A systematic review of rigid, locked, intramedullary nail insertion sites and avascular necrosis of the femoral head in the skeletally immature.

BACKGROUND:
Fracture of the femoral shaft is a common injury that has varying etiology in the pediatric population. Rigid, locked, intramedullary nailing allows for early mobilization, and is usually reserved for older children and adolescents with good success. Avascular necrosis (AVN) of the femoral head is a rare, but serious complication. The entry site of the nail has been speculated to have an effect on the risk of AVN, with different nail entry sites used to avoid the proximal femoral blood supply. The purpose of this study was to complete a review of the literature and elucidate the effects of nail entry site on the risk of AVN of the femoral head.

METHODS:
The English medical literature (Pubmed and Embase) was searched and 1277 articles were identified and reviewed. Articles were excluded if they were case reports, did not examine long-term complications, or if the insertion location of the intramedullary nail could not be determined. Articles were also excluded if they examined both femoral neck and femoral shaft fractures. All of the patients using each insertion site were combined together for analysis to determine the overall AVN complication rate.

RESULTS:
From the 1277 articles found during the searches, 19 relevant articles were identified. The piriform fossa AVN rate was 2%. The AVN rate for the tip of the greater trochanter entry site was 1.4%. There were no reported cases of AVN using the lateral aspect of the greater trochanter as an entry site. The primary limitation of this study is that it reviewed retrospective data and the 3 research groups were not equal in size.

CONCLUSIONS:
The lateral trochanter as an insertion site for rigid, locked intramedullary nailing has the lowest risk of AVN when treating pediatric femur fractures based on the current literature.