Hammer finger

What is the Hammer Finger?

The hammer toe is a deformation of the terminal interphalangeal joint, which makes complete extension of the fingers of the hand impossible.

On most occasions, the hammer toe is caused by a traumatic event : the tendon that extends the third (distal) phalanx can stretch or break; consequently the finger tip remains in a flexed position and its straightening (extension) therefore becomes impossible.

The deformation affects the index or middle finger more commonly and is also known as Mallet finger or Segond-Bush lesion . The diagnosis is based on clinical evaluation, but the practice involves performing an X-ray to assess the possible presence of a bone fragment, which may have come off near the insertion of the tendon following a violent trauma.

Treatment includes immobilization of the finger in a position of passive extension with a brace, for about 6-8 weeks. If the tendon of the common extensor finger muscle is detached from the phalanx or if the fracture is extended, the patient can undergo surgery to facilitate the repair process of the structures concerned. Avulsion fractures are usually recomposed after approximately 6 weeks, but tendon damage requires approximately 8-10 weeks for healing.

Causes

The hammer toe is due to a forced flexion of the distal interphalangeal joint (IFD, in the last part of the finger of the hand), which can cause tendon damage ( stretching or rupture ) or a fracture of the part of the bone in which this tendon fits ( avulsion fracture ).

The causes can be connected both to an important trauma, such as during sports activity, and to more trivial injuries, such as tucking the blankets.

The hammer toe in the hand is a common sports injury, affecting mainly softball players, baseball, volleyball, basketball or goalkeepers: during the game, the ball, to be captured, hits the open hand and can cause a hyperflexion or a rupture of the extensor tendon near its insertion on the distal phalanx.

Symptoms

Symptoms affecting the finger that suffered the damage may include:

• Pain, especially in the case of muscular effort;
• Swelling ;
• Inability or difficulty in fully extending the finger, resulting in severe functional and aesthetic deficit.

In case of trauma, the signs of the lesion appear within a short time.

Delaying the treatment of the hammer finger can cause permanent functional damage or make healing more difficult. After the injury it is advisable to immobilize the affected area and contact your doctor or emergency room as soon as possible so that the extent of the injury is assessed: first the hammer toe is treated, the better the recovery will be. The patient should search for keep the hand raised above the level of the heart, until the extremity is examined during the physical examination. The diagnosis of the hammer toe is confirmed by the evident presence of the clinical signs described above. A radiographic examination allows to establish the type of lesion (stretching or rupture of the tendon) and if there is a possible bone fragment (avulsion fracture) at the base of the distal phalanx. The characteristics of the lesion allow defining the most appropriate therapeutic approach to be adopted.

Care

1. Tendon stretching or tearing: conservative treatment with brace In most cases, the doctor may advise you to put ice on the injured area to limit swelling and to apply a brace (or splint), that is a special rigid plastic splint (or of aluminum), which keeps the finger in an upright position and with the extremity slightly turned backwards (ie with the last phalanx extended). The immobilization of the affected part allows to maintain the terminal interphalangeal joint in extension and allows the rest of the structures involved during healing. The brace should be placed by a qualified professional, who must make sure that the support fits properly and the finger is in the correct position for healing. The splint must be tight enough to keep the finger in a proper position, but not too tight to interrupt the flow of blood (if the skin is white when it is removed, it may be too tight). The brace should be removed from the patient only for daily cleaning.

   Conservative treatment can be adopted for different periods of time:

   • If the tendon is affected by a stretch and is not torn: the hammer toe should heal in about 4 to 6 weeks wearing a brace all the time.
   • If the tendon is torn or there is a small bone detachment: the brace must be worn day and night for 6 - 8 weeks, so as to allow the two ends of the torn tendon and / or bone fracture to heal. After this period, it is necessary to wear this support for another 3 - 4 weeks, but only during the overnight stay.

If you delay starting treatment after injury, you may need to wear the brace longer. Although it is still possible to use your finger, it is important to remember not to move it too much until it is completely healed, as this could delay healing and cause permanent damage.

For pain relief, pain medications such as paracetamol, ibuprofen or naproxen can be taken on medical advice. Even resorting to an ice pack to be applied to the lesion, can help soothe pain and reduce swelling in the acute phase: it is possible to apply the ice bag for 10-20 minutes 3 times a day or as needed.

The patient should consult the doctor if:

• The finger is still swollen at the end of the treatment;
• Pain tends to get worse;
• Numbness or tingling develops at the end of the finger and the skin changes color.
2. Tendon rupture and significant bone detachment: percutaneous Kirschner treatment and blockade in extension

If the damage is more serious (for example, in the presence of a severe bone fracture or eventual subleasing), surgery may be necessary. If the passive extension cannot be reached, the doctor can proceed with immobilization by blocking the extension with Kirschner wires (also called K-wire or K-wire) for 4 weeks. In the most recent trauma, the K-wire facilitates the autonomous reparative process of the tendon and the detached bone fragment. In the less recent injury, however, the finger is immobilized with the same procedure, but after surgical suturing of the tendon. If a large bone fragment is found, ie when the lesion involves more than 30% of the articular surface, the fracture can be stabilized with metal wires to facilitate the repair process.

Other surgical options may be proposed to the patient if conservative treatment is not effective or if too much time has elapsed from the lesion (for example: distal interphalangeal arthrodesis, tenodermodesis or tenotomy).

The healing time depends on the cause and timing of the intervention: early treatment greatly reduces the severity of the injury and accelerates recovery. For this reason, the correct diagnosis of the lesion should take place as soon as possible. The hammer toe should heal within 6-8 weeks. However, it may take a few months to regain full functionality of the finger. Even symptoms such as redness, swelling and pain in the skin covering the end of the finger tend to disappear completely three or four months after the injury. Your doctor may recommend some rehabilitation exercises and indicate if you need to continue wearing the brace for a few weeks at night.

The patient must be informed that the finger may remain slightly flexed at the end of the treatment, but this does not compromise normal working or daily functions. Finally, most people affected by a hammer toe can still practice sports with a brace to protect the joint.