Osteoporosis is a serious health issue among aging postmenopausal women. The majority of postmenopausal women with osteoporosis have bone loss related to estrogen deficiency. The rapid bone loss results from an increase in bone turnover with an imbalance between bone resorption and bone formation. Osteoporosis can also result from excessive glucocorticoid usage, which induces bone demineralization with significant changes of spatial heterogeneities of bone at microscale, indicating potential risk of fracture. This review is a summary of current literature about the molecular mechanisms of actions, the risk factors, and treatment of estrogen deficiency related osteoporosis (EDOP) and glucocorticoid induced osteoporosis (GIOP). Estrogen binds with estrogen receptor to promote the expression of osteoprotegerin (OPG), and to suppress the action of nuclear factor-κβ ligand (RANKL), thus inhibiting osteoclast formation and bone resorptive activity. It can also activate Wnt/β-catenin signaling to increase osteogenesis, and upregulate BMP signaling to promote mesenchymal stem cell differentiation from pre-osteoblasts to osteoblasts, rather than adipocytes. The lack of estrogen will alter the expression of estrogen target genes, increasing the secretion of IL-1, IL-6, and tumor necrosis factor (TNF). On the other hand, excessive glucocorticoids interfere the canonical BMP pathway and inhibit Wnt protein production, causing mesenchymal progenitor cells to differentiate toward adipocytes rather than osteoblasts. It can also increase RANKL/OPG ratio to promote bone resorption by enhancing the maturation and activation of osteoclast. Moreover, excess glucocorticoids are associated with osteoblast and osteocyte apoptosis, resulting in declined bone formation. The main focuses of treatment for EDOP and GIOP are somewhat different. Avoiding excessive glucocorticoid use is mandatory in patients with GIOP. In contrast, appropriate estrogen supplement is deemed the primary treatment for females with EDOP of various causes. Other pharmacological treatments include bisphosphonate, teriparatide, and RANKL inhibitors. Nevertheless, more detailed actions of EDOP and GIOP along with the safety and effectiveness of medications for treating osteoporosis warrant further investigation.

Both focused extracorporeal shockwave (f-ESWT) and radial extracorporeal shockwave therapy (r-ESWT) can alleviate symptoms in patients with knee osteoarthritis, but no trials have directly compared f-ESWT with r-ESWT for knee osteoarthritis. This study aimed to compare the effectiveness of f-ESWT and r-ESWT on knee osteoarthritis. Forty-two patients with bilateral knee osteoarthritis were randomly assigned to receive three sessions of either f-ESWT or r-ESWT at 1-week intervals. The patients were evaluated at baseline and at 4 and 8 weeks after the final treatment. The primary outcome was the change in pain intensity, as measured on the visual analog scale (VAS). Secondary outcomes included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), range of motion of the knee joint, and the 6-minute walk test. At the end of 4 weeks, the VAS score was substantially reduced in both groups (f-ESWT, −4.5 ± 2.5 points; r-ESWT, −2.6 ± 2.0 points), with a greater reduction in the f-ESWT group. Both groups showed significant improvement in secondary outcomes; however, the f-ESWT group yielded greater improvement in the VAS score, WOMAC score, and 6-minute walk test. Our results showed that f-ESWT was more effective than r-ESWT in improving pain and physical function in patients with knee osteoarthritis.

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