Undisplaced femoral neck fractures in children have a high risk of secondary displacement.

Femoral neck fractures in children are rare and known to have a high complication rate (e.g. femoral head necrosis, persistent deformities, and pseudarthrosis). While open reduction and internal fixation is the treatment of choice for displaced fractures, non-operative treatment methods have been proposed if the fracture is undisplaced. Three consecutive patients aged 11, 14 and 16 years with undisplaced femoral neck fractures were seen at our institutions and primarily treated with the recommendation of non-weightbearing and minimal flexion until consolidation. All three cases showed secondary displacement within the first 6 weeks. A second minor indirect trauma caused displacement in one case; in the other two cases, no further trauma had occurred. All three fractures healed uneventfully following reduction and osteosynthesis. Undisplaced femoral neck fractures treated non-operatively evidently bear the risk of secondary displacement. The observations in these patients suggest that primary internal stabilization, even of undisplaced femoral neck fractures in children, should be considered.