Analysis of early stage osteonecrosis of the human femoral head and the mechanism of femoral head collapse

Abstract

We explored the mechanism of early stage osteonecrotic femoral head collapse by analyzing and comparing different regions in human osteonecrotic femoral head samples. Eight osteonecrotic femoral heads (ARCO II-III) were obtained from patients undergoing total hip arthroplasty. Bone structure was observed and evaluated by micro-computed tomography (CT) scans and pathology. Osteoblast and osteoclast activities were detected by tartrate-resistant acid phosphatase, alkaline phosphatase, and immunofluorescent staining. Some trabeculae had microfractures in the subchondral bone and necrotic region, which had lower bone mineral density, as well as trabecular thickness and number, but greater osteoclast activity. A sclerotic band had already appeared in certain samples which had greater trabecular thickness and number, bone mineral density, and osteoblast activity. The appearance of the femoral head did not change significantly in the early stage of osteonecrosis of the femoral head. However, osteoblast and osteoclast activities had already changed in different regions of the osteonecrotic femoral head, which may lead to eventual collapse of the femoral head. Therefore, osteonecrosis of the femoral head must be treated during the early stage. In addition, osteoblast activity should be promoted and osteoclast activity inhibited as early as possible to prevent collapse of an osteonecrotic femoral head.

Steroid-induced osteonecrosis of the femoral head reveals enhanced reactive oxygen species and hyperactive osteoclasts

“…The precise cellular and molecular mechanisms underlying steroid-induced osteonecrosis remain controversial. Recent studies indicate that increased osteoclast number and activity are responsible for the femoral head bone loss and subsequent failure [8,10,11]. Given the increasing number of studies illustrating a role promising or ROS in promoting osteoclast formation and resorption, we sought to elucidate whether alterations of ROS level and osteoclasts lead to the pathogenesis of ONFH following the use of steroids.…”

“…As the ONFH progresses, the loss of bone and altered microarchitecture compromises the integrity of the femoral head resulting in deformity and high vulnerability of collapse [8]. It is widely accepted that excessive osteoclast activity during the regenerative phase, rather than during the necrosis of cells and tissue, directly contributes to the loss of bone integrity and ensuing subchondral bone fracture [8][9][10][11]. This contribution is further supported by studies showing that anti-resorptive agents could effectively reduce the risk of femoral head collapse at early-stage ONFH when compared with placebo treatment [12][13][14].…”

Comparison of core decompression and porous tantalum rod implantation with conservative treatment for avascular necrosis of the femoral head: A minimum 18�month follow‑up study

“…In the present study, the terminal time point for the final follow-up was established as collapse of the femoral head, indicating failure of the mechanical support by the tantalum implants and subchondral bone (31). THA was not selected as the criterion because certain patients would not accept the surgery, despite the presence of symptoms including pain and hip dysfunction, due to the fear of surgery or financial reasons.…”

The potential roles of circular RNAs in osteonecrosis of the femoral head (Review)

“…Bone cell metabolism is irreversibly destroyed by local circulatory disorders, and leads to the disappearance of osteoblasts, activation of osteoclasts, the eventual destruction of trabecular bone and increased bone fragility (59). This destructive pathway was verified by the observation that osteoclast-related activity is increased in the subchondral bone and necrotic areas of onFH tissues, whereas osteoblast activity is increased in the sclerotic region (60).…”