A theoretical plan for scanographic study of the femoropatellar space is proposed, based on the examination of 60 normal knees. The investigation is conducted at 15 degrees and is adapted to the morphology of the femoropatellar space, with the assistance of a "Scout view". Patellar rolling is evaluated before and after quadriceps contraction during indifferent and external rotation. The spatial resolution of the new apparatuses and the adaptation of the plane of the section should permit valid study of the femoropatellar articular cartilages. The operative decision should be based on both the results of scanography and clinical examinations.