ORTHOBIO

 

Human Bone Allograft is available with Gentamicin, Tobramicin or Vancomicin antibiotic. This material is available in the following forms: Granules, powder, discs, wedges, blocks etc...

 

Details of this Synthetic Bone Substitute is available in the Covision General Catalogue.

 

Bone Cement is a product range of bone cements that are used for the fixation of artificial joints. A bone cement fills the free space between the prosthesis and the bone and allows for an immediate and stable fixation of the surgical implant. The Bone Cement products distinguish themselves by convenient mixing characteristics and excellent mechanical properties.

 

The Bone Cement is manufactued in four varieties, differing with respect to viscosity and the presence or absence of Gentamicin, a prophylactic antibiotic. Standard viscosity Bone Cement is intended for manual use. Bone Cement with low viscosity is for syringe use.

 

Bone Cement can both be used in modern vacuum mixing systems (the two low-viscosity types) and by regular hand mixing systems. The mixing process is initiated by bringing together a polymer powder and a monomer liquid. The major component of the polymer is PMMA.

 

All the Bone Cement types have been tested and meet all the relevant ISO standards (ISO 5833:2002). Each criterion is discussed below.

 

Heat is generated when the powder and the liquid components are mixed. This heat may not be too excessive. ISO standards have to be met regarding this maximum temperature and the setting time - the time it takes the dough to reach the temperature midway between maximum and the ambient temperature. Also, the difference between the two test run values may not exceed a certain maximum. All four types of Bone Cement meet all these criteria. Table 2 summarizes the most important data: mean maximum temperature and mean setting time. According to the ISO standards, the maximum temperature may not exceed 90°C. The setting time must be 3 to 15 minutes for dough state usage cement and 6.5 to 15 minutes for syringe type usage cements.

 

The extent to which the cement penetrates or intrudes the trabecular bone is critical for a long lasting result. In the test, which only applies to the cements which are intended for dough usage (Bone Cement 1 and Genta Bone Cement 1), a mould with a perforated bottom face is used as a model. The perforations are cylindrical holes with a depth of 10mm and a diameter of 1mm. After packing and pressurizing the cement, the intrusion depth is measured. Bone Cement 1 and Genta Bone Cement 1 have mean intrusion depths that are far above the ISO-required 2mm (8.4mm and 7.6mm, respectively).

 

To measure compressive strength, the cement is mixed manually and filled in a cylindrical mould. The cylinder is placed in a test machine, which compresses the cylindrical cement structure slowly. The maximum pressure (compressive strength) is recorded and must exceed the ISO-standard of 70 MPa.

 

The bending strength determines the force that the cement sample can bear until it breaks after bending. The bending modulus measures the elasticity of the material. In other words, it measures how much the cement is deformed by stress. The bending modulus and bending strength is calculated from the deflection-versus-force curve. the higher the modulus, the less the material is deformed. All Bone Cement types are well above the required 50 MPa.

 

All four cements in the Bone Cement range are radiopaque and sterile. They are manufactured in compliance with the EEC Guidelines 93/42/Cee, ISO 5833:2002 and ISO13485:2003.

 

The liquid component is composed of methylmethacrylate, butylmethacrylate, N,N dimethyl-p-toluidine and hydroquinone. The liquid is flammable and has a distinctive odour. It is prepared and delivered sterile by aseptic filtration.

 

The powder component is polymethylmethacrylate (PMMA). Benzoyl peroxide is included to initiate the polymerization. In order to obtain the required reactions and viscosities, various polymethylmethacrylates are mixed in adequate proportions. Barium sulphate is included up to 4 grams per unit and complies with the European Pharmacopoeia. The bone cement powder is sterilized by beta radiation (25 kGy).

MISCELLANEOUS