Pediatric Scaphoid Nonunion

Fig. 17.1

a Posteroanterior and b internal oblique views of the right wrist demonstrating a scaphoid waist nonunion. (Courtesy of Shriner’s Hospital for Children, Philadelphia, PA)

Fig. 17.2

Coronal magnetic resonance imaging (MRI) slices demonstrating the nonunion of the scaphoid waist. Note the lack of bridging bone and signal intensity present about the fracture site. (Courtesy of Shriner’s Hospital for Children, Philadelphia, PA)

Management Options

Numerous surgical options exist for the treatment of pediatric and adolescent scaphoid nonunions, with all of them demonstrating excellent results. Kirschner wire fixation has been shown to be successful [1, 2]; however, more commonly compression screw fixation is now performed if the bone is large enough. [3–5] If bone graft is needed to treat the nonunion , union times are increased by approximately 5 weeks, yet union rates still approach 100 %. [1–7] Furthermore, if the distal radial physis is open, distal radial graft should be harvested with great care to avoid physeal bar formation and premature closure of the physis. We prefer instead to use iliac crest in these circumstances. The use of vascularized bone grafting has also been shown to have union rates close to 100 %. [8] However, vascularized graft options are limited in the child with open physes. We prefer a modification of the technique described by Fernandez et al [9] that was later published by Tang et al [10] using the superficial volar branch of the radial artery .

Management Chosen

Patients that present with a chronic scaphoid fracture cannot be expected to have the same outcomes as children and adolescents that present with acute fractures and therefore casting is not recommended. Treatment with surgical reduction, bone grafting and compression screw fixation was warranted .

Surgical Technique

The patient was brought to the operating room to undergo fixation of the scaphoid waist nonunion. A nonsterile pneumatic tourniquet was applied to the extremity, and it was then prepped and draped in the usual sterile fashion. Additionally, the ipsilateral iliac crest was prepped and draped in case autologous bone graft was needed. A Carter hand table is used to allow for traction during the procedure. The hand table attaches to a standard operating room table and has a pulley attachment at the end that fits a braided wire with a weight attachment loop on one end and a finger-trap attachment on the other end. This table allows for hands-free, constant dynamic distraction of the fracture site to open up the area of nonunion. (Fig. 17.3) The patient was placed supine and with the arm abducted 90° on the hand table, and 10 pounds of finger-trap traction was applied. A rolled towel was placed under the wrist to create wrist extension.

Fig. 17.3

Intraoperative photograph depicting the setup for the treatment of a pediatric scaphoid nonunion including the finger-trap applied traction. (Courtesy of Shriner’s Hospital for Children, Philadelphia, PA)

Initially, the wrist was flexed to permit the lunate to obtain a neutral position. Once the neutral alignment was obtained and confirmed fluoroscopically, the lunate was pinned to the distal radius utilizing a 0.062″ Kirschner wire. A modified Wagner approach was then performed to obtain exposure of the volar scaphoid. In an attempt to augment the vascularity of the proximal fragment, it was decided to perform a vascular pedicle transfer. The superficial volar branch of the radial artery was isolated as it crossed the surgical field. The artery was ligated distally as it entered the thenar muscles and preserved for later use (Fig. 17.4).

Fig. 17.4

Identification and isolation of the superficial volar branch of the radial artery. (Courtesy of Shriner’s Hospital for Children, Philadelphia, PA)

Approximately 25 % of the radioscaphocapitate ligament was divided to permit adequate visualization of the fracture site, which demonstrated a 3- to 4-mm gap. The nonunion site was debrided of fibrous tissue and necrotic bone. Excellent punctate bleeding was present from the distal fragment, but only minimal bleeding was present in the proximal fragment. Therefore, it was decided to proceed with autologous bone grafting of the nonunion. The previously dissected vascular pedicle was also placed into the medullary canal of the proximal fragment to augment vascularity to the nonunion site as described above. (Fig. 17.5)

Fig. 17.5

Placement of the superficial volar branch of the radial artery into the proximal fragment medullary canal. (Courtesy of Shriner’s Hospital for Children, Philadelphia, PA)

Next, an oblique incision was performed directly over the ipsilateral iliac crest and dissection was carried down to the bone. A piece of tricortical graft was obtained and fashioned to fit in the defect that remained after debridement of the nonunion site. The donor wound was then irrigated and closed in layers, and attention was brought back to the wrist.

Cancellous bone from the iliac crest was packed around the vascular pedicle, and the tricortical iliac crest was placed in the defect. Once the graft was in position, a headless compression screw was placed across the nonunion site. Excellent alignment and compression were obtained. The Kirschner wire holding the lunate in neutral position was removed, and the traction was released. Lateral fluoroscopic images were obtained, and the lunate was noted to maintain its alignment in a neutral position. Following irrigation and closure of the wound, the patient was placed in a short arm thumb spica cast and awoken from anesthesia.

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