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Date issued: February 2024 

Review date: February 2026 

Ref: C-455/JT Occupational Therapy/Mallet injury v4

PDF:   Mallet injury February 2024 v4.pdf[pdf] 460KB       

Bony mallet injury

A small piece of boneis pulled off along with the extensor tendon.                                             

Soft tissue mallet injury

A tear/break in the extensor tendon.

The bone is not broken.                                                                                  

What is a Mallet injury? 

The extensor tendon attaches the muscle to the end of the bone. It straightens the end joint of your finger / thumb. When the extensor tendon is torn, you are unable to straighten the end joint of your finger / thumb and the tip of your finger / thumb droops.

Soft tissue mallet injury

A soft tissue mallet injury is when the extensor tendon is torn at the base of the end bone (distal phalanx). Soft tissue mallet injuries take longer to heal than bony mallet injuries.

Bony mallet injury

A bony mallet injury is when the extensor tendon pulls a fragment off the base of bone (distal phalanx). The tendon remains attached to the small fragment of bone. The tendon is not torn in this injury.

Symptoms

• Your finger / thumb stays in a bent position, and you are unable to fully straighten it.

• Swelling over the end of the finger / thumb.

• Pain at and around the end joint of your finger / thumb.

• You may have a bump below the nail on your finger / thumb.

Treatment of mallet injury

Most mallet injuries are treated with splinting. Some require surgical treatment.

Mallet splints

Most mallet injuries heal well with splinting. There are different designs of mallet splints. They are made to support the end joint of your finger / thumb in a straight position to allow the bone / tendon to heal. 

Splinting instructions

• The splint is worn continuously 24 hours a day for at least 6 weeks with bony mallet injuries and at least 8 weeks with soft tissue mallet injuries.

• The splint can be washed in lukewarm soapy water.

• Do not attempt to re-shape the splint yourself.

• If the end joint bends during the continuous splinting period, it will affect healing and you may need to re-start splinting again for a further 6-8 weeks.

• You need to wear your splint all the time including when you are in bath / shower and when you are in bed.

• If your gets splint wet in the bath / shower remove immediately to dry the finger and splint as below.

How should you remove and put the splint back on?

Remove your splint once a day to clean and dry your finger.

• When you remove your splint to clean your finger you must not allow the fingertip to bend or leave your finger unsupported. You can place the hand on a flat surface/table, removing your splint to clean your finger. After cleaning, reapply the splint straightaway.

How to remove a volar (palm based) mallet splint

• Lace your finger/ thumb flat on a table and remove the tape.

• Gently pull the splint off your finger / thumb.

How to remove a dorsal (back of hand) mallet splint

• Place your finger flat on a table. Remove the two tapes that go around your finger.                                                                                                             

• Lift the splint off your finger leaving the sticky tape on the palm side of your finger. Keeping your finger flat on the table gently pull the tape from underneath your finger.

How to put on a dorsal (back of hand) mallet splint

• Place a sticky tape on a flat surface

• Use your other hand to hold the end joint of the finger straight and place the finger on the sticky tape. The sticky tape should not cover the palmar side of the middle joint.

• Use your other hand to put the splint on top of your finger                                         

• Use your other hand to pull the tape up from the front of your finger as far as to the splint and stick the tape on  top of the splint 

• Put 2 round tapes to secure the splint on your finger                                                                                                                                                             

Swelling

It is normal to have swelling after the injury or surgery. The swelling after a mallet injury can last for several months. Try elevating your hand and adjust the tapes on the splint if you feel pins and needles in the finger / thumb tip or if you feel the tapes are too tight.

Splinting schedule

Please wear your splint: (delete as appropriate)

• Bony Mallet: 6 weeks from date of splint application

• Soft Tissue Mallet: 8 weeks from date of splint application

Exercises during the period of continuous splinting

Exercise your elbow, shoulder, wrist, and any joints that are not included in the splint.

Can you use your hand while you are still wearing a splint?

• You may use your unaffected digits for light activities.

• You must not use your hand for heavy lifting or activities that require a tight grip.

• Do not engage in contact sports.

• It is your responsibility to decide if you can safely drive and grip the steering wheel in an emergency. It is advisable to contact your insurance company to inform them that you are wearing a splint.

6- OR 8-WEEKS POST-APPLICATION OF SPLINT.

Your therapist will assess the tendon by:

Test 1: Remove splint and lift hand off table if the finger / thumb immediately bends replace splint and continue wearing 24 hours a day for a further 6 or 8 weeks.

Test 2: Bend finger / thumb and straighten, if unable to fully straighten after bending replace splint and continue wearing 24 hours a day for a further 6 to 8 weeks and repeat above assessment.

If you can straighten your finger / thumb after completing the above tests your therapist will give you an exercise sheet and advise you to:

• Remove the splint during the day for exercises only continuing to wear the 24 hours a day for a further 2 weeks.

• Start using your hand for light activities and over the next 2 to 4 weeks gradually use your hand as normal.

• Contact sports including boxing should be avoided until 12 weeks post injury.

• If you have a lifestyle which involves heavy tasks / lifting or risk of forced bending, continue to wear the splint at work, during high-risk activities and overnight for a further 2 weeks.

• If you notice any extension lag develop (the finger/thumb drops at the end), please do the following:

  • Stop exercises.

  • Put the splint back on full time.

  • Call OT on 01752 432220

What outcome can you expect after a mallet injury?

Most mallet injuries heal well with splinting alone. The aim of splinting is to return the end joint to as near normal as possible. There could be a slight loss of full extension at the end joint of your finger at the completion of treatment.

It may take a few months for the swelling and tenderness to settle as well as the redness over the back of the finger. You may also find that the skin of the finger becomes more sensitive. You can massage the skin with a light moisturiser to help desensitise the skin. 

Bony mallet injuries may leave a bump/deformity over the end joint of the finger due to the fracture. You may not regain full normal or pre-injury movement in the end joint of your finger. This generally doesn’t affect the overall function of the hand. 

Occasionally the tendon may not heal at the completion of splinting. It may be necessary to do another course of splinting. If extension still does not improve and the finger remains painful, then you need to see the consultant/your GP for other options.