While treating open fractures it is always important to consider which complications can occur. Here we focus on the early complications, within the first hours to days after the injury.

Complications you can encounter soon after injury happened include:

• Hemorrhage / ongoing bleeding
• Acute ischemia due to vascular injury
• Reperfusion injury
• Nerve injury
• Extensive soft-tissue injury or tissue loss
• Early wound infection
• Tetanus
• Fat embolism syndrome
• Missed associated injuries in polytrauma patients

Hemorrhage

Keep in mind that anemia might occur: even though a patient might not have active arterial bleeding when you perform an initial assessment in hospital, they might have lost a lot of blood at the scene of the accident. 

It is important to check hemoglobin levels, considering that the patient might need surgical treatment. Hemoglobin (Hb) is the main transporting component of oxygen and nutrients to the site of injury. A lowered Hb level can influence the healing process.

Research has shown that patients with mild/moderate to severe anemia have an increased risk of adverse events such as surgical site infection, sepsis, and readmission.⁶ This influences the soft tissue damage in open fractures, which can be extensive.⁴

Acute ischemia^1,9

A complication of an open fracture can be disruption of vascular flow leading to acute ischemia of the affected limb.

Because of the effects of ischemia, it is important to diagnose it in the trauma setting. This can be done during the secondary survey: check distal pulses and perfusion. 

Don’t wait for the secondary survey to evaluate vascular status if definite signs of vascular trauma are present, such as active pulsatile bleeding, rapidly expanding hematoma or signs of compartment syndrome.

The causes of acute ischemia in trauma can range from spasms of the arteries to complete dissections. Sharp traumas are more often associated with the latter, while blunt traumas are more likely to cause intima damage. Both can lead to ischemia of the limb distal to the injury site.

Damage to the intima will not be directly visible as a cause for the ischemia, but it can be found based on ‘soft’ signs, such as neurological findings from associated nerves, hematoma over the artery or diminished unilateral distal pulse.

Tissues have a backup system: they can survive for a while without oxygen by using anaerobic metabolism. The critical tissue time differs depending on the tissue – see the table.

Tissue	Critical tissue ischemic time
Muscle	4 hours
Nerve	8 hours
Fat	13 hours
Skin	24 hours
Bone	4 days

The most important thing is to keep the ischemic time as short as possible. When considering your trauma surgical approach for limb salvage, consider whether you are attempting to salvage a limb that is already beyond the point of repair based on ischemic time.

Reperfusion injury^1,3,10

After an open fracture, there is a possibility that ischemia has occurred in the affected limb. When restoring blood flow to the damaged tissue, it is important to be aware of the possibility of reperfusion injury, due to the anaerobic metabolism that happens during ischemia.

Once oxidative blood flow is restored, this triggers the release of reactive oxygen species, which have negative effects on the muscle cells. They inflict direct damage to cell walls, which can trigger the necrotic cascade.

To prevent this from occurring, restore blood flow before permanent damage to muscle tissue has occurred: a window of less than 6 hours after the start of ischemia. Systemic treatment can extend this window, but restoring blood flow is key in this situation.
Be aware that the necrotic cascade can lead to edema inside the muscles. Therefore, it can be a cause of compartment syndrome, in which a fasciotomy of the limb should be performed. However, some literature advises against this, mainly because performing a fasciotomy means exposing the dying muscle cells, leading to a higher chance of wound infection.

Nerve damage^5,8

Due to the nature of the trauma, open fractures are at a higher risk of nerve entrapment or laceration compared to closed fractures. It is important to perform a quick neurological exam of the limb distal to the injured site.

In the USA, an incidence of 13.0 cases of nerve entrapment or laceration per million patients was identified, with the peroneal nerve being most frequently injured in the lower extremities.

The chance of accompanying nerve damage depends on the grade of the open fracture. It is important to realize this because early nerve repair can help in the functional recovery of the nerve.

Nerve damage is classified into a grading system by Sunderland.

Grade 1 – also known as neurapraxia. There is damage to the myelin sheath of the nerve without damaging the axon or other surrounding tissues. The effect of the damage is mainly a temporary decrease in velocity of conduction, leading to muscle weakness.

The trauma mechanism for this kind of damage is mild traction or compression of the nerve itself. This damage is usually reversable.

Grade 2 – also known as axonotmesis. In addition to myelin damage, there is also damage to the axon. However, there is no disruption of the continuity of the axon.

Grade 3-5 – also known as neurotmesis. There is a complete disruption of the continuity of the nerve. The more severe trauma mechanisms lead to this kind of injury, so consider it in high grade open fractures. It can be caused by a trauma in which a cut is inflicted, but also, for example, when the nerve has been subject to fierce traction.

Diagnosing nerve damage is usually done clinically by testing the patient’s motor function distal from the sight of injury and testing their sensory feedback. If this is inconclusive, a neurological exam with electromyography can be performed.

Nerves can either heal on their own without intervention or they can be surgically fixed.

Factors that complicate nerve healing include:

• The gap between the nerve ends if neurotmesis has occurred.
• The surrounding damage: if there is an open fracture with extended soft tissue damage, the healing of the nerve has a worse prognosis.
• Nerve endings: the cleaner the cut of a nerve in neurotmesis, the better the prognosis for healing.

Compartment syndrome

Compartment syndrome, known as acute compartment syndrome (ACS) when it occurs after trauma, involves increased pressure within a muscle compartment caused by bleeding, swelling or fluid accumulation.

Compartment syndrome is twice as common in open than closed fractures. When a patient is estimated to be high-risk, check regularly for signs of ACS.²

When the tissue pressure exceeds the perfusion pressure, blood flow is restricted, and neuromuscular ischemia occurs. Muscle necrosis can take place after only 3 to 4 hours of warm ischemia.

Recognizing the signs of compartment syndrome can be challenging, but it is crucial. Compartment syndrome can not only result in loss of the limb, but in severe cases also in renal failure and death.

According to research, the incidence rate of ACS is about 4%, and open fractures have double the chance of developing ACS as compared to closed ones. During initial management, it is important to keep these risk factors in mind.
You can recognize ACS using the 5 Ps: pain, paresthesia, pulselessness, pallor and paralysis.⁷

Not all of these symptoms occur at once, and not necessarily in the early stages. Early warning signs are pain out of proportion to the injury or pain on passive stretching of the foot.

Early signs of compartment syndrome:⁷

• Pain that is disproportionate compared to the nature of the injury. This pain is often described as a burning pain and can be evoked by passively stretching the limb. Assess the tibial and common peroneal nerve. 
• Pressure from tensely swollen compartments can be palpated.
• Paresthesia, caused by nerve irritation. In paresthesia, peripheral sensation is decreased. Test the tibial and deep peroneal nerve.

Late manifestations of compartment syndrome:

• Paralysis due to prolonged ischemia and tissue necrosis. Paralysis can be difficult to assess due to pain or the presence of a splint.
• Pallor and a slow capillary refill are not only signs of arterial injury but could also be present in compartment syndrome.
• Pulselessness could be a late sign of compartment syndrome but could also be caused by arterial injury or atherosclerosis. This can be assessed by palpating the posterior tibial and dorsalis pedis artery. 

Later complications

Complications that can occur later include:

• Infection will occur in days or weeks if an open fracture is left untreated
• Non-union or mal-union
• Amputation

For details on later complications, see Complications of open fractures

How to perform: Compartment syndrome

You can manage compartment syndrome by opening the compartments to release the pressure.

1. All four compartments of the lower leg can be opened with two longitudinal incisions in the fascia, one anterolaterally and one on the posteromedial side of the leg. The incisions should be 15-20 cm long.
2. The anterolateral incision opens the anterior and lateral compartments. Place your incision approximately 2 cm anterior to the fibular shaft, 3 cm distal to the tibial crest, and extend it towards the lateral malleolus.
3. Through this incision, you can reach the anterior intermuscular septum and open both compartments. Avoid injuring the superficial peroneal nerve, which exits the fascia in the distal third of the leg.
4. The posteromedial incision opens the deep and superficial posterior compartments. Palpate the posteromedial border of the tibia and place the incision approximately 2 cm posterior to the border, extend it towards the medial malleolus. Avoid the saphenous vein and nerve when placing your initial incision. 
5. Open the fascia covering the deep posterior compartment, making sure you do not injure the posterior tibial vessels and the tibial nerve.