Mallet Finger

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

Other common names

 - Extensor tendon rupture zone 1

Who does it affect?

Anyone

Why does it occur?

When a finger is forcibly stubbed the end finger joint (distal interphalangeal joint) bends forwards quite suddenly. This causes the tendon on the back of the finger that straightens the end joint to pull off the bone. Usually it pulls off without a piece of bone but sometimes it can pull of a fragment.

Symptoms

Sudden inability to fully straighten the end finger joint and the joint is held in a bent position.

Clinical Examination

Your doctor will ask you to try and straighten your end finger joint. You will not be able to do this, no matter how hard you try.

Investigations

An x-ray is required to see whether the tendon has pulled off a piece of bone. This will dictate treatment.

Non-operative treatment

The vast majority of mallet finger injuries do not need an operation. If an x-ray reveals the tendon has pulled off a large fragment of bone with it we recommend surgery. If the x-ray is all clear and show the tendon has just pulled away without a fragment of bone a non operative approach will yield satisfactory results in most patients. A splint is applied to the front of the finger (pulp side) to straighten the joint. It is worn for 6-8 weeks constantly. It can be removed for washing, but it is vital the finger is held straight at the end finger joint by a helper; otherwise the healing tendon will become undone. The splints can be off the shelf stack splints, but often my patients prefer a custom made splint by my hand therapist

Operative treatment

When the x-ray reveals a large bone fragment has pulled off with the tendon an operation may be required.

The surgery is a day case procedure usually under local anaesthetic and takes about 10 minutes. The surgery can be performed using fine wires that hold the bone fragments back in place. The wires can be inserted percutaneously through small1mm stab incisions. The wires are left in place for 4 to 6 weeks and are removed in the clinic with little discomfort.

Complications

Overall greater than 95% are happy with the result. However complications can occur. If a splint is worn the skin may become irritated. This requires regular washing but care to keep the finger straight whilst doing this. This may be a recurrence of the dropped finger or what is called a swan neck deformity. This deformity is the mallet appearance of the end finger joint combined with a bending backwards of the middle knuckle joint the proximal interphalangeal joint (PIPJ). On side profile it has the appearance of a swan's neck. There are surgical options to improve both these complications.