Experimental study on the biomechanical stability of complex acetabular fractures in the quadrilateral area: application of a dynamic anterior titanium-plate screw system.

BACKGROUND AND OBJECTIVE: Complex acetabular fractures involving quadrilateral areas are more challenging to treat during surgery. To date, there has been no ideal internal fixation for these acetabular fractures. The purpose of this study was to evaluate the biomechanical stability of complex acetabular fractures using a dynamic anterior titanium-plate screw system of the quadrilateral area (DAPSQ) by simulating the standing and sitting positions of pelvic specimens. MATERIALS AND METHODS: Eight formal in-preserved cadaveric pelvises aged 30-50 years were selected as the research objects. First, one hip of the normal pelvises was randomly used as the control model (group B) for measurement, and then one hip of the pelvises was randomly selected to make the fracture model in the 8 intact pelvises as the experimental model (group A) for measurement. In group A, acetabular both-column fractures in the quadrilateral area were established, and the fractures were fixed by DAPSQ. The biomechanical testing machine was used to load (simulated physiological load) from 400 N to 700 N at a 1 mm/min speed for 30 s in the vertical direction when the specimens were measured at random in simulated standing or sitting positions in groups. The horizontal displacement and longitudinal displacement of the acetabular fractures in the quadrilateral area were measured in both the standing and sitting simulations. RESULTS: As the load increased, no dislocation or internal fixation breakage occurred during the measurements. In the standing position, the horizontal displacement of the quadrilateral area fractures in group A and group B appeared to be less than 1 mm with loads ranging from 400 N to 700 N, and there was no significant difference between group A and group B (p > 0.05). The longitudinal displacement appeared to be greater than 1 mm with a load of 700 mm in group A (700 N, 2 cases), and the difference was significant between group A and group B (p < 0.05). In the sitting position, the horizontal and longitudinal displacements of the quadrilateral areas were within 0.5 mm in group A and group B, and there was no significant difference between group A and group B (p > 0.05). CONCLUSION: For complex acetabular fractures in the quadrilateral area, DAPSQ fixation may provide early sitting stability, but it is inappropriate for patients to stand too early.

Keel bone fractures affect laying hens' mobility, but no evidence for reciprocal effects.

Keel bone fractures (KBF) are prevalent in commercial laying hens and are considered one of the greatest welfare concerns in the egg-production industry. While clear associations exist between KBF and animal mobility, suggesting that KBF impair mobility, the effect of mobility on KBF remains unclear. We combined data from three studies that assessed keel bone fracture severity through radiographs and monitored hens' transitions between different zones of a multi-tier aviary system (the three tiers, a littered floor, and a winter garden) the week prior to radiograph. For each hen, we extracted two daily movement behaviours: the vertical distance travelled and the mean number of zones crossed within one transition; and two daily space-use behaviours: the time spent in the top tier and the unevenness of time spent across zones. We used hierarchical Bayesian continuous time dynamic modelling to estimate how a change in a behaviour predicted a later change in keel bone fracture severity, and vice versa. Increased fracture severity did not predict later changes in space-use behaviours, but it did predict changes in movement behaviours. Specifically, increased fracture severity led to decreased vertical travelled distance and a tendency to cross more zones within one transition, suggesting impaired mobility in hens with increased fracture severity. In contrast, we found no evidence that movement or space-use behaviours predict later change in fracture severity, challenging previous literature suggesting that vertical locomotion through jumping and flying may exacerbate keel bone fractures in complex three-dimensional systems due to increased risk of collisions. However, similar efforts accounting for the location of fractures on the keel could unveil the potential influence of movement and space-use behaviours in the formation and change (healing or worsening) of KBF and increase our ability to mitigate their effects.

Enhancing the Evaluation of Physical Function Following Orthopaedic Trauma Care: Comparison of PROMIS Computerized Adaptive Testing and Short Musculoskeletal Function Assessment.

OBJECTIVES: To compare measurement properties of Patient-Reported Outcomes Measurement Information System (PROMIS) (physical function [PF] and pain interference [PI]) computerized adaptive testing to traditional Short Musculoskeletal Function Assessment (SMFA) (dysfunction index [DI] and bother index [BI]). To explore factors associated with PROMIS scores. DESIGN: Cross-sectional study. SETTING: Level I Trauma Center. PATIENT SELECTION CRITERIA: Isolated upper/lower extremity fracture patients were recruited from the orthopaedic trauma outpatient clinic (October 1, 2021 to January 1, 2023). OUTCOME MEASURES: Correlations (Pearson), reliability (standard error [SE] [T score]), efficiency (amount of information per item [1 - SE2/Nitems]), and floor/ceiling effects were assessed. An r > 0.7 represented high correlation, and SE ≤ 2.2 represented sufficient reliability. Factors associated with worse PROMIS scores were also identified. RESULTS: In total, 202 patients completed PROMs at median 98 days follow-up. Correlations between PROMIS-PF and SMFA-DI, and PROMIS-PI and SMFA-BI were -0.84 and 0.65. Reliability was very high for both instruments (mean SE 2.0 [PROMIS-PF], SE 2.1 [PROMIS-PI], and SE 1.2 [SMFA-DI], SE 1.8 [SMFA-BI]). Relative efficiency for PROMIS-PF versus SMFA-DI, and PROMIS-PI versus SMFA-BI was 7.8 (SD 2.5) and 4.1 (SD 1.7), respectively. Neither PROMIS nor SMFA exhibited floor/ceiling effects. In the multivariable regression analyses, elevated levels of depression, among other factors, showed an (independent) association with worse PROMIS-PF and PROMIS-PI scores. CONCLUSIONS: PROMIS-PF and PROMIS-PI CATs showed a (high and moderate) correlation with SMFA and hence measure a comparable construct of physical function and discomfort. As computerized adaptive tests are much more efficient to administer, they present a compelling alternative to SMFA for evaluating impact of fracture treatment. The relation between symptoms of depression and PROMIS scores emphasizes the importance of psychosocial aspects of health in orthopaedic trauma patients. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Postoperative recreational sports and subjective shoulder function: a comprehensive analysis following intramedullary stabilization of displaced midshaft clavicular fractures.

Introduction Sports-related outcomes and the role of recreational sports activities for shoulder function after intramedullary stabilization (IMS) of displaced midshaft clavicular fractures (DMCFs) in the general population are not well known. In this study, we aimed to determine the sport-related outcomes (return-to-sports [RTS] rate, type of sports, time until RTS, and intensity) and to explore the role of sports after IMS of DMCFs. Materials and Methods This single-center, retrospective, cohort study included patients who underwent IMS of DMCFs between 2009 and 2022 at a Level II trauma center in Germany, experienced no major complications, and had completed at least 1 year of follow-up. Propensity score matching was conducted to obtain a balanced sample of patients who did not engage (cases) and engaged (controls) in postoperative sports activities by adjusting for age and fracture complexity. Groups were compared to assess the impact of regular sports activities on subjective shoulder functioning at follow-up, as evaluated using the Disabilities of the Arm, Shoulder, and Hand and Oxford Shoulder Score (OSS) questionnaires, after controlling for the patient- (i.e., sex and smoking) and treatment- (i.e., surgery duration and physical therapy) factors. Results Among the 199 patients included, the RTS rate was 97.5%, and 160 patients practiced regular postoperative activity, mostly in the same sport and intensity. In the matched cohort (39 cases and 39 controls), practicing regular sports activities postoperatively was the only independent factor associated with a higher OSS in the multiple regression analysis (unstandardized regression coefficient = 2.40; Bias-corrected and accelerated 95% confidence interval [0.28, 4.69]). Conclusions The sport-related outcomes after IMS of DMCFs in our cohort were comparable to those achieved after plate osteosynthesis, and IMS reported in the literature. Recreational sports activities benefitted subjective shoulder function, thereby encouraging further research and potentially influencing management policies. Level of evidence Grade IV - a retrospective observational cohort study.

Biomechanical role of bone grafting for calcaneal fracture fixation in the presence of bone defect: A finite element analysis.

BACKGROUND: The purpose of this study was to compare the biomechanical stress and stability of calcaneal fixations with and without bone defect, before and after bone grafting, through a computational approach. METHODS: A finite element model of foot-ankle complex was reconstructed, impoverished with a Sanders III calcaneal fracture without bone defect and with moderate and severe bone defects. Plate fixations with and without bone grafting were introduced with walking stance simulated. The stress and fragment displacement of the calcaneus were evaluated. FINDINGS: Moderate and severe defect increased the calcaneus stress by 16.11% and 32.51%, respectively and subsequently decreased by 10.76% and 20.78% after bone grafting. The total displacement was increased by 3.99% and 24.26%, respectively by moderate and severe defect, while that of posterior joint facet displacement was 86.66% and 104.44%. The former was decreased by 25.73% and 35.96% after grafting, while that of the latter was reduced by 88.09% and 84.78% for moderate and severe defect, respectively. INTERPRETATION: Our finite element prediction supported that bone grafting for fixation could enhance the stability and reduce the risk of secondary stress fracture in cases of bone defect in calcaneal fracture.

Transverse patella fracture fixation: A cadaveric biomechanical comparison of cannulated screws and anterior tension band versus low-profile, multiplanar mesh plating.

INTRODUCTION: Multiplanar mesh plating of patella fractures has become more popular in recent years. It was the goal of this study to compare the biomechanical stability of cannulated screw with anterior tension band to multiplanar mesh plating for fixation of transverse patella fractures in cadaver specimens. MATERIALS AND METHODS: Eight matched pairs of fresh frozen cadaveric knees were obtained and soft tissues dissected leaving the extensor mechanism, joint capsule, and retinaculum intact. Transverse fractures were created at the mid-portion of the patella. For each pair, one specimen was repaired using cannulated screws with anterior tension band, and the second was repaired using multiplanar mesh plating. Each specimen underwent cyclic extension loading with loads increasing by 1.1 kg after every 50 cycles. Interfragmentary displacement was measured at the end of each interval at both 5° and 45° of knee flexion angle, with fixation failure defined by >2 mm displacement. RESULTS: The specimens fixed with multiplanar mesh plating survived more cycles and higher loads than the specimens fixed with cannulated screws with anterior tension band (p = 0.011 comparing survival plots). After 150 cycles of extension loading, 3 of 8 of the specimens fixed with screws/tension band had failed, whereas none of the mesh plated specimens had failed. After 400 cycles, 7 of 8 of the screws/tension band had failed, whereas half of the mesh plated specimens had failed. CONCLUSIONS: While a more technically challenging and expensive technique, mesh plating for patella fractures appears to offer greater durability than traditional cannulated screw with tension banding.

Computational Modeling of Bone Fracture Healing Under Different Initial Conditions and Mechanical Load.

OBJECTIVE: Computational model of bone healing can replace animal experiments to study the parameters affecting the bone healing process, thus reducing the damage to experimental animals and saving a lot of time. We propose a computational model for continuous simulation of four phases of bone healing to study the effects of mechanical environmental and biological factors, including initial conditions at the fracture site, mechanical stimulus loading, and vascular growth rate. METHODS: A finite element model of mechanobiological fracture healing containing several pre-determined variables was developed for bone healing after fracture in sheep, which included many relevant parameters and biological effects during fracture healing, such as the effects of mechanical environment, blood supply level in the local fracture area, cell migration and diffusion, and resorption effects of fracture healing. The effects of several parameters on indices such as Young's modulus of the callus during bone healing were obtained by simulation. RESULTS: The initial geometry of the healing tissue and mechanical loading had the greatest effect on fracture healing, and different preset values were likely to cause delayed or non-healing fractures. Changed initial tissue properties of the healing tissue showed a nonlinear effect on fracture healing rather than a linear delay or advancement. Parameters related to angiogenesis had a greater effect on fracture healing compared to those related to cell migration. CONCLUSION: This paper quantified the effect of fracture healing pre-determined variables on fracture healing to better understand the application of mechanobiology in fracture healing simulation models and optimization of treatment strategies. SIGNIFICANCE: The importance of initial conditions and loads on fracture healing has been shown to help physicians treat bone nonunion or delayed bone healing after a fracture.

Computational models of bone fracture healing and applications: a review.

Fracture healing is a very complex physiological process involving multiple events at different temporal and spatial scales, such as cell migration and tissue differentiation, in which mechanical stimuli and biochemical factors assume key roles. With the continuous improvement of computer technology in recent years, computer models have provided excellent solutions for studying the complex process of bone healing. These models not only provide profound insights into the mechanisms of fracture healing, but also have important implications for clinical treatment strategies. In this review, we first provide an overview of research in the field of computational models of fracture healing based on CiteSpace software, followed by a summary of recent advances, and a discussion of the limitations of these models and future directions for improvement. Finally, we provide a systematic summary of the application of computational models of fracture healing in three areas: bone tissue engineering, fixator optimization and clinical treatment strategies. The application of computational models of bone healing in clinical treatment is immature, but an inevitable trend, and as these models become more refined, their role in guiding clinical treatment will become more prominent.

A head-to-head comparison of EQ-5D-5L and SF-6D in Dutch patients with fractures visiting a Fracture Liaison Service.

AIMS: This study compared the psychometric properties of EQ-5D-5L and SF-6D to assess the interchangeability of both instruments in patients with a recent fracture presenting at a Fracture Liaison Service (FLS). MATERIALS AND METHODS: Data from a prospective observational study in a Dutch FLS clinic were used. Over 3 years, subjects were interviewed at several time points using EQ-5D-5L and SF-36. Floor and ceiling effects were evaluated. Agreement was evaluated by intra-class correlation coefficients and visualized in Bland-Altman plots. Spearman's rank correlation coefficients were applied to assess convergent validity. Mann-Whitney U test or Kruskal-Wallis H test as well as effect size (ES) were used to explore known-groups validity. Responsiveness was explored using standardized response mean (SRM) and ES. For each measurement property, hypotheses on direction and magnitude of effects were formulated. RESULTS: A total of 499 patients were included. EQ-5D-5L had a considerable ceiling effect in comparison to SF-6D (21 vs. 1.2%). Moderate agreement between the (UK and Dutch) EQ-5D-5L and SF-6D was identified with intra-class correlation coefficients of 0.625 and 0.654, respectively. Bland-Altman plots revealed proportional bias as the differences in utilities between two instruments were highly dependent on the health states. High correlation between instruments was found (UK: rho = 0.758; Dutch: rho = 0.763). EQ-5D-5L and SF-6D utilities showed high correlation with physical component score but low correlation with mental component score of SF-36. Both instruments showed moderate discrimination (ES > 0.5) for subgroup by baseline fracture type, and moderate responsiveness (SRM > 0.5) in patients that sustained a subsequent fracture. CONCLUSION: Both EQ-5D-5L and SF-6D appeared to be valid utility instruments in patients with fractures attending the FLS. However, they cannot be used interchangeably given only moderate agreement was identified, and differences in utilities and ceiling effect were revealed. Comparable construct validity and responsiveness were indicated, and neither instrument was found to be clearly superior.

The EQ-5D and SF-36 as generic multi-domain questionnaires are widely used to measure the health-related quality-of-life (HRQoL) in a sample of the persons who suffer from the diseases or the general population. Their responses could be converted to patients or societal Health State Utility Values (HSUVs) with the range of 0 ("death") to 1 ("full health"). A specific application of HSUV is to calculate quality-adjusted life years as the indicator of effectiveness to evaluate whether the cost of a new intervention is justified in terms of health gains through cost-utility analysis in health economics, the evidence can be further used to inform decision-making. However, different instruments differ in construct and valuation, potentially leading to different estimates for the person's same "health state", and healthcare decisions could be compromised when researchers or decision-makers are not aware of potential differences in HSUV. Therefore, it is important to gain insight into the specific psychometric properties of these instruments, and to understand whether instruments are interchangeable. Our study is based on data from a Dutch Fracture Liaison Service (FLS is a program for secondary fracture prevention), compared the psychometric properties and interchangeability of two instruments (EQ-5D-5L and SF-6D) in patients with a recent fracture presenting at the FLS, and suggested both instruments are valid in utility elicitation in our target population. However, they cannot be used interchangeably given only moderate agreement and differences in utilities. Neither instrument was found to be clearly superior given comparable construct and longitudinal validity, but different instruments values in different aspects of HRQoL assessment.

Effect of osteoporosis-related reduction in the mechanical properties of bone on the acetabular fracture during a sideways fall: A parametric finite element approach.

PURPOSE: The incidence of acetabular fractures due to low-energy falls is increasing among the geriatric population. Studies have shown that several biomechanical factors such as body configuration, impact velocity, and trochanteric soft-tissue thickness contribute to the severity and type of acetabular fracture. The effect of reduction in apparent density and elastic modulus of bone as well as other bone mechanical properties due to osteoporosis on low-energy acetabular fractures has not been investigated. METHODS: The current comprehensive finite element study aimed to study the effect of reduction in bone mechanical properties (trabecular, cortical, and trabecular + cortical) on the risk and type of acetabular fracture. Also, the effect of reduction in the mechanical properties of bone on the load-transferring mechanism within the pelvic girdle was examined. RESULTS: We observed that while the reduction in the mechanical properties of trabecular bone considerably affects the severity and area of trabecular bone failure, reduction in mechanical properties of cortical bone moderately influences both cortical and trabecular bone failure. The results also indicated that by reducing bone mechanical properties, the type of acetabular fracture turns from elementary to associated, which requires a more extensive intervention and rehabilitation period. Finally, we observed that the cortical bone plays a substantial role in load transfer, and by increasing reduction in the mechanical properties of cortical bone, a greater share of load is transmitted toward the pubic symphysis. CONCLUSION: This study increases our understanding of the effect of osteoporosis progression on the incidence of low-energy acetabular fractures. The osteoporosis-related reduction in the mechanical properties of cortical bone appears to affect both the cortical and trabecular bones. Also, during the extreme reduction in the mechanical properties of bone, the acetabular fracture type will be more complicated. Finally, during the final stages of osteoporosis (high reduction in mechanical properties of bone) a smaller share of impact load is transferred by impact-side hemipelvis to the sacrum, therefore, an osteoporotic pelvis might mitigate the risk of sacral fracture.

Biomechanical duality of fracture healing captured using virtual mechanical testing and validated in ovine bones.

Bone fractures commonly repair by forming a bridging structure called callus, which begins as soft tissue and gradually ossifies to restore rigidity to the bone. Virtual mechanical testing is a promising technique for image-based assessment of structural bone healing in both preclinical and clinical settings, but its accuracy depends on the validity of the material model used to assign tissue mechanical properties. The goal of this study was to develop a constitutive model for callus that captures the heterogeneity and biomechanical duality of the callus, which contains both soft tissue and woven bone. To achieve this, a large-scale optimization analysis was performed on 2363 variations of 3D finite element models derived from computed tomography (CT) scans of 33 osteotomized sheep under normal and delayed healing conditions. A piecewise material model was identified that produced high absolute agreement between virtual and physical tests by differentiating between soft and hard callus based on radiodensity. The results showed that the structural integrity of a healing long bone is conferred by an internal architecture of mineralized hard callus that is supported by interstitial soft tissue. These findings suggest that with appropriate material modeling, virtual mechanical testing is a reliable surrogate for physical biomechanical testing.

Functional outcome of 103 fractures of the proximal fifth metatarsal bone.

BACKGROUND: Metatarsal fractures are common skeletal injuries of the lower extremity in adults. The majority involves the proximal fifth metatarsal bone. In the current literature, there still exists controversy regarding treatment recommendations for the different fracture entities. METHODS: All patients suffering from single fractures to the proximal fifth metatarsal bone between 2003 and 2015 were enrolled in this retrospective analysis. Only patients with a minimum follow-up of 12 months were included. The fractures were classified according to Lawrence and Botte (L&B). Data were collected via patient registry, radiographs and a standardized questionnaire (Foot and Ankle Outcome Score = FOAS). For outcome analysis, the nonparametric Mann-Whitney U test was performed and Spearman's rank correlation coefficient calculated. RESULTS: In total, the functional outcomes of 103 patients suffering from fractures to the proximal fifth metatarsal bone were analyzed. L&B type I fractures (n = 13) had a FAOS score of 91 ± 23, L&B type II (n = 67) presented a score of 91 ± 15 and L&B type III (n = 23) a score of 93 ± 11. Surgically treated patients with an L&B type II fracture had no statistically significant better functional outcome in comparison to conservative management (p = 0.89). Operatively treated L&B type III fractures tended to have a better functional score (p = 0.16). The follow-up time was 58 (min: 15; max: 164) months. CONCLUSIONS: Overall, the functional outcome following fractures to the proximal fifth metatarsal bone is satisfactory. Conservatively treated L&B type II fractures showed an equivalent functional outcome compared to surgical management. Patients with an L&B type III fracture mainly were treated surgically, but difference in FAOS score did not reach level of significance.

HA-g-CS Implant and Moderate-intensity Exercise Stimulate Subchondral Bone Remodeling and Promote Repair of Osteochondral Defects in Mice.

Background: Substantial evidence shows that crosstalk between cartilage and subchondral bone may play an important role in cartilage repair. Animal models have shown that hydroxyapatite-grafted-chitosan implant (HA-g-CS) and moderate-intensity exercise promote regeneration of osteochondral defects. However, no in vivo studies have demonstrated that these two factors may have a synergistic activity to facilitate subchondral bone remodeling in mice, thus supporting bone-cartilage repair. Questions: This study was to clarify whether HA-g-CS and moderate-intensity exercise might have a synergistic effect on facilitating (1) regeneration of osteochondral defects and (2) subchondral bone remodeling in a mouse model of osteochondral defects. Methods: Mouse models of osteochondral defects were created and divided into four groups. BC Group was subjected to no treatment, HC Group to HA-g-CS implantation into osteochondral defects, ME group to moderate-intensity treadmill running exercise, and HC+ME group to both HA-g-CS implantation and moderate-intensity exercise until sacrifice. Extent of subchondral bone remodeling at the injury site and subsequent cartilage repair were assessed at 4 weeks after surgery. Results: Compared with BC group, HC, ME and HC+ME groups showed more cartilage repair and thicker articular cartilage layers and HC+ME group acquired the best results. The extent of cartilage repair was correlated positively to bone formation activity at the injured site as verified by microCT and correlation analysis. Histology and immunofluorescence staining confirmed that bone remodeling activity was increased in HC and ME groups, and especially in HC+ME group. This bone formation process was accompanied by an increase in osteogenesis and chondrogenesis factors at the injury site which promoted cartilage repair. Conclusions: In a mouse model of osteochondral repair, HA-g-CS implant and moderate-intensity exercise may have a synergistic effect on improving osteochondral repair potentially through promotion of subchondral bone remodeling and generation of osteogenesis and chondrogenesis factors. Clinical Relevance: Combination of HA-g-CS implantation and moderate-intensity exercise may be considered potentially in clinic to promote osteochondral defect repair. Also, cartilage and subchondral bone forms a functional unit in an articular joint and subchondral bone may regulate cartilage repair by secreting growth factors in its remodeling process. However, a deeper insight into the exact role of HA-g-CS implantation and moderate-intensity exercise in promoting osteochondral repair in other animal models should be explored before they can be applied in clinic in the future.

Congenital Metabolic Bone Disorders as a Cause of Bone Fragility.

Bone fragility is a pathological condition caused by altered homeostasis of the mineralized bone mass with deterioration of the microarchitecture of the bone tissue, which results in a reduction of bone strength and an increased risk of fracture, even in the absence of high-impact trauma. The most common cause of bone fragility is primary osteoporosis in the elderly. However, bone fragility can manifest at any age, within the context of a wide spectrum of congenital rare bone metabolic diseases in which the inherited genetic defect alters correct bone modeling and remodeling at different points and aspects of bone synthesis and/or bone resorption, leading to defective bone tissue highly prone to long bone bowing, stress fractures and pseudofractures, and/or fragility fractures. To date, over 100 different Mendelian-inherited metabolic bone disorders have been identified and included in the OMIM database, associated with germinal heterozygote, compound heterozygote, or homozygote mutations, affecting over 80 different genes involved in the regulation of bone and mineral metabolism. This manuscript reviews clinical bone phenotypes, and the associated bone fragility in rare congenital metabolic bone disorders, following a disease taxonomic classification based on deranged bone metabolic activity.

Effect of Bone-Marrow-Derived Mesenchymal Stem Cells on the Healing of Bone Fractures.

This study was performed to evaluate the effectiveness of mesenchymal stem cells (MSCs) on bone healing and to assess the role of various chemical stimulants and mediators in healing. Forty female mice were randomly assigned to 4 groups (10 mice each) after the induction of fixed fractures: group I: received fixation only; group II: received phosphate-buffered saline (PBS); group III: received intralesion MSCs (IL-MSCs); and group IV: received intraperitoneal MSCs (IP-MSCs). Serum alkaline phosphatase (ALP) levels and the expression of the osteocalcin (OCN), bone morphogenetic protein-2 (BMP-2), and stromal-derived factor-1 (SDF-1) genes were measured. ALP reached baseline level only in IL-MSCs, whereas OCN reached baseline level in MSCs recipients (IL-MSCs and IP-MSCs). BMP-2 significantly increased in MSCs recipients 3 weeks postfracture and increased in all groups 8 weeks postfracture with significant increases in MSC recipients than the fixation and PBS groups. The highest BMP-2 expression was reached in IL-MSC group. MSCs either locally or systemically improves or accelerates the healing of bone fractures with better results obtained after local injection, as shown by biochemical, radiological, and histological findings. MSCs are effective candidates for bone regeneration.

The endothelium-bone axis in development, homeostasis and bone and joint disease.

Blood vessels form a versatile transport network that is best known for its critical roles in processes such as tissue oxygenation, metabolism and immune surveillance. The vasculature also provides local, often organ-specific, molecular signals that control the behaviour of other cell types in their vicinity during development, homeostasis and regeneration, and also in disease processes. In the skeletal system, the local vasculature is actively involved in both bone formation and resorption. In addition, blood vessels participate in inflammatory processes and contribute to the pathogenesis of diseases that affect the joints, such as rheumatoid arthritis and osteoarthritis. This Review summarizes the current understanding of the architecture, angiogenic growth and functional properties of the bone vasculature. The effects of ageing and pathological conditions, including arthritis and osteoporosis, are also discussed.

Automated bone mineral density prediction and fracture risk assessment using plain radiographs via deep learning.

Dual-energy X-ray absorptiometry (DXA) is underutilized to measure bone mineral density (BMD) and evaluate fracture risk. We present an automated tool to identify fractures, predict BMD, and evaluate fracture risk using plain radiographs. The tool performance is evaluated on 5164 and 18175 patients with pelvis/lumbar spine radiographs and Hologic DXA. The model is well calibrated with minimal bias in the hip (slope = 0.982, calibration-in-the-large = -0.003) and the lumbar spine BMD (slope = 0.978, calibration-in-the-large = 0.003). The area under the precision-recall curve and accuracy are 0.89 and 91.7% for hip osteoporosis, 0.89 and 86.2% for spine osteoporosis, 0.83 and 95.0% for high 10-year major fracture risk, and 0.96 and 90.0% for high hip fracture risk. The tool classifies 5206 (84.8%) patients with 95% positive or negative predictive value for osteoporosis, compared to 3008 DXA conducted at the same study period. This automated tool may help identify high-risk patients for osteoporosis.

Clinical efficacy of closed reduction and percutaneous parallel K-wire interlocking fixation of first metacarpal base fracture.

BACKGROUND: This study aimed to explore the clinical efficacy of treating a first metacarpal base fracture by closed reduction and percutaneous parallel K-wire interlocking fixation between the first and second metacarpals. METHODS: Twenty patients treated by the abovementioned modified technique (modified technique group) and ten patients treated by the traditional percutaneous K-wire fixation technique (traditional technique group) from October 2015 to November 2019 at our institution were retrospectively reviewed. The patients' average age was 38 years (range, 16-61 years). The mean follow-up period was 13 months (range, 10-18 months). At the final follow-up, the functional recovery of the injured hand was assessed and compared between the modified and traditional technique groups. In addition, the functional recovery of the injured hand was compared with that of the uninjured hand within the modified technique group. RESULTS: All patients recovered well, with no cases of infection or nonunion. Compared with the traditional technique group, the modified technique group had a shorter operative time, lower postoperative visual analogue scale pain score, better effective range of motion score of the first carpometacarpal joint (Kapandji score), and had almost no need for auxiliary plaster fixation, enabling functional exercise to be started earlier. Within the modified technique group, the mean hand grip strength, pinch strength, and Kapandji score on the injured side did not significantly differ to the values on the uninjured side in both the extra-articular and intra-articular fracture subgroups. While the abduction and flexion-extension arcs of the thumb on the injured hand were significantly smaller than those on the uninjured hand in both the extra-articular and intra-articular fracture subgroups, the patients felt clinically well with respect to daily activities and strength. CONCLUSION: The percutaneous parallel K-wire and interlocking fixation technique is simple, effective, and economical for first metacarpal base fractures.

Fracture biomechanics influence local and systemic immune responses in a murine fracture-related infection model.

Biomechanical stability plays an important role in fracture healing, with unstable fixation being associated with healing disturbances. A lack of stability is also considered a risk factor for fracture-related infection (FRI), although confirmatory studies and an understanding of the underlying mechanisms are lacking. In the present study, we investigate whether biomechanical (in)stability can lead to altered immune responses in mice under sterile or experimentally inoculated conditions. In non-inoculated C57BL/6 mice, instability resulted in an early increase of inflammatory markers such as granulocyte-colony stimulating factor (G-CSF), keratinocyte chemoattractant (KC) and interleukin (IL)-6 within the bone. When inoculated with Staphylococcus epidermidis, instability resulted in a further significant increase in G-CSF, IL-6 and KC in bone tissue. Staphylococcus aureus infection led to rapid osteolysis and instability in all animals and was not further studied. Gene expression measurements also showed significant upregulation in CCL2 and G-CSF in these mice. IL-17A was found to be upregulated in all S. epidermidis infected mice, with higher systemic IL-17A cell responses in mice that cleared the infection, which was found to be produced by CD4+ and γδ+ T cells in the bone marrow. IL-17A knock-out (KO) mice displayed a trend of delayed clearance of infection (P=0.22, Fisher's exact test) and an increase in interferon (IFN)-γ production. Biomechanical instability leads to a more pronounced local inflammatory response, which is exaggerated by bacterial infection. This study provides insights into long-held beliefs that biomechanics are crucial not only for fracture healing, but also for control of infection.