Drilling and tapping
With the protection of the drill sleeve, drill a 2.5 mm hole as perpendicularly as possible to the fracture plane, parallel and anterior to the K-wire. Do not drill the far cortex.
Care must be taken to avoid penetration of the ankle joint.
Measure the drill depth and tap the malleolar fragment only with the 4.0 mm cancellous bone tap, using the protection sleeve.
Insertion of the anterior screw
The chosen 4.0 mm cancellous bone screw to be inserted should come to rest with its threads completely beyond the fracture line.
The use of a washer is recommended, especially in osteoporotic bone.
Insert the screw without excessive tightening.
Insert posterior screw
Remove the K-wire and widen the K-wire track with a 2.5 mm drill and protection sleeve.
After measuring the length and tapping the malleolar fragment, insert the second chosen 4.0 mm cancellous bone screw.
The fracture will be suitably fixed with the two cancellous screws. The joint surface is now reconstructed.
Indication for a buttress screw
If the fracture line is vertical and has a proximal extension, or in the presence of a reduced medial "corner" fragment, the use of a third screw and washer at the apex of the fracture, acting as a buttress, may be helpful. In the elderly or noncompliant patient, it is often more secure to use a buttress plate.
Locate the apex of the fracture and drill a 2.5 mm hole through both cortices slightly proximal to this point. Place the hole close enough to the fracture line to enable overlapping of the distal fragment by the washer, thus creating a buttressing effect.
Using the protection sleeve, measure the depth and tap both cortices with the 3.5 mm tap.
Add 2 mm to the measured length to allow for the washer and insert the cortex screw with washer.