The most common cause of limp in a child of seven years old is ?

PEHES DISEASE : Its a disease charecterised by avascular necrosis of head of femur of a child The avascular epiphysis is almost always completely revascularised and replaced but resulting in variable degree of deformity of the femoral head and growth disturbance. pathogenesis : 4 stage on the basis of evolution of disease # Stage of Avascular Necrosis # Stage of Revascularization / Fragmentation # Stage of Ossification / Healing # Remodeling / Residual stage symptoms : 5-10yr old child # Characteristic presentation is a painless limp. # May present with limp alone with pain. # The child appears to be well & not sick . # The hip looks to be deceptively normal -- there may be little wasting. # Abduction & Internal rotation are nearly always limited. # Antalgic gait in the irritable phase or Trendelenburg gait. ref : maheswari 9th ed