Purpose: Glucocorticoids (GCs) are widely prescribed drugs in a large variety of diseases. Their use are strongly influenced by their associated negative side effects. Bone-related effects are mainly osteoporosis and osteonecrosis (ON). Despite the strong link between GCs and ON, the pathogenic mechanisms by which GCs cause ON are still unclear. Cumulative evidence shows that dysfunction or activation of endothelial cells (ECs) play an important role in ON.

Method: In this study, we investigated the influence of dexamethasone (Dex) on the Tumor Necrosis Factor-alpha [TNF-alpha] or Lipopolysaccharide [LPS] or Thrombin [IIa] -stimulated Human Umbilical Vein Endothelial Cells (HUVEC). We examined the molecular expression of 9 candidate genes (E-selectin [E-Sel], Intracellular adhesion molecule-1 [ICAM-1], Plasminogen activator inhibitor-1 [PAI-1], Tissue Factor [TF], Tissue plasminogen activator [t-PA], Urokinase plasminogen activator [u-PA], Vascular adhesion molecule-1 [VCAM-1], Von Willebrand Factor [vWF] and Thrombomodulin [THBD]) by real-time PCR. Live cell number of HUVEC under exposure to Dex was also assayed by viability test. All experiments were performed in triplicates and Standard error of the mean (SEM) was obtained.

Results: We showed that Dex alone significantly induced the expression of E-Sel, ICAM-1, TF, VCAM-1 and VWF while downregulating THBD and U-PA expression. Our results also showed a significant priming effect of Dex on E-Sel and TF inflammatory-mediated induction by TNF-alpha and LPS respectively. Comparable results were obtained from Northern Blot analysis; results from FACS analysis and Functional assays will be presented at the meeting.

Conclusion: Our observations suggest a procoagulant activity of Dex on HUVEC. We also observed a priming activity of Dex on E-Sel and TF inflammatory-mediated induction. These results suggest a potential endothelial cell activation mechanism and subsequent microvascular thrombosis in glucocorticoid-induced ON.

A tantalum AVN implant was used in sixteen patients with advanced AVN (Grade 3/4). No reports have been published of use of this implant in advanced disease. Outcomes included radiological, SF36, Harris hip score and secondary surgeries. HHS improved from fifty-two to seventy. SF36 scores approached controls. At over one year average follow-up five patients are revised to THA, however, all hips except one have at least minor pain. Revisions occurred in older patients or those with 100% head involvement. In younger patients, with up to 50% head involvement, this technique seems to be a viable option for advanced AVN. Evaluation of tantalum AVN implants in patients with advanced AVN. In younger patients, with up to 50% hip head involvement, this technique seems to be a viable option for advanced AVN. Revisions in general are in older patients or those with 100% head involvement.

Most treatment options have had poor outcomes with advanced AVN. Surgeons generally perform THA or core decompression in these cases. Market pressure for a non-vascularized option to fill the channel after decompression has resulted in new implants. A tantalum device has been designed to fill the post-core decompression channel to allow subchondral support. This is a minimally invasive procedure with theoretically low morbidity. The average orthopedic surgeon would have no difficulty in the use of this implant.

HHS improved from fifty-two to seventy. SF36 scores were below age-matched controls. At over one-year average follow-up five patients are revised to THA, however, all hips except one have at least minor pain. Revisions in general are in older patients or those with 100% involvement. In younger patients, with up to 50% head involvement, this technique seems to be a viable option.

This device was used in a prospective cohort of sixteen patients with advanced AVN (Grade 3/4) with femoral head fracture/collapse. Operative technique including reduction of the fracture allows for improved results. Outcomes included radiological parameters (advancing disease, placement, ingrowth), SF36, Harris hip score and secondary surgeries.