Consortium to develop fracture putty

The Challenge: Create and develop "fracture putty", a new material that speeds the healing of bone in severe fractures.

Accepting the challenge and a two-year, nearly US$4.5 million contract from the US Defense Advanced Research Projects Agency is a consortium of researchers led by Baylor College of Medicine in Houston.

Current treatments for severely broken bones require bone screws, plates and rods that help healing but often require very long healing times, and can lead to further complications. Through its Fracture Putty Program, the agency hopes to develop a nontoxic putty-like material that, when placed at the site of a severe fracture, provides immediate support, and also promotes the rapid formation of new bone. The material should also degrade over time as normal bone regenerates.

The multidisciplinary and multi-institutional team, led by principal investigator Dr Michael Heggeness, chair of orthopaedic surgery at BCM, is one of three groups selected to take on this challenge.

Diverse group tackles problem

"Our hope is to create a process that would put a stop to the many amputations that too often follow these injuries. We are developing a new treatment that would be implemented quickly and efficiently after such an injury," said Heggeness, also chief of orthopaedic spine service at the Michael E. DeBakey Veterans Affairs Medical Center in Houston. "Our exceptional group includes world-renowned experts in the fields of molecular biology, biomechanical engineering, tissue engineering, imaging and orthopaedic surgery to offer a diverse and thorough team approach to the problem."

"Traumatic battlefield wounds such as compound bone fracture are very difficult to treat, often requiring multiple surgeries and long healing and rehabilitation times. Amputations are not uncommon. Current treatments employing bone screws, plates and rods are deficient and can themselves lead to further complications. We believe that fracture putty represents the ultimate convergence of materials science, mechanics and orthopaedics to help our soldiers recover faster with fewer complications," said Dr Mitchell Zakin, the agency’s program manager for the Fracture Putty Program.

Biocompatible gel

Researchers plan to use bone morphogenic protein producing cells, combined with an innovative gel, to develop a treatment that will facilitate bone growth and provide structural support at the same time. The biocompatible and resorbable gel would then degrade over time, as bone healing occurs.

"By designing synthetic plastic materials to mimic natural tissue components, we are striving to design a fracture putty that can encourage the appropriate wound healing responses, and ultimately degrade in response to bone formation so that only healthy tissue is left behind," said co-principal investigator Dr Jennifer West, professor and chair of bioengineering at Rice University.

(Source: Baylor College of Medicine: February 2009)