Objective：To assess the effects of immobilization on the three-dimensional microstructure of cortical and cancellous bone.

Methods：Eight-week-old specific-pathogen-free Wistar rats were divided into two groups：the control (n＝12) and immobilized group (n＝12). The hind limbs of the rats in the immobilized group were fixed using orthopedic casts for 4 weeks. The cortical bone at the mid-shaft and the cancellous bone at the distal metaphysis of the femur were analyzed using micro-computed tomography.

Results：The values of total cross-sectional area, cortical bone area, and cortical thickness in the immobilized group were significantly lower than those in the control group. Meanwhile, the relative bone volume (bone volume/total volume) and mean trabecular thickness in the immobilized group decreased and the structure model index significantly increased compared with the values in the control group (P＜0.05).

Conclusion：Our rat model can evaluate the effects of load-permitting immobilization. The results of this study indicate that structural changes in immobilized osteopenia-affected bone arise mainly from thinning of the cortex and reduction of cancellous bone volume caused by a reduction of trabecular width.

Methods: A total of 120 patients with AIS who underwent posterior spinal fusion from August 2006 to March 2017 at our facility and were followed up for 2 years or more were included. Radiological parameters were measured on whole-spine anteroposterior and lateral radiographs. Revised SRS-22 (SRS-22r) values were also recorded. Coronal trunk imbalance was defined as a deviation of ≥2.0 cm between the C7PL and the central sacral vertical line. Patients with and without coronal trunk imbalance at 2 years after surgery were defined as D (+) (decompensation type) and D (-), respectively. Mean SRS-22r values, including function, pain, self-image, mental health, and subtotal were compared between the D (+) and D (-) groups. Logistic regression analysis was performed to detect the preoperative factors related to D (+) using predictors, including curve type, maximum Cobb angle, and coronal trunk imbalance. Results: At 2 years after surgery, the D (+) group had a significantly lower self-image in the domain of SRS-22r scores compared with the D (-) group. Preoperative coronal trunk imbalance was significantly related to D (+) but not to significant changes in the postoperative SRS-22 score in any of the SRS-22 domains. Conclusions Postoperative C7PL deviation lowers the self-image in patients with AIS. Patients with preoperative coronal trunk imbalance were significantly more likely to be D (+).

The purpose of this study was to investigate the consciousness among young people (n = 1016) on training body part(s), using a questionnaire-based survey showing participants a picture of a single-joint exercise. The participants were shown a picture of knee-extension exercise (KNEE-EXT), and were asked to identify the body part(s) they felt were being trained. On seeing the picture, more than 90% of the participants felt that KNEE-EXT can train the anterior thigh part. However, more than 90% of the participants who had no experience doing KNEE-EXT felt that the exercise trained not only the anterior thigh part but also other parts, including the trunk, the posterior thigh, and the upper limb. Among those participants who had performed KNEE-EXT without the experience of strength-training under professional supervision, approximately 80% felt that the exercise was appropriate to train not only the anterior thigh but also other parts. These results suggest that performing exercises by referring to only a picture may result in the individuals not properly understanding how the body part(s) should be trained during exercise, even in single-joint exercises. Appropriate supervision is of even greater importance especially for strength-training beginners. Furthermore, even among participants who had an experience of exercise under professional supervision, approximately 60% had a similar response. Therefore, to enhance the benefits of exercises, individuals (even those who have had experience in training under professional supervision) should always be instructed under appropriate supervision on the correct technique and knowledge about the exercises.

Objectives: Diagnosis and treatment of osteoporosis are instrumental in obtaining good outcomes of hip surgery.Measuring bone mineral density (BMD) using dual-energy X-ray absorptiometry (DXA) is the gold standard for diagnosing osteoporosis. However, due to limited access to DXA, there is a need for a screening tool to identify patients at a higher risk of osteoporosis. We analyzed the potential utility of the Osteoporosis Self-assessment Tool for Asians (OSTA) as a screening tool for osteoporosis. Methods: A total of 1378 female patients who underwent hip surgery at 8 institutions were analyzed. For each patient, the BMD of the proximal femoral region was measured by DXA (DXA-BMD), and the correlation with OSTA score (as a continuous variable) was assessed. Receiver operating characteristic (ROC) curve analysis was performed to assess the ability of OSTA score to predict osteoporosis. Lastly, the OSTA score was truncated to yield an integer (OSTA index) to clarify the percentage of patients with osteoporosis for each index. Results: DXA-BMD showed a strong correlation with OSTA (r = 0.683; P < 0.001). On ROC curve analysis, the optimal OSTA score cut-off value of − 5.4 was associated with 73.8% sensitivity and 80.9% specificity for diagnosis of osteoporosis (area under the curve: 0.842). A decrease in the OSTA index by 1 unit was associated with a 7.3% increase in the probability of osteoporosis. Conclusions OSTA is a potentially useful tool for screening osteoporosis in patients undergoing hip surgery. Our findings may help identify high-risk patients who require further investigation using DXA.