[Value of intraoperative diagnostic radiography in diagnosis of femoral head nail penetration].

Most of the complications of surgical treatment for slipped capital femoral epiphysis result from unrecognized joint penetration. Standard radiographic projections are unable to locate implants precisely since the tridimensional joint is viewed in one plane at a time. The use of a single screw placed in the center of the femoral head prevents unrecognized joint penetration.