people believe that to correctly assess the Homans sign, the patient’s knee must be in a flexed position rather than an extended position.
They reason that flexing the knee exerts traction on the posterior tibial vein, which when inflamed, causes the pain symptom.
However, they do not explain the exact mechanism of how this traction on the posterior tibial vein would be increased by flexing the knee.
When applying the Homans test, a positive sign does not automatically conclude a DVT. In fact, a positive Homan’s sign can be triggered by factors such as superficial phlebitis, Achilles tendonitis, and injuries to the gastroc and plantar muscles.
Other conditions, such as herniated spinal discs and shortened heel cords, can also lead to a false positive.
A negative Homans sign, on the other hand, does not automatically conclude an absence of DVT. Thrombosis that develops in the thigh and pelvic veins is often difficult to detect and patients can often remain asymptomatic.
With this in mind, it is essential that therapists understand how reliable and valid the Homans sign is in detecting DVT.
In a study by McLachlin et al., They compared premortem clinical findings in the lower extremities of fifteen seriously ill patients with the results of postmortem venous dissection in these same patients.
They found that 12 of the lower extremities contained thrombi and 18 did not. The thrombi found were twice as frequent in the veins of the thigh than in the vein below the knee.
The Homans sign was evaluated in the lower extremities of these fifteen individuals, and the researchers concluded a true positive value of 8% and a positive value of 6%.
These poor findings for the Homans test could have been attributed to the low frequency of below-knee thrombosis in this study.
In another study for the detection of DVT, Cranlet et al. studied 1,333 lower extremities (124 individuals) who looked at various clinical symptoms, including Homans’ sign, and compared it to a phlebogram, a form of X-ray.
They found that the Homans sign obtained a true positive value of 48% and a true negative value of 41%. This was the least reliable of the clinical symptoms for thrombosis they examined, which also included muscle pain, tenderness, and swelling.
However, it should be noted that the Homans test was only applied to 104 lower extremities, compared to 133 lower extremities assessed for clinical symptoms assessed in the other three categories.
In a similar study that used phlebography as evidence of DVT, Haeger also found comparable unpromising findings when looking at clinical symptoms such as positive Homans sign to interpret DVT.
A true positive value of 33% and a false positive value of 21% were found for this test. This experiment is also plagued by uneven use of sample size across different categories of clinical symptoms, again resulting in a less favorable result in the statistical interpretation of the Homans sign.
While these studies posed some threats to design validity, Homan’s sign is still accurately recognized as insensitive, nonspecific, and not truly diagnostic for DVT.
The literature has shown that it produces almost as many false positives as true positives. Therefore, one cannot rely solely on diagnosing or ruling out DVT.
