Innovative healing implant offered to stifle infected fracture wounds
For 1.5 years, scientists from Kazan Federal University, Kazan State Medical University, and the Republican Clinical Hospital of the Ministry of Health of the Republic of Tatarstan have been developing an implant that simultaneously stabilizes fractures and promotes the treatment of purulent extremity infections.
According to Rashid Shafigulin, a traumatologist and orthopedist at the Republican Clinical Hospital’s Traumatology Department No. 1, the problem is pressing, and its solution was prompted by the desire to improve the quality of treatment for veterans of the special military operation with infectious complications of extremity injuries. The solution, in particular, was used to save a leg of one of the injured servicemen.
A team of researchers from the Shell Mechanics Laboratory of KFU, led by the Chair of the Department of Computer Mathematics and Informatics Oskar Sachenkov, presented a unique medical development – an intramedullary nail designed to treat fractures complicated by bacterial infections, including those caused by Staphylococcus aureus.
Ildar Akhtyamov, Chair of the Department of Traumatology, Orthopedics, and Surgery of Extreme Conditions at Kazan State Medical University, participated in the clinical trial, while Sergey Boychuk, Chair of the Department of General Pathology at Kazan State Medical University, collaborated with Dr Shafigulin to study the release of antibiotics from bone cement in lattice implants.
“Its main feature is the presence of a mesh structure with a complex topology, the free space of which contains antibiotic-containing bone cement. After the pin is installed, the medication is gradually released from the cement, providing an effective treatment for the infection directly at the site of the bone lesion,” emphasized Pavel Bolshakov, a researcher at the Shell Mechanics Laboratory.
One of the key advantages of this development is that the optimized topology of the mesh portion of the pin significantly improves antibiotic elution, i.e., the speed and duration of its release. The antibiotic is released at least twice as intensely and lasts twice as long as with standard designs.
One of the main challenges was the laboratory’s lack of an in-house 3D printer for working with metals, particularly titanium. Only plastic prototypes were produced using this printer, but this problem was resolved through collaboration with a partner organization, Exclusive Solutions LLC, which specializes in 3D printer development. This collaboration allowed for the rapid production of the necessary metal samples.
“The pin itself is made of a titanium alloy with bioinert properties, making it safe for medical use. Due to the complexity of the mesh structure’s geometry, manufacturing the product is only possible using additive manufacturing. Selective laser sintering (SLS) is used for this, allowing for precise reproduction of the specified microstructure and ensuring high strength of the final product,” explained Nikita Kharin, a researcher at the Shell Mechanics Laboratory.
A patent application has already been filed for the invention. Furthermore, based on the identified effects and data, the team, in collaboration with the Synthetic Polymer Materials and Composites Research Laboratory of KFU, is designing new medical devices. The developed lattice has undergone not only mechanical testing but also biomedical testing at the Microorganism Genetics Research Laboratory, in collaboration with Kazan State Medical University. The contribution of students has also been significant. A group led by Igor Bespalov, a research assistant in the Shell Mechanics Laboratory, worked within the Small Student Design Bureau to develop tooling for experimental studies.
“The lattice structure of the pin does more than simply deliver antibiotics to the site of infection. Unlike standard pins, the pin with a lattice microstructure ensures a more intense and prolonged release of the drug within the medullary canal, allowing for faster infection control, enhancing treatment effectiveness, and reducing the risk of recurrence,” emphasized Rashid Shafigulin.
It is important to note that the patient with the pin implanted in his leg is in a stable clinical condition, and the postoperative wounds have completely healed. Laboratory test results confirm successful infection suppression. Before implantation, the patient was treated with an external fixation device, which was accompanied by recurrent purulent discharge from the wound and a constant inflammatory process.
Currently, work is ongoing to study the reasons that contribute to increased antibiotic release from bone cement and to develop implants for other limb segments.