Callus Nail

The need to make a callus nail is Fast fracture healing and allowing controlled micromotion but the nail should be stable that should not allow limb shortening. Because the built flexure nail allows vertical micromotion at the fracture fragment. Tube-in-tube connection of nails prevents bending motion, stronger bone density and early healing compared to rigid Nails. No nail slippage and limb shortening like multiple nails.

The callus nail has proximal and distal holes for interlocking screw more stable fixation. Because of the transverse locking screw, the nail does not slip into the bone, low chances of limb shortening or reduction loss.


The callus nail is made up of 2 cylindrical tubes known as the proximal tube and distal tube. The 1/3 portion of the distal tube goes into the proximal tube. The top portion of the distal tube is attached to the proximal tube with a pin. After the pin attachment distal tube has inbuilt compression spring-type flexures that allow vertical spring action, in medical terminology we call it controlled micromotion. These compression flexures cannot be seen after the assembly of the proximal and distal tube, the complete assembly of the proximal and distal tube called the callus nail has different geometry either it is a straight cylindrical shaped or proximally bent or curved shaped depending bone and medullary canal. Callus nails have proximal and distal transverse holes to pass the locking screw, this locking screw attaches to the bone.

Compression spring flexure is open coiled helical shape design to resist a force applied axially. When the load is applied to this inbuilt compression spring flexure, it compresses and the gap between the flexure reduces when the load is released gap between the flexures comes in the original state like spring. In the callus nail, 1/3 portion of the distal tube goes into the proximal tube, this tube-in tube connection is a strong connection that allows vertical micro motion but doesn’t allow bending motion.