Hand Injuries
Hand injuries are a common presentation to the
Emergency Department, and the importance of good hand function in day-to-day
life requires excellent results. The spectacular range of hand function relies
on complex interplay between muscles, tendons, bones and ligaments, all of
which may be damaged.
History and examination
Hand
dominance, job and hobbies are essential parts of the history. The mechanism of
injury may suggest a likely pattern of injury, e.g. a fifth metacarpal fracture
following a fight. If there is no history of injury, consider infection (e.g.
septic arthritis) or inflammation (e.g. rheumatoid arthritis).
It can be
confusing to describe lesions in relation to the anatomical position, so the
terms volar or palmar, and dorsal are used, rather than anterior and posterior.
Similarly, radial and ulnar are used rather than medial or lateral. Names of
digits (thumb/index/middle/ring/little) should be used, rather than numbers.
Look Look for
swelling/bruising and compare hands. Check the skin over the knuckles for
wounds: human ‘bites’ need treatment (Chapter 12).
Feel Feel the carpal and
metacarpal bones and joints and the ‘anatomical snuff box’ (Chapter 15).
Move Ask the patient to make
a fist: check the fingers are in line, pointing to the scaphoid.
•
Check sensory and motor function. Two-point discrimination testing can
reveal subtle sensory loss.
•
Check the extensor and flexor tendon function.
•
Test the thumb ligaments.
•
Ask the patient to grip your index and middle fingers ‘as tight as they
can’.
Management
Immobilise and elevate
Neighbour/buddy
strapping involves strapping an injured finger to an adjacent finger, providing
protection against hyperextension while still allowing good function.
Volar slab:
a strip of plaster on the palmar/volar side of the hand with the wrist in
extension and the metacarpophalangeal joints (MCPJs) in flexion provides
support and prevents contraction of tendons or muscles.
Multiple
layers of elastic or plaster strapping around the thumb is called a thumb
‘spica’, and provides protection against abduction or hyperextension.
The
compartments of the hand have little room to accommodate soft tissue swelling,
so elevation in a sling is used to keep the hand above the heart. Rings should
be removed.
The majority
of hand injuries can be managed as outpatients or by GPs; however, open
fractures, or those listed below under ‘Do not miss’, should be reviewed by the
inpatient team.
Common injuries
Metacarpal neck fractures
Little or
ring finger metacarpal neck fractures caused by punch injuries are quite
stable. Angulation <30° gives a good
functional outcome. If more angulated, the fracture may be reduced by flexing the MCPJ to 90° and
pushing dorsally.
Fractures and dislocations of the
phalanges
Dislocations
and fractures with marked deformity should be reduced in the Emergency
Department using N2O/O2 or a ring block. Mid-shaft or
spiral fractures may be unstable due to fracture pattern or muscle action, and
require operative fixation, particularly if there is any rotational deformity.
Hammer/mallet finger
Forced
flexion of the extended distal phalanx pulls a flake of bone off the distal
phalanx. Treat with a mallet splint to ensure the patient does not flex their
distal phalanx at all for 6 weeks.
Thenar eminance sprain
The powerful
muscles of the thenar eminence can be torn by forced abduction of the thumb – a
common injury when falling on a slippery surface, e.g. skiing or skating. More
serious injuries, e.g.
Bennett’s/scaphoid
fractures must be excluded.
Nail and fingertip injuries
Injuries to
the fingertip are common, and require X-ray to exclude bone injury, but rarely
need operative treatment. If the nail is displaced, remove under ring block,
trim, and use as a dressing for the nailbed. Nailbed injuries rarely need
treatment.
Lacerations
Uncomplicated
lacerations (that do not involve underlying structures) on the hand and digits
less than 2 cm long do not require suturing, providing the wounds are not at
high risk of infection (Chapter 12). Clean, dress and consider topical
antibiotic ointment. Above this size, sutures are usually used. Ensure that
distal neurovascular function is documented.
Fish-hook injury
Fish-hooks
have a barb to prevent fish (or humans) from pulling the hook out. After
anaesthetising the area, it may be necessary to advance the hook through the
skin to cut off the barb and allow removal.
Diagnoses not to miss
Bennett’s fracture
This is a
fracture of the base of the thumb or first metacarpal bone, caused by thumb
hyperextension. It is unstable and needs operative fixation.
Gamekeeper’s thumb
Gamekeeper’s
thumb is a tear of the ulnar collateral ligament of the thumb at MCPJ level by
forced abduction. Complete tears do not heal without surgery.
Tendon injuries
Tendon
injuries are easy to miss unless the tendons are individually tested. Tendon
lacerations can occur when an extensor, or less commonly, a flexor tendon hits
a sharp object, particularly when the is running over a bony prominence. Complete
tendon division requires operative repair.
Tendon sheath infection
Tendons run
in fibrous sheaths that protect and lubricate the tendon. If infection
penetrates the sheath, it may track down the finger and into the hand. Such
infections need urgent drainage, washout and antibiotic treatment.
Amputations
All
amputations involving bone loss should be referred and reimplantation
considered, especially for thumb and index fingers. The amputated part should
be wrapped in clean cloth, and then put in a plastic bag inside an ice bath.
The amputated part should not touch ice. Successful reimplantation of digits
severed distal to the distal interphalangeal joint (DIPJ)
