Inflammation, fracture and bone repair

Abstract

The reconstitution of lost bone is a subject that is germane to many orthopaedic conditions including fractures and non-unions, infection, inflammatory arthritis, osteoporosis, osteonecrosis, metabolic bone disease, tumors, and periprosthetic particle-associated osteolysis. In this regard, the processes of acute and chronic inflammation play an integral role. Acute inflammation is initiated by endogenous or exogenous adverse stimuli, and can become chronic in nature if not resolved by normal homeostatic mechanisms. Dysregulated inflammation leads to increased bone resorption and suppressed bone formation. Crosstalk amongst inflammatory cells (polymorphonuclear leukocytes and cells of the monocyte-macrophage-osteoclast lineage) and cells related to bone healing (cells of the mesenchymal stem cell-osteoblast lineage and vascular lineage) is essential to the formation, repair and remodeling of bone. In this review, the authors provide a comprehensive summary of the literature related to inflammation and bone repair. Special emphasis is placed on the underlying cellular and molecular mechanisms, and potential interventions that can favorably modulate the outcome of clinical conditions that involve bone repair.

Treatments and Preventative Measures for Trauma‐Induced Heterotopic Ossification: A Review

“…Although small animal models cannot directly mimic the formation of clinically relevant HO, each type of animal study provides the opportunity to better understand the pathophysiology and pathogenesis under unique circumstances. A comprehensive evaluation of the mechanistic pathways of bone growth, healing, and complications that may contribute to HO is beyond the scope of this review but some of the discussions are provided for further investigation 28, 29, 30, 31, 32, 33, 34, 35, 36, 37. With improved understanding, better physical and pharmacological therapeutic protocols can be developed for use in human patients.…”

Modeling the effects of inflammation in bone fracture healing

“…Furthermore, the risk of impaired healing increases with bone diseases, age, and severe traumas [8]. In addition, clinical consequences of fractures include surgical management, prolonged hospitalization, and rehabilitation resulting in a high socioeconomic costs [10]. A better understanding of bone healing would enable to find optimal conditions for successful outcomes as well as to develop strategies for fracture treatments under normal or pathological scenarios.…”

“…However, the exact mechanisms and functions of the immune cells present at the fracture site are still not completely understood [15]. High concentration of inflammatory cytokines leads to increase bone resorption and suppresses bone formation [10]. Prolonged and chronic inflammation results in delay or nonunion healing [8].…”

Post-Traumatic Arthritis: The Role of Cytokine Levels in Serum and Synovial Fluid

“…Distal radius fractures, on the other hand, are the most common type of fractures among individuals under 75 years old. To improve functionality and avoid long-term disability, treatments should be based on the patients' personal characteristics (Loi et al, 2016).…”

“…IL-1, IL-6, and TNF-α that signal the beginning of recovery processes, have been identified as important members of the first group (Gibon et al, 2016;Loi et al, 2016). These factors are not only produced by macrophages and inflammatory cells, but also by mesenchymal cells in the periosteoma.…”