Risk Factors for Avascular Necrosis of the Femoral Head in Pediatric Femoral Neck Fractures

Introduction A neck of femur fracture is a rare injury in the pediatric population and is of foremost importance, as it is associated with a high rate of complications. It usually occurs due to high-velocity trauma or a fall from a height. There is a scarcity of data on risk factors and their role in the prognostication of avascular necrosis. The purpose of the study was to retrospectively analyze the association of various risk factors with avascular necrosis (AVN) of the femoral head in patients with a neck of femur fracture in the pediatric age group. Material and methods The study included 21 (13 males and 8 females) pediatric patients with a neck of femur fracture treated at a university-level hospital. The patients were followed for a minimum of one year and the clinico-radiological outcome was analyzed using Ratliff criteria. The association of AVN with age, gender, side, fracture type, and injury with treatment delay, type of reduction, and type of internal fixation used was studied. Results The mean age of the treated patients was 11 (+/- 3.178) years (range=5-16 years). Avascular necrosis was seen in four patients and coxa vara occurred in two of them. A statistically significant association was seen between the Delbet fracture type and avascular necrosis, and three out of four cases of AVN were a Type I fracture (p-value=0.006). Three out of six patients having concomitant skeletal or other organ injuries developed AVN (p-value=0.022). The rate of AVN was higher in patients who were managed after 48 hours of initial injury but no statistically significant correlation was found (p-value=0.314). No statistically significant association with AVN was found between gender, age, type of reduction (closed/open), or the implant used (cannulated screws/k-wires). Conclusions Multiple independent factors may have a role in the development of AVN of the femoral head in children. Prognostication should not be based on a single factor. Statistically significant results in this study have shown that the type of fracture and concomitant skeletal or other organ injuries are important risk factors and should be kept in mind. All independent risk factors must be noted and should be considered while prognosticating the outcome of a child with a neck of femur fracture.