General FAQ

They are made of a blend of rigid and elastic polymers selected for their strength, malleability and degradation properties.

By tailoring the polymer selections, fabrication processes and product designs each implant has optimal strength, malleability and absorption profiles to meet their specific clinical requirements.

The polymers in the Inion Optima^TM materials are: L-Lactide, D,L-lactide, Trimethylene carbonate(TMC).The presence of TMC has a strong impact on the malleability (flexibility) of the final products and contributes to the product’s ease of use by surgeons.

Bioabsorbable polymers are a special class of plastic materials that allow the material to serve a function, and then gradually break down, metabolise and be eliminated from the body.

It is imperative to match the degradation time with the initial period during which the material must function.

The ideal bioabsorbable material will provide appropriate strength while degrading in a predictable fashion without adverse reactions occurring in the body throughout the healing process.

There are three main types of bioabsorbable polymers used in orthopaedics:

1. PGA: although highly crystalline, PGA absorbs very quickly into the body, losing virtually all strength within 1 month and all mass within about 6 to 12 months. During this phase of rapid absorption, large quantities of a glycolic acid monomer are released, potentially causing clinical complications within a few months following implantation.
2. PLLA: Poly (L) Lactic Acid has a much slower rate of absorption than PGA. The L (Levo) version of this polymer is highly crystalline due to the ordered pattern of the monomers, (i.e. L-L-L-L-L- L-L) and has been documented to take as much as 5-7 years to absorb.
3. PDLA: the D (Dexo) Isomeric form of PLA, has a much faster absorption rate.
    

Bio-absorbable implants have many advantages over metal implants, including:

1. Load sharing versus stress shielding
2. Eliminates the problem of leaving a permanent (metal) non-biologic implant in the body
3. Reduced risk of articular damage (refer to case study below)
4. MRI compatible for Post-Op diagnosis
5. Reduce radiographic scatter
6. Minimised risk of obstruction during revision surgery if required
7. Safe and biocompatible material, no risk of metal allergic reactions
8. Minimised risk of stress risers normally associated with implant removal.
9. As with all bioabsorbable implants, they biologically resorb over time, allowing the load to transfer to the bone after primary bone healing and eventually completely disappear through safe biological resorbtion.
10. Bioabsorbable polymers are a special class of plastic materials that allow the material to serve a function, and then gradually break down, metabolise and be eliminated from the body. Thus eliminating the need for metal implants to me used during surgery.

By scientific definition, biodegradable refers to a biological mediated degradation process such as enzymatic and/or cellular processes. Bioresorption refers to a chemically mediated degradation process such as hydrolysis where the degradation products are then incorporated into normal metabolic pathways like the Krebs Cycle. Bioasbsorbable also refers to a chemically mediated degradation, but the degradation products are generally excreted through one of the body’s organ systems. All three terms are unfortunately used indiscriminately in both scientific and clinical literature and this has caused significant confusion. The above definitions are of course too much for this Q/A info sheet. Perhaps the best answer is to say the terms are in general the same in the sense that degradation occurs in the human body, but there differences are related to the degradation process. Then mention the indiscriminate use of the terms in the literature and suggest that Inion has chosen the term “bioabsorbable” for materials that breakdown in the human body

Inion Optima^TM materials are made by the blending of rigid polymer components and elastic polymer components. The resulting polymer blends possess extraordinary combination of strength, toughness (malleability) and degradation profile.

The presence of TMC (Trimethylene Carbonate)  has a strong impact on the malleability (flexibility) of the final products and contributes to the product’s ease of use in the surgical environment. Copolymers using trimethylene carbonate as a minor component have been on the market since the 1980s as sutures and guided tissue membranes, and more recently as sports medicine implants

Most problems that have been reported in printed publications were thought to be due to the fast degradation of polymers and possibly particulates from semi-crystalline materials. Inion Optima Materials used in all of the implants and have been tailored to degrade gradually in each application. In addition Inion materials are completely or substantially amorphous, even after processing, and therefore are not crystalline or semi crystalline.

The time frame is usually between 35 weeks and 3 years but this varies from patient to patient. Also resorption is also dependant on a number of other factors including:

implant mass

material processing

implantation area, e.g. vascularity 

The implants initially lose molecular weight, then strength and finally mass.

The implants degrade by hydrolysis and over a period of time are metabolized into carbon dioxide and water which is then exhaled and excreted.

Inion Optima^TM materials are both safe and biocompatible with the human body. They are completely or substantially amorphous – the ideal for biodegradable implants.

Crystalline polymers have a regular internal structure and because of the orderly arrangement are slow to degrade. Amorphous polymers have a random structure and are completely & more easily degraded. Semi-crystalline polymers have crystalline and amorphous (random structure) regions. Hydrolysis begins from the amorphous area leaving the more slowly degrading crystalline debris. These crystalline regions (crystals) are extremely small.

Absolutely not. All Inion^® implants are packaged as single use only. This prevents the potential cross infection risk and alleviates problems of decontamination.

No. The screw holes can be seen in post operative X-rays

Lactose is a natural sugar found in most mammalian milk. The chemical structure of lactose is very different from that of lactic acid which is a natural metabolite of carbohydrate metabolism. One would not expect any interaction all from lactic acid on lactose intolerant people. There is a much higher risk for patient allergies to metal implants due to beryllium and copper additives.

It is quite common for Sales Representatives to store bio-absorbable products in the trunk or interior of their car. This practice can cause serious product performance issues with bio-absorbable products. The nature of the material and the process of production does not protect it from the temperatures within a car or trunk during the summer months, many near the temperature seen in production. This may cause a warpeage in the implant and thus cause deployment and insertion issues. To prevent this, no bio-absorbable product or otherwise should ever be continually left in a car interior or trunk