What line is used to identify early slip?
Line of Klein describes a line along the superior edge of the neck of femur. The line should normally intersect the lateral part of the superior femoral epiphysis.
Pre slip, the earliest detectable change, has normal alignement but a widened growth plate.
As the epiphysis slips, the metaphysis can be divided into thirds, which allows grading into mild, moderate, and severe.
- mild: lateral edge of epiphysis is within the lateral third of the metaphysis
- moderate: middle third
- severe: medial third