Medical device manufacturer, Invibio, has announced a new material for trauma devices used in internal fracture fixation. The high-performance, polymer-based composite material is advertised as being fifty times more fatigue resistant than metallic equivalents while being closer to the properties of bone.
Fractured bones often require fixation to ensure the bone heals in proper alignment. Misalignment (malunion), delayed healing (delayed union) and lack of healing (non-union) can be costly for medical providers and painful for patients. Predicting healing times can be difficult due to a wide range of variables, and implanted devices for fixation can fail before the fracture heals.
According to their press release, “Delayed or non-unions cost healthcare providers more than $2 billion in failed operations in the US alone. Non-union rates in the literature have been detailed as high as 18% for distal femur plating.”
The new material, known as PEEK-OPTIMA Ultra-Reinforced polymer, combines the popular, biocompatible polyether ether ketone (PEEK) with continuous carbon fibers to create a material with high strength yet a lower stiffness than metallic biomaterials. Materials which are too rigid can cause stress shielding, which results in poor osseointegration or even degeneration of the bone around the implant.
A couple of other nice features that come with the material are that it resists tissue adhesion and simplifies post-op imaging. Many implants rely on a thoroughly integrated interface between the bone and the implant. Because the material is used as a fixation device, which simply assists in natural bone regeneration, the “non-stick” surface is not detrimental and makes revisional surgery easier if necessary.
PEEK is naturally radiolucent, so medical imaging of the injured area is not encumbered as occurs with metallic plates which appear opaque. The ability to image the fracture site through the plate is very important to accurately monitoring progress and assessing if revisional surgery is needed.
In addition to fracture plates the company produces intramedullary rods, or nails, used to stabilize fractures by being placed into the medullary cavity of the bone. As with the plates, the composite’s fatigue and load-sharing properties serve to assist in healing. Composites offer the ability to tailor properties based on the matrix and reinforcement phases, thereby allowing engineers more options in design and allowing physicians to provide better care.
Images from Invibio