Flynn_Ch030.indd

258

Operative Techniques in Pediatric Orthopaedic Surgery

■ Elastic Intramedullary Nail Fixation ■ The surgeon begins by selecting the proper nail size. Usually, nails should be 0.4 times the diameter of the tibial isthmus. ■ The nails are contoured so that there is a C shape with its apex at the fracture site. This will cause cortical contact at the apex, yielding three-point fixation (proximal, cortical at fracture level, and distal). ■ By contouring rods of equal diameter symmetrically, the elastic- ity of the nails resists deformation of the fracture, as opposed to reamed nailing, where the fracture is statically supported by the strength of the nail. Preparation for Nail Insertion ■ The nails are inserted in the tibial metaphysis. ■ The proper starting point is at least 1 cm distal to the proxi- mal tibial physis and 2 cm posterior to the tibial tubercle physis ( TECH FIG 3A,B ). ■ The relevant landmarks should be identified fluoroscopically and marked on the skin (physis, tubercle, starting points) before pro- ceeding ( TECH FIG 3B ). ■ The incision should be 1 to 1.5 cm long, with its most distal extent roughly 1 cm proximal to the physis. ■ This will allow an oblique passage of the nail at the correct proximal to distal angle. ■ A small hemostat is used to carefully spread through the tissue down to bone, and a drill sleeve and drill are placed on the bone. The drill should be 1 to 1.5 mm larger than the diameter of the nail.

■ After checking the position of the drill tip with fluoroscopy ( TECH FIG 3C ), a starting hole is drilled along the proposed path of the nail ( TECH FIG 3D ). ■ Care is taken not to drill across the tibia out the opposite cortex. ■ Alternatively, an awl can be used by hand to create this opening in the cortex. Nail Pattern and Placement ■ Multiple nail patterns have been described, 6 but the standard is one medial and one lateral nail ( TECH FIG 4A,B ). ■ Alternately, if soft tissue compromise precludes the use of an entry site, the first nail is bent into a C shape, with the second bent into an S shape. The apex of the more distal curve in the nail should be at the fracture site. ■ The first nail is contoured into a C shape. It should be placed on the tibia and a fluoroscopic image obtained ( TECH FIG 4C,D ). ■ A gentle bend is placed in the nail, centered at the fracture. ■ The nail is placed up to the fracture site under fluoroscopic guid- ance. Initially, it is helpful to direct the bend posteriorly, as in the passage of a guidewire for a standard reamed nail, but it is important to rotate the bend into the proper plane to prevent a recurvatum deformity ( TECH FIG 4E,F ). ■ The second nail is placed in the same fashion. Fracture Reduction and Fixation ■ The fracture is then manually reduced. ■ It is rarely necessary to open the fracture to obtain a reduc- tion, as the fracture can be easily manipulated.

T E C H N I Q U E S

2 cm

1 cm

A

B

C

TECH FIG 3 ● A. The proper starting point for nail insertion lies at least 1 cm distal to the proximal tibial growth plate and 2 cm posterior to the tubercle physis. B. Patient undergoing elastic intra- medullary nailing of the tibia. Marked on the skin are the proximal growth plate and proposed entry sites as well as the fracture. The incision is made proximal to the line of the physis, and an oblique angle matching the final path of the nail is dissected with a he- mostat down to the bone. C. After confirming the entry site radio- graphically, a drill is used through a guide to open the cortex 1 to 2 mm larger than the nail diameter. D. The drill starts perpendicular to the bone and is advanced distally. Care is taken not to drill into a previously placed nail or through the far cortex.

D