Timothy P. Carey M.D., FRCSC
University of Western Ontario
The treatment of paediatric femoral shaft fractures has undergone significant change over the last ten years. Although nonoperative treatment modalities such as traction and casting have a proven record of safety and efficacy, there has been a "spill over" effect from the adult trauma experience. It has been recognized for many years that stable internal fixation of femoral shaft fractures with rigid locked intramedullary (IM) nails in adults provides vastly improved results, both in terms of fracture healing, rehabilitation and prevention of complications such as pulmonary compromise1. In view of the impressive results obtained with adults, it was perhaps a natural progression to apply the same principles to the skeletally immature patient with a femur fracture.
Early reports of the experience in the paediatric age group were encouraging. Some concern was voiced in the literature about possible damage to the greater trochanteric apophysis, or the superior aspect of the femoral neck and limb length discrepancy due to overgrowth2,3. However, more important than these were the later reports of avascular necrosis of the femoral capital epiphysis. This unexpected and potentially devastating complication was described in a few published case reports and informal surveys suggest that the incidence was perhaps higher than reported4,5. Theories regarding the complication of avascular necrosis (AVN) following IM nailing centre on the possibility of injuring retinacular branches of the medial femoral circumflex artery in the piriformis fossa.
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|Figure1 : Unstable high energy fracture in 14 yr old male ||Figure 2 : Fixation with 8.5mm Trochanteric Antegrade Nail |
In response to these concerns, flexible intramedullary nailing has become a common treatment method in the pediatric patient above the age of eight years. The use of unreamed flexible nails inserted in a predominantly retrograde technique has avoided the complications of AVN and growth arrest, while still providing the ability to avoid cast immobilization and institute earlier rehabilitation. It has also markedly shortened the hospital stay of patients with femur fractures6,7,8.
Numerous series of rigid IM nailing in the paediatric population exist in the literature and, results with regards to fracture healing and return to function mirror the adult experience. Femoral overgrowth has not been a significant functional issue and alterations of the proximal femoral morphology have been minimal. AVN has been a rare complication, but is obviously extremely serious. Almost all the reported cases occurred with a piriformis fossa insertion point, although a few trochanteric antegrade nail series have been reported9,10,11.
What then is the indication for a rigid reamed intramedullary nail in the paediatric patient? The skeletally immature adolescent involved in a high energy injury, such as MVC, often sustains an adult type femoral fracture with significant comminution. In this scenario, it is difficult to prevent shortening and angulation with flexible IM nails. Likewise, pathological femoral fractures through benign lesions such as bone cysts can often leave an unstable fracture pattern (Fig.1,2). In these situations, options become limited to traction followed by casting, internal fixation with plates, or external fixation - all of which have major drawbacks.
|Figure 3 : Ambulatory rehabilitation with weight bearing leads to rapid healing |
Recognizing the risk of AVN with reamed IM nailing, and postulating that it is due to damage of the femoral head blood supply by reamed nailing through a piriformis fossa insertion point, some have advocated reamed IM nails inserted through a greater trochanteric insertion point. The theory behind this is that by avoiding the blood supply to the femoral head in the piriformis fossa, one eliminates the complication of AVN, while benefiting from the additional stability of a locked IM nail. The potential problem of growth disturbance of the greater trochanter is felt to be small in the adolescent, as most of the growth in this region after the age of eight is appositional12.
Technical issues exist with a trochanteric insertion point however. Varus malalignment is a frequent result of this start point, and a relatively small nail that has a degree of flexibility is required to avoid a medial wall fracture in the proximal segment. As well, one must strictly avoid any encroachment of the piriformis fossa. Many of these issues have been dealt with in modern IM nail systems. Trochanteric antegrade nails are now readily available, designed with a proximal bend to facilitate insertion in the tip of the trochanter. Titanium alloy nails are sufficiently flexible to allow atraumatic insertion, yet are very strong in relatively small diameters. With the immediate stability afforded by proximal and distal locking screws, a large nail with tight intramedullary fit is not required and often an 8.5 mm diameter nail is sufficient. Modern instrumentation with rigid threaded guide pins and rigid small diameter cannulated "starter" reamers allow extremely accurate percutaneous placement of the start point with excellent control.
The role for rigid IM nailing in the paediatric population is therefore a limited one. The older child and adolescent with a stable fracture pattern should most probably be treated with flexible IM nailing, as it delivers the benefits of early mobilization and short hospital stay with a low risk of significant complications. Skeletally mature adolescents are obviously treated as adults with standard rigid locked IM nails. Rigid IM nails in the skeletally immature adolescent are at present limited to older adolescents (>10 yrs) with unstable fracture patterns not amenable to flexible nailing. Strict adherence to the technique as discussed above is required to avoid complications. As we obtain longer-term follow-up with this technique and with the use of appropriately designed implants, it is likely that indications may expand to include uses such as deformity correction (Fig. 3).
- Bucholz, R., Jones, A.: JBJS 1991 Dec 73-A(10);pp1561-1566
- Beaty J., Austin S., Warner W.C., et al. Interlocking intramedullary nailing of femoral shaft fractures in adolescents:preliminary results and complications. J Pediatr Orthop 1994;14:178-183
- Galpin R.D., Willis R.B., Sabano N. Intramedullary nailing of pediatric femoral fractures. J Pediatr Orthop 1994;14:184-189
- Aston D., Wilber J., et al. Avascular necrosis of the capital femoral epiphysis after intramedullary nailing for a fracture of the femoral shaft. A case report. J Bone Joint Surg (Am)1995;77:1092-4
- Mileski R., Garvin K.L., Huurman W.W. Avascular necrosis of the femoral head after closed intramedullary shortening in an adolescent. J Pediatr Orthop 2000;20:482-4.
- Ligier J.N., Metaizeau J.P., Prevot J., Lascombes P. Elastic stable intramedullary nailing of femoral shaft fractures in children. J Bone Joint Surg (Br) 1988; 70:74-7.
- Carey T.P., Galpin R.D. Flexible intramedullary nail fixation of pediatric femoral fractures. Clin Orthop. 1996;332:110-118.
- Heinrich SD, Drvaric D.M., Darr K., MacEwen G.D. The operative stabilization of pediatric diaphyseal femur fractures with flexible intramedullary nails: a prospective analysis. J Pediatr Orthop. 1994 Jul-Aug;14(4):501-7.
- Momberger N., Stevens P, Smith J, et al. Intramedullary nailing of femoral fractures in adolescents. J Pediatr Orthop 2000;20:482-4
- Townsend D., Hoffinger S. Intramedullary nailing of the femoral shaft fractures in children via the trochanteric tip.
- Green N., Letts M., Stanitski C.L., Stanitski C.L. Debate: a healthy 12-year-old boy with an isolated mid-diaphyseal femur fracture should be treated with an antegrade, locked, intra-medullary rod. J Pediatr Orthop. 2002 Nov-Dec;22(6):821-6.
- Gage J.R., Cary J.M. The effects of trochanteric epiphyseodesis on growth of the proximal end of the femur following necrosis of the capital femoral epiphysis. J Bone Joint Surg Am. 1980 Jul;62(5):785-94.