Iwasaki, Tomohiro Shimizu declare that they have no conflict of interest.

Introduction We aimed to compare the efficacy after switching from either bisphosphonates (BPs) or non-BPs (NBPs) to combination therapies of denosumab (DMAb) or zoledronic acid (Zol) with eldecalcitol (ELD) in bone mineral density (BMD) and bone metabolism and investigate the prognostic and risk factors of side effects of this therapy. Materials and methods One-hundred forty-eight patients with postmenopausal osteoporosis were recruited; their therapy was switched from BPs or NBPs to Zol or DMAb plus ELD (BP-Zol: 43, NBP-Zol: 32, BP-DMAb: 35, and NBP-DMAb: 38). Longitudinal changes in bone metabolic markers (P1NP and TRACP-5b) and BMD were evaluated. Results In the BP-Zol group, P1NP did not change after 6 months and increased by 38.9% after 12 months. TRACP-5b decreased 15.8% after 6 months, but came back to baseline values 12 months after administration. In the rest of the groups, the bone metabolic markers remained suppressed after 6 and 12 months. Compared with baseline, all groups showed increase in BMD after 6 and 12 months. Bone metabolic markers at baseline were correlated with %change in lumbar spine BMD from baseline to 12 months. P1NP and 25-hydroxy vitamin D levels at baseline were identified as potential predictors of development of acute-phase reactions. Conclusions The combination therapy of Zol or DMAb and ELD may increase BMD at 12 months after the first administration in Japanese patients with postmenopausal osteoporosis, regardless of BPs pretreatment. Bone metabolic markers at baseline may be useful predictors for reaction to the therapy and side effects caused by these combination therapies in postmenopausal osteoporosis.

Despite the availability of long‐term follow‐up data, the effect of pelvic osteotomy on the natural history of osteoarthritis is not yet fully understood, partly because there is untapped potential for radiographs to better describe osteoarthritis. Therefore, this study aimed to assess the distribution of subchondral bone mineral density (BMD) across the acetabulum in patients with hip dysplasia immediately (2 weeks) and 1 year after undergoing periacetabular osteotomy (PAO). To that end, we reviewed 40 hips from 33 patients with developmental dysplasia of the hip who underwent PAO between January 2016 and July 2019 at our institution. We measured subchondral BMD through the articular surface of the acetabulum using computed tomography osteoabsorptiometry, dividing the distribution map into nine segments. We then compared the subchondral BMD between 2 weeks and 1 year after PAO in each area. At 2 weeks after PAO, the high‐density area tended to be localized particularly in the lateral part of the acetabulum, whereas 1 year after PAO, the high‐density area moved to the central and lateral parts. The percentage ratios of the subchondral BMD for the central–posterior, lateral–central, and lateral–posterior areas relative to the central–central area were significantly decreased at 1 year after PAO, as compared to those at 2 weeks after PAO. These findings suggest that loading was altered by PAO to be more similar to physiological loading. A long follow‐up observational study is warranted to confirm the association between early changes in subchondral BMD by PAO and joint degeneration.