HypothenarHammerSyndrom

Hypothenar hammer syndrome is a vascular disorder caused by repetitive blunt trauma to the hypothenar eminence, where the ulnar artery courses around the hook of the hamate. The repeated impact can injure the artery, leading to thrombosis, stenosis, or aneurysm formation and resulting distal ischemia of the ulnar side digits and hand.

The condition most often affects middle-aged adults who perform activities involving repeated forceful use of the hand, such as hammering, bricklaying, construction work, or other manual labor. It can also occur in cyclists or those with use of vibrating tools. Factors such as smoking or other vascular risk factors may worsen outcomes.

Clinical features include intermittent or persistent ischemic symptoms of the ring and little fingers, such as cold sensitivity, numbness, pallor or cyanosis, and pain. A palpable tender mass in the hypothenar region may be present if a ulnar artery aneurysm has formed. Symptoms may be episodic and related to hand use or cold exposure.

Diagnosis is guided by vascular imaging. Doppler or duplex ultrasound is often performed first to assess arterial flow and look for aneurysm. Angiography, CT angiography, or MR angiography can delineate the site of injury, presence of aneurysm, thrombosis, and collateral circulation.

Management ranges from protective measures and risk factor modification to medical therapy with antiplatelets for mild cases. Surgery is indicated for aneurysm, ongoing ischemia, or failure of conservative treatment. Surgical options include excision of the aneurysm with reconstruction or interposition grafting, or bypass of the involved arterial segment.

Prognosis depends on timely diagnosis and removal of ongoing trauma; with appropriate management, symptoms can improve, though recurrence risk exists if exposure to repetitive hand trauma continues. Differential diagnoses include other causes of digital ischemia such as Raynaud phenomenon and embolic or vasculitic disorders.