Association and Risk Factors of Osteonecrosis of Femoral Head in Sickle Cell Disease: A Systematic Review.

Objective: The objective was to evaluate the level of evidence about the associated factors and the risk factors of osteonecrosis of femoral head (ONFH) in sickle cell individuals.

Methods: The review was based on the search and selection of studies available in the electronic databases PubMed, SCIELO, LILACS, BVS. As descriptors, the terms of Medical Subject Headings (MeSH) and Health Sciences Descriptors (DeCS) corresponding to "Osteonecrosis", "Necrosis avascular" and "Aseptic necrosis" and "Femoral head" and "sickle cell disease" and "risk factor" and "predictor".

Results: Among clinical and laboratorial factors the most promising risk factors were the severity of sickle cell disease and acute chest syndrome. As a result, from studies of a moderate level of quality, blood pressure, body weight, previous trauma, haemoglobin to haematocrit ratio (Hb/HCT), and number of hospitalizations can be highlighted. Others, such as genetic markers and male gender, have also been positively associated in lower quality studies.

Conclusion: For a better clarification of what the risk factors are for the ONFH, it is necessary to study with populations of different origins, different ages, different profiles of Hb, which present greater methodological rigor and perform a multivariate analysis to control confounding factors. Further study is also needed to understand the genetic determinants of ONFH.