**Core Concept**
Varicose vein surgery, also known as vein stripping or avulsion, is a surgical procedure used to remove or repair varicose veins. The procedure involves making incisions in the skin to access the affected veins, which can lead to various post-operative complications.

**Why the Correct Answer is Right**
Ecchymosis, or bruising, is a common complication following varicose vein surgery due to the manipulation of the skin and underlying tissues during the procedure. The incisions made in the skin can cause bleeding into the surrounding tissue, resulting in ecchymosis. The risk of ecchymosis is increased in patients who have a history of bleeding disorders, are taking anticoagulant medications, or have a coagulopathy. The ecchymosis usually resolves on its own within a few weeks following the surgery.

**Why Each Wrong Option is Incorrect**
**Option B:** Deep vein thrombosis (DVT) is a potential complication of varicose vein surgery, but it is not the most common complication. DVT occurs when a blood clot forms in the deep veins of the legs, which can be a serious condition that requires prompt medical attention.

**Option C:** Recurrence of varicosity is a possible outcome of varicose vein surgery, but it is not an immediate post-operative complication. Recurrence can occur if the underlying cause of the varicosity is not addressed or if the patient develops new risk factors for varicose veins.

**Option D:** Venous ulcer is a potential complication of untreated varicose veins, but it is not a direct complication of varicose vein surgery. Venous ulcers occur when the veins become severely damaged and the skin becomes weakened, leading to an open sore.

**Clinical Pearl / High-Yield Fact**
It is essential for surgeons to take steps to minimize the risk of ecchymosis following varicose vein surgery, such as using compression stockings, elevating the affected limb, and applying topical hemostatic agents to the incision sites.

**✓ Correct Answer: A. Ecchymosis**