Irisin, a myokine derived from fibronectin type III domain-containing 5 (FNDC5), is increasingly recognized for its protective role in musculoskeletal health through the modulation of mitochondrial quality control. This review synthesizes the current understanding of irisin’s impact on mitochondrial biogenesis, dynamics, and autophagy in skeletal muscle, elucidating its capacity to bolster muscle strength, endurance, and resilience against oxidative-stress-induced muscle atrophy. The multifunctional nature of irisin extends to bone metabolism, where it promotes osteoblast proliferation and differentiation, offering a potential intervention for osteoporosis and other musculoskeletal disorders. Mitochondrial quality control is vital for cellular metabolism, particularly in energy-demanding tissues. Irisin’s influence on this process is highlighted, suggesting its integral role in maintaining cellular homeostasis. The review also touches upon the regulatory mechanisms of irisin secretion, predominantly induced by exercise, and its systemic effects as an endocrine factor. While the therapeutic potential of irisin is promising, the need for standardized measurement techniques and further elucidation of its mechanisms in humans is acknowledged. The collective findings underscore the burgeoning interest in irisin as a keystone in musculoskeletal health and a candidate for future therapeutic strategies.

Objectives: The aim of this study was to investigate the incidence of vertebral refractures following percutaneous kyphoplasty (PKP) and to explore risk factors for augmented vertebral refractures, thereby assisting spinal surgeons in clinical practice. Methods: We analyzed the records of 495 patients with single-segment osteoporotic vertebral compression fractures (OVCFs) who were treated with single-entry PKP at our institution from March 2016 to August 2022. Univariate analysis, binary logistic regression, and ROC curve analysis were performed to determine potential risk factors, independent risk factors, and discrimination ability. Results: A total of 168 patients were included in the study, with a median follow-up duration of 7.00 months. In total, 143 patients did not experience vertebral refracture after surgery, while 25 patients did, including 22 augmented vertebral fractures and 3 adjacent vertebral compression refractures. The correction rate of the Cobb angle (p < 0.001; OR = 1.070) and postoperative anti-osteoporosis treatment (p = 0.002; OR = 0.021) were independently associated with augmented vertebral refracture. The ROC curves showed that these variables demonstrated satisfactory predictive values for augmented vertebral refracture. Conclusions: A high degree of restoration of the Cobb angle was the factor contributing to vertebral refracture after PKP. Conversely, postoperative anti-osteoporosis treatment was observed to be a protective factor against subsequent vertebral refracture.

BACKGROUND Bone cement displacement (BCD), which has received increasing attention from scholars, is a serious complication following vertebroplasty in patients with osteoporotic vertebral fractures (OVFs), and percutaneous kyphoplasty (PKP) might promote its occurrence. However, few studies have systematically explored the risk factors of BCD after PKP. This research aimed to study the risk factors for BCD following PKP. MATERIAL AND METHODS The clinical data of patients with OVFs treated with PKP from June 2016 to August 2022 in our department were retrospectively reviewed. Patients were categorized into the bone cement displacement group and the bone cement non-displacement group. Data on the subjects and their radiologic images were gathered for univariate analysis and binary logistic regression analysis. The receiver operating characteristic (ROC) curve and confusion matrix were utilized to assess the discrimination ability. RESULTS We included 181 patients, of which 12 had BCD after PKP. Binary logistic regression analysis revealed that independent risk factors associated with BCD after PKP were: high BMI, high restoration rate of the Cobb angle, high distance between the bone cement and the vertebral endplates, and presence of bone cement leakage. The ROC curve and confusion matrix indicates that logistic regression exhibited a strong predictive value for BCD. CONCLUSIONS Patients with a high BMI, a high restoration rate of the Cobb angle, a high distance between the bone cement and the vertebral endplates, and bone cement leakage have an increased risk of BCD after PKP.

Study Design: Retrospective study. Objectives: To investigate the prevalence of cervical kyphosis, identify factors influencing cervical sagittal alignment and analyze its relationship with spino-pelvic parameters in asymptomatic children and adolescents. Methods: 410 asymptomatic children and adolescents aged 4-18 years were included. Cervical sagittal alignment types and radiographic parameters were measured in the full-length spine X-ray. Three groups were assigned according to Toyama method: lordotic group, straight and sigmoid group, kyphotic group. Participants were stratified by gender and age, and differences in spinal parameters were analyzed. To determine factors influencing cervical sagittal alignment, a multinomial logistic regression was conducted. Results: Among the 410 participants, 119 (29.0%) were classified as lordotic, 170 (41.5%) as straight, 5 (1.2%) as sigmoid, and 116 (28.3%) as kyphotic of the cervical sagittal alignment. Females exhibited a higher prevalence of kyphosis compared to males (35.8% vs 19.0%). Furthermore, kyphosis prevalence increased with age, from 0% in the 4-6-year-old group to 39.2% in the 16-18-year-old group. Strong positive correlations were observed between T1 slope and C2-C7 Cobb angle (r = 0.667, P < 0.01), as well as between lumbar lordosis and sacral slope (r = 0.758, P < 0.01). Age and C2-C7 Cobb angle were identified as predictors of cervical sagittal alignment via multinomial logistic regression analysis. Conclusions: This study revealed that cervical kyphosis prevalence was comparable to lordosis in asymptomatic pediatric population, which challenged the traditional view of kyphosis as pathological. Additionally, cervical sagittal alignment showed significant gender- and age-related differences. These findings contribute to understanding pediatric cervical morphology and refining surgical strategies.

Low back pain (LBP) is a leading cause of global disability. While frailty is a known risk factor, previous studies have been largely cross-sectional, thus the impact of dynamic changes in frailty on incident LBP is unclear. This study aimed to investigate the association of changes in frailty status with incident LBP. This prospective cohort study utilized data from the China Health and Retirement Longitudinal Study (CHARLS), including 9,174 participants aged ≥45 years without LBP at the start of follow-up. Frailty status (robust, pre-frail, frail) was determined using a 30-item Frailty Index (FI) at baseline (2011) and two years later (2013). Dynamic changes were defined by transitions between these states. Incident LBP was the primary outcome, ascertained via follow-up until 2020. Multivariable Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). The study included 9,174 participants (mean age 59.2 years; 47.9% female) followed for a median of 7.48 years, during which 3,437 incident LBP cases were identified. Compared with participants who remained robust, those who progressed to a pre-frail or frail status had a significantly increased risk of incident LBP (HR 1.48, 95% CI 1.32-1.66). Progression from pre-frail to frail also increased risk (HR 1.51, 95% CI 1.35-1.69) compared to remaining pre-frail. Conversely, recovery was protective; participants improving from pre-frail to robust (HR 0.69, 95% CI 0.61-0.78) or from frail to less frail status (HR 0.77, 95% CI 0.66-0.90) had significantly lower risks than their stable counterparts. Frailty is a dynamic and powerful predictor of incident LBP. Progression towards frailty significantly elevates LBP risk, while recovery is protective. These findings establish a temporal relationship, positioning frailty as a critical, modifiable target for LBP prevention. Integrating frailty assessment into routine clinical care may be a key strategy to reduce the burden of LBP in aging populations.