Experimental background--review of animal studies.
UNLABELLED: Most of the research on the physiological effects of intramedullary nailing is technically difficult or ethically impossible to perform in humans. A substantial range of factors apply in clinical cases, which means that the data obtained from this source may lack the control needed to reveal the basic mechanisms of pathophysiology associated with this surgical procedure. Consequently, animal studies have been relied upon to provide answers that would otherwise be unavailable. This review manuscript summarizes the available literature on animal studies dealing with the local and systemic effects of intramedullary nailing. It focuses on whether these studies have contributed to our clinical knowledge of the procedure's impact on perfusion and fracture healing, as well as the medical relevance of coincident systemic effects. DATA SOURCES: Medline, personal library of the first author and of the Department of Trauma Surgery, University of Pittsburgh Medical Center. STUDY SELECTION: All animal studies on intramedullary stabilization published in English, German, and French. CONCLUSIONS: The relevance of animal studies investigating the impact of a surgical procedure and its influence on concomitant injuries depends on the design and the type of the animal model. If this fact is considered, and if a model is selected that simulates a systemic impact comparable with the clinical situation, then animal studies may provide a valuable source of otherwise unobtainable information. Such an example is the study of fat embolization associated with intramedullary nailing. Animal subjects enable assessment of the intervention's additive surgical impact, measurement of side effects that may have adverse results, and influence of cofactors (eg, thoracic trauma, severe shock, polytrauma) that predispose the individual to postoperative complications.