title: Fracture healing under healthy and inflammatory conditions.
abstract: Optimal fracture treatment requires knowledge of the complex physiological process of bone healing. The course of bone healing is mainly influenced by fracture fixation stability (biomechanics) and the blood supply to the healing site (revascularization after trauma). The repair process proceeds via a characteristic sequence of events, described as the inflammatory, repair and remodeling phases. An inflammatory reaction involving immune cells and molecular factors is activated immediately in response to tissue damage and is thought to initiate the repair cascade. Immune cells also have a major role in the repair phase, exhibiting important crosstalk with bone cells. After bony bridging of the fragments, a slow remodeling process eventually leads to the reconstitution of the original bone structure. Systemic inflammation, as observed in patients with rheumatoid arthritis, diabetes mellitus, multiple trauma or sepsis, can increase fracture healing time and the rate of complications, including non-unions. In addition, evidence suggests that insufficient biomechanical conditions within the fracture zone can influence early local inflammation and impair bone healing. In this Review, we discuss the main factors that influence fracture healing, with particular emphasis on the role of inflammation.
authors.affiliation: Institute of Orthopedic Research and Biomechanics, Center of Musculoskeletal Research, University of Ulm, Helmholtzstraße 14, 89081 Ulm, Germany. lutz.claes@uni-ulm.de
authors.forename: Lutz
authors.initials: L
authors.lastname: Claes
authors.forename: Stefan
authors.initials: S
authors.lastname: Recknagel
authors.forename: Anita
authors.initials: A
authors.lastname: Ignatius
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D016723:Bone Remodeling / Q000502:physiology; D004195:Disease Models, Animal; D005592:Fracture Fixation / Q000379:methods; D017102:Fracture Healing / Q000502:physiology*; D006801:Humans; D007249:Inflammation / Q000503:physiopathology*; D012756:Sheep