Cemented vertebra and adjacent vertebra refractured in a chronic kidney disease-mineral and bone disorder patient: A case report

BACKGROUND Although percutaneous vertebral augmentation(PVA)is a commonly used procedure for treating vertebral compression fracture(VCF),the risk of vertebral refracture should be considered.Chronic kidney disease-mineral and bone disorder(CKD-MBD)is a systemic disease of mineral and bone metabolism.It is associated with an increased risk of fracture.Few studies have reported the use of PVA in patients with CKD-MBD.We herein report a rare case wherein the cemented vertebra and the adjacent vertebra refractured simultaneously in a CKD-MBD patient after PVA.CASE SUMMARY A 74-year-old man suffered from low back pain after taking a fall about 3 wk ago.According to physical examination,imaging and laboratory findings,diagnoses of T12 VCF,CKD-MBD,and chronic kidney disease stage 5 were established.He then received percutaneous vertebroplasty at T12 vertebra.Fourteen weeks later,he presented with T12 and L1 vertebral refractures caused by lumbar sprain.Once again,he was given PVA which was optimized for the refractured vertebrae.Although the short-term postoperative effect was satisfactory,he reported chronic low back pain again at the 3-month follow-up.CONCLUSION It is necessary that patients with CKD-MBD who have received PVA are aware of the adverse effects of CKD-MBD.It may increase the risk of vertebral refracture.Furthermore,the PVA surgical technique needs to be optimized according to the condition of the patient.The medium-and long-term effects of PVA remain uncertain in patients with CKD-MBD.

Clinical Effectiveness of the Plate Screw Internal Fixation Technique in the Treatment of Patients with Traumatic Fractures of Long Bones in the Lower Extremities

Objective: To investigate the effectiveness of the plate screw internal fixation technique on the clinical outcomes of patients with traumatic fractures of long bones in the lower extremities. Methods: From January 2022 to December 2023, 70 patients with traumatic fractures of long bones in the lower extremities were admitted to the hospital and randomly divided into two groups: the control group and the observation group, each consisting of 35 cases. The control group underwent traditional closed interlocking intramedullary nailing, while the observation group received internal fixation with steel plates and screws. Relevant surgical indicators, treatment effectiveness, and postoperative complication rates were compared between the two groups. Results: The observation group exhibited significantly short surgical duration (80.65 ± 5.01 vs. 88.36 ± 5.26 minutes), fracture healing time (13.27 ± 0.32 vs. 15.52 ± 0.48 weeks), and hospitalization days (10.49 ± 1.13 vs. 16.57 ± 1.15 days) compared to the control group (P = 0.000). The effective treatment rate was significantly higher in the observation group (29/82.86%) than in the control group (21/60.00%), with a significant difference observed (χ2 = 4.480, P = 0.034). Additionally, the complication rate in the observation group (2/5.71%) was significantly lower than that in the control group (8/22.86%), with a correlated difference (χ2 = 4.200, P = 0.040). Conclusion: The plate screw internal fixation technique demonstrates significant clinical efficacy in treating traumatic fractures of long bones in the lower extremities. It improves the healing rate, reduces complications, and represents a safe and effective treatment strategy worthy of widespread use and application.

Parathyroidectomy restored bone mineral density in a neglected femoral neck fracture with renal osteodystrophy:A case report

BACKGROUND This case report contributes to the medical literature by highlighting the successful management of a neglected femoral neck fracture in a patient with renal osteodystrophy and secondary hyperparathyroidism(SHPTH)who was on dialysis due to end-stage renal disease(ESRD).It underscores the efficacy of parathyroidectomy(PTX)in restoring bone mineral density(BMD)and promoting fracture healing,addressing a significant complication in ESRD patients.CASE SUMMARY A 36-year-old female with renal osteodystrophy and on dialysis due to ESRD presented with a history of left patellar tendon rupture and later,a right achilles tendon avulsion fracture.Persistent right hip pain led to the discovery of a neglected right femoral neck fracture,which was initially overlooked due to the patient’s complex medical history.Two months post-achilles tendon repair,the patient underwent PTX to manage the refractory SHPTH.The postoperative course included rehabilitation and weight-bearing exercises.Remarkably,2 years after osteosynthesis,radiographic assessments indicated a solid union of the periprothesis fracture and significant improvement in BMD,showcasing the efficacy of the treatment approach.CONCLUSION PTX,combined with appropriate rehabilitation,is crucial for improving BMD and fracture healing in ESRD patients with SHPTH.

Outcomes of early versus late irrigation and debridement of pediatric open long bone fractures

BACKGROUND Open long bone fractures are a major concern for pediatric patients due to the risk of surgical site infection(SSI).Early studies have recommended irrigation and debridement of open fractures within 6 hours-8 hours for the prevention of SSI.According to the American College of Surgeons(ACS)Best Practice Guidelines,in 2015,irrigation and debridement should be done within 24 hours.AIM To identify whether early irrigation and debridement,within 8 hours,vs late,between 8 hours and 24 hours,for pediatric open long bone fractures impacts rate of SSI.METHODS Using retrospective data review from the National Trauma Data Bank,Trauma Quality Improvement Project(TQIP)of 2019.TQIP database is own by the ACS and it is the largest database for trauma quality program in the world.Propensity matching analysis was performed for the study.RESULTS There were 390 pediatric patients with open long bone fractures who were incl-uded in the study.After completing propensity score matching,we had 176 patients in each category,irrigation and debridement within 8 hours and irrigation and debridement between 8 hours and 24 hours.We found no significant differences between each group for the rate of deep SSI which was 0.6%for patients who received surgical irrigation and debridement within 8 hours and 1.1%for those who received it after 8 hours[adjusted odd ratio(AOR):0.5,95%CI:0.268-30.909,P>0.99].For the secondary outcomes studied,in terms of length of hospital stay,patients who received irrigation and debridement within 8 hours stayed for an average of 3.5 days,and those who received it after 8 hours stayed for an average of 3 days,with no significant difference found,and there were also no sig-nificant differences found between the discharge dispositions of the patients.CONCLUSION Our findings support the recommendation for managing open long bone fractures from the ACS:Complete surgical irrigation and debridement within 24 hours.

Effectiveness of out-fracture of the inferior turbinate with reduction nasal bone fracture

BACKGROUND The nasal bone,being the most protruding bone in the center of the facial bones,is particularly susceptible to damage.Nasal bone fractures can often result in secondary deformation and dysfunction of the nose,including septal fractures.Studies on functional or intra-nasal complications have been rarely reported after nasal bone fracture reduction.AIM To evaluate the severity of nasal obstruction and its improvement following nasal bone fracture reduction using inferior turbinoplasty.METHODS We conducted a retrospective review of data from 50 patients with symptomatic nasal obstruction between January to December 2010.All patients underwent preoperative Computed tomography evaluation,and symptom changes and nasal cavity volume were analyzed using a visual analog scale and acoustic rhinometry before and after surgery.Closed reduction and out-fracture of both inferior turbinates performed by the same surgeon.Treatment outcomes were assessed by comparing changes in the nasal airway volume measured using acoustic rhinometry before and after surgery.The minimal cross-sectional area(MCA)was also analyzed based on the Stranc classification.RESULTS Before reduction,the mean MCA for all cases was 0.59±0.06 cm^(2),which represented an 11%decrease compared to the average size of a Korean adult(0.65±0.03 cm^(2)).The MCA for frontal impact was 0.60±0.02 cm^(2) and for lateral impact,it was 0.58±0.03 cm^(2).After reduction via inferior turbinoplasty,the MCA improved to 0.64±0.04 cm^(2).CONCLUSION This study suggests that turbinoplasty is helpful in addressing nasal obstruction.Out-fracture of the inferior turbinate is an effective and durable technique that can be easily performed to enlarge the nasal airway with minimal morbidity.

Exclusive Fibula Osteosynthesis for Treating Open Fractures Gustillo I-III B of the Distal Half of the Leg Bones in a Resources-Limited Setting

Introduction: Management of open leg bones fractures is a challenging health issue for the surgeon, particularly true in resource-limited settings. In this study, we evaluate exclusive fibular osteosynthesis in the treatment of open fractures of the distal half of the leg bones as a therapeutic option in our context. Methods: This is a prospective, experimental, multicenter study of 30 open fractures of the distal half of the leg bones treated with exclusive fibula osteosynthesis, conducted in 3 hospitals in the DRC from January 1, 2013 to September 30, 2016. Results: The age range of 20 to 40 years grouped 22 (73.4%) patients, the sex ratio was 1:1 and the unemployed were the most involved with 16 (53.3%) cases. The Gustilo II, I, III B and III A types represented 40%, 33.3%, 20% and 6.7%, respectively. The fractures were located in the distal third in 12 (40%) cases, in the middle third in 11 (36.7%) cases, and in both malleoli in 7 cases (23.3%). Osteosynthesis of the fibula by screw plate was applied in 22 (73.3%) patients and pinning in 8 (26.7%). Satisfactory reduction of the tibial fracture site was achieved in 29 (96.7%) cases and 100% bone healing was achieved within an average of 10 weeks. Four (13.3%) loss of alignment, 1 (3.3%) infection, 1 (3.3%) skin necrosis and 2 (6.7%) ankle stiffness complicated our fractures. Conclusion: Exclusive osteosynthesis of the fibula as a common technique for fractures of the distal half of the leg bones allowed us to reduce, immobilize and consolidate the tibial fracture in the required time and to preserve the mobility of the ankle.

A segmental defect adaptation of the mouse closed femur fracture model for the analysis of severely impaired bone healing

Objective: To better characterize nonunion endochondral bone healing and evaluate novel therapeutic approaches for critical size defect healing in clinically challenging bone repair, a segmental defect model of bone injury was adapted from the threepoint bending closed fracture technique in the murine femur.Methods: The mouse femur was surgically stabilized with an intramedullary threaded rod with plastic spacers and the defect adjusted to different sizes. Healing of the different defects was analyzed by radiology and histology to 8 weeks postsurgery. To determine whether this model was effective for evaluating the benefits of molecular therapy, BMP-2 was applied to the defect and healing then examined.Results: Intramedullary spacers were effective in maintaining the defect. Callus bone formation was initiated but was arrested at defect sizes of 2.5 mm and above, with no more progress in callus bone development evident to 8 weeks healing. Cartilage development in a critical size defect attenuated very early in healing without bone development, in contrast to the closed femur fracture healing, where callus cartilage was replaced by bone. BMP-2 therapy promoted osteogenesis of the resident cells of the defect, but there was no further callus development to indicate that healing to pre-surgery bone structure was successful.Conclusions: This segmental defect adaptation of the closed femur fracture model of murine bone repair severely impairs callus development and bone healing, reflecting a challenging bone injury. It is adjustable and can be compared to the closed fracture model to ascertain healing deficiencies and the efficacy of therapeutic approaches.

Metformin accelerates bone fracture healing by promoting type H vessel formation through inhibition of YAP1/TAZ expression

Due to increasing morbidity worldwide,fractures are becoming an emerging public health concern.This study aimed to investigate the effect of metformin on the healing of osteoporotic as well as normal fractures.Type H vessels have recently been identified as a bone-specific vascular subtype that supports osteogenesis.Here,we show that metformin accelerated fracture healing in both osteoporotic and normal mice.Moreover,metformin promoted angiogenesis in vitro under hypoxia as well as type H vessel formation throughout fracture healing.Mechanistically,metformin increased the expression of HIF-1α,an important positive regulator of type H vessel formation,by inhibiting the expression of YAP1/TAZ in calluses and hypoxia-cultured human microvascular endothelial cells(HMECs).The results of HIF-1αor YAP1/TAZ interference in hypoxia-cultured HMECs using si RNA further suggested that the enhancement of HIF-1αand its target genes by metformin is primarily through YAP1/TAZ inhibition.Finally,overexpression of YAP1/TAZ partially counteracted the effect of metformin in promoting type H vessel-induced angiogenesis-osteogenesis coupling during fracture repair.In summary,our findings suggest that metformin has the potential to be a therapeutic agent for fractures by promoting type H vessel formation through YAP1/TAZ inhibition.

AN IMMUNOCYTOCHEMICAL STUDY OF BONE MORPHOGENETIC PROTEIN IN EXPERIMENTAL FRACTURE HEALING OF THE RABBIT MANDIBLE

A monoclonal antibody raised against bone morphogenetic protein (BMP-McAb) has been used to demonstrate the presence of bone morphogenetic protein(BMP) in experimental fracture healing. Rabbit mandibles were fractured using standardized methods and left to heal for 3, 7, 14, 21 and 24 d, respectively. The avidin-biotin complex (ABC) method demonstrated an accumulation of positively stained primitive mesenchymal cells at the fracture site in the hematoma stage of bone repair. These cells appeared to undergo differentiation into positively-stained chondroblasts and osteoblasts during the phase of callus formation. Undifferentiated mesenchymal cells showed a high positive reactivity in the early post-fracture stages but a much lower reactivity during the remodelling phase.The results of our study suggest that bone inductive processes are accompanied by the presence of BMP in osteoprogenitor cells during fracture healing of the mandible and that BMP may play a significant role in osteogenesis during bone healing.

Fracture of Limbs Bones in a Rural and Post Conflict Health Zone

Background: Trauma is major public health problem in developing countries where they are associated with many factors, mainly such as lack of road safety, poverty and inadequate urban planning. We aim to highlight the epidemiology of the fractures limbs bones in a rural area where people live in a context of low economy, low education and insecurity. Methods: We conducted a cross-sectional, retrospective study involving all patients admitted for fracture in the surgical department of FOMULAC-KATANA General Reference Hospital from 1st January 2011 to 31st December 2014. The patients whose medical records were not completed were excluded. Results: Among 136 patients included in our study, 140 bones limbs were registered. Most of them (60.1%) were aged between 15 - 44 years and the average age is 30, 1 year. Male predominance is noticed (72.8%) with a male/female ratio of 2.7/1, and informal professionals are the most found in our patients (67.6%). The main circumstances of fracture occurrence are, respectively, road traffic accidents (57.4%), falls (22.3%) and firearms (10.3%). The leg bones (33.6%) and forearm bones (20%) are the most concerned bones. Open fractures are recorded in 40.7% of patients. The supporting treatment is mainly orthopedic (64.5%) but also surgical (35.5). The mortality rate is 3.6%. Conclusion: The fractures of the limbs bones in Katana General Reference Hospital mainly affect young male which is informal professional. The road traffic accidents are the first circumstance leading to fractures followed by falls. The leg bones are the most fractured body part and fractures are commonly opened.

Locked Posterior Shoulder Dislocation with Impression Fracture Treated All Arthroscopically with the Use of an Allograft Bone Block: A Case Report

Background: Locked posterior shoulder dislocations are uncommon and possess many difficulties in diagnosis. They are often overlooked during the initial examination and delayed diagnosis adversely affects healing process. Apart from many open treatment options, there are reports of single attempts to treat such cases arthroscopically. Purpose: We present an original case of a posterior locked dislocation of the shoulder joint with a fracture of the lesser tuberosity followed by reverse Hill-Sachs fracture, treated in a novel fashion all-arthroscopically with the use of allogenic bone graft. Method: According to Constant Shoulder Score that tries to assess functional and subjective performance of the shoulder joint before the operation and after 12 months, we achieved a leap from 11 to 84. Results: The patient restored almost full range of motion and painless movement in activities of daily life as well as during sports. Conclusion: The use of an arthroscope reduces the invasiveness of the procedure, improves visualization of the joint and allows augmentation of the bone loss without performing an open approach. We believe that this is a promising method of treatment for selected cases of locked posterior shoulder dislocation.

Bone mineral density in fracture neck of femur patients:What's the significance?

BACKGROUND The National Institute for Health and Care Excellence(NICE)guidelines have advised further research is required into investigating the added prognostic value of bone mineral density(BMD)in the assessment of fracture risk with the Fracture Risk Assessment Tool(FRAX)score.AIM To investigate the significance of BMD in fracture neck of femur patients and compare it to the outcome of the FRAX score.METHODS Inclusion criteria for this study were all patients who underwent dual-energy Xray absorptiometry(DXA)scan following fracture neck of femur between 2015 and 2017.Analysis of BMD,FRAX scores and patient demographic data was undertaken.RESULTS A total of 69 patients were included in the study,mean age 74.1 years.There was no significant difference between mean BMD of the femoral neck in males(0.65)as compared to females(0.61)(P=0.364).Analyses showed no significant correlation between BMD and menopause age(rs=-0.28,P=0.090).A significant difference was seen of the femoral neck BMD between the different fracture pattern types(P=0.026).A stronger correlation was observed between BMD of femoral neck and FRAX major score(rs=-0.64,P<0.001)than with BMD of lumbar spine and FRAX major score(rs=-0.37,P=0.003).CONCLUSION This study demonstrated that BMD of the femoral neck measured by DXA scan is of added prognostic value when assessing patients for risk of fracture neck of femur in combination with the FRAX predictive scoring system.

Bone Injury and Fracture Healing Biology

Bones are organs of the skeletal system, providing shape, mechanical support, and protection to the body and facilitating the movement. In addition, bones contribute to the mineral homeostasis of the body and have recently been found to participate in endocrine regulation of energy metabolism. The well-known limitations associated with clinical use of autografts and allografts continue to drive efforts to develop bone graft substitutes, using the principles of biomaterials and tissue engineering. Under some stressful and continuous compressive conditions, the ability of the bone tissue to tolerate strength decreases. Whenever these forces overcome the toleration of the bone tissue, bone fracture occurs. years

Vertebral Bone Drilling (Puncture) Attenuates the Intractable Pain Due to Vertebral Fractures without Collapse

Purpose: Osteoporotic vertebral fractures with no sign of vertebral collapse on initial radiographs, which is so-called occult vertebral fractures (VFs), exist. Occult VFs have a high rate of missed diagnosis, and the treatment of these fractures has rarely been discussed in the literature. We evaluated the effects of vertebral bone drilling for the pain due to occults VFs. Materials and Methods: Eighteen patients with painful osteoporotic occult VFs underwent the vertebral bone drilling. We evaluated the clinical outcome by comparing numerical rating scale (NRS) and activity of daily life (ADL) values between before and after the vertebral bone drilling. Comparisons were made by using Wilcoxon signed rank test. Results: The mean baseline NRS and ADL score, and the mean NRS and ALD score after the bone drilling were 8.4 ± 0.8, 2.2 ± 0.6, 2.4 ± 1.0, 4.6 ± 0.5, respectively. Among the patients, we detected significant improvements in NRS pain score and ADL score after the drilling compared with baseline score (p < 0.0002). Conclusion: Vertebral bone drilling at the site of painful vertebral compression fractures alleviated the intractable pain due to osteoporotic occult VFs.

HYBRID EXTERNAL FIXATOR FOR THE TREATMENT OF UNICAMERAL BONE CYSTS WITH PATHOLOGICAL FRACTURE IN THE PROXIMAL HUMERUS

Objective: Unicameral bone cyst is a nonneoplasticbone lesion characterized by its tenacity and risk ofrecurrence. Pathological fracture is common and is often the presenting symptom. The objective of the present study was to evaluate the results of hybrid external fixator for thetreatment of a unicameral bone cyst with a pathologicalfracture. Methods: Hybrid external fixator for thetreatment of a unicameral bone cyst was performed intwelve patients. These patients presented with a pathological fracture and were managed immediately with hybridexternal fixator, of whom four had been managedconservatively at other clinics before they were referred toour department. The cyst was located in the proximalhumerus in all patients. The mean age of the patients at the time of surgery was 8.7 years, and the mean duration offollow-up was 32.6 months. Radiographic evaluation wasperformed according to the criteria of Capanna et al., andthe cyst was classified as completely healed, healed withresidual radiolucency (osteolysis), recurred, or having noresponse. Results: The healing period ranged from three to eight months. Eight cysts healed completely, and threehealed with residual radiolucent areas visible onradiographs. There was recurrence of one cyst that hadhealed with residual radiolucency. All of the cysts in thepresent study responded to treatment. A modulation ofhybrid external fixator was necessary in three patients, asthe bars had become too short after bone growth or the pins had been loose. No major complications were observed.Conclusion: Hybrid external fixator provides earlystability, which allows early mobilization and thus obviates the need for a plaster cast. This method of treatment alsoallows for an early return to normal activity.

Vitamin D and bone fracture healing

AIM： To examine whether vitamin D is of potential relevance in the healing process of fractures. METHODS： The present narrative review examined the bulk of the evidence based literature on the topic of vitamin D and bone healing in key electronic data bases from 1980 onwards using the terms vitamin D and bone healing, callus, fracture healing. All data were examined carefully and categorized according to type of study. A summary of the diverse terms and approaches employed in the research, as well as the rationale for hypothesizing vitamin D has a role in fracture healing was detailed.RESULTS： The results show very few human studies have been conducted to examine if vitamin D is effective at promoting post fracture healing, and the different ani-mal models that have been studied provide no consensus on this topic. The terms used in the related literature, as well as the methods used to arrive at conclusions on this clinical issue are highly diverse, there is no standardization of either of these important terms and methodolo-gies, hence no conclusive statements or clinical guide-lines can be forthcoming. There is a strong rational for continuing to examine if vitamin D supplements should be administered post-fracture, and ample evidence vitamin D is an essential hormone for functioning in general, as well as bone health and muscle as this relates to bone density.CONCLUSION： Whether those with low vitamin D levels can beneft from supplements if their nutritional practices do not cover recommended daily amounts, remains in question.

Calcaneal quantitative ultrasound-bone mineral density value for evaluating bone metabolism and bone turnover in patients with osteoporotic fracture

Objective:To study the calcaneal quantitative ultrasound-bone mineral density (QUS-BMD) value for evaluating bone metabolism and bone turnover in patients with osteoporotic fracture. Methods: A total of 150 patients who were diagnosed with osteoporotic fracture in Nuclear Industry 417 Hospital between January 2010 and March 2017 were selected as the fracture group of the research, and 70 subjects with normal bone mineral density confirmed by physical examination during the same period were selected as the control group of the research. QUS-BMD apparatus was used to measure bone mineral density of calcaneus, and the serum was collected to determine the biochemical indexes of bone metabolism and bone turnover. Results:QUS-BMD value as well as serum BALP, OC, OPG levels of fracture group was significantly lower than those of control group while serum TRACP5b, RANKL, PINP, PICP, CTX and NTX levels were significantly higher than those of control group;serum BALP, OC, OPG levels of patients with osteoporosis and osteopenia were significantly lower than those of subjects with normal bone mass while TRACP5b, RANKL, PINP, PICP, CTX and NTX levels were significantly higher than those of subjects with normal bone mass;serum BALP, OC, OPG levels of patients with osteoporosis was significantly lower than those of patients with osteoporosis while TRACP5b, RANKL, PINP, PICP, CTX and NTX levels were significantly higher than those of patients with osteoporosis.Conclusion:Calcaneal QUS-BMD is valuable for evaluating the bone metabolism activity and bone turnover process in patients with osteoporotic fracture.

Occult Fractures in the Carpal Region:Incidental Findings on Bone Scintigraphy

The aim of this study was to evaluate the number and distribution of fractures around the wrist found on bone scintigraphy in patients with a clinically suspected scaphoid fracture and negative initial radiographs. We retrospectively included 445 consecutive patients with a suspected scaphoid fracture who underwent routine bone scintigraphy. None of the radiographs showed evidence of a fracture. We analyzed the type and number of other fractures incidentally found on bone scintigraphy. On average, bone scintigraphy was done in 4 days (1 - 9). The outcome of bone scintigraphy: 80 (18.0%) a scaphoid fracture, 145 (32.6%) another fracture in the carpal region, 208 (46.7%) normal and the diagnosis of 12 (2.8%) was unclear. In the present study, we demonstrated that in patients with a clinically suspected scaphoid fracture and negative initial radiographs, bone scintigraphy detected in many cases (64.4%) other fractures in the carpal region. This suggests that radiographs not only miss scaphoid but also many other carpal and distal radius fractures. Solutions should be found to solve this problem and probably advanced imaging techniques like CT, MRI or bone scintigraphy should be used in the correct clinical scenario.

Bone three-dimensional microstructural features of the common osteoporotic fracture sites

Osteoporosis is a common metabolic skeletal disorder characterized by decreased bone mass and deteriorated bone structure, leading to increased susceptibility to fractures. With aging population, osteoporotic fractures are of global health and socioeconomic importance. The three-dimensional microstructural information of the common osteoporosis-related fracture sites, including vertebra, femoral neck and distal radius, is a key for fully understanding osteoporosis pathogenesis and predicting the fracture risk. Low vertebral bone mineral density(BMD) is correlated with increased fracture of the spine. Vertebral BMD decreases from cervical to lumbar spine, with the lowest BMD at the third lumbar vertebra. Trabecular bone mass of the vertebrae is much lower than that of the peripheral bone. Cancellous bone of the vertebral body has a complex heterogeneous three-dimensional microstructure, with lower bone volume in the central and anterior superior regions. Trabecular bone quality is a key element to maintain the vertebral strength. The increased fragility of osteoporotic femoral neck is attributed to low cancellous bone volume and high compact porosity. Compared with age-matched controls, increased cortical porosity is observed at the femoral neck in osteoporoticfracture patients. Distal radius demonstrates spatial inhomogeneous characteristic in cortical microstructure. The medial region of the distal radius displays the highest cortical porosity compared with the lateral, anterior and posterior regions. Bone strength of the distal radius is mainly determined by cortical porosity, which deteriorates with advancing age.

Virtual Reconstruction of Long Bone Fracture in Car-to-pedestrian Collisions Using Multi-body System and Finite Element Method

Lower limb injures are frequently observed in passenger car traffic accidents.Previous studies of the injuries focus on long bone fractures by using either cadaver component tests or simulations of the long bone kinematics,which lack in-depth study on the fractures in stress analysis.This paper aims to investigate lower limb impact biomechanics in real-world car to pedestrian accidents and to predict fractures of long bones in term of stress parameter for femur,tibia,and fibula.For the above purposes,a 3D finite element(FE) model of human body lower limb(HBM-LL) is developed based on human anatomy.The model consists of the pelvis,femur,tibia,fibula,patella,foot bones,primary tendons,knee joint capsule,meniscus,and ligaments.The FE model is validated by comparing the results from a lateral impact between simulations and tests with cadaver lower limb specimens.Two real-world accidents are selected from an in-depth accident database with detailed information about the accident scene,car impact speed,damage to the car,and pedestrian injuries.Multi-body system(MBS) models are used to reconstruct the kinematics of the pedestrians in the two accidents and the impact conditions are calculated for initial impact velocity and orientations of the car and pedestrian during the collision.The FE model is used to perform injury reconstructions and predict the fractures by using physical parameters,such as von Mises stress of long bones.The calculated failure level of the long bones is correlated with the injury outcomes observed from the two accident cases.The reconstruction result shows that the HBM-LL FE model has acceptable biofidelity and can be applied to predict the risk of long bone fractures.This study provides an efficient methodology to investigate the long bone fracture suffered from vehicle traffic collisions.