Percutaneous pinning is a surgical technique in which thin metal pins are driven through the skin and into bone fragments to hold a fracture in alignment while it heals. The word “percutaneous” simply means “through the skin,” and that is the defining feature: instead of cutting open the injury site to access the bone directly, the surgeon uses small puncture points and real-time imaging to guide each pin into place. The technique dates back over a century, when Martin Kirschner introduced his wire in 1909, and it remains one of the most widely used methods for stabilizing fractures in children’s elbows, hands, wrists, and other sites where a full open surgery would cause unnecessary tissue damage.
How the Procedure Works
The basic sequence is straightforward. First, the surgeon manipulates the broken bone back into proper alignment, a step called closed reduction, done by feel and confirmed with fluoroscopy (a live X-ray feed on a screen). Once the fragments are lined up, stainless-steel pins, most commonly Kirschner wires (K-wires), are drilled through the skin and into the bone to lock the fragments together. K-wires come in diameters ranging from about 0.7 to 3.2 mm, with pointed tips in either trocar or diamond configurations that help them pass through soft tissue and bone cortex without excessive force.1PubMed Central. Orthopedic hardware and equipment for the beginner: part 1: pins and wires The surgeon watches the fluoroscope throughout, adjusting pin angle and depth in real time.
After the pins are placed, their ends are typically cut short, bent at the skin surface to prevent them from migrating deeper into the body, and a cast or splint is applied over the top. The whole operation often takes less than 15 minutes for simple fractures. In a study comparing percutaneous pinning to open surgery for metacarpal fractures, the average operating time for the pinning group was about 14 minutes compared to roughly 32 minutes for the open approach.2Hand and Microsurgery. Percutaneous Pinning Versus ORIF For Treatment Of Extraarticular Metacarpal Fractures
Where It Is Used Most Often
Percutaneous pinning shows up across orthopedic surgery, but two areas dominate: children’s elbow fractures and hand or wrist injuries in both children and adults.
Supracondylar fractures of the humerus, the bone above the elbow, are the most common elbow fracture in children. The standard treatment for displaced types is closed reduction followed by percutaneous pinning. The surgeon typically places two or three divergent pins from the lateral (outer) side of the elbow, checks stability under live fluoroscopy, and applies a long-arm cast. Pins come out in the office three to four weeks later, and while the elbow is often stiff for another month or so, a near-full range of motion is expected.3PubMed Central. Closed Reduction and Percutaneous Pinning of Pediatric Supracondylar Humeral Fractures A prospective study of lateral pinning in these fractures found excellent or good outcomes in all patients, with 92% achieving excellent results.4PubMed Central. Functional Outcomes of Percutaneous Lateral Pinning in Pediatric Supracondylar Humerus Fractures: A Prospective Study with Emphasis on Postoperative Analgesic Management
In the hand and wrist, percutaneous pinning is commonly used for metacarpal fractures (the long bones in the palm) and certain distal radius fractures (the wrist bone closest to the hand). A clinical trial of percutaneous transverse pinning for metacarpal fractures reported that grip strength was preserved in 88% of patients, all returned to work or normal activities within two months, and 96% were highly satisfied with the technique.5PubMed Central. Percutaneous transverse pinning for metacarpal fractures: a clinical trial These results reflect the method’s strength in the hand: it stabilizes the bone without the scarring, tendon adhesions, and stiffness that open surgery can introduce in such a tight, mobile area.
Pin Configuration and Why It Matters
Where and how pins enter the bone is not arbitrary. The configuration affects both the mechanical strength of the fixation and the risk of hitting nerves. In children’s supracondylar fractures, for example, there is a long-standing debate between lateral-only pins and a combined medial-lateral approach. Lateral-only pins avoid the ulnar nerve, which runs along the inner side of the elbow, but earlier studies suggested they provide less torsional stability. Combined medial-lateral pins are biomechanically stronger, but placing a pin on the medial side puts the ulnar nerve at risk of being injured by the pin itself.6PubMed Central. A comparative study of two percutaneous pinning techniques (lateral vs medial–lateral) for Gartland type III pediatric supracondylar fracture of the humerus
Pin alignment within the bone also plays a role. A biomechanical study tested three configurations in supracondylar fracture models and found that the direction of the pins in the sagittal plane (front to back) significantly affected how much force was needed to displace the fracture. The strongest configuration required roughly 40% more torque to fail than the weakest.7PubMed Central. Sagittal plane alignment affects the strength of pin fixation in supracondylar humerus fractures In practice, this means the surgeon is not just placing pins in bone; they are engineering a construct whose geometry determines whether the fracture stays put during healing.
Nerve Safety Around the Pins
Because the surgeon cannot see the soft tissues directly, percutaneous pinning carries an inherent risk of injuring nearby nerves. The anatomy dictates where that risk is greatest.
At the elbow, the ulnar nerve is the primary concern on the medial side. Children’s ulnar nerves tend to subluxate, or shift position, when the elbow is flexed, which is exactly the position used during most of the procedure. One study found that all children in their series had a subluxating ulnar nerve, and that the elbow had to be extended to about 90 degrees before a medial pin could be safely inserted. Using ultrasound guidance during pin placement, none of the children suffered ulnar nerve injury.8PubMed Central. Ultrasound-guided Percutaneous Medial Pinning of Pediatric Supracondylar Humeral Fractures to avoid Ulnar Nerve Injury On the lateral side of the elbow, the radial nerve can be at risk if pins are placed too high. Anatomic research has identified a safe zone for lateral pin entry: the lower 70% of a line measured from the lateral epicondyle upward, using the patient’s own trans-epicondylar distance as the measuring stick.9PubMed. Anatomic relationship of the radial nerve to the elbow joint: clinical implications of safe pin placement
In the wrist and hand, the dorsal sensory branch of the ulnar nerve is the structure most at risk. A cadaveric study measured how close percutaneous pins come to this nerve at various sites and found the margins razor-thin in some locations. At the ulnar styloid, the average distance was less than 1 mm, and two of eleven pins in the study directly penetrated the nerve. At the base of the fifth metacarpal the average clearance was only about 2 mm.10PubMed. Risk of Injury to the Dorsal Sensory Branch of the Ulnar Nerve With Percutaneous Pinning of Ulnar-Sided Structures These findings underscore why surgeons may opt for open visualization in certain wrist fixations, even when a percutaneous approach is otherwise preferred.
Fluoroscopy-guided percutaneous pinning is a minimally invasive alternative to open surgery, but relying on two-dimensional imaging alone without understanding the three-dimensional anatomy can lead to poor pin orientation and even violation of joint surfaces. Specialized pinning guides and advanced imaging techniques are emerging to improve accuracy and reduce the number of fluoroscopy shots needed.11PubMed Central. Evaluation of a novel percutaneous pinning guide for femoral head or neck fracture: an ex vivo study
Buried Versus Exposed Pins
After pins are placed, the surgeon decides whether to leave the ends protruding through the skin (exposed) or cut them short and bury them beneath the surface. Each approach involves a genuine trade-off.
Exposed pins are simpler to remove. They can be pulled in a clinic visit without anesthesia, often in seconds. However, the wire sticking out of the skin creates a direct pathway for bacteria. A meta-analysis of hand fracture fixation found that burying K-wires significantly reduced superficial pin-site infections compared to leaving them exposed.12PubMed Central. Buried Versus Exposed K-Wires in Hand Fracture Fixation: A Meta-Analysis of Outcomes A separate systematic review focused on children’s upper-extremity fractures found the infection risk with buried wires was roughly a third that of exposed wires.13Injury. Buried or exposed kirschner wires in paediatric upper extremity fracture fixation: A systematic review and meta-analysis of infection rates and complications In a study of hand and wrist fractures, metacarpal fractures with exposed wires were about twice as likely to develop a pin-site infection as those with buried wires.14The Journal of Hand Surgery. Comparison of Pin-Site Infection Rates Between Exposed and Buried Kirschner Wires in Hand and Wrist Surgery
Buried pins have their own downsides. They need a second procedure with anesthesia to remove, which adds cost and time. Skin erosion, where the healing tissue pushes the buried wire toward the surface, occurred in about 13% of cases in one pooled analysis. And because the surgeon waits longer before removing buried wires (about 11 weeks on average versus about 5 weeks for exposed wires), children spend more time with hardware in place.13Injury. Buried or exposed kirschner wires in paediatric upper extremity fracture fixation: A systematic review and meta-analysis of infection rates and complications Bone union rates and deep infection rates requiring further surgery are similar between the two approaches, so the choice often comes down to patient factors: a cooperative older child who can keep a pin site clean may do fine with exposed wires, while a young child or a fracture in a high-motion area may benefit from burying them.
Infection and Pin Migration
Pin-site infection is the most talked-about complication. The reported rates vary widely depending on how infection is defined and how long the hardware stays in. In a prospective study of patients with external ring fixators, which involve more pins and longer treatment times than simple percutaneous pinning, some degree of pin-site inflammation was documented at 30% of pin sites. Most of these were minor, classified as low-grade, and over half the patients received antibiotics at some point during treatment.15PubMed Central. Prospective evaluation of pin site infections in 39 patients treated with external ring fixation Factors that influence infection risk include surgical technique, pin design, whether antibiotics are given, and the pin-care routine after surgery, which typically involves regular cleaning and dressing changes.16PubMed Central. Prevention of pin site infection in external fixation: a review of the literature
Despite the attention given to pin care protocols, evidence for any one method being clearly superior is limited. A Cochrane systematic review of pin-site care for external fixators found that, aside from one small study showing benefit from an antimicrobial gauze, there were no statistically significant differences between the various cleaning strategies tested.17PubMed Central. Pin site care for preventing infections associated with external bone fixators and pins In other words, keeping the pin sites clean matters, but which cleaning product you use probably does not.
Pin migration is rarer but potentially more serious. Smooth wires can slide through bone, especially if the diameter is too small for the job. In a review of hand and wrist cases, pin migration was noted in seven patients and attributed to the use of small-diameter wires.18PubMed Central. Evaluation and Management of Complications Following Percutaneous K-Wire Fixation in Hand and Wrist Fractures Migration tends to be a larger concern in areas with high motion or when pins are placed around the shoulder, where case reports have documented pins traveling to unexpected locations despite efforts to secure them.19Orthopedics. The Migration of a Broken Pin Following Fixation of the Acromioclavicular Joint Bending the exposed end of the wire helps prevent this, and threaded wires grip the bone more securely than smooth ones.
Recovery and When the Pins Come Out
For children’s supracondylar fractures, the most studied setting, pins are usually removed between three and four weeks after surgery. The procedure is quick: if the wires are exposed, a nurse or surgeon grabs the bent end with pliers and pulls. It is uncomfortable but brief, and the pain settles quickly afterward. For younger children, the anxiety surrounding wire removal can be more distressing than the physical sensation, and poor management of that anxiety has been identified as an area needing improvement in pediatric clinics.
There is ongoing discussion about whether pins can come out earlier. A study dividing children into early (less than three weeks), intermediate (three to four weeks), and late (more than four weeks) removal groups found no cases of loss of reduction or refracture in any group and no significant differences in functional or radiological outcomes.20Formosan Journal of Musculoskeletal Disorders. Time to Pin Removal in Pediatric Supracondylar Humerus Fractures: The Pros and Cons Another study reached the same conclusion, noting that in younger children who show adequate stability and radiographic signs of healing, early removal appears safe and may reduce the need for prolonged follow-up visits.21PubMed Central. Timing of Kirschner wire removal in pediatric supracondylar humerus fractures: Is early removal a safe and effective option? The practical upside of early removal is obvious: fewer clinic visits, less time in a cast, and lower risk of pin-related complications like infection or skin erosion.
How Percutaneous Pinning Compares to the Alternatives
The two main alternatives are casting alone (no surgery) and open reduction with internal fixation (ORIF), where the surgeon makes an incision, directly visualizes the fracture, and fixes it with plates, screws, or wires under direct sight.
Against casting, the advantage of pinning is stability. A randomized study of displaced distal radius fractures in children found that 39% of those treated with casting alone lost their reduction and needed remanipulation, whereas none of the pinned fractures shifted.22PubMed. Cast immobilization versus percutaneous pin fixation of displaced distal radius fractures in children: a prospective, randomized study For fractures that are significantly displaced, pinning simply keeps the bones where they belong more reliably than a cast can.
Against ORIF, the advantages of percutaneous pinning are its lower invasiveness, shorter operating time, less scarring, and lower cost. A comparison of the two approaches for displaced lateral condyle fractures of the humerus found comparable outcomes, but the percutaneous group had the added benefits of no visible scar and no need for a second anesthetic procedure for hardware removal.23PubMed Central. Closed reduction and percutaneous pinning vs open reduction and internal fixation in pediatric lateral condylar humerus fractures displaced by > 4 mm: an observational cross-sectional study The cost difference can be substantial. In a study of metacarpal fractures, the average hospital expense for percutaneous pinning was about $258, compared to $660 for ORIF.2Hand and Microsurgery. Percutaneous Pinning Versus ORIF For Treatment Of Extraarticular Metacarpal Fractures
ORIF remains the better choice when the fracture is too complex for a closed reduction, when the joint surface needs to be perfectly restored, or when soft tissue is trapped between fragments. Percutaneous pinning is not a universal replacement; it occupies the middle ground between casting and open surgery, suited to fractures that are too unstable for a cast but not complex enough to require direct visualization.
Bioabsorbable Pins
One of the persistent inconveniences of metal K-wires is that they have to be removed. A growing body of research is exploring bioresorbable pins, which dissolve in the body over months, eliminating the need for a second procedure. A multicenter retrospective study comparing bioresorbable implants to standard K-wires in severely displaced pediatric radius and forearm fractures found that children in the bioresorbable group required no second surgery. By six months, wrist range of motion was equivalent between groups, and no child reported persistent pain or disability at one year. Growth disturbance was absent in all children at 18 months.24PubMed Central. Bioresorbable implants vs. Kirschner-wires in the treatment of severely displaced distal paediatric radius and forearm fractures – a retrospective multicentre study
The appeal is obvious, particularly for children, who would be spared both the anxiety of wire removal and the risks that come with leaving metal in the body longer than necessary. Bioresorbable pins are not yet standard of care for most fracture types, partly because they are more expensive upfront and partly because long-term data across a wider range of fracture patterns is still accumulating. But for the relatively straightforward fractures where percutaneous pinning already excels, they may eventually replace metal wires altogether.