Articulotrochanteric distance in slipped capital femoral epiphysis.

The difference in altitude between the proximal limit of the femoral head and the tip of the greater trochanter--the articulotrochanteric distance (ATD)--was recorded in 312 patients with slipped capital femoral epiphysis and compared with that in normal hips. The ATD was markedly reduced after severe slipping, independent of the method of treatment. In mild or moderate slippings, the ATD differed with the method of treatment. The shortest ATD was seen after osteosynthesis with AO screws. Nonoperative treatment and osteosynthesis with the Johansson nail or Nyström pin caused a slight reduction of the ATD, while no reduction was seen after hook-pinning. These differences probably reflect various degrees of damage to the subcapital growth plate, which may result in leg length difference and abduction insufficiency.