An ulna fracture is the fracture of the ulna, one of the long bones of the forearm that lies on the inside when the palm of the hand is facing upwards.
The forearm consists of 2 bones: the spoke (radius) and the ulna (ulna).
The ulna forms at the level of the elbow a joint with the humerus, at the level of the wrist a joint with the 8 small carpal bones.
In the case of accidental trauma (such as a fall on the hand with an outstretched elbow), the force acts on the ulna.
If the absorbed force exceeds the elastic strength of the bone, a fracture may occur.
Ulna fracture is common in the elderly, but can also occur in younger patients.
This fracture often occurs along with other injuries: distortion or dislocation of the wrist or elbow, Colles fracture or other bone injuries to the hand, wrist or forearm.
Ulna fractures vary depending on:
- Type of fracture (tear, stress fracture, fracture of the coronoideus, olecranon fracture, displaced, incomplete, shattered, etc.).
- If the displacement of the fragments is less than 30%, the fracture is stable.
- Greenwood fracture: the periosteum and interosseous membranes are intact and help block rotation.
- If the displacement of the bone fragments is more than 30% or the angle is greater than 10-15°.
- With an angled fracture, displacement or injury to the interossea membrana.
- Possible concomitant injuries: radial head fracture or elbow dislocation.
Causes of ulna fracture
The mechanism of injury is usually:
- a very severe trauma to the bones during a traffic accident,
- a direct blow,
- a fall,
- a sports accident.
Fractures in children
Fractures in children can be complete or incomplete (greenwood).
Greenwood fracture means that although the bone is broken, the periosteum (external coating) is still intact.
A complete fracture can be undisplaced, displaced or shattered.
A fracture of the proximal third (elbow) is relatively rare.
Fractures of the middle third (middle of the forearm) occur in around 20% of cases, whereas fractures in the distal third (wrist) account for almost 75%.
Most often, the fracture occurs as a result of a fall on the outstretched arm.
Only rarely is it caused by direct trauma to the forearm.
The forearm has redness, swelling and deformation at the point of fracture.
Unlike adults, many fractures of the forearm in children can be treated with a closed reposition.
After reposition, the inward and outward rotation (pronation and supination) of the forearm must be checked and a plaster cast applied.
The operation involves open reposition with plates and intramedullary nails, depending on the degree of malposition of the bone segment.
Signs and symptoms of ulna fracture
Patients with greenwood fracture have pain, swelling, focal stiffness, and abrasions above the fracture site.
Patients with a Monteggia fracture have swelling, a malposition, crunching of the fracture site (crepitation) and pain during some movements, such as pro- and supination.
Since the posterior or radial interosseal nerve is often injured, it is essential to perform a neurovascular examination.
With all ulna fractures in adults, the symptoms are:
- restriction of movement,
- Crepitation when moving the elbow and wrist.
The forearm hurts, is swollen and there may be a malposition.
Also, an injury or strain of a nerve can occur, which could cause numbness (loss of sensitivity), paralysis or loss of limb function.
Care should be taken not to move the forearm as much as possible, otherwise the soft tissues could be additionally injured.
The presence of open wounds can carry the risk of dangerous infections.
In case of fracture, radiography of the forearm, wrist and elbow must be made immediately in anterior-posterior and lateral projection.
Displaced fractures are the most common injuries in adults.
In these cases, an operation for internal fixation or intramedullary nailing must be performed.
Closed reposition may be attempted if no nerves and blood vessels are affected.
Diagnosis of ulna fracture
Radiography is the recommended method of examination.
X-rays can show whether the bone is broken and whether there has been a displacement of the fragments.
The images can be very useful to see how many bone fragments are present in the forearm.
In an ulna fracture, the elbow, forearm and wrist must be X-rayed in anterior-posterior, lateral and oblique projection.
In this way, injuries to other bones can also be detected, such as the spoke.
Treatment of ulna fracture
The treatment of fractures follows a basic rule: the fragments of the fracture must be repositioned and stabilized by means of a plaster cast or surgery.
Thus, the fragments can no longer shift until complete healing.
If the bones are not aligned correctly, problems can arise later, the movements of the wrist and elbow could remain limited.
Most displaced fractures of the forearm require surgical intervention to ensure that the bones remain stabilized and aligned during the healing phase.
If it is an undisplaced fracture (the bone fragments have not shifted), it is sufficient to immobilize the arm with a plaster cast for about 30 days.
In the emergency room, depending on the displacement of the fragments, the doctor may try to align the bones. The technical term for this process is “fracture reduction”.
This is not a surgical procedure, but a manipulation.
The pain can be relieved with analgesic or anti-inflammatory drugs.
The doctor then applies a splint (such as a plaster cast) to the forearm to support it and hold the arm in the correct position.
Unlike a full plaster cast, an orthosis can be adjusted.
It is very important to limit the ability of movement of a broken bone.
Moving a broken bone can cause further damage to blood vessels, nerves, and other tissues surrounding the bone.
Immediate treatment involves the use of ice to reduce swelling and pain.
If the bone is broken and the fracture is undisplaced, it can be treated with a plaster cast or orthosis.
This is indicated for forearm fractures with a deflection of less than 10-15 degrees and more than 50-75% contact of the bone fragments.
Plaster casts or orthoses on the forearm must be well placed to block the movement of the wrist and elbow.
The doctor must carefully monitor the course of the fracture by regularly taking X-rays.
If the fracture shifts, surgical intervention may be necessary to bandage the fragments.
If both forearm bones are broken or the skin has been punctured (open fracture), surgery is usually required.
Due to the risk of infection, open fractures must be treated promptly.
Normally, the doctor administers antibiotics in the emergency room via the vein (intravenously) and can also refresh the tetanus vaccination if necessary.
During the operation, the incisions caused by the accident must be carefully cleaned. As a rule, the broken bones are also fixed.
If the skin around the fracture is not injured, the doctor may wait until the swelling has decreased before operating.
By immobilizing and elevating the arm for several days, the swelling can decrease.
Open reposition and internal fixation with plates and screws
Open reposition is the most common type of surgical recovery for forearm fractures.
In this procedure, the bone fragments are returned to their original position (fracture reduction).
Then they are held together with special screws and metal plates, which are attached to the outer surface of the bone.
The orthopedist may advise removing these artificial materials one year after the procedure.
The removal is done in a small operation, in which the screws and nails are taken out. In most cases, treatment of the wound is sufficient and no physiotherapy is required.
Open fractures must be treated as an emergency, but fixation can be delayed for up to 24 hours.
Immediate open surgery can achieve very good results with not too severe fractures (low infection rate).
If necessary, an autologous bone graft can be used.
Even if the orthopedist works cleanly, infections can occur.
Finally, the wound must be sutured.
The doctor prescribes antibiotics after each procedure of this type.
Open reposition and internal fixation with Kirschner wires
In internal fixation with Kirschner wires, a specially designed metal wire is inserted into the medullary space in the center of the bone.
If skin and bones are severely damaged, the use of plates and screws can additionally injure the skin and lead to a serious infection.
In this case, one can make do with the use of an external fixation of the bone.
External fixation consists in inserting screws and metal pins into the bones above and below the fracture.
The pins and screws are then fixed with a rod outside the skin.
This device forms a stabilizing frame that holds the bones in the correct position.
Rehabilitation after surgery for an ulna fracture
When the orthopedist removes the cast, the patient first feels more pain than before. The movements of the elbow and wrist are very limited and the skin of the hand is very dry.
It is important to start magnetic therapy as soon as possible to relieve the pain. This treatment can also be done with an attached plaster cast.
Rehabilitation and physiokinesitherapy must be started immediately to ensure a speedy recovery.
The most restricted movements are pro- and supination (rotation of the wrist and elbow) and flexion-extension of the elbow.
Complications of an ulna fracture
Even if this happens only rarely, an instability of the radius head can result after an anatomical reposition of the ulna.
If the radial head shifts again in the first 6 weeks after surgery, it means that the quality of the ulna reposition did not go well. If the reduction is not anatomical, it can be repeated with an open reposition of the radius head.
A possible dislocation of the radius head after more than 6 weeks after the operation can be better treated with an ablation of the radius head.
An injury to the ulnar nerve is also common in an ulna fracture.
The most affected nerves are the radialis, median and interosseus posterior or anterior.
A nerve injury can also occur due to too violent movements during the reposition of the fracture or during an open reposition.
If the nerve paralysis persists for more than 3 months, surgery must be performed.
Poor consolidation of the fracture (the ulna does not heal) occurs especially in older women with osteoporosis.
In this case, magnetic therapy and shock wave therapy are very important.
In the case of a debris fracture of the elbow, the patient often does not regain full mobility.
How long does it take to heal? Prognosis
In the case of an undisplaced fracture, the doctor applies a plaster cast for about a month. The fracture usually heals completely within about 3 months, as long as there are no complications.
If the fracture is displaced, the orthopedist can perform an operation and then immobilize the arm with a plaster cast or orthosis for about 30 days.
In this case, healing occurs faster. Already 2-3 weeks after the removal of the plaster cast you can drive again (depending on the pain).
The forearm remains swollen at the level of the fracture site over the first 3-4 months, but can decongest earlier in young men.