Loughborough team optimises topology to promote bone growth

2 min read

New orthopaedic implant devices that promote faster healing could be available in the future following research that reveals which structures best promote bone healing.

bone healing
Different designs used in the study, comprising 2 TPMS-type structures (1st and 2st from the left), 2 Trabecular-like structures (3rd and 4th from the left), and the typical Lattice currently used as a control (far right). Image: LU/Multifunctional Materials Manufacturing Lab

The study, led by Dr Carmen Torres-Sanchez, a Reader in Multifunctional Materials Manufacturing at Loughborough University, tested implant designs currently in use and compared them to novel designs to better understand what structures bone-building cells favour.

Dr Torres-Sanchez and her team found that the cells are sensitive to topology and this can be exploited to help tissue heal faster.

The new paper, published in the Advanced Engineering Materials Journal, shows that the researchers were able to accelerate bone healing by making design adjustments. This study has also been published in a special series titled Women in Engineering Materials.

Dr Torres-Sanchez said she hopes the study findings will “see clinical application in the very near future to help trauma and bone cancer patients.”

Orthopaedic implants are used to replace missing joints or bone sections, or to support a damaged or diseased bone.

Bones are comprised of voids and pores, which help give bone its biological and mechanical properties. Implants look to mimic this porous structure in a bid to promote faster healing and integration of the implant in the body, and replicate the mechanical properties of bone, including its ability to withstand forces generated by movement.

Two new types of designs were used in Dr Torres-Sanchez’s study, namely triply periodic minimal surface (TPMS) and trabecular-like structures.

Dr Torres-Sanchez and team, in collaboration with industrial partners Alloyed Ltd and Core Specialists Ltd, tested the mechanical properties of TPMS and trabecular-like structures by 3D printing cube-shaped scaffolds using a biocompatible material such as titanium.

The mechanical properties of these scaffolds were tested by applying forces that replicate the physiological loads that implants would be subjected to in the body, to find out whether the new designs can withstand them, and at which point they would fail.

The biological performance of the designs was assessed by adding pre-osteoblasts – precursor cells to osteoblasts (bone-building cells) – to the inside the scaffolds to see if the cells could evolve into mineral matter, which forms bone.

The researchers found that cells prefer the more random distribution of porosity, such as that seen in trabecular scaffolds, as they seem to ‘identify them as home’ when pore structure is not organised.

The researchers were able to adjust the design of the site to accelerate the formation of mineral matter.

In a statement, Dr Torres-Sanchez said: “Long-lasting successful implants, those that promote faster healing, without setbacks such as loosening or infections, without having second surgeries, are a no brainer: for the NHS, for the patient, for society.

“The patient can go back to doing their normal life sooner, relieving the burden on hospitals, physiotherapy, carers, and contributing to a healthier, happier, more active life.

“We engineers can contribute to that by providing designs and scaffolds that promote healing and help speed up the patient recovery, including supporting mental health.

“We are continuing to research on finetuning the designs, so we can find subsequent evolutions of these multifunctional scaffolds that are even more appealing to the cells.”