The molecular aetiology of steroid-induced osteonecrosis (ON) is unclear. The aim of this study was to investigate changes in the femoral head blood supply and vascular endothelial growth factor (VEGF) protein levels following steroid-induced ON of rabbit femoral heads in the early stage of the disease, and to investigate a possible mechanism for ON. Using a classic protocol, ON was induced in 30 male 28-week old New Zealand white rabbits. An additional 15 untreated rabbits served as controls. Change of blood supply in the proximal femur was assessed by dynamic magnetic resonance imaging and microangiography. The VEGF protein and mRNA levels were assessed by immunohistochemistry and quantitative real-time polymerase chain reaction, respectively. After 6 weeks, the results indicated that VEGF protein and mRNA levels were significantly lower and femoral head blood supply had also decreased significantly in ON(+) rabbits compared with controls. The down-regulation of VEGF may play a critical role in the disease process of ON.

ObjectivesCirculating exosomes represent novel biomarkers for multiple diseases. In this study, we investigated whether circulating exosome levels could be used as a diagnostic biomarker for steroid-induced osteonecrosis of the femoral head (ONFH).MethodsWe assessed the serum exosome level of 85 patients with steroid-induced ONFH and 115 healthy donors by Nanosight detection. We then assessed the diagnostic accuracy of serum exosomes by receiver operating characteristic curve analysis.ResultsThe circulating exosome level of the ONFH group was significantly lower than that of control group. The area under the curve was 0.72, suggesting that the level of serum exosomes has moderate diagnostic accuracy for steroid-induced ONFH.ConclusionCirculating exosome levels are valuable in the diagnosis of steroid-induced ONFH.Cite this article: H-Y. Zhu, Y-C. Gao, Y. Wang, C-Q. Zhang. Circulating exosome levels in the diagnosis of steroid-induced osteonecrosis of the femoral head. Bone Joint Res 2016;5:276–279. DOI: 10.1302/2046-3758.56.BJR-2015-0014.R1.

The purpose of this study was to review the radiographs of symptomatic femoral head osteonecrosis in patients with systemic lupus erythematosus (SLE) and to assess the results of treatment using free vascularised fibular grafting. We retrospectively reviewed 50 patients (80 hips) with SLE who underwent free vascularised fibular grafting for osteonecrosis of the femoral head. All patients were followed up for at least 2 or more years (average, 4.3 years). The mean Harris hip score improved from 72 to 88. At the latest follow-up, we found improved or unchanged radiographs in 12 of initially Stage II hips and in 60 of 64 Stage III or IV hips. No hips failed treatment and underwent total hip arthroplasty. The data suggest that free vascularised fibular grafting was successful in maintaining joint function and in delaying the need for joint replacement procedure.