The seating chisel is meant to be driven exactly parallel to the guide wire
in both planes. The seating chisel is hammered into the distal femur with a
mallet. Particular in the young, the seating chisel “back-slapped” using the
slotted hammer. For each 15 mm of insertion this back-slapping should be
performed. Otherwise, the seating chisel will become jammed in the bone.
Repeatedly check parallelism with the guide wire.
In hard bone, it may become necessary to pre-drill the seating chisel track,
but this requires great care to keep the 4.5 mm drill bit exactly parallel to
the guide wire.