Complications of hip fractures in children.

Background: Hip fractures account for < 1% of all pediatric fractures. Most are caused by a high-energy mechanism. Complications occur at a high rate because the vascular and osseous anatomy of the child's proximal femur is vulnerable to injury. The purposes of this study were to evaluate whether osteonecrosis influences the functional results and to analyze the risk factors for the development of osteonecrosis.

Methods: We conducted a retrospective review of the complications of hip fractures (3 transepiphyseal fractures, 13 transcervical fractures, 6 cervico-trochanteric fractures, and 1 intertrochanteric fracture) in 23 patients (15 boys and 8 girls) between January 1988 and December 1997. Most injuries were caused by falling from a height or a motorcycle accident. The medical records and serial radiographs of all patients were reviewed. The function of the injured site was evaluated using Ratliff's criteria.

Results: The ages of these children at the time of injury ranged from 1.5 to 16 years (average 11.1 years). The mean follow-up was 4.91 years (range, 1 year to 12 years and 7 months). Overall, complications included osteonecrosis in 11 (48%) patients, premature physeal closure in 11 (48%), coxa vara in 3 (13%) and coxa valga in 2 (9%). There was no nonunion. Poor outcomes were related to the development of osteonecrosis. The time to surgery (≤ 12 hours) and the quality of reduction significantly influenced the occurrence of osteonecrosis. The occurrence and severity of femoral head osteonecrosis significantly influenced the functional results (p < 0.001, and p < 0.048, respectively).

Conclusion: Osteonecrosis is the most severe complication after hip fractures in children and is associated with poor functional results. The time to surgery and the quality of reduction were the significant predictors in our study.