Bone stress injuries

Advancement in smart bone implants: the latest multifunctional strategies and synergistic mechanisms for tissue repair and regeneration

Artificial implants have consistently been recognized as the most effective clinical strategy for repairing bone fractures and defects, particularly in orthopedics and stomatology. Nowadays, the focus of bone repair has shifted from basic fixation and structural restoration to the reconstruction of multifunctional "live" tissue to mimic the natural bone microenvironment. However, developing the smart implants with ideal osteogenesis-related multi-functions remains challenging, as the effects of physicochemical properties of implant materials on intracellular signaling, stem cell niches, and tissue regeneration are not yet fully understood. Herein, we systematically explore recent advancements in innovative strategies for bone repair and regeneration, revealing the significance of the smart implants that closely mimic the natural structure and function of bone tissue. Adaptation to patient-oriented osteogenic microenvironments, dynamic osteoblastogenesis-osteoclastogenesis balance, antibacterial/bactericidal capacity, vascularization, and osteoimmunomodulatory capacity and their regulatory mechanisms achieved by biomaterials design and functional modifications are thoroughly summarized and analyzed. Notably, the popular research on multifunctional platforms with synergetic interactions between different functions and treatment of complex clinical issues, including the emerging neurogenic bone repair, is also significantly discussed for developing more intelligent implants. By summarizing recent research efforts, this review proposes the latest multifunctional strategies and synergistic mechanisms of smart bone implants, aiming to provide better bone defect repair applications that more closely mimic the natural bone tissue.

Soft Pneumatic Device Designed to Mimic the Periosteal Environment for Regulating the Fate of Mesenchymal Stem Cells

Replicating the complex mechanical forces of muscle movement and fluid flow in in vitro cell culture systems is crucial for understanding cell differentiation and development. However, previous research focused on cell differentiation on static micro/nanotextures without a force field or flat 2-dimensional substrates under a continuous in-plane mechanical force. In this study, cell differentiation is reported using a spatial geometric platform that can periodically modulate complex mechanical forces through a custom-made soft pneumatic device (SPD) to mimic the interfaces between periosteum and interstitial fluid. To elucidate fluidic dynamics and cell fates relevant to bone physiology, the platform exhibited distinct functional responses based on mechanical force levels: low mechanotransduction induced mesenchymal stem/progenitor cells differentiation into osteoprogenitor cells (≈1.5-fold increase in osteo-differentiation), while high mechanotransduction resulted in structural disruptions resembling cell detachment without protein degradation (≈2-fold increase in effective cell detachment). Numerical simulations of SPD elucidated the principal mechanical components for programmable cell differentiation and detachment by deconvoluting the in-plane and out-of-plane mechanical forces of the SPD complex mode. This study offers comprehensive and novel insights into the correlation between mechanical forces and cell differentiation, recovery, and injury in organisms.

Association of visceral fat metabolic score with bone mineral density and osteoporosis: a NHANES cross-sectional study

BACKGROUND

Metabolic Score for Visceral Fat (METS-VF) is commonly used as an indicator for assessing visceral fat metabolism. However, the relationship between METS-VF, Bone Mineral Density (BMD), and osteoporosis remains unclear in the American population.

METHODS

This study utilized cross-sectional data from the National Health and Nutrition Examination Survey (NHANES), including participants aged 20 years and older, from the survey cycles conducted between 2005 and 2010, 2013-2014, and 2017-2018. Multivariable weighted linear regression and logistic regression analyses were first applied to investigate the associations between the METS-VF, femoral BMD, and osteoporosis. In addition, subgroup interaction analyses were performed to evaluate the robustness of these associations. To address potential non-linear relationships, restricted cubic spline regression was employed. All statistical analyses were conducted using R software version 4.3.3. P values were two-tailed, with P < 0.05 considered statistically significant.

RESULTS

After adjusting for all covariates, the positive correlations between METS-VF and BMD measurements at all sites remained statistically significant (p < 0.001 & p for trend < 0.001). Multivariable logistic regression analysis indicated that, after adjusting for covariates related to osteoporosis, each one-unit increase in METS-VF was associated with a 63.1% reduction in the risk of developing osteoporosis. Moreover, the direction of the associations between METS-VF and both BMD and osteoporosis remained consistent across all subgroups, while restricted cubic spline (RCS) analyses suggested nonlinear relationships. The 5.82-7.35 METS-VF range yielded a mean 51.9% osteoporosis risk reduction (sustained ≥ 30% peak efficacy in 66.7% of participants).

CONCLUSIONS

METS-VF demonstrated a nonlinear positive association with BMD and a nonlinear inverse relationship with osteoporosis risk. Future studies should establish optimal biological thresholds of METS-VF for skeletal health.

CLINICAL TRIAL NUMBER

Not applicable.

Integrating personalized shape prediction, biomechanical modeling, and wearables for bone stress prediction in runners

Running biomechanics studies the mechanical forces experienced during running to improve performance and prevent injuries. This study presents the development of a digital twin for predicting bone stress in runners. The digital twin leverages a domain adaptation-based Long Short-Term Memory (LSTM) algorithm, informed by wearable sensor data, to dynamically simulate the structural behavior of foot bones under running conditions. Data from fifty participants, categorized as rearfoot and non-rearfoot strikers, were used to create personalized 3D foot models and finite element simulations. Two nine-axis inertial sensors captured three-axis acceleration data during running. The LSTM neural network with domain adaptation proved optimal for predicting bone stress in key foot bones-specifically the metatarsals, calcaneus, and talus-during the mid-stance and push-off phases (RMSE < 8.35 MPa). This non-invasive, cost-effective approach represents a significant advancement for precision health, contributing to the understanding and prevention of running-related fracture injuries.

Considerations for the Rehabilitation Management of the Female Athlete

This article discussed the anatomic, physiologic, hormonal, and psychosocial factors unique to the female athelte that can affect a female athlete's injury risk and rehabilitation trajectory. A review of considerations unique to different stages of life in the female athlete and a discussion of the prevalence of certain injuries in female athletes are discussed. The purpose of this narrative review is to highlight how understanding the unique characteristics of the female athlete can allow for optimization of rehabilitation protocols.

Injectable mineralized hydrogel microspheres for accelerated osteocyte network reconstruction and intelligent bone regeneration

The disruption and limited reconstruction capacity of the osteocyte network are pivotal factors underlying impaired bone regeneration. This study developed an injectable mineralized hydrogel microsphere that provides a mineral-rich environment and optimal matrix stiffness for osteocyte network restoration. Furthermore, it spatially activates Notch signaling through osteocyte-derived vesicles with high Jagged1 expression, promoting osteocyte differentiation and enhancing angiogenic regulatory function. Specifically, hydrogel microspheres combining gelatin methacrylate (GelMA), alginate methacrylate (AlgMA), and osteocyte membrane vesicles (OMVs) were fabricated via gas-shear microfluidics and photopolymerization, followed by in situ pre-mineralization to produce mineralized microspheres. Findings indicate that mineralized hydrogel microspheres exhibit significantly increased compressive modulus and in situ formation of amorphous calcium phosphate particles within the gel matrix. In vitro, the mineralized microspheres effectively facilitated osteogenic differentiation in bone marrow-derived mesenchymal stem cells (BMSCs), with adherent cells displaying accelerated osteocyte marker expression. Co-culture experiments further revealed enhanced vascular formation potential. Ectopic bone regeneration studies demonstrated that mineralized hydrogel microspheres promote rapid formation of mature osteocyte networks in vivo. Moreover, in a femoral critical bone defect model, these microspheres accelerated defect healing. Collectively, mineralized hydrogel microspheres expedite osteocyte network reconstruction, supporting intelligent bone regeneration, and present a promising approach for critical-sized bone defect repair.

An electrostatic encapsulation strategy to motivate 3D-printed polyelectrolyte scaffolds for repair of osteoporotic bone defects

Repair of osteoporotic bone defects (OBD) remains a clinical challenge due to dysregulated bone homeostasis, characterized by impaired osteogenesis and excessive osteoclast activity. While drug-loaded 3D-printed scaffolds hold great potential in the restoration of bone homeostasis for enhanced OBD repair, achieving the controlled release and targeted delivery of drugs in a 3D-printed scaffold is still unmet. Herein, we developed an electrostatic encapsulation strategy to motivate 3D-printed polyelectrolyte scaffolds (APS@P) with bone-targeting liposome formulation of salvianolic acid B (SAB-BTL). Benefiting from this strategy, SAB, an unstable and untargetable plant-derived osteogenic compound, was effectively encapsulated in APS@P, demonstrating stable and precise delivery with improved therapeutic efficacy. Owing to SAB-mediated bone homeostasis, APS@P significantly promoted angiogenesis and new bone formation while suppressing bone resorption, resulting in a significant 146 % increase in bone mass and improved microstructure compared to the OBD group. It was confirmed that the encapsulation of SAB into APS@P could promote the osteogenic differentiation of MSCs by stimulating Tph2/Wnt/β-catenin signaling axis, coupled with the stimulation of type H angiogenesis and the suppression of RANKL-mediate bone resorption, thereby enhance OBD repair. This study provides a universal platform for enhancing the bioactivity of tissue-engineered scaffolds, offering an effective solution for the efficient regeneration of osteoporotic bone.

Effect of acute performance fatigue on tibial bone strain during basketball maneuvers

The tibia is one of the most common sites for bone stress injury (BSI) in active individuals. BSIs are thought to occur in response to damage accumulation from repetitive loading below the tissue's yield limit. The effect of fatigue on musculoskeletal biomechanics and tibial bone strain during athletic movements remains unclear. In this study, participant-specific finite element (FE) and musculoskeletal models in 10 collegiate-basketball players were used to analyze the effect of acute performance fatigue on joint kinematics and torques, ground reaction forces (GRFs), and the magnitude and distribution of tibial bone strains during select basketball maneuvers. Participants were fatigued by performing repeated exercises wearing a weighted vest until their vertical jump height decreased by 20 %. Fatigue reduced the vertical GRF during midstance of a jump task, and lowered hip and knee peak extension torques and ankle plantarflexion. However, fatigue had limited impact on tibial bone strain magnitude and distribution during jumping. In contrast, there was a shift in peak strain timing following fatigue during a lateral cut task and reduced strain at various times of stance during sprinting. The results suggest that fatigue was induced and, if anything, reduced tibial bone strain. As increased bone strain is thought to be associated with increased BSI risk, the reduced strain observed in the current study suggests that fatigue may actually be partly protective, possibly as a result of reduced muscle activation and force production.

Global epidemiology of lower limb fractures: Trends, burden, and projections from the GBD 2021 study

BACKGROUND

Lower limb fractures are a significant global public health issue, imposing considerable social and economic burdens. Despite their prevalence, comprehensive analyses of the global epidemiology of lower limb fractures remain scarce. This study aims to address this gap.

METHODS

Using data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021, we analyzed four types of lower limb fractures: fractures of foot bones excluding the ankle (FFB), hip fractures (FH), fractures of the patella, tibia or fibula, or ankle (FPTFA), and femur fractures excluding the femoral neck (FF), and conducted a detailed assessment of them.

RESULTS

FPTFA was the most burdensome fracture type, with Slovenia showing the highest age-standardized incidence rate (ASIR), and Saudi Arabia having the highest age-standardized prevalence rate (ASPR) and years lived with disability rate (ASYR). The burden of lower limb fractures increased with age, but FFB and FPTFA showed a "double peak" age distribution, with FFB most common in the 20-24 age group. Lower limb fractures were more prevalent in males among younger individuals and in females among older populations. From 1990 to 2021, the burden of lower limb fractures, excluding FH, decreased (EAPC <1), though the incidence of FF is projected to increase (EAPC = 0.14, 95 % CI 0.1-0.18) over the next decade.

CONCLUSION

Although the global burden of lower limb fractures, excluding FH, has decreased in recent years, vigilance is still needed. Given the projected rise in FF incidence over the next decade, preventive measures should be implemented early.

Ribbing disease of the femur: a rare entity

Ribbing disease is a rare benign bone dysplasia characterized by progressive cortical thickening of the diaphyses of long bones in adult patients. The literature provides limited insight into its natural radiological progression and anatomical distribution. Single-bone involvement is particularly uncommon, with prior cases exclusively affecting the tibia. This case report outlines the unique presentation of Ribbing disease in a 20-year-old male, localized to the left femur. The patient's history revealed intermittent left thigh pain persisting for more than 2 years, with no identifiable triggers or relief factors. Early radiographic imaging revealed no significant abnormalities, but subsequent imaging, conducted 1 year after the initial presentation, revealed focal fusiform widening and cortical thickening of the mid-diaphysis of the left femur. MRI further revealed circumferential cortical thickening with bone marrow edema, corroborated by CT, which revealed cortical thickening with near-complete obliteration of the intramedullary cavity. The patient was managed with nonsteroidal anti-inflammatory drugs and activity modifications. Misinterpretation of the radiographic findings of the osteoid osteoma led the patient to undergo radiofrequency ablation. This case highlights the challenges in diagnosing Ribbing disease and emphasizes the importance of considering it in the differential diagnosis of chronic limb pain. Continued reporting of cases contributes to enhancing our understanding and management of this rare skeletal dysplasia.

Recommendations for use of extracorporeal shockwave therapy in sports medicine: an international modified Delphi study

OBJECTIVES

While extracorporeal shockwave therapy (ESWT) may be an efficacious adjunctive treatment option for musculoskeletal injuries, current research is limited by significant heterogeneity within treatment protocols. This study aims to establish international expert consensus recommendations on ESWT terminology, parameters, procedural considerations, contraindications and side effects in the application of ESWT to sports injuries.

METHODS

A systematic literature search was performed on the use of ESWT for musculoskeletal and sports medicine injuries to identify potential panellists, followed by the development of a steering committee-led questionnaire. A three-stage, modified Delphi questionnaire was provided to a panel of 41 international clinical and research experts across 13 countries. Panellists had the opportunity to suggest edits to existing statements or recommend additional statements in Round 1. Consensus was defined as≥75% agreement.

RESULTS

All 41 panellists completed Rounds 1, 2 and 3. Consensus was reached on 69/118 statements (58.5%), including recommendations on terminology and fundamental concepts, indications for use, procedural aspects for tendinopathy and bone pathologies, treatment correlations with imaging, periprocedural and postprocedural considerations, absolute and relative contraindications and potential side effects. Of the 49 statements that did not reach consensus, 17/49 (34.7%) were related to procedural aspects of bone pathology.

CONCLUSION

This international panel presents recommendations on ESWT terminology, indications and treatment considerations to guide ESWT use and decision-making by sports medicine clinicians. While our panel supported the use of ESWT in the treatment of bone pathologies, certain procedural aspects of ESWT specific to these injuries did not reach consensus and require further investigation.

Differences in metatarsal structure and mechanical behavior are small in runners with and without acute metatarsal bone stress injury

Purpose

To investigate differences in metatarsal bone structure and training habits in runners with and without a recent metatarsal bone stress injury (BSI).

Methods

Fifty-four runners (14 male/40 female, age 25.8±7.3 yrs) who ran 47±32 kilometers weekly participated in this study. Training and injury history data were collected, along with CT images from metatarsals 2-4 of the non-injured foot of recently injured runners (n=11, 5 male), and the left foot from the healthy runners (n=43, 9 male). Quantitative CT analysis was performed and subject-specific finite element (FE) models simulated a "virtual mechanical test" on each bone at a range of biomechanically relevant angles. Key FE outcomes included principal strains and a measure of total damaged volume, which is related to fatigue life.

Results

Injured runners reported significantly higher training volume (78.9±33.9 km/week) than healthy runners (39.2±20.2 km/week) and had lower BMI (21.3±1.7 vs. 22.7±2.6 kg/m2) but the groups were otherwise similar. In the female group, injured runners had significantly larger bone volume and BMC, similar bone strains, and significantly higher damaged volume metrics than healthy females. The FE simulations showed that decreasing the loading angle of the metatarsals by 10 degrees was associated with a 22% decrease in strain and damaged volume.

Conclusion

The metatarsals of injured and healthy runners are only slightly different from each other, and there are no obvious structural deficits in the injured runners. Other factors including training volume, footstrike biomechanics, and sex differences may explain BSI in this cohort. Interventions that decrease metatarsal loading angle or magnitude may reduce BSI risk by reducing bone microdamage.

Increase in paediatric bone stress injuries: a single-center study during the COVID-19 pandemic

BACKGROUND

Melbourne, Australia was considered the most locked-down city during the COVID19 Pandemic. School was conducted from home and all organized sport ceased. Our institution noted an increased presentation of bone stress injuries (BSI) ranging from periostitis to stress fractures. This study reviews the prevalence of these injuries to gain insights into BSI presentation, diagnosis and best management.

METHODS

A retrospective review of lower limb long bone stress injuries between April 1st 2020 and March 31st 2022, and from 2018 to 2020 for comparison, was conducted. A chart review of those meeting inclusion criteria for demographics, fracture characteristics, investigations, and treatment administered was conducted.

RESULTS

Thirteen patients (two female, 11 male) met inclusion criteria. Only four patients were identified in the comparison period. The average age was 11.6 years, and average symptom duration was 7 weeks. Distinct morphologies were noted, specifically three discrete patterns of tibial injury were identified. Patients underwent an average of three imaging studies prior to diagnosis. Nine of 13 patients were prescribed a period of non-weight bearing, averaging 3.5 weeks. Seven of 13 patients were prescribed a formal 'partial weight bearing' (50%) period averaging 6.4 weeks.

CONCLUSION

There was a significant increase in paediatric BSI presentation over the COVID-19 lockdowns. This may be linked to the effect of reduced physical activity. Knowledge of the three clear tibial morphologies identified in this study will inform future diagnosis and reduce investigation expenditure. These findings may inform public health measures during mandated lockdowns and raise a diagnostic framework for such injuries.

A review of sodium alginate-based hydrogels: Structure, mechanisms, applications, and perspectives

With the global emphasis on green and sustainable development, sodium alginate-based hydrogels (SAHs), as a renewable and biocompatible environmental material, have garnered widespread attention for their research and application. This review summarizes the latest advancements in the study of SAHs, thoroughly discussing their structural characteristics, formation mechanisms, and current applications in various fields, as well as prospects for future development. Initially, the chemical structure of SA and the network structure of hydrogels are introduced, and the impact of factors such as molecular weight, crosslinking density, and environmental conditions on the hydrogel structure is explored. Subsequently, the formation mechanisms of SAHs, including physical and chemical crosslinking, are detailed. Furthermore, a systematic review of the applications of SAHs in tissue engineering, drug delivery, medical dressings, wastewater treatment, strain sensor, and food science is provided. Finally, future research directions for SAHs are outlined. This work not only offers researchers a comprehensive framework for the study of SAHs but also provides significant theoretical and experimental foundations for the development of new hydrogel materials.

The effect of early weight-bearing on bone fusion after triple arthrodesis

Triple arthrodesis is an effective method for treating stiff horseshoe feet and severe osteoarthritis. However, it is still a challenge to improve postoperative bone fusion by changing early weight-bearing. This study improved the classical bone remodeling algorithm, established a mathematical relationship between density change rate and mechanical stimulation, and combined it with finite element theory. The proposed algorithm can not only predict the effect of early weight-bearing on triple arthrodesis but also visually demonstrate the change of bone mineral density with time. The analysis results indicated that 2.5% of the initial load was a potential factor leading to bone nonunion, and 50% of the initial load would result in bone resorption. Meanwhile, it was found that 25% of the external load was more conducive to postoperative rehabilitation. The study results have theoretical significance for enhancing the effect of postoperative bone fusion and formulating a more scientific rehabilitation program, thereby supporting patients' postoperative rehabilitation exercise.

A Descriptive Analysis of the Seasonal Patterns of Bone Stress Injury Incidence in Division I Collegiate Distance Runners

BACKGROUND

A bone stress injury (BSI) is a common overuse injury in collegiate athletes, particularly cross-country and track and field runners. Limited work describes the seasonality of BSIs or the differences in rates and anatomic locations of BSIs in collegiate runners.

PURPOSE

To describe seasonally related trends in anatomic locations of BSIs in National Collegiate Athletic Association (NCAA) Division I male and female middle- and long-distance runners.

STUDY DESIGN

Descriptive epidemiological study.

METHODS

Data from a 7-year prospective study of 2 NCAA Division I cross-country and track and field programs characterized BSIs over the years 2013 to 2020. Femoral neck, pelvic, sacral, lumbar spine, and calcaneal BSIs were considered trabecular-rich. All remaining BSIs were classified as cortical-rich. Total athlete-years of follow-up were calculated by subtracting the number of days an athlete was unable to run from the number of total study participation days. Annual incidence rates were calculated by dividing the number of BSIs by the total athlete-years of follow-up for that year, and monthly incidence rates were calculated by dividing the number of BSIs in a given month by the total athlete-years of follow-up for that month.

RESULTS

Participants included 221 collegiate distance runners (114 female, 107 male). There were 154 BSIs across 482 total athlete-years, resulting in an incidence rate of 32 BSIs per 100 athlete-years. The female BSI rate was more than double that of the male BSI rate: 45 versus 20 BSIs per 100 athlete-years, respectively. The highest monthly BSI rates occurred during competitive months, with the lowest monthly BSI rates occurring during noncompetitive months. Tibial and femoral shaft BSI rates peaked during the early competitive phases of each season, whereas metatarsal BSI rates remained relatively constant. Cortical-rich BSI rates varied by sex and seasonal phase, whereas trabecular-rich BSI rates remained relatively consistent.

CONCLUSION

BSIs were common in collegiate distance runners, especially among female athletes, with higher rates during the competitive phases of the running season. Tibial and femoral shaft BSI rates were highest during the competitive phases and lowest during the noncompetitive phases, while metatarsal BSI rates remained consistent throughout the season. Cortical-rich BSI rates varied by seasonal phase and sex, whereas trabecular-rich BSI rates were relatively constant.

Standardising health history and injury surveillance of participants in endurance events: a modified Delphi consensus statement from the AMSSM runner health consortium

Endurance events are popular worldwide and have many health benefits. However, runners and Para athletes may sustain musculoskeletal injuries or experience other health consequences from endurance events. The American Medical Society for Sports Medicine (AMSSM) Runner Health Consortium aimed to generate consensus-based survey items for use in prospective research to identify risk factors for injuries in runners and Para athletes training and competing in endurance events. The study design employed a modified Delphi approach, with a panel comprising 28 experts, including healthcare professionals, coaches, and athletes. Potential survey items were generated by panel members who subsequently engaged in three rounds of voting using Research Electronic Data Capture. Items were graded by clarity, relevance, and importance. Items achieving 80% consensus on all three aspects were retained. The response rate was 100% in R round 1 and 96% in Rrounds 2 and 3. Of 124 initial survey items, consensus was reached on 53, 34 and 22 items during Rrounds 1, 2, and 3, respectively. Two accepted items were removed due to redundancy. Combined with 10 non-voting items, 117 items covered key domains, including training and injury history, dietary behaviours and associated factors (such as menstrual function), footwear, mental health, and specific considerations for Para athletes. The consensus-based survey items should be considered by researchers to better understand the health of runners and Para athletes who train and compete in endurance sports to identify risk factors for injury.

Synthetic nanointerfacial bioengineering of Ti implants: on-demand regulation of implant-bone interactions for enhancing osseointegration

Titanium and its alloys are the most commonly used biometals for developing orthopedic implants to treat various forms of bone fractures and defects, but their clinical performance is still challenged by the unfavorable mechanical and biological interactions at the implant-tissue interface, which substantially impede bone healing at the defects and reduce the quality of regenerated bones. Moreover, the impaired osteogenesis capacity of patients under certain pathological conditions such as diabetes and osteoporosis may further impair the osseointegration of Ti-based implants and increase the risk of treatment failure. To address these issues, various modification strategies have been developed to regulate the implant-bone interactions for improving bone growth and remodeling in situ. In this review, we provide a comprehensive analysis on the state-of-the-art synthetic nanointerfacial bioengineering strategies for designing Ti-based biofunctional orthopedic implants, with special emphasis on the contributions to (1) promotion of new bone formation and binding at the implant-bone interface, (2) bacterial elimination for preventing peri-implant infection and (3) overcoming osseointegration resistance induced by degenerative bone diseases. Furthermore, a perspective is included to discuss the challenges and potential opportunities for the interfacial engineering of Ti implants in a translational perspective. Overall, it is envisioned that the insights in this review may guide future research in the area of biometallic orthopedic implants for improving bone repair with enhanced efficacy and safety.

Bone Stress Injury Epidemiology and Risk Factors in Female Off-Road Runners: A Systematic Review

BACKGROUND

Off-road running is a growing sport with little research investigating injury profiles of female participants. Bone stress injuries (BSIs) are a particularly detrimental injury with little known about their incidence and risk factors in female off-road runners.

OBJECTIVE

Collate and review the available evidence reporting epidemiological data and risk factors associated with BSI in female off-road runners.

DESIGN

Systematic literature review, without meta-analyses.

DATA SOURCES

MEDLINE OVID, PubMed, SPORTDiscus, and MEDLINE EBSCO. Searches were finalized in July 2024.

ELIGIBILITY CRITERIA

Studies that reported injury surveillance statistics and/or risk factors associated with BSIs in female off-road runners.

RESULTS

Seventeen eligible studies were included, of which all reported surveillance statistics and 2 reported risk factors associated with BSI among 897 female runners. Owing to the scarcity of data, cross-country runners were included in the population of off-road runners. Most BSIs were high severity and in the lower leg, with an overall incidence ranging from 0 to 34.39 BSIs per 100,000 athlete-exposures and prevalence ranging from 0% to 40.9%. Study characteristics were reported alongside risk of bias, quality, and level of evidence assessment outcomes from varying tools. Eight significant intrinsic risk factors were associated with BSIs in female off-road runners: increasing age, disrupted menstruation, previous BSI, increased female triad risk, and lower calcium, vitamin D, and calorie intake.

DISCUSSION

Limited by the number of studies available reporting data on the specific target population, which highlights the need for performing high-quality prospective studies in the future, this review summarizes the current epidemiological data and risk factors associated with BSIs in female off-road runners.

International Delphi consensus on bone stress injuries in athletes

Bone stress injuries, commonly referred to as stress reactions and stress fractures, represent overuse injuries to bone. These injuries result in physical limitations in activity and can be career-ending for high-level athletes. While bone stress injuries have received increased attention in recent years, international consensus is lacking on definitions, risk factors and strategies for management and prevention. This study aimed to ascertain and improve the level of agreement on bone stress injuries by utilising a three-part modified Delphi approach on (1) pathophysiology, diagnosis, terminology and classification systems; (2) risk factors, screening and prevention; and (3) management and return to sport. A multidisciplinary steering committee initiated the consensus process. A panel of 41 members from six continents was formed to complete three rounds of voting, including experts (scientists and clinicians) and representatives (athletes and coaches). Thirty-three, 28 and 28 panel members completed Delphi rounds 1, 2 and 3, respectively. Consensus was reached on 41 out of 58 statements. Findings from this Delphi study outline a multifactorial approach to identify and manage bone stress injuries and to promote bone health in athletes. This includes recommendations for diagnostic workup and treatment to assist clinicians in caring for patients with bone stress injuries. Finally, this consensus process identifies knowledge gaps and provides a framework for future research to advance the clinical care and prevention of bone stress injuries.

The effects of endurance trainability phenotype, sex, and interval running training on bone collagen synthesis in adult rats

Bone is influenced by many factors such as genetics and mechanical loading, but the short-term physiological effects of these factors on bone (re)modelling are not well characterised. This study investigated the effects of endurance trainability phenotype, sex, and interval running training (7-week intervention) on bone collagen formation in rats using a deuterium oxide stable isotope tracer method. Bone samples of the femur diaphysis, proximal tibia, mid-shaft tibia, and distal tibia were collected after necropsy from forty-six 9 ± 3-month male and female rats selectively bred for yielding low (LRT) or high (HRT) responses to endurance training. Bone collagen proteins were isolated and hydrolysed, and fractional synthetic rates (FSRs) were determined by the incorporation of deuterium into protein-bound alanine via GC-pyrolysis-IRMS. There was a significant large main effect of phenotype at the femur site (p < 0.001; η2g = 0.473) with HRT rats showing greater bone collagen FSRs than LRT rats. There was a significant large main effect of phenotype (p = 0.008; η2g = 0.178) and a significant large main effect of sex (p = 0.005; η2g = 0.196) at the proximal site of the tibia with HRT rats showing greater bone collagen FSRs than LRT rats, and male rats showing greater bone collagen FSRs compared to female rats. There was a significant large main effect of training at the mid-shaft site of the tibia (p = 0.012; η2g = 0.159), with rats that underwent interval running training having greater bone collagen FSRs than control rats. Similarly, there was a significant large main effect of training at the distal site of the tibia (p = 0.050; η2g = 0.156), with rats in the interval running training group having greater bone collagen FSRs compared to rats in the control group. Collectively, this evidence highlights that bone responses to physiological effects are site-specific, indicating that interval running training has positive effects on bone collagen synthesis at the tibial mid-shaft and distal sites, whilst genetic factors affect bone collagen synthesis at the femur diaphysis (phenotype) and proximal tibia (phenotype and sex) in rats.

Relationship between the microstructural energy release rate of cortical bone and age under compression condition

Most studies evaluated the energy release rate of cortical bone macrostructure under Mode I, Mode II, and mixed Mode I-II loading conditions. However, testing the macrostructural energy release rate requires an initial crack and recording the applied load and the corresponding crack length in real-time, which may introduce measurement errors and differences with the actual fracture scenarios. To further understand how the energy release rate contributed to the cortical bone fracture characteristics, this study predicted the microstructural energy release rate of cortical bone and then investigated its age-related varitions. The microstructural energy release rate of femoral cortical bone in rats from different ages was back-calculated by fitting the experimental and simulated load-displacement curves under compression load. The trends in the microstructural energy release rate were revealed, and the underlying reasons for the age-related changes were investigated by integrating the discussion on the cortical bone mechanical parameters at various levels obtained from the previous experiment. The predicted microstructural energy release rate of femoral cortical bone in the rats from 1, 3, 5, 7, 9, 11, and 15 months of age were in the range of 0.08-0.12, 0.12-0.14, 0.15-0.19, 0.25-0.28, 0.23-0.25, 0.19-0.22, and 0.13-0.16 N/mm, respectively. The statistical analyses showed the significant differences in the microstructural energy release rate at different ages. The results indicated an increasing trend followed by a decrease from 1 to 15 months of age, and the correlations between microstructural energy release rate and age were significant. The age-related variations in the microstructural energy release rate may be linked to the changes in the microarchitecture, and the fracture load is influenced by the micro-level mechanical parameters. Notably, the age-related trends in microarchitecture and energy release rate were similar. These findings were valuable for understanding the mechanism underlying the weakening mechanical properties of cortical bone microstructure with age from an energy perspective.

The Influence of Nutrition Intervention on the P1NP and CTX-1 Response to an Acute Exercise Bout: A Systematic Review with Meta-Analysis

BACKGROUND

Although nutrition and exercise both influence bone metabolism, little is currently known about their interaction, or whether nutritional intervention can modulate the bone biomarker response to acute exercise. Improved understanding of the relationships between nutrition, exercise and bone metabolism may have substantial potential to inform nutritional interventions to protect the bone health of exercising individuals, and to elucidate mechanisms by which exercise and nutrition influence bone.

OBJECTIVE

The aim was to synthesise available evidence related to the influence of nutrition on the response of the bone biomarkers procollagen type 1 N-terminal propeptide (P1NP) and C-terminal telopeptide of type 1 collagen (CTX-1) to acute exercise, using a systematic review and meta-analytic approach.

METHODS

Studies evaluating the influence of nutritional status or intervention on the bone biomarker response to an acute exercise bout were included and separated into four categories: (1) feeding status and energy availability, (2) macronutrients, (3) micronutrients and (4) other. Studies conducted on healthy human populations of any age or training status were included. Meta-analysis was conducted when data from at least five studies with independent datasets were available. In the case of insufficient data to warrant meta-analysis, results from individual studies were narratively synthesised and standardised mean effect sizes visually represented.

RESULTS

Twenty-two articles were included. Of these, three investigated feeding status or energy availability, eight macronutrients, eight micronutrients (all calcium) and six other interventions including dairy products or collagen supplementation. Three studies had more than one intervention and were included in all relevant outcomes. The largest and most commonly reported effects were for the bone resorption marker CTX-1. Meta-analysis indicated that calcium intake, whether provided via supplements, diet or infusion, reduced exercise-induced increases in CTX-1 (effect size - 1.1; 95% credible interval [CrI] -  2.2 to - 0.05), with substantially larger effects observed in studies that delivered calcium via direct infusion versus in supplements or foods. Narrative synthesis suggests that carbohydrate supplementation may support bone during acute exercise, via reducing exercise-induced increases in CTX-1. Conversely, a low-carbohydrate/high-fat diet appears to induce the opposite effect, as evidenced by an increased exercise associated CTX-1 response, and reduced P1NP response. Low energy availability may amplify the CTX-1 response to exercise, but it is unclear whether this is directly attributable to energy availability or to the lack of specific nutrients, such as carbohydrate.

CONCLUSION

Nutritional intervention can modulate the acute bone biomarker response to exercise, which primarily manifests as an increase in bone resorption. Ensuring adequate attention to nutritional factors may be important to protect bone health of exercising individuals, with energy, carbohydrate and calcium availability particularly important to consider. Although a wide breadth of data were available for this evidence synthesis, there was substantial heterogeneity in relation to design and intervention characteristics. Direct and indirect replication is required to confirm key findings and to generate better estimates of true effect sizes.

Cross-sectional size, shape, and estimated strength of the tibia, fibula and second metatarsal in female collegiate-level cross-country runners and soccer players

Bone stress injuries (BSIs) frequently occur in the leg and foot long bones of female distance runners. A potential means of preventing BSIs is to participate in multidirectional sports when younger to build a more robust skeleton. The current cross-sectional study compared differences in tibia, fibula, and second metatarsal diaphysis size, shape, and strength between female collegiate-level athletes specialized in cross-country running (RUN, n = 16) and soccer (SOC, n = 16). Assessments were performed using high-resolution peripheral quantitative computed tomography and outcomes corrected for measures at the radius diaphysis to control for selection bias and systemic differences between groups. The tibia in SOC had a 7.5 % larger total area than RUN, with a 29.4 % greater minimum second moment of area (IMIN) and 8.2 % greater estimated failure load (all p ≤ 0.02). Tibial values in SOC exceeded reference data indicating positive adaptation. In contrast, values in RUN were similar to reference data suggesting running induced limited tibial adaptation. RUN did have a larger ratio between their maximum second moment of area (IMAX) and IMIN than both SOC and reference values. This suggests the unidirectional loading associated with running altered tibial shape with material distributed more in the anteroposterior (IMAX) direction as opposed to the mediolateral (IMIN) direction. Comparatively, SOC had a similar IMAX/IMIN ratio to reference data suggesting the larger tibia in SOC resulted from multiplane adaptation. In addition to enhanced size and strength of their tibia, SOC had enhanced structure and strength of their fibula and second metatarsal. At both sites, polar moment of inertia was approximately 25 % larger in SOC compared to RUN (all p = 0.03). These data support calls for young female athletes to delay specialization in running and participate in multidirectional sports, like soccer, to build a more robust skeleton that is potentially more protected against BSIs.

Bone marrow aspirate concentrate for the treatment of fifth metatarsal head stress fracture: a case report

Metatarsal head stress fractures pose treatment challenges with no established consensus. In this article, we introduce a percutaneous treatment involving autologous bone marrow aspirate concentrate (BMAC) injection without surgical fixation in a 21-year-old basketball player with a stress fracture of the right fifth metatarsal head. He underwent this procedure following unsuccessful 8 months of conservative treatment. Twelve weeks after the procedure, a CT scan confirmed complete healing, facilitating his return to sports. This innovative method offers a promising alternative, avoiding the associated morbidity of surgical intervention. Further research, comparing refracture rates with surgical options, is warranted to inform treatment decisions for this uncommon injury and validate the efficacy of percutaneous BMAC injection.

Exertional Leg Pain in Athletes

ABSTRACT

Exertional leg pain is a relatively common condition that can negatively impact athletic performance and may pose a diagnostic and management challenge for the sports medicine physician. A comprehensive clinical evaluation is important to narrow the broad differential associated with exertional leg pain and focus the selection of the most appropriate diagnostic tests and treatment modalities in the care of these individuals. This article will provide an update on recent literature regarding the etiologies, pathophysiology, clinical presentation, workup/diagnosis, and treatment of exertional leg pain in athletes with a focus on vascular etiologies, chronic exertional compartment syndrome, and bone stress injury.

A novel mesenchymal stem cell-targeting dual-miRNA delivery system based on aptamer-functionalized tetrahedral framework nucleic acids: Application to endogenous regeneration of articular cartilage

Articular cartilage injury (ACI) remains one of the key challenges in regenerative medicine, as current treatment strategies do not result in ideal regeneration of hyaline-like cartilage. Enhancing endogenous repair via microRNAs (miRNAs) shows promise as a regenerative therapy. miRNA-140 and miRNA-455 are two key and promising candidates for regulating the chondrogenic differentiation of mesenchymal stem cells (MSCs). In this study, we innovatively synthesized a multifunctional tetrahedral framework in which a nucleic acid (tFNA)-based targeting miRNA codelivery system, named A-T-M, was used. With tFNAs as vehicles, miR-140 and miR-455 were connected to and modified on tFNAs, while Apt19S (a DNA aptamer targeting MSCs) was directly integrated into the nanocomplex. The relevant results showed that A-T-M efficiently delivered miR-140 and miR-455 into MSCs and subsequently regulated MSC chondrogenic differentiation through corresponding mechanisms. Interestingly, a synergistic effect between miR-140 and miR-455 was revealed. Furthermore, A-T-M successfully enhanced the endogenous repair capacity of articular cartilage in vivo and effectively inhibited hypertrophic chondrocyte formation. A-T-M provides a new perspective and strategy for the regeneration of articular cartilage, showing strong clinical application value in the future treatment of ACI.

Influence of Menstrual Cycle and Oral Contraceptive Phases on Bone (re)modelling Markers in Response to Interval Running

To explore how sex hormone fluctuations may affect bone metabolism, this study aimed to examine P1NP and β-CTX-1 concentrations across the menstrual and oral contraceptive (OC) cycle phases in response to running. 17β-oestradiol, progesterone, P1NP and β-CTX-1 were analysed pre- and post-exercise in eight eumenorrheic females in the early-follicular, late-follicular, and mid-luteal phases, while 8 OC users were evaluated during the withdrawal and active pill-taking phases. The running protocol consisted of 8 × 3min treadmill runs at 85% of maximal aerobic speed. 17β-oestradiol concentrations (pg·ml-1) were lower in early-follicular (47.22 ± 39.75) compared to late-follicular (304.95 ± 235.85;p =  < 0.001) and mid-luteal phase (165.56 ± 80.6;p = 0.003) and higher in withdrawal (46.51 ± 44.09) compared to active pill-taking phase (10.88 ± 11.24;p < 0.001). Progesterone (ng·ml-1) was higher in mid-luteal (13.214 ± 4.926) compared to early-follicular (0.521 ± 0.365; p < 0.001) and late-follicular phase (1.677 ± 2.586;p < 0.001). In eumenorrheic females, P1NP concentrations (ng·ml-1) were higher in late-follicular (69.97 ± 17.84) compared to early-follicular (60.96 ± 16.64;p = 0.006;) and mid-luteal phase (59.122 ± 11.77;p = 0.002). β-CTX-1 concentrations (ng·ml-1) were lower in mid-luteal (0.376 ± 0.098) compared to late-follicular (0.496 ± 0.166; p = 0.001) and early-follicular phase (0.452 ± 0.148; p = 0.039). OC users showed higher post-exercise P1NP concentrations in withdrawal phase (61.75 ± 8.32) compared to post-exercise in active pill-taking phase (45.45 ± 6;p < 0.001). Comparing hormonal profiles, post-exercise P1NP concentrations were higher in early-follicular (66.91 ± 16.26;p < 0.001), late-follicular (80.66 ± 16.35;p < 0.001) and mid-luteal phases (64.57 ± 9.68;p = 0.002) to active pill-taking phase. These findings underscore the importance of studying exercising females with different ovarian hormone profiles, as changes in sex hormone concentrations affect bone metabolism in response to running, showing a higher post-exercise P1NP concentrations in all menstrual cycle phases compared with active pill-taking phase of the OC cycle.

Criteria and Guidelines for Returning to Running Following a Tibial Bone Stress Injury: A Scoping Review

Tibial bone stress injuries (BSIs) are common among long-distance runners. They have a high recurrence rate, and complexity emerges in the wider management and successful return to running. Following a tibial BSI, a critical component of complete rehabilitation is the successful return to running, and there is a lack of consistency or strong evidence to guide this process. The objectives of this review were to outline the criteria used in clinical decision-making prior to resuming running, and to establish evidence-based guidelines for the return to running process following a tibial BSI. Electronic databases including MEDLINE, CINAHL, Scopus, SPORTDiscus and AMED were searched for studies that stated criteria or provided guidelines on the objectives above. Fifty studies met the inclusion criteria and were included. Thirty-nine were reviews or clinical commentaries, three were retrospective cohort studies, two were randomised controlled trials, two were pilot studies, one was a prospective observational study, and three were case studies. Therefore, the recommendations that have been surmised are based on level IV evidence. Decisions on when an athlete should return to running should be shared between clinicians, coaches and the athlete. There are five important components to address prior to introducing running, which are: the resolution of bony tenderness, pain-free walking, evidence of radiological healing in high-risk BSIs, strength, functional and loading tests, and the identification of contributing factors. Effective return to running planning should address the athlete's risk profile and manage the risk by balancing the athlete's interests and reinjury prevention. An individualised graduated return to running programme should be initiated, often starting with walk-run intervals, progressing running distance ahead of speed and intensity, with symptom provocation a key consideration. Contributing factors to the initial injury should be addressed throughout the return to run process.

Spatiotemporal Characterization of Microstructure Morphology, Mechanical Properties and Bone Remodeling of Rat Tibia Under Uniaxial Compressive Overload Loading

Bone tissue is subjected to increased mechanical stress during high-intensity work. Inadequate bone remodeling reparability can result in the continuous accumulation of microdamage, leading to stress fractures. The aim of this work was to investigate the characteristics and repair mechanisms of tibial microdamage under several degrees of overload. Also, we aimed at better understanding the effects of overload on the multi-scale structure and mechanical properties of bone. Sixty 5-month female rats were divided into three groups with different time points. Micro-CT was used to evaluate the three-dimensional microstructure, and three-point bending, quasi-static fracture toughness and creep mechanical test were carried out to evaluate the mechanical properties. SEM was used to observe the morphological characteristics of fracture surfaces. Section staining was used to count the microdamage parameters and numbers of osteoblasts and osteoclasts. The microarchitectures of cancellous and cortical bones in the three overload groups showed different degrees of damage. Overload led to a messy crystal structure of cortical bone, with slender microcracks mixed in, and a large number of broken fibers of cancellous bone. The properties associated with the elastic plasticity, fracture toughness, and viscoelasticity of cortical bone reduced in three groups, with that corresponding to day 30 presenting the highest damage. The accumulation of microdamage mainly occurred in the first 14 days, that is, the crack density peaked on day 14. Peak-targeted bone remodeling of cortical and cancellous bones occurred mainly between days 14 and 30. The influence of overload mechanical environment on bone quality at different time points was deeply investigated, which is of great significance for the etiology and treatment of stress fractures.

Predicting Tibia-Fibula Geometry and Density From Anatomical Landmarks Via Statistical Appearance Model: Influence of Errors on Finite Element-Calculated Bone Strain

State-of-the-art participant-specific finite element models require advanced medical imaging to quantify bone geometry and density distribution; access to and cost of imaging is prohibitive to the use of this approach. Statistical appearance models may enable estimation of participants' geometry and density in the absence of medical imaging. The purpose of this study was to: (1) quantify errors associated with predicting tibia-fibula geometry and density distribution from skin-mounted landmarks using a statistical appearance model and (2) quantify how those errors propagate to finite element-calculated bone strain. Participant-informed models of the tibia and fibula were generated for thirty participants from height and sex and from twelve skin-mounted landmarks using a statistical appearance model. Participant-specific running loads, calculated using gait data and a musculoskeletal model, were applied to participant-informed and CT-based models to predict bone strain using the finite element method. Participant-informed meshes illustrated median geometry and density distribution errors of 4.39-5.17 mm and 0.116-0.142 g/cm3, respectively, resulting in large errors in strain distribution (median RMSE = 476-492 με), peak strain (limits of agreement =±27-34%), and strained volume (limits of agreement =±104-202%). These findings indicate that neither skin-mounted landmark nor height and sex-based predictions could adequately approximate CT-derived participant-specific geometry, density distribution, or finite element-predicted bone strain and therefore should not be used for analyses comparing between groups or individuals.

Extrusion 3D-printed tricalcium phosphate-polycaprolactone biocomposites for quercetin-KCl delivery in bone tissue engineering

Critical-sized bone defects pose a significant challenge in advanced healthcare due to limited bone tissue regenerative capacity. The complex interplay of numerous overlapping variables hinders the development of multifunctional biocomposites. Phytochemicals show promise in promoting bone growth, but their dose-dependent nature and physicochemical properties halt clinical use. To develop a comprehensive solution, a 3D-printed (3DP) extrusion-based tricalcium phosphate-polycaprolactone (TCP-PCL) scaffold is augmented with quercetin and potassium chloride (KCl). This composite material demonstrates a compressive strength of 30 MPa showing promising stability for low load-bearing applications. Quercetin release from the scaffold follows a biphasic pattern that persists for up to 28 days, driven via diffusion-mediated kinetics. The incorporation of KCl allows for tunable degradation rates of scaffolds and prevents the initial rapid release. Functionalization of scaffolds facilitates the attachment and proliferation of human fetal osteoblasts (hfOB), resulting in a 2.1-fold increase in cell viability. Treated scaffolds exhibit a 3-fold reduction in osteosarcoma (MG-63) cell viability as compared to untreated substrates. Ruptured cell morphology and decreased mitochondrial membrane potential indicate the antitumorigenic potential. Scaffolds loaded with quercetin and quercetin-KCl (Q-KCl) demonstrate 76% and 89% reduction in bacterial colonies of Staphylococcus aureus, respectively. This study provides valuable insights as a promising strategy for bone tissue engineering (BTE) in orthopedic repair.

Bone stress injuries in athletics (track and field) championships: findings from a prospective injury surveillance conducted across 24 international championships with 29,147 registered athletes

BACKGROUND

Athletics (track and field) athletes are prone to develop bone stress injuries (BSIs) but epidemiological data on BSIs from top-level sports events are scarce.

OBJECTIVE

To describe the incidence and characteristics of BSIs during 24 international athletics championships held from 2007 to 2023.

METHODS

BSI-related data were prospectively collected during 24 international athletics championships, including the Olympic Games (n = 3), World Outdoor Championships (n = 4), European Outdoor Championships (n = 6), World Indoor Championships (n = 3) and European Indoor Championships (n = 8). Descriptive and comparative statistics were used to assess the epidemiological characteristics of BSIs.

RESULTS

BSIs accounted for 1.5% of all reported injuries (n = 36; 1.2 per 1000 registered athletes (95%CI 0.8 to 1.6)). No significant difference of BSI incidence was detected between female (2.0 per 1000 athletes (95%CI: 0.9 to 2.3)) and male athletes (0.9 per 1000 athletes (95%CI: 0.4 to 1.4)) (relative risk (RR) = 1.73, 95%CI: 0.88 to 3.40). BSI incidence was significantly higher during outdoor championships (1.6 per 1000 registered athletes (95%CI: 1.0 to 2.1)) as compared to indoor championships (0.2 per 1000 registered athletes (95%CI: 0.0 to 0.5)) (RR = 10.4, 95%CI: 1.43 to 76.0). Most BSIs were sustained in the foot (n = 50%) or leg (n = 33%). BSIs were reported in athletes participating in endurance disciplines (52.8%) or in explosive disciplines (47.2%).

CONCLUSIONS

BSIs represent a small portion of injuries sustained during international athletics championships. Collective results suggest that injury rates are higher in outdoor competitions as compared to indoor competitions. The most common injury locations comprise the foot and leg.

CLINICAL TRIAL NUMBER

Not applicable.

Fatigue Performance of 3D-Printed Poly-Lactic-Acid Bone Scaffolds with Triply Periodic Minimal Surface and Voronoi Pore Structures

Bone scaffolds serve a crucial role in tissue engineering, particularly in facilitating bone regeneration where natural repair is insufficient. Despite advancements in the fabrication of polymeric bone scaffolds, the challenge remains to optimize their mechanical resilience. Specifically, research on the fatigue behaviour of polymeric bone scaffolds is scarce. This study investigates the influence of pore architecture on the mechanical performance of poly-lactic-acid (PLA) scaffolds under quasi-static and cyclic compression. PLA scaffolds with a 60% porosity were fabricated using extrusion-based 3D printing in various designs: Gyroid, Lidinoid, Fischer-Koch, IWP, and Voronoi. Results demonstrated that Gyroid scaffolds had the highest compressive strength (6.6 MPa), followed by Lidinoid, Fischer-Koch, IWP, and Voronoi designs. Increased strut thickness was linked to higher compressive strength. However, normalized fatigue resistance showed a different pattern. While scaffolds resisted fatigue cycles at low strain amplitudes, fatigue damage was observed at higher strains. Voronoi structures exhibited the highest normalized fatigue performance, enduring around 58,000 cycles at 85% strain amplitude, followed by Gyroid, Fischer-Koch, Lidinoid, and IWP structures. Enhanced fatigue performance in different topologies correlated with the minimum cross-sectional area of scaffolds. Given the importance of both static and fatigue strength, the Gyroid topology emerges as the superior choice overall.

Perception and response of skeleton to mechanical stress

Mechanical stress stands as a fundamental factor in the intricate processes governing the growth, development, morphological shaping, and maintenance of skeletal mass. The profound influence of stress in shaping the skeletal framework prompts the assertion that stress essentially births the skeleton. Despite this acknowledgment, the mechanisms by which the skeleton perceives and responds to mechanical stress remain enigmatic. In this comprehensive review, our scrutiny focuses on the structural composition and characteristics of sclerotin, leading us to posit that it serves as the primary structure within the skeleton responsible for bearing and perceiving mechanical stress. Furthermore, we propose that osteocytes within the sclerotin emerge as the principal mechanical-sensitive cells, finely attuned to perceive mechanical stress. And a detailed analysis was conducted on the possible transmission pathways of mechanical stress from the extracellular matrix to the nucleus.

Factors Associated With High-Risk and Low-Risk Bone Stress Injury in Female Runners: Implications for Risk Factor Stratification and Management

Background

Bone stress injury (BSI) is a common overuse injury in active women. BSIs can be classified as high-risk (pelvis, sacrum, and femoral neck) or low-risk (tibia, fibula, and metatarsals). Risk factors for BSI include low energy availability, menstrual dysfunction, and poor bone health. Higher vertical load rates during running have been observed in women with a history of BSI.

Purpose/Hypothesis

The purpose of this study was to characterize factors associated with BSI in a population of premenopausal women, comparing those with a history of high-risk or low-risk BSI with those with no history of BSI. It was hypothesized that women with a history of high-risk BSI would be more likely to exhibit lower bone mineral density (BMD) and related factors and less favorable bone microarchitecture compared with women with a history of low-risk BSI. In contrast, women with a history of low-risk BSI would have higher load rates.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Enrolled were 15 women with a history of high-risk BSI, 15 with a history of low-risk BSI, and 15 with no history of BSI. BMD for the whole body, hip, and spine was standardized using z scores on dual-energy x-ray absorptiometry. High-resolution peripheral quantitative computed tomography was used to quantify bone microarchitecture at the radius and distal tibia. Participants completed surveys characterizing factors that influence bone health-including sleep, menstrual history, and eating behaviors-utilizing the Eating Disorder Examination Questionnaire (EDE-Q). Each participant completed a biomechanical assessment using an instrumented treadmill to measure load rates before and after a run to exertion.

Results

Women with a history of high-risk BSI had lower spine z scores than those with low-risk BSI (-1.04 ± 0.76 vs -0.01 ± 1.15; P < .05). Women with a history of high-risk BSI, compared with low-risk BSI and no BSI, had the highest EDE-Q subscores for Shape Concern (1.46 ± 1.28 vs 0.76 ± 0.78 and 0.43 ± 0.43) and Eating Concern (0.55 ± 0.75 vs 0.16 ± 0.38 and 0.11 ± 0.21), as well as the greatest difference between minimum and maximum weight at current height (11.3 ± 5.4 vs 7.7 ± 2.9 and 7.6 ± 3.3 kg) (P < .05 for all). Women with a history of high-risk BSI were more likely than those with no history of BSI to sleep <7 hours on average per night during the week (80% vs 33.3%; P < .05). The mean and instantaneous vertical load rates were not different between groups.

Conclusion

Women with a history of high-risk BSI were more likely to exhibit risk factors for poor bone health, including lower BMD, while load rates did not distinguish women with a history of BSI.

The importance of bone health for pediatric athletes: From juvenile osteochondritis dissecans to relative energy deficiency in sports

Vitamin D is pivotal for bone health, muscle strength, recovery, and overall athletic performance. This article discusses the effects of vitamin D deficiency among athletes, with a specific focus on its connection to sports-related conditions like Relative Energy Deficiency in Sport (RED-S) and Juvenile Osteochondritis Dissecans (JOCD). Additionally, we review the importance of vitamin D for muscle strength and muscle repair. Vitamin D deficiency exacerbates the risk of stress fractures in RED-S patients due to its impact on bone biology. Research points to an increased incidence of vitamin D deficiency in JOCD patients, indicating a potential connection between the condition and low vitamin D levels. Children and athletes should be screened for vitamin D deficiency as supplementation has been found to have positive outcomes. This article underscores the pivotal role of vitamin D in athletic performance. Further research is essential to elucidate how vitamin D deficiency contributes to sports-related pathologies and to establish the optimal vitamin D levels for injury prevention in athletes.

Total body water percentage and 3rd space water are novel risk factors for training-related lower extremity muscle injuries in young males

PURPOSE

To identify the risk factors for training-related lower extremity muscle injuries in young males by a non-invasive method of body composition analysis.

METHODS

A total of 282 healthy young male volunteers aged 18 - 20 years participated in this cohort study. Injury location, degree, and injury rate were adjusted by a questionnaire based on the overuse injury assessment methods used in epidemiological studies of sports injuries. The occurrence of training injuries is monitored and diagnosed by physicians and treated accordingly. The body composition was measured using the BodyStat QuadScan 4000 multifrequency Bio-impedance system at 5, 50, 100 and 200 kHz to obtain 4 impedance values. The Shapiro-Wilk test was used to check whether the data conformed to a normal distribution. Data of normal distribution were shown as mean ± SD and analyzed by t-test, while those of non-normal distribution were shown as median (Q1, Q3) and analyzed by Wilcoxon rank sum test. The receiver operator characteristic curve and logistic regression analysis were performed to investigate risk factors for developing training-related lower extremity injuries and accuracy.

RESULTS

Among the 282 subjects, 78 (27.7%) developed training injuries. Lower extremity training injuries revealed the highest incidence, accounting for 23.4% (66 cases). These patients showed higher percentages of lean body mass (p = 0.001), total body water (TBW, p = 0.006), extracellular water (p = 0.020) and intracellular water (p = 0.010) as well as a larger ratio of basal metabolic rate/total weight (p = 0.006), compared with those without lower extremity muscle injuries. On the contrary, the percentage of body fat (p = 0.001) and body fat mass index (p = 0.002) were lower. Logistic regression analysis showed that TBW percentage > 65.35% (p = 0.050, odds ratio = 3.114) and 3rd space water > 0.95% (p = 0.045, odds ratio = 2.342) were independent risk factors for lower extremity muscle injuries.

CONCLUSION

TBW percentage and 3rd space water measured with bio-impedance method are potential risk factors for predicting the incidence of lower extremity muscle injuries in young males following training.

Osseous Stress Injuries: Treatment Algorithms and Return to Play

Osseous stress injuries are common in athletes. Specifically, lower extremity injuries are prevalent in running athletes and upper extremity injuries are prevalent in throwing athletes. Such injuries are suspected when there is focal bone tenderness and increased pain with the inciting activity. In elite athletes, osseous stress injuries are a relatively common culprit in lost play time. Thus rapid diagnosis and treatment is imperative to expedite return to play (RTP). The radiologist's role in these cases is not only for diagnosis, but also to grade the injury, which has implications in determining a treatment regimen. The high sensitivity and specificity of magnetic resonance imaging is thus the preferred imaging modality. This article discusses common osseous stress injuries, the imaging findings, and how different treatment regimens affect RTP.

The Middle Pleistocene human metatarsal from Sedia del Diavolo (Rome, Italy)

The peopling of Europe during the Middle Pleistocene is a debated topic among paleoanthropologists. Some authors suggest the coexistence of multiple human lineages in this period, while others propose a single evolving lineage from Homo heidelbergensis to Homo neanderthalensis. The recent reassessment of the stratigraphy at the Sedia del Diavolo (SdD) site (Latium, Italy), now dated to the beginning of marine isotope stage (MIS) 8, calls for a revision of the human fossils from the site. In this paper, we present the morphometric, biomechanical and palaeopathological study of the second right metatarsal SdD2, to both re-evaluate its taxonomical affinities and possibly determine the levels of physical activity experienced by the individual during lifetime. Results demonstrate the persistence of archaic features in SdD2 suggesting new insights into the technology and hunting strategies adopted by Homo between MIS 9 and MIS 8.

Use of extracorporeal shockwave therapies for athletes and physically active individuals: a systematic review

OBJECTIVE

To determine the efficacy of extracorporeal shockwave therapy (ESWT) and investigate outcomes following the use of ESWT for athletes and physically active individuals.

DESIGN

Systematic review.

DATA SOURCES

We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and searched four databases: PubMed (NLM), Embase (Elsevier), CINAHL Complete (EBSCO) and Web of Science (Clarivate).

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Included studies were randomised controlled trials, cohort and case-control studies, cases series and reports that evaluated outcomes following ESWT for athletes, physically active individuals and occupational groups requiring regular physical activity such as military cadets.

RESULTS

56 studies with 1874 athletes or physically active individuals were included. Using the Oxford level of evidence rating, included studies were 18 level I (32.1%), 3 level II (5.4%), 10 level III (17.9%), 13 level IV (23.2%) and 12 level V (21.4%). Based on the level I studies, ESWT may be effective alone in plantar fasciitis, lateral epicondylitis and proximal hamstring tendinopathy and as an adjunct to exercise treatment in medial tibial stress syndrome and osteitis pubis in athletes or physically active individuals. In most studies, athletes were allowed to continue activities and training and tolerated ESWT with minimal side effects.

CONCLUSION

ESWT may offer an efficacious treatment alone or as an adjunct to concurrent exercise therapy in selected sports-related injuries and without major adverse events. Further high-level research is needed to better define the role and clinical outcomes of ESWT.

Understanding the first injury in athletics and its effect on dropout from sport: an online survey on 544 high-level youth and junior athletics (track and field) athletes

Objective

To describe the first injury and to investigate whether it plays a role in altering athletics' sustainable practice.

Methods

We conducted a cross-sectional study using an exploratory survey on the first injury and its consequences on athletics practice. In 2021, we asked all high-level athletes licensed with the French Federation of Athletics (FFA) under 18 years, under 20 years and under 23 years categories between 2007 and 2021.

Results

Out of 6560 emails sent by FFA, 544 athletes responded, and 93.6% (n=510) reported experiencing at least one injury during their career. The first injury occurred at a mean age of 17.5±3.3 years after 6.1±4.1 years of athletics practice. The main locations of the first injury were the posterior thigh (28.9%), the ankle (16.5%) and the knee (12.6%), and the principal reported injury types were muscle (37.7%), tendon (17.5%) and ligament (15.5%). More than a third of injured athletes (36.7%) reported experiencing ongoing symptoms or sequelae after their first injury, and about half (48.5%) experienced recurrences. About 20% had stopped athletics at the time of the survey, with injury problems the primary cause of athletes dropping out (46.2%), including the first injury (9.4%).

Conclusions

Injuries played an important role in altering sustainable athletics practice, with injury accounting for about 50% of all reported dropouts and the first injury accounting for about 10% of all reported causes. Our results provide evidence to target the prevention of the first injury, which could be considered the origin of the 'vicious circle' of injuries.

Appraising the Methodological Quality of Sports Injury Video Analysis Studies: The QA-SIVAS Scale

BACKGROUND

Video analysis (VA) is commonly used in the assessment of sports injuries and has received considerable research interest. Until now, no tool has been available for the assessment of study quality. Therefore, the objective of this study was to develop and evaluate a valid instrument that reliably assesses the methodological quality of VA studies.

METHODS

The Quality Appraisal for Sports Injury Video Analysis Studies (QA-SIVAS) scale was developed using a modified Delphi approach including expert consensus and pilot testing. Reliability was examined through intraclass correlation coefficient (ICC3,1) and free-marginal kappa statistics by three independent raters. Construct validity was investigated by comparing QA-SIVAS with expert ratings by using Kendall's tau analysis. Rating time was studied by applying the scale to 21 studies and computing the mean time for rating per study article.

RESULTS

The QA-SIVAS scale consists of an 18-item checklist addressing the study design, data source, conduct, report, and discussion of VA studies in sports injury research. Inter- and intra-rater reliability were excellent with ICCs > 0.97. Expert ratings revealed a high construct validity (0.71; p < 0.001). Mean rating time was 10 ± 2 min per article.

CONCLUSION

QA-SIVAS is a reliable and valid instrument that can be easily applied to sports injury research. Future studies in the field of VA should adhere to standardized methodological criteria and strict quality guidelines.

SOX family transcription factors as therapeutic targets in wound healing: A comprehensive review

The SOX family plays a vital role in determining the fate of cells and has garnered attention in the fields of cancer research and regenerative medicine. It also shows promise in the study of wound healing, as it actively participates in the healing processes of various tissues such as skin, fractures, tendons, and the cornea. However, our understanding of the mechanisms behind the SOX family's involvement in wound healing is limited compared to its role in cancer. Gaining insight into its role, distribution, interaction with other factors, and modifications in traumatized tissues could provide valuable new knowledge about wound healing. Based on current research, SOX2, SOX7, and SOX9 are the most promising members of the SOX family for future interventions in wound healing. SOX2 and SOX9 promote the renewal of cells, while SOX7 enhances the microvascular environment. The SOX family holds significant potential for advancing wound healing research. This article provides a comprehensive review of the latest research advancements and therapeutic tools related to the SOX family in wound healing, as well as the potential benefits and challenges of targeting the SOX family for wound treatment.

Risk factors and injury prevention strategies for overuse injuries in adult climbers: a systematic review

Introduction

Climbing is an increasingly popular activity and imposes specific physiological demands on the human body, which results in unique injury presentations. Of particular concern are overuse injuries (non-traumatic injuries). These injuries tend to present in the upper body and might be preventable with adequate knowledge of risk factors which could inform about injury prevention strategies. Research in this area has recently emerged but has yet to be synthesized comprehensively. Therefore, the aim of this study was to conduct a systematic review of the potential risk factors and injury prevention strategies for overuse injuries in adult climbers.

Methods

This systematic review was conducted in accordance with the PRISMA guidelines. Databases were searched systematically, and articles were deemed eligible based upon specific criteria. Research included was original and peer-reviewed, involving climbers, and published in English, German or Czech. Outcomes included overuse injury, and at least one or more variable indicating potential risk factors or injury prevention strategies. The methodological quality of the included studies was assessed with the Downs and Black Quality Index. Data were extracted from included studies and reported descriptively for population, climbing sport type, study design, injury definition and incidence/prevalence, risk factors, and injury prevention strategies.

Results

Out of 1,183 records, a total of 34 studies were included in the final analysis. Higher climbing intensity, bouldering, reduced grip/finger strength, use of a "crimp" grip, and previous injury were associated with an increased risk of overuse injury. Additionally, a strength training intervention prevented shoulder and elbow injuries. BMI/body weight, warm up/cool downs, stretching, taping and hydration were not associated with risk of overuse injury. The evidence for the risk factors of training volume, age/years of climbing experience, and sex was conflicting.

Discussion

This review presents several risk factors which appear to increase the risk of overuse injury in climbers. Strength and conditioning, load management, and climbing technique could be targeted in injury prevention programs, to enhance the health and wellbeing of climbing athletes. Further research is required to investigate the conflicting findings reported across included studies, and to investigate the effectiveness of injury prevention programs.

Systematic Review Registration

https://www.crd.york.ac.uk/, PROSPERO (CRD42023404031).