External Fixation: Indications, Contraindications, Types, and Complications

Introduction

The concept of external fixation dates back centuries, with early records of wooden splints and metal devices used to stabilize fractures in ancient civilizations. However, modern external fixation techniques developed in the early 20th century. During World War I, surgeons first started experimenting with external fixation to treat complex limb injuries on the battlefield. Over time, advancements in materials and techniques have made external fixation a valuable tool in orthopedic surgery.

What Is External Fixation?

External fixation is a method used to stabilize fractures. It involves the use of external devices, such as pins, wires, screws, and rods, which are attached to the affected bone or bones, and then connected to an external frame. This frame is typically made of metal or carbon fiber and is positioned outside the body, providing stability and support to the injured area.

What Are the Indications for External Fixation?

External fixation devices find applications in various medical fields, including orthopedic trauma, pediatric orthopedics, and plastic surgery, to address various conditions.

Some of the indications for employing external fixation devices include:

• Managing unstable pelvic ring injuries.

• Providing fracture stabilization for patients who are hemodynamically unstable or unsuitable for open surgical procedures.

• Addressing fractures with substantial bone loss.

• Treating comminuted periarticular fractures, such as those affecting the pilon, distal femur, tibial plateau, elbow, and distal radius.

• Addressing fractures accompanied by significant soft tissue swelling.

• Tackling comminuted (shattered) fractures involving long bones.

• Managing open fractures that involve soft tissue loss.

• Managing nonunion (failure of bones to heal) and malunion (improperly healed fractures).

• Correcting limb deformities and facilitating limb lengthening.

• Immobilizing joints following soft tissue flap procedures.

• Combating infections related to bone and surrounding tissues.

• Implementing traction for intraoperative fracture reduction to optimize surgical outcomes.

• Aiding in arthrodesis, a surgical fusion of joints.

• Treating osteomyelitis cases associated with bone loss.

What Are the Commonly Used External Fixation Techniques or External Fixators?

An external fixation device is a medical apparatus used in orthopedic and trauma surgery to stabilize fractured bones and manage various orthopedic conditions. Several techniques or fixators are commonly used in external fixation, each tailored to the patient's specific needs and injury.

These techniques include:

• Unilateral External Fixation: In this method, pins or wires are inserted into the bone on one side of the fracture, and an external frame is attached on the same side. It is suitable for simple fractures or injuries.

• Bilateral External Fixation: Pins or wires are inserted on both sides of the fracture, with an external frame connecting them. This technique provides greater stability and is often used for complex fractures and lengthening bones.

• Hybrid Fixation: Combining internal and external fixation, this technique is useful in cases where a combination of stabilization methods is required.

• Circular Fixators: Circular frames, such as the Ilizarov apparatus, consist of rings connected by wires or pins. This method allows for precise control of bone alignment and is commonly used in limb lengthening procedures and deformity corrections.

What Are the Contraindications for External Fixation?

External fixation is generally considered a safe and minimally invasive procedure in orthopedics, offering significant benefits when applied appropriately. However, there are some relative and general contraindications that healthcare providers should consider when determining its suitability for a patient:

• Obesity - In severely obese patients, the excess adipose tissue can make it challenging to safely and effectively place the pins or wires required for external fixation. This limitation may lead to reduced fixation stability and an increased risk of complications.

• Non-Compliance - Patients who are non-compliant with postoperative care, follow-up appointments, or weight-bearing restrictions pose a relative contraindication. External fixation demands strict adherence to these guidelines for successful outcomes, and non-compliance may lead to complications.

• Peri-Prosthetic Fractures - When dealing with peri-prosthetic fractures (fractures around an existing joint prosthesis), limited bone stock may be available to secure the pins or wires. The presence of the prosthesis can complicate the fixation process, making it a relative contraindication.

• Patient Refusal - If a patient refuses to undergo external fixation, it is a clear contraindication. Informed consent and patient cooperation are essential for any surgical procedure.

• Physiological Inability - Patients who cannot withstand the procedure from a physiological standpoint, such as those with severe cardiovascular compromise or unstable medical conditions, are generally unsuitable candidates for external fixation.

• Inadequate Bone Stock - External fixation relies on the availability of sufficient bone to anchor the pins or wires securely. In cases where there is inadequate bone stock, such as severe bone loss or osteoporosis, the stability of the fixation may be compromised.

• Severe Soft Tissue Infection - An active soft tissue infection at the site of planned external fixation can increase the risk of spreading the infection and complicate wound healing.

What Are the Complications of External Fixation?

External fixation treatment can be associated with various complications like:

• Pin Site Infection - Infections at the pin insertion sites are usually treatable with proper care.

• Frame or Pin/Wire Loosening - Pins, wires, or frame components may become loose over time, affecting stability.

• Osteomyelitis -Severe bone infection, occasionally resulting from untreated pin site infections.

• Malunion - Fractured bones are healing improperly, causing misalignment.

• Neurovascular Injury - Damage to nearby nerves or blood vessels, potentially leading to sensory or motor deficits.

• Compartment Syndrome - Increased muscle compartment pressure, occasionally related to external fixation and requiring prompt intervention.

• Non-union - Fractured bones fail to heal, necessitating further treatment.

• Soft-Tissue Impalement - Pins or wires accidentally penetrate soft tissues, potentially causing injury.

• Refracture Around Pin - Bones may fracture again near pin sites due to stress or inadequate fixation.

What Are the Recent Advancements in External Fixation?

External fixation techniques have evolved significantly in recent years due to advancements in materials and technology. Some notable developments include:

• The materials used in external fixation devices have become more durable and lightweight, reducing the risk of complications and making the treatment more comfortable for patients.

• Computer-assisted systems allow for more precise pin placement and frame construction, enhancing the overall accuracy of the procedure.

• Minimally invasive external fixation techniques reduce tissue trauma and promote quicker recovery. This is especially beneficial in pediatric orthopedics.

• Using growth factors, stem cells, and other biological adjuncts with external fixation has shown promise in accelerating bone healing and tissue regeneration.

• Some modern external fixation devices are equipped with telemetry systems that allow for remote monitoring of frame parameters, improving patient care and reducing the need for frequent in-person visits.

Conclusion

External fixation is indispensable in modern fracture care, providing temporary and definitive stabilization. Its rapid application, minimal invasiveness, and ability to reduce the ‘second hit’ phenomenon in damage control settings make it a valuable tool. Additionally, allowing time for soft tissue swelling to subside significantly reduces the risk of infection and wound complications, reinforcing its critical role in enhancing patient outcomes in fracture management.