Treatment of a Pediatric T-type Intercondylar Humerus Fracture With Hybrid Percutaneous Pinning and External Fixation

Case Report

A healthy 8-year-old boy fell at a height of approximately 2.4 m from a tree onto his dominant right elbow. He presented to the emergency department with a painful, swollen elbow and was found to have a closed injury with no evidence of neurologic or vascular compromise. Diagnostic radiographs showed a Gartland type III supracondylar fracture and intercondylar humerus fracture with a T-type pattern along with a simple fracture line that extended to the articular surface at the capitellotrochlear groove. Comminution of the medial column about the supracondylar metadiaphysis was also evident (Figure 1). After discussion with the family, he was taken to the operating room for surgical intervention with closed reduction and percutaneous pinning.

Figure 1: Preoperative anteroposterior radiograph of the right elbow of an 8-year-old boy after a fall. An intercondylar humerus fracture with a T-type pattern along with a simple fracture line that extended to the articular surface is shown.

Combined medial and lateral pinning with large-diameter smooth Steinmann pins was selected, given the uncertainty of purchase in the comminuted medial metadiaphyseal cortex. The medial pin was inserted first, using a small incision and visualization to avoid the ulnar nerve. The pin was used to “joystick” the fracture out of varus and apex anterior alignment and then was driven up the medial column through the lateral metadiaphyseal cortex. The lateral pin was inserted percutaneously and secured in the lateral column. Intraoperative imaging confirmed the suspected intercondylar split. The articular fracture was then compressed by applying a small AO external fixator bar between these 2 pins (Figure 2), closing the fracture gap.

Figure 2: Photographs of the right elbow (A) and upper extremity (B) of an 8-year-old boy with a small AO external fixator bar between 2 pins. Intraoperatively, hand compression was observed after reduction and percutaneous pinning.

The patient's arm was protected for 6 weeks in a well-padded posterior slab fiberglass splint. After 6 weeks, the fixator and pins were removed in the clinic uneventfully. On physical examination, the patient had a strong radial pulse, nearly full range of motion, and minimal pain. Radiographs showed good bone healing with maintenance of reduction (Figure 3). Six months postoperatively, the patient had full range of motion and minimal rigidity of the right elbow.

Figure 3: Postoperative anteroposterior (A) and lateral (B) radiographs of the right elbow of an 8-year-old boy who presented with an intercondylar T-type fracture. Progression of healing and grossly anatomic alignment is shown 6 weeks after medial and lateral percutaneous pin placement.

Discussion

Classic principles of fracture management evoke the need for direct reduction for perfect alignment of articular fractures, followed by compression for primary bone healing. For simple intercondylar split patterns of the distal humerus, this can be achieved by lag screw fixation laterally or medially across articular fragments or, as described in the current case, with compression via an external fixator construct. The current technique is simple, cost-effective, and familiar to most orthopedic surgeons, and it avoids permanent implants around the joint. This technique is also percutaneous. This less invasive approach saves dissection but does not permit visualization of the articular surface. Substantial limitations to range of motion after open approaches to these fractures were common in the case series reported; however, functional deficits were uncommon.^3,5 Unlike lateral-only pinning, crossed pinning is a technique that can stabilize the supracondylar component effectively despite minor medial cortical comminution.

The current technique has some disadvantages. The external fixator apparatus may be vulnerable to patient manipulation, so splinting or casting is still advisable. Bars positioned too close to the skin could cause pressure necrosis. Finally, medial pinning poses a risk to the ulnar nerve.¹²

The literature has described good and excellent functional results after percutaneous pinning for simple intercondylar fractures.^9–11 Although limited to fewer than 20 patients, there was only 1 reported range-of-motion deficit. To address the intercondylar component, authors have suggested either smooth or partially threaded transfixion Kirschner wires.^10,11 These wires may migrate, and the fixation is less robust than that afforded by a screw or external compression.

The use of an open approach for simple intercondylar split patterns is debatable. In such intercondylar fractures, the surrounding fascia and joint capsule of the lateral or medial elbow are often disrupted, and open approaches can use these planes. Complete visualization of the distal humeral articular surface can be limited by the window created from the injury, the coronoid or radial head, or the fracture pattern, which may course strictly between the capitellum and the trochlea. Only an olecranon osteotomy permits complete visualization and inspection of the articular surface of the distal humerus.¹³ Triceps-splitting⁶ and triceps-sparing⁸ approaches have been advocated for pediatric fractures, but the risks of dissection to the posterior periosteum must be considered to avoid devascularizing fracture fragments. As in fractures of the tibial plateau, imaging-assisted reduction and prevention of articular diastasis can be effective. Fracture lines may traverse the nonarticular portion between the capitellum and the trochlea, which is an area that may not require direct reduction.

Conclusion

The current technique may be useful in planned fixation of simple T-type intercondylar fractures of the distal humerus or as a conversion after unexpected intraoperative imaging of a presumed supracondylar fracture. Fractures with more complex articular involvement may not be amenable to this technique. Further multicenter research is warranted to determine the long-term outcomes and safety of hybrid percutaneous pinning and external fixation for these rare pediatric intercondylar distal humerus fractures.