Hypothenar Hammer Syndrome

By admin Last updated Sep 23, 2023

Ovid: 5-Minute Sports Medicine Consult, The

Tarek Hadla

Holly J. Benjamin

Basics

Description

Lesion of the superficial palmar arch of the ulnar artery in the hand mainly owing to repetitive compression or blunt trauma or even a single severe trauma over the hook of the hamate (1,2)

Epidemiology

Traditionally regarded as a rare condition, though may be underdiagnosed

Etiology

Etiology (1,2):
- Trauma: By frequent use of the hand as a “hammer”
- Vascular pathology: Thrombosis, abnormal anatomy, or aneurysm of the ulnar artery, prothrombotic factors
- Work-related: Auto mechanics, metal workers, lathe operators, miners, machinists, butchers, bakers, carpenters, and brick layers
- Sport-related: Golf, baseball catchers, heavy weight lifting, martial arts, mountain biking
Anatomy and pathophysiology: Hypothenar relates to the muscles of the 5th finger: AFO:
- Abductor digiti minimi
- Flexor digiti minimi
- Opponens digiti minimi
The hand obtains its arterial supply through the ulnar and radial arteries. The ulnar artery and nerve pass through Guyon's canal next to the hamate bone before dividing into the superficial and deep palmar branches. Just distal to the canal, a short segment of the superficial branch that forms the origin of the superficial palmar arch is unprotected between the skin and the bone in the hypothenar area. Chronic trauma to this area can lead to pathology of the ulnar artery.
Types of hypothenar hammer syndrome (HHS): Arteriographic patterns of HHS:
- Type 1: Stenosis of superficial palmar arch around the hook of the hamate
- Type 2a: Occlusion of the superficial palmar arch around the hook of the hamate
- Type 2b: Occlusion of superficial and deep palmar arches around the hook of the hamate
- Type 3a: Occlusion of the ulnar artery at the proximal part of the wrist
- Type 3b: Occlusion of the ulnar artery near the wrist

Diagnosis

History

Symptoms (2,3):

Paresthesias in fingers with “pins and needles” sensation
Pain in fingers caused by cold or repetitive movements
Reynaud-like phenomenon that spares thumb

Physical Exam

Signs:
- A hypothenar mass or callus
- Tenderness of the hypothenar eminence
- Raynaud phenomenon in the fingers and on the ulnar side of the hand (as above) (3)
- Positive Allen test (see below)
- Dependent rubor
- Ulceration of fingertips or gangrene

P.319

Allen test: The Allen test is often used before cannulating the radial artery or in assessment of hand trauma. The technique is as follows:
- Patient elevates the hand and makes a fist for 20 sec.
- Firm pressure is held against both the radial and ulnar arteries.
- The patient opens the hand, and it should blanche white.
- The examiner releases compression of the ulnar but not radial artery.
- A normal hand flushes within 5–7 sec.
- If the hand remains white, there is abnormal circulation.

Diagnostic Tests & Interpretation

Lab

CBC and international normalization ratio (INR) if thrombosis is suspected

Imaging

Doppler US
MR angiography (4)
CT angiography
Arteriography (“gold standard”)

Differential Diagnosis

Hand-arm vibration syndrome (5)
Raynaud phenomenon (3)

Treatment

Nonsurgical:
- Avoidance of further trauma or modification of sport activity
- Urokinase has been used to clear obstruction, as has prostaglandin E₁ with heparin.
- Calcium channel blockers, vasodilators. and platelet inhibitors also have been used (6).
- Treat underlying atherosclerotic and prothrombotic factors, eg, smoking and lipids.
Surgical:
- Surgical reconstruction (end-to-end anastomosis of the ulnar artery) requires microsurgical techniques. Arteries may be transplanted from other sites, or a venous graft may be used (7).
- Sympathectomy appears to give poor results.

Ongoing Care

Complications: Gangrene of the fingers in severe cases, which may require surgery
Prognosis: Many patients improve with nonsurgical treatments (see above). Results of reconstructive surgery were variable, and recurrence was fairly common (2).
Prevention: Prevention should focus at improving work practices, sports modification, and avoiding use of the palm of the hand as a hammer to pound, push, or twist objects (2).

References

1. Ferris BL, Taylor LM, Oyama K, et al. Hypothenar hammer syndrome: proposed etiology. J Vasc Surg. 2000;31:104–113.

2. Jagenburg A, Goyen M, Hirschelmann R, et al. [Hypothenar hammer syndrome: causes, sequelae and diagnostic aspects] Rofo. 2000;172:295–300.

3. Pineda CJ, Weisman MH, Bookstein JJ, et al. Hypothenar hammer syndrome. Form of reversible Raynaud's phenomenon. Am J Med. 1985;79:561–570.

4. Van de Walle PM, Moll FL, De Smet AA. The hypothenar hammer syndrome: update and literature review. Acta Chir Belg. 1998;98:116–119.

5. Cooke RA. Hypothenar hammer syndrome: a discrete syndrome to be distinguished from hand-arm vibration syndrome. Occup Med (Lond). 2003;53:320–324.

6. Conn J, Bergan JJ, Bell JL. Hypothenar hammer syndrome: posttraumatic digital ischemia. Surgery. 1970;68:1122–1128.

7. Brodmann M, Stark G, Aschauer M, et al. Hypothenar hammer syndrome caused by posttraumatic aneurysm of the ulnar artery. Wien Klin Wochenschr. 2001;113:698–700.

Codes

ICD9

904.9 Injury to blood vessels of unspecified site
923.20 Contusion of hand(s)