A fracture fixation device is hardware used to stabilize a broken bone, holding fragments in the correct position while natural healing takes place. Stabilization is accomplished using implants placed entirely inside the body or a structure applied externally. The primary purpose of these devices is to ensure the bone pieces remain aligned, preventing movement that could disrupt the formation of new bone tissue. Modern fixation techniques allow for earlier patient mobilization and rehabilitation, which can lead to a more complete functional recovery. The choice of device is determined by factors such as the type, location, and severity of the fracture.
Internal Versus External Stabilization Methods
Orthopedic surgeons categorize stabilization into two main methods based on the hardware’s placement relative to the skin. Internal fixation involves the use of implants, such as plates and rods, which are positioned completely beneath the skin and muscle. This method provides stability from within the limb and is preferred for fractures that require precise and long-term support. Internal fixation allows the patient to avoid external components, often leading to a quicker return to normal activity.
Conversely, external fixation utilizes a frame that remains outside the body, connected to the bone via metal pins or wires inserted through the skin. This approach is often chosen when the surrounding soft tissues are severely damaged or swollen. An external fixator provides immediate fracture stability without causing further disruption to the soft tissue envelope. It can also be applied quickly in emergency situations, acting as a temporary measure until the patient is stable enough for definitive internal fixation.
Components of Internal Fixation
Internal fixation relies on specific implants to secure the bone fragments after they have been surgically realigned. These implants are constructed from biocompatible materials like stainless steel or titanium alloys. The primary internal devices are plates, screws, and intramedullary rods, each serving a distinct mechanical purpose.
Plates function like an internal splint, spanning the fracture site and securing the bone fragments with multiple screws. They can be used in two main ways: as compression plates, which pull the bone ends together to promote direct healing, or as bridging plates, which maintain the overall length and alignment without compressing the fragments. The plate material and design are engineered to withstand forces applied to the bone during recovery.
Screws are employed both independently and to anchor plates and rods. A lag screw is designed to apply compression across the fracture, pulling the two bone fragments tightly against each other to enhance stability. Position screws are used simply to hold bone fragments in a specific alignment, such as securing a plate to the bone surface.
Intramedullary rods, often referred to as nails, are the standard treatment for fractures of long bones like the femur and tibia. This specialized device is inserted down the medullary canal of the bone. The rod acts as a strong internal column that supports the bone’s weight-bearing capacity from the inside out. Locking screws are placed through the bone and the rod at both ends to prevent the fracture from shortening or rotating during the healing period.
Function and Use of External Fixators
External fixation involves a system where metal pins or wires pass through the skin and muscle to anchor directly into the bone fragments. These pins are then connected to an adjustable metal frame or ring structure positioned outside the limb. This frame provides rigid support, maintaining the bone’s alignment and length while allowing the surgeon to easily access the surrounding soft tissues.
The device is particularly useful in managing severe open fractures, which involve contamination and a high risk of infection. The external frame avoids placing foreign material directly within the contaminated wound, which can allow for effective wound care and monitoring. External fixation is also commonly used for temporary stabilization in polytrauma patients, providing rapid fixation until the patient’s overall condition improves enough for a more involved internal procedure.
External fixators can also be used as a definitive treatment to correct complex deformities or achieve limb lengthening. The external frame can be gradually adjusted over time, a process known as distraction osteogenesis, to slowly separate bone segments. This controlled tension stimulates the body to generate new bone tissue in the gap, successfully increasing the length of the limb or correcting angular misalignment.
Life with Fixation Devices and Removal
The patient’s experience with a fixation device is highly dependent on the type of hardware and the specific bone involved in the injury. Internal implants, once the incisions have healed, are largely unnoticeable, allowing for relatively unrestricted physical therapy and rehabilitation. External fixators, while allowing for immediate stabilization, require diligent pin-site care to prevent infection where the metal pins enter the skin. The external frame can also be bulky and may require adjustments to clothing and daily routines during the healing phase.
The recovery timeline varies, but hardware removal is considered once the fracture is fully healed, which can take six months to a year or more. Internal hardware is often designed to remain in the body permanently unless it causes symptoms. A primary reason for elective removal is localized pain or irritation caused by the implant being close to a tendon or nerve, or if it is prominent under the skin.
Hardware removal is not routine and is usually only performed if the device causes a problem or if the patient is young and has completed skeletal growth. Other indications for removal include infection, which requires prompt surgical intervention, or if the hardware interferes with joint function. The decision to remove any fixation device is made only after radiographic imaging confirms the bone has achieved complete and stable union.