Hypothenar hammer syndrome (HHS) is a relatively uncommon cause of ulnar artery injury following repeated, blunt trauma to the hypothenar region of the palm. This is predominantly associated with occupational or sporting activity that involves repetitive striking of objects with the base of the hand.
Here we discuss the management of a 36-year old fit and well mechanic presenting with HHS.
The patient initially presented with a 6-week history of severe pain and numbness to his left middle and ring fingers following a fall onto the left hand at work. This was also associated with Raynauds type symptoms, which did not resolve until later in the day. In the subsequent weeks following injury he went on to develop necrosis of the left middle fingertip with associated pain and swelling at the distal phalanx. Prior to this the patient was completely asymptomatic, but did describe repetitive trauma to the left hand from using it as a backstop when using a pounding machine at work.
A duplex ultrasound of the left upper limb demonstrated a 7mm aneurysm of the distal ulnar artery at the level of the hook of the hamate. An arteriogram demonstrated reduced arterial supply to the middle finger in keeping with a digital embolic event.
The ulnar artery was explored surgically and the aneurysm was excised. After mobilisation, the ulnar artery was able to be directly repaired. The left middle fingertip scar was subsequently excised and reconstructed with a V-Y advancement flap.
Medical management includes long-term antiplatelet therapy and removing aggravating factors. Surgical treatment aims to resect the diseased segment followed by repair of the ulnar artery either by primary re-anastomosis or with an arterial graft. A delay in diagnosis or treatment can lead to serious embolic complications and therefore the priority is early diagnosis and targeted treatment to avoid this.