RESUMO
The purpose of this study was to report eight additional cases of habitual dislocation of the hip (HDH) and to combine the authors' data with a compilation of the cases from the literature. The authors attempted to investigate the various causative factors, outcomes, and indications for conservative and operative treatments. The results suggest that an unusual ability to dislocate the hip voluntarily at a young age constitutes a specific pediatric entity, and no single factor can be determined to be the definite cause of HDH. Multiple triggering factors (generalized ligamentous laxity, excessive anteversion of the femur and acetabulum, osteocartilaginous defect of acetabulum, coxa valga, psychiatric immaturity) appear to be associated with HDH. Treatment should be conservative in the first instance; it includes simple observation with or without psychiatric counseling and immobilization with cast or brace. Hip stabilization by surgical means is selectively indicated when the episodes of hip dislocation do not fade away in due time despite conservative treatment and when primary or secondary capsular laxity or osteocartilaginous deformation or defect of the hip is severe enough to cause repeated dislocation or residual subluxation, which may cause persistent pain or discomfort.