[Traumatic hip dislocations in children].

PURPOSE OF THE STUDY

Traumatic hip dislocation is a rare event in children. Appropriate management remains a subject of debate. The purpose of this study was to investigate the epidemiological, therapeutic features of this situation and the long-term outcome after treatment.

MATERIAL AND METHODS

This was a retrospective analysis of 15 traumatic hip dislocations collected over a period of 20 years in pediatric patients with at least two years follow-up. We searched for predisposing factors and factors affecting prognosis.

RESULTS

The series included 11 boys and three girls, mean age eight years. Dislocation was posterior in 13 hips and anterior in two. Time to reduction was less than 3h in eight cases, 3-6h in five and greater than 6h in two. After reduction, traction was performed in nine children, for 20 days on average, followed in five cases by immobilization for 40 days on average. Five hips were immobilized directly after reduction. We identified two groups by age: group 1 with dislocations in children aged less than six years (seven children) were characterized by low-energy trauma. Dislocation was not associated with other lesions. Predisposing factors (overt ligament hyperlaxity, insufficient superolateral head cover, coax valga) were noted in six children. Reduction was simple. Later treatment consisted in immobilization with a pelvispedious cast for 30-45 days. Group 2 were dislocations in children aged over six years (seven children) victims of high-energy trauma. Associated injuries were frequent. Predisposing factors were not present. At mean 11 years follow-up, all hips are considered normal clinically. The radiograph was normal for 14 hips. In one case, there was a slight coax magna. In three patients, defective femoral head cover persisted. Coxa valga persisted in two patients.

DISCUSSION

Traumatic dislocation of the hip joint is rare in very young children, but results from a minimally traumatic event. This suggests the presence of predisposing factors in this category of patients, particularly capsuloligamentary hyperlaxity. After reduction, immobilization can be recommended. Traumatic hip dislocations in children are different from the adult variety due to their rarity, the general absence of associated fractures, easy reduction and better prognosis. The epidemiological and therapeutic features in children older than six years are however similar to those in adults.