Grading of SUFE (slipped upper femoral epiphysis) can be made on both AP and true lateral projections.
On an AP radiograph a line along the superior margin of the femoral neck (line of Klein) should intersect the lateral corner of the epiphysis.
As the epiphysis slips, the metaphysis can be divided into thirds.
- mild: lateral edge of epiphysis is within the lateral third of the metaphysis
- moderate: middle third
- severe: medial third
On a true lateral radiograph, the angle (slip angle) which the epiphysis makes with the metaphysis may also be employed (sometimes known as the Southwick head shaft angle).
- normal: ~0 degrees
- mild: 0-30 degrees
- moderate: 30-60 degrees
- severe: >60 degrees