Recognition of Soft-tissue Hand Injuries

Tendon rupture

Tendon rupture may occur without overlying skin laceration.

Tendons may rupture internally due to the following:

• The sharp bone edges at a fracture site
• Vascular insufficiency e.g. extensor pollicis longus in distal radius fracture
• Closed avulsion e.g. mallet finger
• Closed rupture e.g. central slip injury of the proximal interphalangeal joint (PIPJ)

Nerve injury

Nerve injury is an important consideration in all hand injuries.

Sensory loss following a proximal crush injury or closed fracture suggests ongoing nerve compression and may require surgical decompression.

Sensory loss in relation to a hand laceration is a sign of nerve division and requires surgical exploration.

Temporary nerve malfunction may occur in a closed injury due to mechanical trauma (neuropraxia). Serial examinations by the same observer may be useful in distinguishing neuropraxia from progressive compression neuropathy in the hand.

Two-point discrimination is the most reliable test for sensory examination of the hand [2-3]. A paper clip is usually adequate to perform this test. It can be performed as either a static or a dynamic examination. The patient should be asked to close or avert their eyes to remove any visual compensation.

The static two-point discrimination test is performed using progressively narrowing prongs from a starting point of 8 mm.

In the moving examination the prongs are moved progressively proximally to distally – across the finger being examined.

Two-point discrimination of greater than 6 mm static or 4 mm moving is abnormal [2-3].

Normal skin is slightly moist. The absence of sweating in the skin of the hand or fingers is a sign of nerve injury due to loss of sympathetic innervation. The body of a pen glides smoothly across such dry skin but not across slightly moist normal skin (pen test) [4].

Open hand injuries

In open hand injuries when the deep fascia or palmar aponeurosis are breached, clinical examination alone is unreliable, as it cannot exclude the presence of non-radio-opaque foreign bodies, or partial injuries of tendons or nerves. (Fig 3)