The Trendelenburg test is used to determine the site of valvular incompetence in a patient with varicose veins.
Ask the patient to lie down. Elevate the leg, and empty the veins by massageing distal to proximal. Using a tourniquet, occlude the superficial veins in the upper thigh. Ask the patient to stand. If the tourniquet prevents the veins from re-filling rapidly, the site of the incompetent valve must be above this level i.e. at the sapheno-femoral junction. If the veins re-fill, the communication must be lower down.
Observing the same protocol, proceed down the leg until the tourniquet controls re-filling. As necessary, test:
- above the knee - to assess the mid-thigh perforator
- below the knee - to assess competence between the short saphenous vein and popliteal vein
If re-filling cannot be controlled, the communication is probably by one or more distal perforating veins.