Fig 5.

Right leg. (A) To elevated the cartilage flap, an osteotome is used approximately 5 mm below the chondral surface on the lateral trochlea to penetrate the subchondral bone approximately 5 to 10 mm. This initial cut is started approximately 1 to 1.5 cm distal (green line, with hash ends marking this distance) to the location of the distal aspect of the planned new groove and is continued all the way around to the distal aspect of the medial trochlea (blue line). (B) A specialized offset marking hook and burr (Arthrex) are loaded on an anterior cruciate ligament guide (Arthrex). The burr is advanced into the subchondral bone and is used in a pivoting motion with the tip of the burr and marking hook held stationary while the hand holding the drill moves back and forth to resect bone.