Titanium use in the orthopedic field – latest developments

It was almost 70 years ago that titanium began to be used for orthopedic implants. As technology progressed and titanium became more available, the metal was employed for the development of shoulder joints and hip sockets. Even dental implants and hearing aids are made from titanium, with a guaranteed longer service life (in comparison to other materials).

Titanium, a common choice for orthopedic implants

Manufacturers started to use titanium for orthopedic implants, as they recognized the natural properties this metal had to offer. It had an incredible strength-to-weight ratio, excellent corrosion resistance and, most importantly, it was 100% biocompatible.

It was soon discovered that titanium even promoted the osseointegration process, developing a physical bond with the bone (no additional adhesive substances necessary). Moreover, it was determined that titanium implants could withstand high energy forces (no breakage). They did not react to the environment in which they were placed and lasted for a long period of time (no replacement required in some cases).

Titanium is nowadays used not only for internal fixation but also for prosthetics, medical instruments and inner-body devices. There are certain alloys which are preferred for both medical and dental implants, such as Ti-6Al-4V and Ti-6Al-4V ELI. These are alpha-beta alloys, commonly alloyed with aluminum and vanadium. They offer a high level of fracture resistance, not to mention they facilitate osseointegration (faster recovery).

It is a well known fact that titanium is an inert metal, thanks to the protective oxide film that forms upon being exposed to oxygen (natural occurrence). The metal is resistant to damage caused by bodily fluids and tissues, which means it will not be rejected by our bodies.

For this reason, you will see titanium being used for cranial plates, elbow and knee joints and even ribs. Bone screws, staples and cables can be made from titanium. All orthopedic implants developed from titanium provide excellent support to broken bones, facilitating the fixation process.

New titanium alloy developed for orthopedic implants

Beta titanium alloys have long been in the spotlight with regard to orthopedic implants, as they have good formability and excellent mechanical properties. They have amazing corrosion resistance, as well as a high level of mechanical and fatigue resistance.

One of the main reasons for which beta titanium alloys are used for orthopedic implants is their low elastic modulus. Recently, a new beta alloy was developed for such applications – Ti-35Nb-7Zr-5Ta. This alloy was produced through powder metallurgy, having a porous structure and being a suitable choice for the successful osseointegration.

Titanium elastic nailing system for long bone fractures in children

The titanium elastic nailing system (TEN) is intended to fixate diaphyseal fractures of long bones. Such bones have a narrow medullary canal and it is important to be able to use an implant that is flexible. TEN is a preferred option, as it has a reduced risk of complications.

A major benefit of using the titanium elastic nailing system is the immediate post-operative stability. This allows for the early mobilization of the involved segment, with the patient returning to normal activities in a shorter period of time. Moreover, such orthopedic implants have a low complication rate, being a minimally-invasive procedure.

It can be used on pediatric fractures in children between 5 and 14 years of age. The system is safe and reliable, being recommended for long bones. The intervention has a reduced duration and the recovery is fast, with a good functional outcome.

Thanks to TEN, the patient can bear weight early on and heal rapidly, the bone growth being only minimally disturbed. It is also worth mentioning that the titanium elastic nailing system can be used in such fractures, regardless of their location or pattern.

Vertical expandable prosthetic titanium rib

The prosthetic titanium rib is an innovative device, designed to stabilize both the spine and ribs in children with deformities of the chest wall. The curved metal rod is meant to improve breathing, being recommended as a treatment for severe scoliosis as well. Medical specialists have also used the titanium rib in children who needed chest reconstruction after cancer surgery (involving the removal of several ribs).

Children diagnosed with the thoracic insufficiency syndrome can benefit from the prosthetic titanium rib as well. The device can straighten the spine and separate the ribs, thus allowing the lungs to expand more efficiently in the newly created space. Moreover, it can stabilize the diaphragm, the muscle used for breathing.

The prosthetic titanium rib is adjusted in accordance with each child and his/her necessities. It is important to understand that the device is expandable; as the child grows, new interventions will be performed to add length.

Titanium nanotubes for more efficient osseointegration

Titanium nanotubes can improve the osseointegration of orthopedic implants, reducing the risk of bacterial colonization at the same time. Given this discovery, researchers have enhanced titanium implant surfaces with titanium nanotubes.

Orthopedic implants treated with titanium dioxide nanotubes guarantee a more effective osseointegration. Thus, the bond between the implant and bone is strengthened. In patients who received such kind of implants, the early weight bearing is excellent.

Graphene-coated titanium alloys – more effective osteogenesis and osseointegration

The coating of titanium alloys with graphene can actually enhance their surface bioactivation, which will further support the effective osteogenesis and osseointegration processes. The graphene coating improves the biocompatibility of titanium alloys, promoting the regeneration of the bone tissue and improving the bone-implant bonding.

Graphene is an innovative nano-coating material, which can facilitate the biological activity of titanium alloys and promote the above-mentioned processes. Such orthopedic implants have a high mechanical strength and fracture toughness, being resistant to corrosion and 100% biocompatible.

Final word

In conclusion, titanium is an excellent choice for orthopedic implants, being strong, resistant to corrosion and biocompatible. Researchers are continuously working on developing innovative devices, with each of them targeting a subsequent need. In the future, titanium will be used even more often, as doctors are interested in orthopedic implants that can resist for longer periods of time, without being rejected by the body.