Aquired non-inflammatory and non-traumatic hypoplasia-dysplasia of the femoral neck

Recently DiFazio et al reported four children with remarkable femoral neck deformity who had extracorporeal membrane oxygenation (ECMO) therapy. We report two patients with similar femoral neck changes who did not have ECMO treatment but have had complicated, strenuous first few weeks after birth. The first patient had been operated on twice for diaphragm repair at the age of 18 hours and 1 month. The second patient had cardiac surgery at the age of two months, with one hour of extracorporeal cardiorespiratory bypass. We agree with DiFazio et al and believe that four of their patients and both of ours have femoral neck growth cartilage injury secondary to hypoxia, vascular disturbance and coagulopathy.