Physiological challenges of bone repair.

Bone healing after fracture occurs in a well-organized manner and involves a multitude of cell types, inflammatory cytokines, growth factors, prostaglandins, and certain vitamins. Some of the means by which alterations in these essential components affect bone repair are understood, whereas others still need to be delineated. Based on clinical experience and basic science research, certain clinical conditions have become associated with delays in bone repair after fracture. These conditions include chronic inflammation, diabetes, hypovitaminosis, aging, and polytrauma. This brief report reviews some of the ways by which these conditions have been shown to negatively influence bone repair.