Percutaneous pinning is a minimally invasive orthopedic procedure used to stabilize bone fractures. The term “percutaneous” means the pins are inserted through the skin, avoiding the need for a large surgical incision. This technique uses small metal pins, frequently Kirschner wires (K-wires), which act as temporary internal scaffolding to hold fractured bone fragments in the correct position. The primary goal is to achieve and maintain proper bone alignment until the natural healing process is complete, minimizing disruption to surrounding soft tissues like muscles and ligaments.
The Mechanics of the Surgical Technique
The procedure typically begins with the patient under anesthesia, which may be general or a regional block, after the surgical site is prepared. The surgeon first performs a closed reduction, manipulating the fractured bone fragments back into an acceptable anatomical position without making a large open incision. Maintaining this precise alignment is then achieved by inserting the metal pins through the skin and into the bone.
The technique relies on fluoroscopy, a specialized form of live X-ray imaging, often using a C-arm device. This real-time imaging allows the orthopedic surgeon to visualize the bone and the path of the pin, ensuring accurate placement across the fracture site. The pins are either carefully pushed or drilled across the fracture line, fixing one fragment to the other to create stability.
Once the bone fragments are fixed, the external ends of the pins are usually trimmed just outside the skin surface, making them accessible for later removal. This method offers less surgical trauma compared to procedures requiring extensive cutting of the skin and muscle to expose the bone. The technique’s success depends on the surgeon’s ability to guide the pins precisely using the live imaging.
Common Fractures Treated with Pinning
Percutaneous pinning is a preferred treatment for many fractures, especially those in the extremities that can be realigned without extensive open surgery. It is commonly employed for displaced fractures of the distal radius (the forearm bone near the wrist), certain ankle fractures, and those in the small bones of the hand and foot.
The technique is important in pediatric orthopedics, particularly for supracondylar humerus fractures in the elbow, which are common childhood injuries. Pinning is often favored in children because it minimizes disturbance to the growth plates (areas of developing cartilage at the ends of long bones). Avoiding large incisions reduces the risk of damage to these sensitive growth areas, promoting normal bone development.
Pinning offers benefits like a decreased risk of tissue damage and a generally faster operative time than traditional open reduction and internal fixation. It is most effective for fractures that are either stable or can be successfully reduced into a stable position before the pins are inserted.
Post-Operative Care and Pin Removal
Following the procedure, the limb is typically immobilized with a cast or splint to protect the fracture site during the initial healing phase. A major focus of post-operative care is meticulous pin site hygiene, since the pins protruding through the skin create a direct path for bacteria to enter the body. Patients or caregivers must follow specific cleaning instructions, often involving a sterile saline or mild soap and water solution, to minimize the risk of infection.
Patients are instructed to monitor the pin sites closely for signs of infection, including increased redness, swelling, warmth, pain, or thick, colored drainage. Immediate medical attention is necessary if these symptoms appear, as a pin tract infection is the most common potential complication. Other less frequent complications include pin migration (where a pin loosens or moves) or irritation of nearby nerves or tendons.
The pins remain in place until X-rays confirm the fracture has healed enough to maintain stability, typically between three and six weeks post-surgery. Pin removal is a straightforward procedure, usually performed in the orthopedic clinic or a doctor’s office, not in an operating room. It is often a quick process requiring minimal to no anesthesia, though some patients may receive a local anesthetic injection for comfort. Once the pins are withdrawn, the small skin openings close quickly, and the patient begins rehabilitation to restore full range of motion and strength.