Necrosis of the femoral head, X-ray microtomography (microCT) and histology of retrieved human femoral heads

Osteonecrosis of the Femoral Head in People Living With Human Immunodeficiency Virus: A Micro-Computed Tomography Study

Background

The incidence of osteonecrosis of the femoral head (ONFH) in people with human immunodeficiency virus (HIV) is 10-100 times higher than that in the general population. However, the specific bone microstructure and extent of damage within the femoral head in PWH are still unclear.

Methods

Femoral head samples were obtained by total hip arthroplasty, micro-computed tomography (micro-CT) was employed to investigate the microstructure of trabecular bone across 4 representative regions within necrotic femoral heads, and quantitative analysis was performed.

Results

On general observation, different degrees of degenerative cartilage, fibrocartilage, hyperplastic bone, and exposed bone were presented alternately, with a "map-like" appearance. On micro-CT, compared with the normal and necrotic areas, the bone volume/tissue volume and bone mineral density of the sclerotic areas were significantly increased, the number of trabeculae was significantly increased, and the gap was smaller (P < .05). There was no significant difference in trabecular thickness among the groups (P < .05).

Conclusions

The systemic immune syndrome caused by HIV itself may interfere with the normal metabolism of bone, including osteoblasts and osteoclasts, and thus participate in HIV-related ONFH.

Ultrasound-responsive hyaluronic acid hydrogel of hydrocortisone to treat osteoarthritis

One of the practical ways to manage the disease flares of arthritis is using an intra-articular depot formulation of glucocorticoids. Hydrogels, as controllable drug delivery systems, are hydrophilic polymers with distinctive properties, such as remarkable water capacity and biocompatibility. This study aimed to design an injectable thermo-ultrasound-triggered drug carrier based on Pluronic® F-127, hyaluronic acid, and gelatin. The in situ hydrogel loaded by hydrocortison was developed and D-optimal design was used to formulate the process. The optimized hydrogel was combined with four different surfactants to better regulate the release rate. In situ gels composed of the hydrocortisone-loaded hydrogel and hydrocortisone-loaded mixed-micelle hydrogel were characterized. The hydrocortisone-loaded hydrogel and selected hydrocortisone-loaded mixed-micelle hydrogel showed a spherical shape and were nano-sized with a unique thermo-responsive nature able to prolong drug release. The ultrasound-triggered release study showed that drug release was time-dependent. By inducing osteoarthritis in a rat model, behavioral tests and histopathological analyses were carried out on the hydrocortisone-loaded hydrogel and a particular hydrocortisone-loaded mixed-micelle hydrogel. In vivo results showed that the selected hydrocortisone-loaded mixed-micelle hydrogel improved the status of the disease. Results highlighted the potential of ultrasound-responsive in situ-forming hydrogels as hopeful formulas for efficient treatment of arthritis.