What is the significance of Homan's sign in diagnosing deep vein thrombosis (DVT) in adults with risk factors such as recent surgery, immobility, or a history of clotting disorders?

Homan's Sign Has No Clinical Utility in DVT Diagnosis

Homan's sign should not be used to diagnose or exclude deep vein thrombosis, as it has very poor predictive value for the presence or absence of DVT. 1

Why Homan's Sign is Unreliable

• Homan's sign (calf pain with dorsiflexion of the foot) is frequently taught and tested, but clinical evidence demonstrates it is an inaccurate diagnostic tool with no meaningful sensitivity or specificity for DVT 1
• Clinical assessment alone, including any individual physical examination finding like Homan's sign, is unreliable and insufficient for diagnosis or exclusion of DVT 2
• Approximately 80% of DVTs are clinically asymptomatic, and the 20% that demonstrate signs and symptoms can easily be confused with other musculoskeletal disorders 3

The Correct Diagnostic Approach

All patients with suspected lower extremity DVT must be evaluated using the Wells score to determine pretest probability before ordering imaging. 4

Step 1: Calculate Wells Score

• The Wells score incorporates: active cancer, paralysis/paresis/recent immobilization, recent bedrest >3 days, localized tenderness along deep veins, entire leg swelling, calf swelling >3 cm compared to asymptomatic leg, pitting edema, collateral superficial veins, and previously documented DVT 4, 5
• A score ≥2 indicates DVT is "likely" (53% prevalence), while <2 indicates "unlikely" (5% prevalence) 2

Step 2: Risk-Stratified Testing Algorithm

For LOW pretest probability (Wells <2):

• Start with high-sensitivity D-dimer testing; if negative, DVT is excluded without imaging 4
• If D-dimer is elevated, proceed to complete duplex ultrasound 4

For INTERMEDIATE/MODERATE pretest probability:

• Use whole-leg ultrasound as the initial test, or proximal ultrasound followed by serial imaging at days 3 and 7 if initially negative 4

For HIGH pretest probability (Wells ≥2):

• Proceed directly to complete duplex ultrasound from inguinal ligament to ankle 4
• Do not use D-dimer as a standalone test in this population 4

Step 3: Ultrasound Interpretation

• The diagnostic criterion is inability to fully collapse the femoral or popliteal vein under gentle probe pressure (sensitivity 94.2%, specificity 93.8% for proximal DVT) 2
• Compression must be performed at 2-cm intervals with spectral and color Doppler imaging 4

Critical Pitfalls to Avoid

• Never rely on clinical signs alone (including Homan's sign, leg swelling, or calf tenderness) to diagnose or exclude DVT 1, 5
• Never use D-dimer alone in high pretest probability patients or in hospitalized patients where false-positives are common 2
• Never accept limited proximal-only ultrasound when symptoms suggest calf involvement, as this misses isolated distal DVT that may propagate 4
• Ultrasound has poor performance above the inguinal canal and below the knee, and cannot reliably distinguish acute from chronic DVT 2

High-Risk Populations Requiring Special Consideration

• Patients >60 years with recent surgery, immobility, prior VTE, cancer, or thrombophilia have substantially elevated risk and warrant prophylactic anticoagulation 6
• Active cancer patients should proceed directly to imaging without D-dimer testing due to high false-positive rates 4
• Post-surgical patients (especially orthopedic, abdominal, pelvic procedures) have 15-75% DVT incidence depending on procedure type 6