A world first: Robots used in the reclamation of hip bones for implants

Belgian start-up Texere Biotech has recently begun production at a fully automated plant, the first of its kind in the world. The company takes femoral heads (i.e. the top end of the human thigh bone) and processes them into cuboid implants or “allografts”. Six Stericlean robots supplied by Stäubli handle this bone replacement material under cleanroom conditions.

The layout of the facility is not overly complicated and has been designed based on automated production standards. Six processing stations transform the raw material into a packaged end product, with the handling and packaging being performed in its entirety by six robots.

What makes the set-up at the Texere Biotech site in Frasnes-lez-Gosselies, Belgium so unusual, is the exceptionally clean work environment and the enclosure of the production line in a hermetically sealed and extensively glazed 40ft container. The product which emerges from this fully automated system is spectacularly different, too. The raw material is human femoral heads which have been removed from patients undergoing hip replacement surgery. The system processes the femoral heads in such a way that only the mineral material remains, cutting the bone into blocks of a standardized size.

These “allografts” (non-endogenous implants) are in great demand, as Denis Dufrane, founder of Texere, explains: “Natural bone is the best material for a bone transplant. Its micro porosity ensures that it engrafts well after tumour excision and spinal fusion etc. At the same time, the patient is spared the painful removal of autologous bone.”

Objective: Fully automated production of implant material

The material is ideally suited for grafting, but unfortunately is in short supply. This is partly because the bone banks, which can be found in every European country, have so far managed to prepare the bone materials only manually. Denis Dufrane: “The rate at which these bone banks typically work is two femoral heads per day. They extract two or possibly three blocks out of each bone, but around 50 percent of the material goes to waste.”

This is what inspired Dufrane – who himself spent many years working in a bone and tissue bank – to create his own company for the automated production of bone allografts. The project was more than ten years in the making, but it has at last come to fruition. The plant has gone into production and has the capacity to process 5,000 femoral heads a year. As these are meticulously measured and optimally segmented, each produces an average of five blocks plus bone chips and powder.

Water jet cutting machine replaces old-fashioned bone saw

In addition to increased efficiency in the processing of femoral heads, the other main advantages brought about by full automation are the traceability of each allograft block and the reliable avoidance of contamination, including cross-contamination.

In the course of the project, a new cutting procedure has also been developed. Daniel Dufrene: “Previously, the heads were cut manually with a band saw. Instead, we work with a 5,000-bar water jet cutting machine. In contrast to sawing or milling, this does not generate the sort of high temperatures that might destroy natural structures. We don’t use any additives either.”

Stericlean robots make the impossible possible

A major consideration at the project planning stage was the selection of robots. From Texere’s perspective, this turned out to be a straightforward matter: “Together with 1-2-3 Automation, our partner for automation, we contacted various robot manufacturers. The Stericlean range from Stäubli quickly proved to be the best solution for us, the range had unrivalled hygiene standards and the numerous references from satisfied customers in the medical technology sector, including operating theatres.”

Stericlean robots have been designed from the ground up for such applications. All-round encapsulation to protection class IP 67 permits use under harsh conditions as well as in hygiene-sensitive environments. Parts subject to extreme stress are made of stainless steel. The surface treatment enhances resistance to corrosion, guaranteeing reliable performance in VHP (Vaporized Hydrogen Peroxide) environments; the top coat of paint produces an exceptionally durable surface. As a result, all members of the Stericlean six-axis series are compliant with the strict GMP (Good Manufacturing Practice) guidelines.

Six robots – six tasks

The six identical TX60 Stericlean robots are positioned at six stations along the processing line. The first of them lifts one whole femoral head off a tray and conveys it to an image processor which assesses it for size and shape. This data is used to map out the cutting lines for the next stage in which the second robot presents the bone material to the fully encapsulated water jet cutting machine.

Robot number three retrieves the resulting cuboid allografts and places them on a tray. The next two robots in line are responsible for handling the allografts as they undergo chemical treatment and sterilization. At station number six, the last of the Stericlean robots inserts the individual cubes in vials. After they have been vacuum-sealed and individually labelled, the vials are stored in deep freeze pending delivery to clients.

A unique automation project

Even though there is nothing unusual about the type of task performed by the robots, the project is nonetheless unique, not least because of the product and the stringent conditions attached to the handling of natural implants. The robots not only impress by virtue of their cleanroom compatibility but also in terms of dynamics, precision and reliability.

Various other aspects of the project illustrate the challenges that had to be resolved during the design stage. For example, a separate kit of vials, labels and even grippers has to be provided for each hip bone. The Stericlean at Station 2 takes on the role of master robot, operating the pump drive of the water jet cutting system and performing various other key functions. Before any of the robots could be installed, 1-2-3 Automation carried out extensive simulations to test all of the motion sequences in the system.

Multiple benefits for bone banks, hospitals and patients

Daniel Dufrene is satisfied that the time, effort and capital investment in the system has been  worth it: “For the first time, we have realized a completely automated system for processing bone material. The results include a significantly better yield, higher volumes and lower costs. But above all, full automation gives us a very high level of safety, because contamination, including cross-contamination, can be excluded. This is now the gold standard for bone implants.” An assessment that is also borne out by GMP certification which, according to Daniel Dufrene, cannot be granted for manually operated systems.

The ultimate beneficiaries of this highly specialized form of robot-assisted automation technology will be hospital patients because, thanks to the pioneering work done by Texere, it is now possible to dramatically reduce the shortage of human replacement bone material. First to benefit will be the Benelux countries and neighbouring states. The Texere founders are not ruling out the construction and operation of similar facilities in other regions such as Asia. After all, allografts are just as scarce and in equally great demand elsewhere.