Search

Neuromuscular junction (NMJ) degeneration is one of pathological factors of sarcopenia. Low‐magnitude high‐frequency vibration (LMHFV) was reported effective in alleviating the sarcopenia progress. However, no previous study has investigated treatment effects of LMHFV targeting NMJ degeneration in sarcopenia. We first compared morphological differences of NMJ between sarcopenic and non‐sarcopenic subjects, as well as young and old C57BL/6 mice. We then systematically characterized the age‐related degeneration of NMJ in SAMP8 against its control strain, SAMR1 mice, from 3 to 12 months old. We also investigated effects of LMHFV in SAMP8 on the maintenance of NMJ during the onset of sarcopenia with respect to the Agrin‐LRP4‐MuSK‐Dok7 pathway and investigated the mechanism related to ERK1/2 signaling. We observed sarcopenic/old NMJ presented increased acetylcholine receptors (AChRs) cluster fragmentation and discontinuity than non‐sarcopenic/young NMJ. In SAMP8, NMJ degeneration (morphologically at 6 months and functionally at 8 months) was observed associated with the sarcopenia onset (10 months). SAMR1 showed improved NMJ morphology and function compared with SAMP8 at 10 months. Skeletal muscle performance was improved at Month 4 post‐LMHFV treatment. Vibration group presented improved NMJ function at Months 2 and 6 posttreatment, accompanied with alleviated morphological degeneration at Month 4 posttreatment. LMHFV increased Dok7 expression at Month 4 posttreatment. In vitro, LMHFV could promote AChRs clustering in myotubes by increasing Dok7 expression through suppressing ERK1/2 phosphorylation. In conclusion, NMJ degeneration was observed associated with the sarcopenia onset in SAMP8. LMHFV may attenuate NMJ degeneration and sarcopenia progression by increasing Dok7 expression through suppressing ERK1/2 phosphorylation. [ABSTRACT FROM AUTHOR]

Objective: Therapy of very severe osteoporotic compression fractures (VSOVCF) has been a growing challenge for spine surgeons. Opinions vary regarding the optimal surgical procedure for the treatment of VSOVCF and which internal fixation method is more effective is still under debate, and research on this topic is lacking. This retrospective study was conducted to compare the efficacy and safety of various pedicle screw fixation methods for treating VSOVCF. Methods: This single‐center retrospective comparative study was conducted between January 2015 and September 2020. Two hundred and one patients were divided into six groups according to different surgical methods: 45 patients underwent long‐segment fixation (Group 1); 39 underwent short‐segment fixation (Group 2); 30 received long‐segment fixation with cement‐reinforced screws (Group 3); 32 received short‐segment fixation with cement‐reinforced screws (Group 4); 29 had long‐segment fixation combined with kyphoplasty (PKP) (Group 5); and 26 cases had short‐segment fixation combined with PKP (Group 6). The clinical records were reviewed and the visual analogue scale (VAS) score and the Oswestry Disability Index (ODI) score were used for clinical evaluation. The vertebral height (VH), fractured vertebral body height (FVBH), and Cobb's angle were objectively calculated and analyzed on lateral plain radiographs. Student's t‐tests and one‐way ANOVA among groups were conducted to analyze the continuous, and the chi‐squared test was used to compare the dichotomous or categorical variables. The difference was considered statistically significant when the P‐value was less than 0.05. Results: The six groups had similar distributions in age, gender, course of the disease, follow‐up period, and injured level. In the postoperative assessment of the VAS score, the surgical intervention most likely to rank first in terms of pain relief was the short‐segment fixation with cement‐reinforced screws (Group 4). For the functional evaluation, the surgical intervention that is most likely to rank first in terms of ODI score was a short‐segment fixation with cement‐reinforced screws (Group 4), followed by long‐segment fixation (Group 1). The long‐segment fixation with cement‐reinforced screws was the first‐ranked surgical intervention for the maintenance of Cobb's angle and vertebral height, whereas the short‐segment fixation performed the worst. The highest overall complication rate was in Group 6 with an incidence of 42.3% (11/26), followed by Group 2 with an incidence of 38.5% (15/39). Conclusion: For the treatment of VSOVCF, the short‐segment fixation with cement‐reinforced screws is the most effective and optimal procedure, and should be used as the preferred surgical method if surgeons are proficient in using cemented screws; otherwise, directly and unquestionably use long‐segment fixation to achieve satisfactory clinical results. [ABSTRACT FROM AUTHOR]

Summary: Aging and obesity are two global concerns in public health. Sarcopenic obesity (SO), defined as the combination of age‐related sarcopenia and obesity, has become a pressing issue. This systematic review and meta‐analysis summarize the current clinical evidence relevant to SO. PubMed, Embase, and Web of Science were searched, and 106 clinical studies with 167,151 elderlies were included. The estimated prevalence of SO was 9% in both men and women. Obesity was associated with 34% reduced risk of sarcopenia (odds ratio [OR] 0.66, 95% CI 0.48–0.91; p < 0.001). The pooled hazard ratio (HR) of all‐cause mortality was 1.51 (95% CI 1.14–2.02; p < 0.001) for people with SO compared with healthy individuals. SO was associated with increased risk of cardiovascular disease and related mortality, metabolic disorders, cognitive impairment, arthritis, functional limitation, and lung diseases (all ORs > 1.0, p < 0.05). The attenuated risk of sarcopenia in elderlies with obesity ("obesity paradox") was dependent on higher muscle mass and strength. Apart from unifying the diagnosis of SO, more research is needed to subphenotype people with obesity and sarcopenia for individualized treatment. Meanwhile, the maintenance of proper body composition of muscle and fat may delay or attenuate the adverse outcomes of aging. [ABSTRACT FROM AUTHOR]

Objective: Prevention of fragility fractures is one of the public health priorities worldwide, whilst the incidence of osteoporotic vertebral compression fractures (OVCF) continues to rise and lacks the corresponding accurate prediction model. This study aimed to screen potential causes and risk factors for primary non‐traumatic osteoporotic vertebral compression fractures (NTOVCF) in the elderly by characterizing a patient population with NTOVCF and comparing it with a population of osteoporotic patients. Methods: Between January 2013 and January 2022, 208 elderly patients with unequivocal evidence of bone fragility manifested as painful NTOVCF were enrolled, and compared with 220 patients with osteoporosis and no fractures. The demographic data, bone turnover markers, blood routine, serum biochemical values, and radiological findings were investigated. Differences between the fracture and non‐fracture groups were analyzed, and variables significant in univariate analysis and correlation analysis were included in the logistic analysis to build the risk prediction model for osteoporotic vertebral fractures. Univariate analysis using student's t‐tests for continuous variables or a chi‐squared test for categorical variables was conducted to identify risk factors. Results: No significant differences were revealed regarding age, gender, BMI, smoking, alcohol consumption, blood glucose, propeptide of type I procollagen (P1NP), and N‐terminal middle segment osteocalcin (N‐MID) (P > 0.05). Parathyroid Hormone (PTH), 25(OH)D, serum albumin (ALB), hemoglobin (HB), bone mineral density (BMD), and cross‐sectional area (CSA) of the paraspinal muscle in the fracture group were significantly lower than those in the control group; however, b‐C‐terminal telopeptide of type I collagen (β‐CTX), total cholesterol (TC), high‐density lipoprotein cholesterol (HDL‐C), non‐prostatic acid phosphatase (NACP), and fatty degeneration ratio (FDR) were significantly higher than those in the control group (P < 0.05). Logistic regression analysis showed that ALB, HB, CSA, and BMD were negatively correlated with NTOVCF, while β‐CTX, HDL‐C, NACP, and FDR were positively correlated with NTOVCF. Conclusion: Decreased physical activity, anemia, hypoproteinemia, imbalances in bone metabolism, abnormal lipid metabolism, and degenerative and decreased muscle mass, were all risk factors for OVCF in the elderly, spontaneous fractures may be the consequence of cumulative declines in multiple physiological systems over the lifespan. Based on this risk model, timely detection of patients with high OVCF risk and implementation of targeted preventive measures is expected to improve the effect of fracture prevention. [ABSTRACT FROM AUTHOR]

Background: This study aimed to adjust and cross‐validate skeletal muscle mass measurements between bioimpedance analysis (BIA) and dual‐energy X‐ray absorptiometry (DXA) for the screening of sarcopenia in the community and to estimate the prevalence of sarcopenia in Hong Kong. Methods: Screening of sarcopenia was provided to community‐dwelling older adults. Appendicular skeletal muscle mass (ASM) was evaluated by BIA (InBody 120 or 720) and/or DXA. Handgrip strength and/or gait speed were assessed. Diagnosis of sarcopenia was based on the 2019 revised Asian Working Group for Sarcopenia cut‐offs. Agreement analysis was performed to cross‐validate ASM measurements by BIA and DXA. Multiple regression was used to explore contribution of measured parameters in predicting DXA ASM from BIA. Results: A total of 1587 participants (age = 72 ± 12 years) were recruited; 1065 participants were screened by BIA (InBody 120) with 18 followed up by DXA, while the remaining 522 participants were assessed by the BIA (InBody 720) and DXA. The appendicular skeletal muscle mass index (ASMI) evaluated by BIA showed a mean difference of 2.89 ± 0.38 kg/m2 (InBody 120) and 2.97 ± 0.45 kg/m2 (InBody 720) against DXA gold standard. A significant overestimation of muscle mass was measured by BIA compared with DXA (P < 0.005). BIA data were adjusted using prediction equation and mean difference reduced to −0.02 ± 0.31 kg/m2 in cross‐validation. Prevalence of sarcopenia in older adults ≥65 ranged from 39.4% (based on ASMI by DXA) to 40.8% (based on predicted DXA ASMI from BIA). Low ASMI by DXA was found in 68.5% of the older adults screened. The percentage of older adults exhibited low handgrip strength ranged from 31.3% to 56%, while 49% showed low gait speed. Conclusions: Bioimpedance analysis was found to overestimate skeletal muscle mass compared with DXA. With adjustment equations, BIA can be used as a quick and reliable tool for screening sarcopenia in community and clinical settings with limited access to better options. [ABSTRACT FROM AUTHOR]

Background: Gut microbiota dysbiosis and sarcopenia commonly occur in the elderly. Although the concept of the gut–muscle axis has been raised, the casual relationship is still unclear. This systematic review analyses the current evidence of gut microbiota effects on muscle/sarcopenia. Methods: A systematic review was performed in PubMed, Embase, Web of Science, and The Cochrane Library databases using the keywords (microbiota* OR microbiome*) AND (sarcopen* OR muscle). Studies reporting the alterations of gut microbiota and muscle/physical performance were analysed. Results: A total of 26 pre‐clinical and 10 clinical studies were included. For animal studies, three revealed age‐related changes and relationships between gut microbiota and muscle. Three studies focused on muscle characteristics of germ‐free mice. Seventy‐five per cent of eight faecal microbiota transplantation studies showed that the recipient mice successfully replicated the muscle phenotype of donors. There were positive effects on muscle from seven probiotics, two prebiotics, and short‐chain fatty acids (SCFAs). Ten studies investigated on other dietary supplements, antibiotics, exercise, and food withdrawal that affected both muscle and gut microbiota. Twelve studies explored the potential mechanisms of the gut–muscle axis. For clinical studies, 6 studies recruited 676 elderly people (72.8 ± 5.6 years, 57.8% female), while 4 studies focused on 244 young adults (29.7 ± 7.8 years, 55.4% female). The associations of gut microbiota and muscle had been shown in four observational studies. Probiotics, prebiotics, synbiotics, fermented milk, caloric restriction, and exercise in six studies displayed inconsistent effects on muscle mass, function, and gut microbiota. Conclusions: Altering the gut microbiota through bacteria depletion, faecal transplantation, and various supplements was shown to directly affect muscle phenotypes. Probiotics, prebiotics, SCFAs, and bacterial products are potential novel therapies to enhance muscle mass and physical performance. Lactobacillus and Bifidobacterium strains restored age‐related muscle loss. Potential mechanisms of microbiome modulating muscle mainly include protein, energy, lipid, and glucose metabolism, inflammation level, neuromuscular junction, and mitochondrial function. The role of the gut microbiota in the development of muscle loss during aging is a crucial area that requires further studies for translation to patients. [ABSTRACT FROM AUTHOR]

Background: Sarcopenia is an aging‐induced deterioration of skeletal muscle mass and function. Low‐magnitude high‐frequency vibration (LMHFV) was shown to improve muscle functions and β‐hydroxy‐β‐methylbutyrate (HMB) to increase muscle mass and strength. Muscle‐derived stem cells (MDSCs) are progenitor cells important for muscle regeneration. We hypothesized that LMHFV and HMB could retard sarcopenia by reducing fat infiltration through inhibiting adipogenesis in MDSCs. Methods: Senescence‐accelerated mouse P8 male mice were randomized into control (CTL), HMB, LMHFV (VIB), and combined (COM) groups. Interventions started at age of month 7 and assessed at 1, 2, and 3 months post‐intervention by densitometry, histology, and functional tests. In vitro, MDSCs isolated from gastrocnemius of senescence‐accelerated mouse P8 mice were characterized, randomized into CTL, VIB, HMB, and COM groups, and assessed by oil red O staining, mRNA, and protein expression. Results: At 2 months post‐intervention, percentage lean mass of HMB, VIB, and COM groups were significantly higher than CTL group. Twitch, tetanic, and specific tetanic forces of COM group were higher, while specific twitch force of both VIB and COM groups were higher. Grip strength of HMB, VIB, and COM groups were higher. Histologically, both VIB and COM groups presented lower oil red O area than CTL group. Type I muscle fibre in CTL group was higher than HMB, VIB, and COM groups. MDSC were detected in situ by immunofluorescence stain with stem cell antigen‐1 signals confirmed with higher β‐catenin expression in the COM group. The observations were also confirmed in vitro, MDSCs in the HMB, VIB, and COM groups presented lower adipogenesis vs. the CTL group. β‐Catenin mRNA and protein expressions were lower in the CTL group while their relationship was further validated through β‐catenin knock‐down approach. Conclusions: Our results showed that combined LMHFV and HMB interventions enhanced muscle strength and decreased percentage fat mass and intramuscular fat infiltration as compared with either treatment alone. Additive effect of LMHFV and HMB was demonstrated in β‐catenin expression than either treatment in MDSCs and altered cell fate from adipogenesis to myogenesis, leading to inhibition of intramuscular lipid accumulation. Wnt/β‐catenin signalling pathway was found to be the predominant regulatory mechanism through which LMHFV and HMB combined treatment suppressed MDSCs adipogenesis. [ABSTRACT FROM AUTHOR]

Sarcopenia is highly prevalent in fragility fracture patients and is associated with delayed healing. In this study, we investigated the effect of low‐magnitude high‐frequency vibration (LMHFV) on osteoporotic fracture with sarcopenia and the potential role of myostatin. Osteoporotic fractures created in sarcopenic SAMP8, non‐sarcopenic SAMR1 were randomized to control or LMHFV (SAMP8, SAMR1, SAMP8‐V, or SAMR1‐V) groups. Healing and myostatin expression were evaluated at 2, 4, and 6 weeks post‐fracture. In vitro, conditioned‐media were collected from myofibers isolated from aged and young SAMP8 or C2C12 myoblasts with or without LMHFV. Osteoblastic MC3T3‐E1 under osteogenic differentiation were treated with plain or conditioned‐medium (±myostatin propeptide). LMHFV significantly enhanced callus formation was in non‐sarcopenic SAMR1 mice; but the enhancement effect was not significant in SAMP8 mice at week 2. Myostatin expressions in callus and biceps femoris of SAMP8 group were significantly higher all groups with significant negative correlation with callus size (R2 = 0.7256; p = 0.0004). Mechanical properties (week 4) and callus remodeling (week 6) were inferior in SAMP8 versus SAMR1 and were significantly enhanced by LMHFV. Alkaline Phosphatase (ALP) and Runx2 expression of MC3T3‐E1 was lower in aged myofiber compared with young, but upregulated by LMHFV or myostatin inhibition; also confirmed with C2C12. LMHFV enhanced early callus formation, microarchitecture, callus remodeling and mechanical properties of fracture healing in both SAMP8 and SAMR1; however, more effective in non‐sarcopenic SAMR1 mice. Impaired fracture healing in sarcopenic SAMP8 mice is attributed by elevated myostatin expression in callus and muscle, which correlated negatively with callus formation. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:277‐287, 2020 [ABSTRACT FROM AUTHOR]

ABSTRACT Low magnitude high frequency vibration (LMHFV) has been shown to improve anabolic and osteogenic responses in osteoporotic intact bones and during osteoporotic fracture healing; however, the molecular response of LMHFV during osteoporotic fracture healing has not been investigated. It was hypothesized that LMHFV could enhance osteoporotic fracture healing by regulating the expression of genes related to chondrogenesis (Col-2), osteogenesis (Col-1) and remodeling (receptor activator for nuclear factor- κ B ligand (RANKL) and osteoproteger (OPG)). In this study, the effects of LMHFV on both osteoporotic and normal bone fracture healing were assessed by endpoint gene expressions, weekly radiographs, and histomorphometry at weeks 2, 4 and 8 post-treatment. LMHFV enhanced osteoporotic fracture healing by up-regulating the expression of chondrogenesis-, osteogenesis- and remodeling-related genes (Col-2 at week 4 ( p = 0.008), Col-1 at week 2 and 8 ( p < 0.001and p = 0.008) and RANKL/OPG at week 8 ( p = 0.045)). Osteoporotic bone had a higher response to LMHFV than normal bone and showed significantly better results as reflected by increased expression of Col-2 and Col-1 at week 2 ( p < 0.001 for all), larger callus width at week 2 ( p = 0.001), callus area at week 1 and 5( p < 0.05 for all) and greater relative area of osseous tissue ( p = 0.002) at week 8. This study helps to understand how LMHFV regulates gene expression of callus formation, mineralization and remodeling during osteoporotic fracture healing. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1572-1579, 2014. [ABSTRACT FROM AUTHOR]

ABSTRACT Fibrous tissue is often formed in delayed healing of tendon bone insertion (TBI) instead of fibrocartilage. Extracorporeal shockwave (ESW) provides mechanical cues and upregulates expression of fibrocartilage-related makers and cytokines. We hypothesized that ESW would accelerate fibrocartilage regeneration at the healing interface in a delayed TBI healing model. Partial patellectomy with shielding at the TBI interface was performed on 32 female New Zealand White Rabbits for establishing this delayed TBI healing model. The rabbits were separated into the control and ESW group for evaluations at postoperative week 8 and 12. Shielding was removed at week 4 and a single ESW treatment was applied at week 6. Fibrocartilage regeneration was evaluated histomorphologically and immunohistochemically. Vickers hardness of the TBI matrix was measured by micro-indentation. ESW group showed higher fibrocartilage area, thickness, and proteoglycan deposition than the control in week 8 and 12. ESW increased expression of SOX9 and collagen II significantly in week 8 and 12, respectively. ESW group showed a gradual transition of hardness from bone to fibrocartilage to tendon, and had a higher Vickers hardness than the control group at week 12. In conclusion, ESW enhanced fibrocartilage regeneration at the healing interface in a delayed TBI healing model. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:507-514, 2014. [ABSTRACT FROM AUTHOR]

Low intensity pulsed ultrasound (LIPUS) was proven to enhance fracture healing effectively. Similar effect of LIPUS on accelerating the osteoporotic fracture healing was therefore hypothesized. The normal and osteoporotic fracture healings under this non-invasive biophysical intervention of LIPUS were compared and investigated. Closed femoral fracture procedures were performed on 120 Sprague-Dawley rats, in which 60 of them were ovariectomized (OVX). The rats were randomly assigned into four groups: sham OVX with treatment (Sham-T), sham OVX control (Sham-C), OVX with treatment (OVX-T) and OXV control (OVX-C). LIPUS treatment was 20 min a day, 5 days a week for durations of 2, 4, or 8 weeks. Results from weekly radiography, histomorphometry, micro-computed tomography and mechanical test showed both the treatment groups were with better healing responses than their control groups. Moreover, between the normal and the osteoporotic treatment groups, a significantly higher ( p = 0.015) callus width (week 4), higher ratio of increment in bone volume to tissue volume ratio value (7.4% more), faster response of endochondral ossification and a higher stiffness measurement were observed in the osteoporotic treatment group. These comparable results on healing responses imply that LIPUS can be applied clinically to enhance both normal and osteoporotic fracture healing. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:129-136, 2012 [ABSTRACT FROM AUTHOR]

We aimed to establish a novel approach with 3D high frequency power Doppler ultrasonography (3D-HF-PDU) to assess microvasculature at the fracture site in rat femurs by comparing with microCT-based microangiography. Twenty-four 9-month-old ovariectomized (OVX) osteoporotic rats and age-matched sham-ovariectomized (Sham) rats were used for establishing closed fracture models on right femora. At 2, 4, and 8 weeks post-operatively, four rats in each group underwent in vivo 3D-HF-PDU scanning for evaluation of vascularization and blood flow at the fracture site. Then the fractured femora were harvested for ex vivo microangiography, and neovasculatures within the callus were reconstructed for vascular volume analysis. Correlation between the vascular volumes of the two methodologies was examined. Both 3D-HF-PDU and microangiography showed a decline of vascular volume at the fracture site from 2 to 8 weeks and a significantly larger volume in the Sham group than the OVX group. A significant linear positive correlation ( r = 0.87, p < 0.001) was detected between the volumes measured by the two methodologies. Osteoporotic rats had a diminished angiogenic response and lower blood perfusion than Shams. We believe 3D-HF-PDU is feasible and reproducible for in vivo assessment of microvasculature during femoral fracture healing in rats. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:137-143, 2012 [ABSTRACT FROM AUTHOR]

Physeal fracture is a common pediatric fracture that would result in premature physeal closure in long bones, and there is currently no gold standard for its management. In this study, we investigated the application of a Bioengineered Cartilage Pellet (BCP) in repairing a rabbit physeal fracture model, and the possible effects of Low Intensity Pulsed Ultrasound (LIPUS) treatment. Rabbits with physeal fracture created were assigned to the NC group (no BCP, no LIPUS), GC group (BCP, no LIPUS), and GT group (BCP and LIPUS). Femoral lengths and cartilage area were assessed at 4, 8, and 16 weeks post-defect. After transplantation, the BCP showed continuous growth in the host and demonstrated resemblance to a natural growth plate. The GC group showed 34.1, 32.1, and 41.1% advantage in lengthening over the NC group and the GT group showed 51.1, 41.6, and 26.9% improved lengthening than the NC group, at 4 ( p = 0.203), 8 ( p = 0.543) and 16 weeks ( p = 0.049), respectively. Cartilage area was shown to be significantly higher in GC and GT group compared to NC group ( p < 0.05). No significant difference was found between GC and GT group. Femoral longitudinal growth was shown to be improved by the BCP, however no additional enhancement effect was shown to be provided by LIPUS. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011. [ABSTRACT FROM AUTHOR]

Purpose: To determine whether low-intensity pulsed ultrasound (LIPUS) is able to facilitate the uptake of a superparamagnetic iron oxide (SPIO) nanomaterial by cells that do not express high endocytosis capacity. Materials and Methods: The human osteosarcoma cell line U2OS and a silica-coated SPIO functionalized peripherally with amines groups (overall diameter 8 nm) were used in this study. Adherent U2OS cells were labeled with SPIO by incubating with culture media containing the SPIO at 4.5 μg[Fe]/mL. LIPUS with the same parameters as those used in clinical application to accelerate bone fracture healing (1.5 MHz, duty cycle 1:4, spatial-average temporal-average intensity 30 mW/cm2) was applied to the cells at the beginning of the labeling process for 0, 0.5, 1, or 3 hours. The total incubation time with SPIO was 12 hours. SPIO labeling efficiency was evaluated with Prussian blue staining and a blueness measurement method, and magnetic resonance imaging (MRI) of cell pellets via measuring areas of SPIO-induced signal void. Results: Both Prussian blue staining and in vitro MRI demonstrated that LIPUS application increased the SPIO nanomaterial labeling efficiency for U2OS cells in an exposure-duration-dependent manner. Conclusion: This study is a 'proof of concept' that LIPUS can facilitate the cellular take-up of SPIO nanomaterial. J. Magn. Reson. Imaging 2010;31:1508-1513. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Healing at the osteotendinous junction (OTJ) is challenging in orthopedic surgery. The present study aimed to test extracorporeal shockwave (ESW) in treatment of a delayed OTJ healing. Twenty-eight rabbits were used for establishing a delayed healing (DH) model at patella-patellar-tendon (PPT) complex after partial patellectomy for 4 weeks and then were divided into DH and ESW groups. In the ESW group, a single ESW treatment was given at postoperative week 6 to the PPT healing complex. The samples were harvested at week 8 and 12 for radiographic and histological evaluations with seven samples for each group at each time point. Micro-CT results showed that new bone volume was 1.18 ± 0.61 mm3 in the ESW group with no measurable new bone in the DH group at postoperative week 8. Scar tissue formed at the OTJ healing interface of the DH group, whereas ESW triggered high expression of VEGF in hypertrophic chondrocytes at week 8 and regeneration of the fibrocartilage zone at week 12 postoperatively. The accelerated osteogenesis could be explained by acceleration of endochondral ossification. In conclusion, ESW was able to induce osteogenesis at OTJ with delayed healing with enhanced endochondral ossification process and regeneration of fibrocartilage zone. These findings formed a scientific basis to potential clinical application of ESW for treatment of delayed OTJ healing. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:70-76, 2010 [ABSTRACT FROM AUTHOR]

Fracture healing is a biological regenerative process that follows a well-orchestrated sequence. Most healing is uneventful and enhancement of normal fracture healing is not commonly done, although it is clinically important in the recovery and regain of functions after fracture. This study investigated the osteogenic effect of low-magnitude high-frequency vibration (LMHFV, 35 Hz, 0.3 g) on the enhancement of fracture healing in rats with closed femoral shaft fracture by comparing with sham-treated control. Assessments with plain radiography, micro-CT as well as histomorphometry showed that the amount of callus was significantly larger ( p = 0.001 for callus area, 2 weeks posttreatment); the remodeling of the callus into mature bone was significantly faster ( p = 0.039, 4 weeks posttreatment) in the treatment group. The mechanical strength of the healed fracture in the treatment group at 4 weeks was significantly greater ( p < 0.001). The results showed the acceleration of callus formation, mineralization, and fracture healing in the treatment group. It is concluded that LMHFV enhances healing in the closed femoral shaft fracture in rats. The potential clinical advantages shall be confirmed in the subsequent clinical trials. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 458-465, 2009 [ABSTRACT FROM AUTHOR]

Distraction osteogenesis of bone or callotasis causes poor bone formation when the distraction rate is beyond the optimal rate. Low-intensity pulsed ultrasound was reported to enhance fracture healing, treatment of nonunion, and accelerate bone maturation and remodeling during consolidation stage of distraction osteogenesis. In this study, we evaluated the efficacy of different durations of LIPUS treatments during rapid bone lengthening. After 7-day latent period, osteotomized New Zealand white rabbit tibiae were lengthened at the rate of 2 mm per day for 1 week. Two different LIPUS treatment durations of 20 min and 40 min were selected for treatment groups. Rabbits without treatment served as the control group. Plain X-ray, peripheral quantitative computed tomography (pQCT) and histology were performed to assess bone acquisition in the distraction callus. The results showed that LIPUS increased bone mineral content and volume of the mineralized tissue of distraction callus in a dose-dependent manner. The different regions of distraction callus exhibited various spatial response to LIPUS treatment. Moreover, LIPUS enhanced dose-dependant endochondral formation. Compared with 20-min treatment, the 40-min LIPUS treatment was a more favorable treatment duration for bone regeneration in the distraction callus. In conclusion, LIPUS was able to enhance bone regeneration under rapid distraction, and its effect was dose-dependent. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:2072-2079, 2006 [ABSTRACT FROM AUTHOR]