Testosterone is a Potent Accelerator of Fracture Healing: Early Structural Reconstruction and Improved Biomechanical Stability

Abstract

Sex steroids (e. g., estrogen and testosterone) are known to have an integral function in skeletal homeostasis. Though they are known to improve bone strength, their role in fracture healing has not been well defined. The aim of this study was to examine the influence of testosterone on skeletal repair mechanisms, in order to test the hypothesis that sex steroids could be used to accelerate fracture healing after intramedullary nailing. Fracture healing was studied in 60 eugonadal female and male mice treated either with testosterone or placebo. To make mouse models accessible to fracture modulation studies that also allow biomechanical analysis, we modified the Einhorn tibial fracture model and developed a standardized closed femur fracture model. Mice treated with testosterone showed a significant acceleration of fracture healing. Callus size as assessed by contact-radiography and microCT was significantly enhanced. This beneficial effect could be demonstrated in female as well as in male mice. Furthermore, not only radiological and histological data demonstrated a positive morphological interference of testosterone with the fracture healing process, but also the functional competence, as assessed by three-point bending tests, was dramatically improved. This study shows that testosterone can be used to enhance and accelerate fracture healing.

Key words

Sex steroids - biomechanics - fracture repair

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1 * These authors contributed equally and therefore share first authorship.