DeJour sulcus-deepening trochleoplasty. A, Drawing of the new trochlear limits. B, Removal of subchondral bone under the trochlea to correct the prominence and reshape the groove. C, Shape of the trochlea before (above) and after (below) sulcus-deepening trochleoplasty. D, Fixation of new trochlea with two staples after restoration of trochlear sulcus and more “anatomic” shape. (From DeJour D, Saggin P: The sulcus deepening trochleoplasty—the Lyon’s procedure, Int Orthop 34:311–316, 2010.) SEE TECHNIQUE 47.4.