GRAFTYS® HBS

About

GRAFTYS® HBS is a patented phosphocalcic, macroporous, injectable, hardening, resorbable cement. Its physicochemical structure confers suitable osteoconductive properties adapted to trauma surgery. Its low viscosity provides excellent injectability along with a means to bond bone fragments by stabilization of the osteosynthesis eigther primarily through void filling and secondarily by resorption/substitution of the material by mineralized healthy bone. This ease of injection minimizes risks of anatomical reduction loosening and provides the option to inject after the implants are in place (eg. use of screw holes in plates, cephalic screw hole for inter trochanteric nails). This capability ensures a perfect interface between both bone/material and implant/material. The slow setting time (15 min) allows multiple injections with the same syringe. Finally, GRAFTYS® HBS facilitates injection throught the trabecular structure, without damaging it.

Composition

The powder mineral phase is composed of calcium phosphates including an organic phase (HPMC) which confers wettability and porosity to facilitate percolation of the body fluids throughout the implant and improves the cohesion, elasticity, rheological properties, and injectability. The liquid phase (sodium phosphate solution) participates to mix homogenization and setting time management (crystallization) of cement.
After complete hardening the final product is apatite crystals apatite similar to native bone crystals.

Physicochemical properties

Global Porosity: 68% distributed as below:
• Micro porosity (<10 µm): 84%;
• Meso porosity ([10 - 100 µm]): 8%;
• Macro porosity (>100 µm): 8%
Available Initial Porosity measured after complete hardening (72h) at 37 °C (98°F body temperature) in biological conditions (Ringer's solution).

• No shrinkage during the crystallization process
• Non exothermic reaction: 1-3 °C
• Mechanical compressive strength(3): 12MPa (72 hours after implantation). This product has to be used in an intrinsic stable site or in association with material which will stabilize the surgical site.
• Cohesiveness: good resistance to fluid.

Preparation

GRAFTYS HBS provides an easy, closed mixing system (which eliminates the messy bowl/spatula). Ring on injection end of syringe is shipped in "Closed" position. To initiate mixing, hold injection end upright and rotate ring to "Transfer". Press fluid into the powder side. Mix thoroughly for 2 minutes. Rotate ring to "Inject" and inject the material directly by hands or with injection gun. (Cf. synoptic of preparation)
• Mixing time (room temperature): 2 min
• Injection time (room temperature): 15 min
• Low sensitivity to temperature variations of a functional operating theatre
• Diameter of usable cannulas: ≤14 Ga
• Initial setting time (37°C -98°F body temperature- in biological conditions): 15 min
• Complete hardening (37°C -98°F body temperature- in biological conditions): 72 hours

Mechanism of action

GRAFTYS® HBS is a macroporous injectable hardening resorbable cement. The mineral part allows the formation of a close bond with the native bone. Its is gradually resorbed by osteoclast cells participating to the natural bone remodeling cycle. Conduction and formation of mineralized healthy bone occurs as the material resorbs without formation of voids (rapid dissolution leads to fibrosis). The organic part confers suitable wettability a nd porosity to facilitate percolation of body fluids throughout the implant and improves cohesion, elasticity, rheological properties and injectability.

Features