Materials


DUOSORB

Duosorb is a synthetic biocomposite biomaterial composed of Tricalcium Phosphate (β-TCP) and Polylactic Acid (PLDL).

Safety

Duosorb is a synthetic compound, which eliminates the risk of microbiological contamination of human or animal origin (AIDS, hepatitis, bovine or ovine spongiform encephalopathies).

Similarity and biocompatibility

Duosorb is made of β-TCP and PDLLA. Pure poly-lactic acid (PLLA) may cause inflammatory reactions during the resorption phase. Its association with β-TCP significantly reduces these reactions. Offered in two different β-TCP concentrations, 30% and 60%, Duosorb thus has biological properties that are similar to pure β-TCP (29), to support bone healing.

Mechanical Properties

With 60% β-TCP, tissue reactions have priority. With its high compressive strength and rigidity, this material is suitable for the production of implants subjected primarily to compressive stresses in indications where consolidation is the dominant factor, such as the creation of interbody cages, or ACL reconstruction with DSTG type grafts.

With 30% β-TCP, Duosorb has increased torsional and bending strength and greater elasticity. It is thus the preferred material for making implants that will be subjected to high stresses, in surgical indications where stability is essential, such as ACL reconstruction with KJ type grafts (29).

Osteoconduction and osseointegration

Duosorb guides bone growth, facilitating the colonization of the implant surface by osteoblasts, which will proliferate and synthesize the extracellular matrix in direct contact with the material. The implant is thus gradually replaced by newly formed bone (29) (Fig. 1).

osteointegration

Figure 1: In vivo study of the degradation of β-TCP / PDLLA implanted in rabbit femurs (29).

β-TCP/PDLLA one week post-implantation (Toluidine blue (x400)).
A - bone tissue detected in direct contact with the implant.
B - the trabecular bone in contact with the composite shows no signs of inflammation.
C - β-TCP/PDLLA 3 months post-implantation. Some particles of calcium phosphate have detached from the matrix and integrated into the bone tissue. The bone tissue is in direct contact with the implant.

Resorption

Simultaneous to bone formation, the β-TCP undergoes resorption by osteoclasts that will break down its inorganic structure. The PDLLA is also absorbable by hydrolysis in contact with inter-cellular fluids. Thus, the compound formed by Duosorb® is absorbed within 12 to 24 months post-implantation, depending on the implant volume (29) (Fig. 2).

resorption

Figure 2: Resorption of Ligafix 60 screws over time.

Indications

Duosorb is used in the reconstruction of the anterior cruciate ligament (Translig to ensure a strong and rigid femoral ACL fixation, Ligafix 30 for all types of transplants - it is ideal for use in the KJ technique - Ligafix 60 for ACL reconstruction with a doubled semitendinosus/gracilis autograft - soft tissue), and in degenerative or traumatic cervical spine arthrodesis (Duocage).

Bibliography

 

29 - Biological performance of a new β-TCP/PLLA composite material for applications in spine surgery: In vitro and in vivo studies.
AUNOBLE S, CLEMENT D., FRAYSSINET P., HARMAND MF., LE HUEC JC.: J of Biomed Res Part A, 78, 416-22, 2006.

 

 

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