What is a ganglion cyst?
A ganglion cyst is most common mass that develops in
the hand. Ganglion cysts are benign lesions. A ganglion
is a fluid-filled sac arising from an adjacent joint
capsule or tendon sheath. A ganglion can form from
almost any joint or tendon sheath in the wrist or hand.
The following drawings describe the most common
sites for presentation of a ganglion.

What are the causes?
The exact cause of ganglions remains uncertain. The most popular
theory is that ganglions form after trauma or degeneration of the
tissue layer responsible for producing the synovial fluid which
normally lubricates the joint or tendon sheath. The cyst arises from
accumulation of this fluid outside the joint or tendon sheath in a
sac or cyst.

Ganglion (or mucous) cysts of the distal interphalangeal
joint of the finger (below left) occur in people over
40 years of age and are associated with underlying
arthritis. Ganglia of the distal interphalangeal joint may
put pressure on the nailbed and cause grooving of the
nail (see below). Ganglion cysts of the tendon sheath
of the fingers (below right) tend to occur from teenage
years to 40 years and respond well to aspiration which
ruptures the fluid sac.

How is it treated?
Ganglion cysts often change in size and may even disappear spontaneously.
For this reason, if the ganglion is not symptomatic, it may be best to simply
wait for a period of time. Painful wrist ganglia may respond to wrist bracing.
Wrist ganglia may be aspirated using ultrasound to guide the radiologist
who also puts a small dose of steroid at the site of origin of the ganglion
cyst. After this treatment a wrist brace is worn constantly for 4 weeks to
prevent recurrence. The success of this technique is approximately 30% if
aspirated once and 50% if aspirated twice.
Ganglions of the tendon sheath of the fingers respond much better to
aspiration (performed in the surgeon’s office with local anaesthetic) with
a cure rate of 50%.

If surgery is required
The most reliable method of removal of ganglion cysts is day surgery (90% cured). Ganglions
of the fingers can be removed under local anaesthetic but those of the wrist require general
anaesthetic. The ganglion is removed with a small piece of the joint capsule or tendon sheath
from which it has arisen to avoid recurrence. In the treatment of a mucous cyst of the distal
interphalangeal joint it is important to remove any osteophytes (bony spurs) that may be
associated with the origin of this type of ganglion.

Following ganglion cyst removal at the wrist, a bulky dressing with a plaster splint incorporated
is worm for 10-14 days. Physiotherapy is then started to get the wrist moving again. It will take
3 months regain almost normal strength and movement, both of which will improve gradually.
Recovery is rapid for tendon sheath ganglions (2-3 weeks) whereas distal interphalangeal ganglia
take 6-8 weeks to recover due to the surgery to the joint bony spurs. Physiotherapy is not
usually required for finger ganglion cysts.