Hydroxyapatite Coated Cortical Bone Screw

Hydroxyapatite Coated Cortical Bone Screw

Citieffe

Hydroxyapatite Coated Cortical Bone Screw

The double diameter stainless steel bone screw are self-drilling and self-tapping and have been designed for optimal grip with minimal bone damage.

Hydroxyapatite is the inorganic or mineral phase of the bone and can be synthetically reproduced.
A device coated with hydroxyapatite favours the formation of new bone substance and therefore guarantees excellent integration with the bone, reducing the risk of osteolysis. Hydroxyapatite Coated Cortical Bone Screw increase the holding power in the bone when the screws remain in place for long periods.

When the bone screw is inserted,

  • The self-drilling tip creates a hole with the size of the smaller diameter
  • The smaller diameter enters easily into the bone; the first self-tapping portion cuts the thread in the bone
  • The second self-tapping portion cuts the thread for the larger diameter
  • The larger diameter is inserted by recovering from the possible ovalization of the first hole

A bone fixator system subjected to a load causes different stresses on the two cortices through which the bone screw goes: the cortex on the fixator side will be more stressed than that on the opposite side.

The two-diameter profile of the citieffe bone screws allows better balancing stress distribution over the two cortices: the greater stresses will be distributed over the larger diameter part, while the smaller stresses will discharge on the smaller diameter.

This balance limits the risk of ovalization of the insertion hole caused by asymmetrical stresses thus ensuring greater strength of the bone screw over time.

Finally, with the two-diameter architecture, the bone screw is less invasive thanks to the reduced cross-section in proximity of the tip.

Practical advantages:

  • Manual bone screw insertion without having to predrill because of the self-drilling and self-tapping tips.
  • Any hole ovalization is recovered when the larger diameter goes through the bone.
  • The two-cylindrical geometry of the threaded part allows recovery of any excessive sinking without compromising the strength.
  • NOTE: Excessive sinking can be recovered by turning the screw anticlockwise.