NEW PEDIATRIC PRODUCTS
27
Richard Reynolds
NEW PEDIATRIC PRODUCTS Adolescent Lateral Entry Femoral Nail The adolescent lateral entry femoral nail (ALFN) is intended for use in adolescents and small stature adults depending on the persons' weight, body size, physiological development, neurological development, and neuromuscular coordination. The ALFN is indicated to stabilize fractures of the femoral shaft, subtrochanteric, ipsilateral neck/shaft and impending pathological fractures, as well as nonunions and malunions of the femur (Fig 1). The ALFN can also be used to stabilize corrective osteotomies in bone dysplasias such fibrous dysplasia where femoral deformity is an issue.
Fig 1 ALFN.
Conventional antegrade nailing of the femur in this age group is a concern because of the possibility of avascular necrosis of the femoral head. This is rare but devastating. The ALFN has a lateral trochanteric entry point and a double curved configuration (double bend in two planes and additional tip bend) to avoid compromising the ascending branch of the medial femoral circumflex artery near the piriformis fossa. The recommended entry site is on the bare aspect of the greater trochanter 15–20 mm distal to the tip of the greater trochanter and forms an angle of 12–14° lateral to the greater trochanter, as measured from the lateral entry point to a point 20 mm distal to the lesser trochanter (Fig 2). The ALFN is cannulated and has 8.2 mm shaft diameter and a proximal diameter of 11 mm. The nail comes in lengths from 240–400 mm in 20 mm increments. Additional diameters of 9 mm and 10 mm are under development. For the opening, a 13.0 mm cannulated drill bit is used.
Fig 2 Insertion point.
The ALFN features the same proximal locking options as the LFN (two recon locking screws, one transverse slot for a static or dynamic locking screw, and one 120° antegrade locking screw). The recon screws are 5.0 mm solid, self-tapping shaft screws available in lengths from 50–125 mm. For distal locking, two lateral to medial locking screws can be used. It is of major importance to ensure that the wires and drill bits used for the recon screw insertion do not cross the capital femoral physis, and that the distal end of the nail stops 15 mm short of the distal femoral physis. The adolescent lateral entry femoral nail is part of the expert nail family, therefore most instrumentation is identical, except for a new insertion handle aiming arm (Fig 3), 13 mm drill sleeve, and 5.0 mm recon screw drill bit. The ease of finding the entry point is maximized if the greater trochanter is positioned in profile to the beam of the C-arm. This can be done in either supine or lateral decubitus position.
Fig 3 Nail with new insertion handle.