Mucus Cyst

Mr Mike Hayton
FRCS(Trauma and Orth) FFSEM (UK)
Consultant Orthopaedic Hand Surgeon

Other common names

None

Who does it affect?

Usually females over 40 years.

Why does it occur?

It is a fluid filled sac, that occurs at the end finger joint (DIP joint), on its back surface to one side or the other. They are caused by a small extra bit of bone around the joint (osteophyte) that occurs as a result of arthritis in the joint. The cyst and bone can cause pressure on the nail bed to cause uneven nail growth.

Symptoms

A small lump that develops on the back of the joint to one side. The joint itself may be stiff and tender. The outline is quite smooth and may feel tense like a small ball or balloon (cystic). The overlying skin may become thin and even breakdown.

Clinical Examination

A mucus cyst has quite typical features both in its location and appearance. In the clinical photograph above, the finger in the middle of the picture ,that has been marked with a black dot on the nail has a classic mucus cyst. The finger on the right of the picture has advanced arthritis and as a result of irregular cartilage wear is bending to one side.

Investigations

An x-ray will usually show wear and tear (osteoarthritis) in the joint.

Non-operative treatment

If it does not cause a problem I recommend leaving it alone.

Operative treatment

If causing problems I usually recommend surgery. The surgery is a day case procedure usually under local anaesthetic and takes about 10 minutes. Some patients prefer general anaesthetic. A tourniquet is used; which is like a blood pressure cuff around the upper arm that prevents blood from obscuring the surgeons view. It is quite tight, but well tolerated for up to 20 minutes.

Local anaesthetic is infiltrated at the base of the finger. Once numb the skin is incised and the skin flap elevated. The ganglion is dissected taking care not to puncture it. The base of the ganglion is identified and excised. A small extra bony area (osteophyte) is seen and needs to be removed. The skin is sutured and a bulky dressing is applied.

Post-operative rehabilitation

The patient is fit to go home soon after the operation. The anaesthetic will wear off after approximately 6 hours. Simple analgesia usually controls the pain and should be started before the anaesthetic has worn off. The hand should be elevated as much as possible for the first 5 days to prevent the hand and fingers swelling. Gently bend and straighten the fingers from day 1. My preference is to remove the dressing at 2 days. The wound is cleaned and redressed with a simple dressing. The sutures are removed at about 10 days.

Return to activities of daily living

It is my advice to keep the wound dry until the stitches are out at 10 days.

Return to driving:

The hand needs to have full control of the steering wheel and left hand the gear stick. It is probably advisable to delay returning to driving for at least 7 days or even when the stitches are removed.

Return to work:

Everyone has different work environments.

Returning to heavy manual labour should be prevented for approximately 4 to 6 weeks. Early return to heavy work may cause the tendons and nerve to scar into the released ligament. Please ask your surgeon for advice on this.

Complications

Overall, greater than 95% are happy with the result. However complications can occur.
There are complications specific to Mucus Cyst surgery and also general complications associated with hand surgery.

General complications:

 - Infection (Less than 1%) 
 - Neuroma (Less than 1% coiled painful nerve bundle) 
 - Numbness

Reflex Sympathetic Dystrophy - RSD (2% bad reaction to surgery with painful stiff hands - this can occur with any hand surgery from a minor procedure to a complex reconstruction.)

Specific complications:

Recurrence: We are not sure whether it is the same ganglion recurring or simply another one forming nearby. The joint is arthritic and may need treatment in the future.