In Japan, where allograft bone transplantation is not widespread, prospects for artificial bones are very high. Therefore, artificial bones with various compositions, porous structures, and porosities have been developed and employed for clinical use. Both Affinos^® and Regenos^® (made of beta-tricalcium phosphate and hydroxyapatite, respectively) are artificial bones with a unique unidirectional porous structure, in which pores with a diameter suitable for tissue penetration (25–300 μm) are aligned in one direction. The unidirectional porous structure allows rapid penetration of blood deep into the materials by a capillary effect. In animal experiments, Affinos^® showed well-balanced resorption and was replaced with the host’s own bone from an early stage after implantation and new bone formation and remodeling were observed in the cortical bone and medullary cavity. When implanted for clinical situation, resorption from an early stage and good replacement with the patient’s own bone were also observed. Regenos^® has an internal osteon-like material and a vascular-like structure that is maintained within the pores even after long-term implantation, as noted in an animal experiment. When implanted for clinical situation, good osteoconductivity was observed from an early stage of implantation. In addition, the material was observed to be slowly absorbed over time in some cases. We have discussed the beneficial effects of combining teriparatide and platelet-rich plasma impregnation and the potential prospects of these artificial bones.

Study Design: Prospective experimental study in humans.Purpose: To determine whether the hybrid assistive limb (HAL) for Care Support can reduce lumbar load during a patient transfer.Overview of Literature: The prevalence of work-related low back pain (LBP) among nurses is high. In particular, transferring patients poses a high risk for LBP due to the large lumbar load. Attempts to reduce the lumbar load are crucial to avoid the risk of LBP. Therefore, we investigated the effects of the HAL for Care Support.Methods: Nineteen volunteers (16 men, three women) lifted a 60-kg doll from a seated position to a standing position. The first transfer was performed without the HAL for Care Support, and the second was performed with the HAL for Care Support assistive robot. We evaluated transfer performance, the visual analog scale (VAS) score for lumbar fatigue, and electromyogram analyses of the trunk and hip.Results: Four participants (two men, two women) succeeded with the HAL for Care Support even though they were unable to perform the task without it. The mean lumbar fatigue VAS score for all participants without the HAL for Care Support was 62 mm, while that with it was 43 mm. With lumbar assistance from the HAL for Care Support, subjective lumbar fatigue during the transfer decreased significantly. A power analysis indicated adequate statistical power to detect a difference in the VAS score for lumbar fatigue (0.99). The activity of the left gluteus maximus alone increased significantly during transfers with the HAL for Care Support. No adverse events occurred during use of the HAL for Care Support for transfers.Conclusions: The HAL for Care Support was able to reduce lumbar load in a simulated patient transfer.

Unidirectional porous hydroxyapatite (UDPHAp) is an artificial bone substitute with a unique microstructure consisting of 100–300-µm oval pores that present the material unidirectionally. UDPHAp has a compression strength of 14 MPa and a porosity of 75%, which promotes cell migration and capillary formation within the material. Despite these advantageous properties, bone remodeling and bone formation with UDPHAp remain unclear. To examine long-term remodeling and differences in bone formation based on the defect site, trapezoidal prism-shaped UDPHAp blocks were implanted into rectangular-shaped cortical bone defects in the proximal tibia of Japanese white rabbits. Histological analysis performed at 52 and 104 weeks after implantation revealed that bone and capillaries had formed within the implanted UDPHAp material. Bone formed within the UDPHAp implanted in the cortical defect of rabbit tibia and remodel up to two years. The percentage of new bone area within UDPHAp was larger in cortical lesions than that in medullary lesions. These findings suggest that UDPHAp is a promising material for the repair of non-critical-sized cortical bone defects.

Update: This article was updated on October 19, 2022, because of previous errors, which were discovered after the preliminary version of the article was posted online. On page 1787, in the legend for Figure 2, the sentence that had read “The vertebral collapse rate (in %) was defined as 1 − (A/P) × 100, and vertebral instability (in %) was defined as the difference in vertebral collapse rate between the loaded and non-loaded images.” now reads “The vertebral collapse rate (in %) was defined as (1 − [A/P]) × 100, and vertebral instability (in %) was defined as the difference in vertebral collapse rate between the loaded and non-loaded images.” On page 1788, in the section entitled “Data Collection,” the sentence that had read “The vertebral collapse rate (in %) was defined as 1 − (anterior vertebral wall height/posterior vertebral wall height) × 100, and vertebral instability (in %) was defined as the difference in vertebral collapse rate between the loaded and non-loaded images⁹.” now reads “The vertebral collapse rate (in %) was defined as (1 − [anterior vertebral wall height/posterior vertebral wall height]) × 100, and vertebral instability (in %) was defined as the difference in vertebral collapse rate between the loaded and non-loaded images⁹.” Finally, on page 1791, in Table IV, the footnote for the “Primary outcome” row that had read “N = 113 in the rest group and 99 in the no-rest group.” now reads “N = 116 in the rest group and 108 in the no-rest group.” Background: Although imaging findings that predict resistance to conservative treatment in patients with osteoporotic vertebral fracture (OVF) have recently been reported, no conservative treatment method has been standardized. In this study, the effects of initial bed rest on the outcomes of patients with OVF and in patients with and without poor prognostic findings on magnetic resonance imaging (MRI) were compared. Methods: This prospective cohort study at 2 facilities involved consecutive patients aged ≥65 years with OVF who began treatment within 2 weeks after their injury and were observed for 6 months. Patients at one hospital rested for 2 weeks (116 patients; mean age, 80.4 years), whereas those at the other hospital were not instructed to rest (108 patients; mean age, 81.5 years). Patients were further divided according to the presence or absence of poor prognostic MRI findings. The primary end point was the rate of transition to surgery; secondary end points included bone union rate, vertebral collapse progression, local kyphosis progression, and changes in activities of daily living (ADL). Results: Forty-five patients in the rest group (including 3 who required surgery) and 37 patients in the no-rest group (including 9 who required surgery) had poor prognostic MRI findings. Although the difference in the rate of transition to surgery between the rest and no-rest groups did not reach significance among all patients (p = 0.06), the transition rate in the rest group was significantly lower (p = 0.02) in the patients with poor prognostic MRI findings. Both the bone union rate and changes in ADL were not significantly different between the rest and no-rest groups. The mean vertebral collapse progression was 6.4% in the rest group and 20.9% in the no-rest group (p < 0.001), and the mean local kyphosis progression was 2.4° in the rest group and 8.8° in the no-rest group (p < 0.001). Conclusions: Although bed rest is not recommended for all patients, hospitalized bed rest for 2 weeks reduced the number of patients with OVF who require surgery among patients with poor prognostic MRI findings. Bed rest also reduced progression of vertebral collapse and kyphosis, regardless of the MRI findings. Level of Evidence: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.