Physical exercise impacts bone remodeling around bio-resorbable magnesium implants

Abstract

Physical exercise has been shown to induce positive reactions in bone healing but next to nothing is known about how it affects the nanostructure, in particular around implants. In this study, we established this link by using small-angle X-ray scattering tensor tomography (SASTT) to investigate nanostructural parameters in 3D such as mineral particle orientation and thickness. As a model system, rat femoral bone with a bio-resorbable implant (ultra-high purity magnesium) was used. One half of the rats underwent treadmill exercise while the other half were moving freely in a cage. At two- and six-weeks post-surgery rats were sacrificed, and samples were taken. Our results point to an earlier start and stronger remodeling when physical exercise is applied and to a stronger reorientation of the mineralized collagen fibers around the implant. This study reveals the nanostructural response of bone with bio-resorbable implants to physical exercise. Understanding this response is very important for designing post-surgery treatments.