Effects of composite intramedullary nail on cell phenotype-related activities and callus growth during the healing of tibial bone fractures

Flexible composite prostheses provide favorable conditions for bone healing. Simulation of the human body is a complicated process, and accurate techniques are needed as physiological behavior is chaotic. We propose appending the mechanoregulation (MR) algorithm with callus volume changes, implant-dependent growth, and cell phenotype-specific activities for use with composite prostheses. The MR algorithm and simulation technique were validated, and simulation results were compared with developed models and in vivo sheep data. Healing of transverse diaphyseal tibial fractures with a fixed conventional stainless steel intramedullary nail and the flexible glass/polypropylene composite was compared. The flexible implants promoted better callus growth and volume and healthy cell phenotype.