"Orthopaedics is not carpentry, it's gardening."

Open fractures present a significant clinical challenge because of their high risk of complications. Exposure of bone to the external environment increases the risk of infection, and together with the associated soft-tissue injury can impair bone healing, resulting in delayed union, non-union, or malunion.

Malalignment 

Malalignment occurs when the bones are not aligned correctly during the reduction process, or secondarily, due to insufficient construct stability. Achieving a perfect anatomic reduction is often not mandatory in extra-articular fractures for good functional outcomes. Minor degrees of varus or valgus angulation, antecurvation (anterior bowing), or recurvation (posterior bowing) are generally acceptable and do not significantly affect function. However, rotational malalignment must be carefully avoided, as it can lead to long-term functional problems.

Malalignment in different planes can occur:

To prevent malalignment several principles can help:

• Alignment should be checked clinically during surgery. A practical method to assess limb alignment is to ensure that a straight line can be drawn through the following anatomical landmarks:
  - the anterior superior iliac spine (ASIS),
  - the centre of the patella,
  - the second toe web space into a straight line.
• This alignment should then be compared with the contralateral, uninjured limb.
• Direct visualization of the fracture if an open reduction is performed may help to confirm the correct alignment.
• Intra-operative fluoroscopy - If available, use fluoroscopy to control your fracture reduction and adjust if needed. A useful fluoroscopy protocol to control rotational alignment of tibial shaft fractures is called C-Arm Rotational View (CARV)¹ .

The CT scan of this case, shows more than 20 degrees of internal rotation of the left tibia after intramedullary nailing. The rotational malalignment was revised to an acceptable angle.

Inadequate stabilization

If the fixation is not robust enough, it can lead to excessive movement of the fracture site, hindering the natural healing process and potentially results in a (hypertrophic) non-union. A sign of insufficient fracture stability can be excessive callus formation on a follow-up x-ray.

Different techniques in intrinsic stability:

Absolute stability
Generally speaking only internal fixation with plate and screws will create absolute stability leading to primary bone healing.

Relative stability
Whereas most other techniques, like nailing, external fixation and POP, will create relative stability leading to secondary bone healing with the formation of callus. With appropriate alterations and proper application, external fixation can provide sufficient stability for definitive treatment and allow bone healing.

Modern ring fixation systems can be seen as ultimate forms of enhanced modular external fixation for definitive fracture treatment, including computer assisted options to postoperatively correct for malalignment if needed.

Tip - Tighten the clamps every week on the ward to prevent loosening.

Definitive fixation with an external fixator for tips on strengthening an external fixator.

Skin necrosis

Pressure sores or necrosis may occur at the sites where the external fixator components contact the skin or if the limb expands because of swelling. Placing the bars too close to the skin can lead to pressure ulcers and skin necrosis. Therefore, careful attention to pin and bar placement is essential to minimize the risk of these soft tissue problems. 

To prevent pressure ulcers, consider the following:

• Skin distance - Position the bars at an adequate distance from the skin, ideally two fingerbreadths between the skin and the bar.
• Leg elevation - Elevate the leg for the first few days after surgery.
• Early mobilization - Encourage early mobilization and gentle, non-weight-bearing exercises.
• Regular turning - Implement regular turning and repositioning while in bed.
• Patient education - Provide the patient with thorough instructions for skin care and pressure sore prevention techniques.
• Kickstand - Utilize a vertical support bar, also known as a kickstand, beneath the heel to allow it to hang freely off the bed, reducing pressure on the skin of the heel.

Even with internal fixation, metal directly under the skin can cause pressure of the skin, which may lead to skin necrosis.

Pin tract infections

Two types of pin tract infection can be distinguished in external and ring fixators:

1 Pin site infections
These occur around the wounds where the pin enters the limb. They are mostly superficial. Free loose movement of the skin around the pin will decrease the risk for this. Prompt treatment with antibiotics, and local debridement during wound care, is essential to prevent it from leading to deeper tissue or pin tract infections. If a pin is still fixed, it can often be left in place.

2 Pin tract infections
This infection included a deeper infection along the pin tract extending into the bone, which can ultimately lead to a fracture-related infection. In such cases, the involved pins should be removed and new pins placed in a non-infected location. If microbiological testing is available, obtain samples to guide appropriate antibiotic therapy alongside surgical debridement.

Pin tract infections are primarily caused by bacteria entering the skin at the pin insertion site during or after the initial procedure. Factors such as poor wound care, inadequate sterilization during pin insertion, or prolonged use of external fixators heighten the risk of infection. 

Symptoms include:

• Redness
• Swelling
• Warmth
• Tenderness
• The presence of pus or drainage at the pin site

To prevent pin site and tract infections:

• Adhere to sterile techniques
• Minimize heat generation
• Provide stability to the pins
• Make sure there is no skin tension around the pin by creating a large enough skin incision
• Following pin insertion, thoroughly clean and dress the pin sites

Thermal osteonecrosis
During pin or wire insertion, heat generation must be carefully managed to avoid thermal necrosis of the surrounding bone, formation of ring sequestra, and loosening of the pin, which elevate the risk of bacterial infiltration and potential infection.

Pin loosening

Pin loosening often stems from factors like pin infection or inadequate pin placement (for example mono-cortical) during the procedure. Pin infection weakens the bone-implant interface, increasing the risk of loosening. Inadequate pin insertion contributes to this, impacting fracture reduction and overall success. Careful pin insertion, monitoring for infection, and ensuring proper fixation are crucial preventive measures. 

In case of pin loosening, take the following steps:

• Pin Removal - Remove all involved pins and place new pins in a healthy location
• Debridement - Debride the pin sites in the operating theater, using curettage and irrigation

Fracture related infection (FRI)

Deep infection is one of the most feared complications of open fractures. Many measures can reduce this risk, including safe surgical practice, choosing an appropriate fixation strategy for the local setting, and good postoperative care. When the risk of fracture-related infection is high: for example with severe soft-tissue damage, limited sterility, or significant comorbidity; external fixation, such as a bar-to-bar frame or, if available, a ring fixator, should be strongly considered.

An introduction to Fracture-Related Infection (FRI)

Neurovascular damage

Apart from neurovascular damage at time of injury as seen in Gustilo Anderson class 3C injuries, iatrogenic neurovascular damage is especially a risk in open fracture surgery because the high energy of the trauma has led to tissue damage. This may result in more difficult recognition of anatomical planes and structures. In both casting, internal and external fixation there is risk of nerve (peroneal nerve!) or blood vessel damage. 

For external fixation, understanding safe zones for pin placement and adhering to proper anatomical principles is essential for minimizing the risk of neurovascular complications:

• Correct pin placement technique
• Tissue protector - Use a tissue protector or drill bit during drilling and pin insertion to prevent interference with muscles and neurovascular structures.
• Neurovascular status - Conduct direct postoperative neurovascular checks to assess for any signs of compromise or impairment.

Non-union

Non-union is the failure of a fractured bone to heal despite appropriate treatment and a sufficient time frame. 

Persistent pain, lack of radiographic evidence of healing, and the absence of clinical improvement are indicative of a potential non-union. Diagnostic tools such as X-rays, can help to assess the extent of healing or identify factors contributing to the lack of union.

Non-union can result from various factors, including:

• Excessive movement or distraction/malaligment at the fracture site. This also know as hypertrophic non-union, showing excessive callus formation at the fracture site.
• Inadequate blood supply
• Infection
• The presence of systemic conditions that impede the body's natural healing processes (e.g. diabetes, malnutrition, smoking, chronic illness).

As previously mentioned: "Orthopaedics is not carpentry, it's gardening." The identification of the underlying cause of non-union is essential, as successful treatment depends on correcting the biological or mechanical problem preventing union.

Treatment may include surgical intervention to:

• Enhance bone compression at the fracture site.
• Create more fracture stability for example by adjusting an external frame (in hypertrophic non-unions)
• Enhance blood supply. This may include a vascular work-up.
• Treat fracture-related infections
• Improve patient-specific factors.

Joint Stiffness and Muscle Atrophy

Inadequate reduction of intra-articular fractures and prolonged use of external fixation can lead to joint stiffness and muscle atrophy. Early initiation of rehabilitation exercises can help mitigate these issues. A construct should be strong enough for partial weight bearing.