Computer-assisted retrograde drilling of osteochondral lesions of the talus

Treatment principles of osteochondral lesions of the talus usual ty consist of debridement of the chondral part and methods that attempt To stimulate revascularization of the necrotic bony part of the lesion. The latter is mo stly achieved through multiple drilling of the subchondral zone. Dorsomedia l talar dome lesions are frequently inaccessible with antegrade drilling te chniques. In addition, if the cartilage surface over the bony lesion is sti ll intact, it can be injured by antegrade drilling. To overcome these potential problems, retrograde drilling techniques have b een developed using drill guides or intraoperative fluoroscopy. Our propose d method of computer-assisted retrograde drilling is an advancement of thes e techniques. The use of 3D navigation provides the possibility for placing a guide wire exactly in the center of the lesion defined on preoperative M RI or CT scans. This guide wire can then be over-reamed with cannulated rea mers followed by retrograde bone grafting of the lesion or allows multiple retrograde drilling of the subchondral plate using a parallel drill guide. We found that computer-assisted retrograde drilling could improve precision , avoid misplacement of guide wires,and reduce the time of surgery and intr aoperative fluoroscopy.