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.

Efficacy of fascia iliaca compartment nerve block as part of multimodal analgesia after surgery for femoral bone fracture

BACKGROUND: Fascia iliaca compartment nerve block(FICNB) has been an established technique for postoperative analgesia after surgery for femoral bone fracture. FICNB is technically easy, effective for postoperative pain control after operation for femoral bone fracture and decreases the complications induced by systemic analgesic drugs. The severity of postoperative pain is affected by genetics, cultural and social factors across the world. In this study we assessed the efficacy of fascia iliaca compartment nerve block when it is used as part of multimodal analgesia after surgery for femoral bone fracture.METHODS: An institution-based case control study was conducted from September, 2013 to May, 2014. All patients who had been operated on under spinal anesthesia for femoral bone fracture were included. The patients divided into a FICNB group(n=20) and a control group(n=20). The FICNB group was given 30 mL of 0.25% bupivacaine at the end of the operation. Postoperative pain was assessed within the f irst 24 hours, i.e. at 15 minutes, 2 hours, 6 hours, 12 hours and 24 hours using 100 mm visual analogue scale(VAS), total analgesic consumption, and the time for the f irst analgesic request.RESULTS: VAS pain scores were reduced within the f irst 24 hours after operation in the FICNB group compared wtih the control group. VAS scores at 2 hours were taken as median values(IQR) 0.00(0.00) vs.18.00(30.00), P=0.001; at 6 hours 0.00(0.00) vs. 34.00(20.75), P=0.000; at 24 hours 12.50(10.00) vs. 31.50(20.75), P=0.004; and at 12 hours(17.80±12.45) vs.(29.95±12.40), P=0.004, respectively. The total analgesic consumption of diclofenac at 12 and 24 hours was reduced in the FICNB group, and the time for the fi rst analgesic request was signifi cantly prolonged(417.50 vs. 139.25 minutes, P=0.000).CONCLUSIONS: A single injection for FICNB could lead to postoperative pain relief, reduction of total analgesic consumption and prolonged time for the fi rst analgesic request in the FICNB group after surgery for femoral bone fracture. We recommend FICNB for analgesia after surgery for femoral bone fracture and for patients with femoral bone fracture at the emergency department.

THE SYNTHESIS AND CHARACTERIZATION OFPOLY-L-LACTIDE USED FOR THE INTERNALFIXATION OF BONE FRACTURE

A high Mw of PLLA was synthesized, it intended to be used in the manufacture ofbioabsorbable screw applied in bone fracture internal fixation. The optical reactionconditions have been discussed.

Combined Subtemporal-Supralabyrinthine Approach to Geniculate Ganglion for Management of Facial Paralysis in Temporal Bone Fracture

Objective To investigate the clinical outcomes of facial never decompression via a combined subtemporal-su- pralabyrinthine approach to geniculate ganglion for management of facial paralysis in temporal bone fracture. Methods Eighteen patients with unilateral facial paresis due to temporal bone fracture were treated between March 2003 and March 2011. Facial function was House-Braekmann（HB） grade m in 6 patients, HB grade V in 9 patients and HB grade VI in 3 patients. The preoperative mean air conduction threshold was 52 dB HL for the 15 cases with longitudinal temporal bone fracture and showed severe sensorineural heating loss in the 3 cases with transverse temporal bone fracture. Fracture lines were detected in 15 cases on temporal bone axial CT scans and ossicular disruption was determined in 11 cases by virtual CT endoscopy. The geniculate ganglion or the tympanic mastoid segment of the facial nerve showed an irregular morphology on curved planar reformation images of the facial nerve canal. After an intact canal wall mastoi- do-epitympanectomy, the ossicular chain recess was opened by drilling through the was disrupted, the incus was removed to damage was evaluated. If the ossicular chain was intact, the supralabyrinthine cells between the tegmen tympani and ossicular chain. If the ossicular chain access the supralabyrinthine recess. The geniculate ganglion and the distal labyrinthine segment of the facial nerve were exposed. After completing facial nerve decompression, the dislocated incus was replaced, or a fractured incus was reshaped to bridge the space between the malleus and the stapes. Results Pronounced ganglion geniculatum swelling was found in 15 cases of longitudinal temporal bone fracture, with greater petrosus nerves damage in 3 cases and bleeding in 5 cases. Disrupted ossicular chains were seen in 11 cases, including dislocated incus resulting in crushing of the horizontal portion of the facial nerve in 3 cases and fracture of the incus long process in 1 case. In 3 cases of transverse fractures, dehiscence on the promontory, semicircular canal or oval window was found. All cases had primary healing with no complication. At follow-ups ranging from 0.5 to 3 years （average 1.2 years）, facial nerve function recovered to HB grade I in 11 cases, 11 in 5 cases and m in 2 cases. Overall hearing recovery was 33 dB. Conclusion The clinical outcomes concerning facial nerve function and hearing recovery are satisfactory via a combined subtemporal-supralabyrinthine approach to the geniculate ganglion for facial nerve decompression in temporal bone fracture patients with facial paralysis.

CT VIRTUAL ENDOSCOPY IN ASSESSING OSSICULAR CHAIN DISRUPTION CSUSED BY TEMPORAL BONE FRACTURE AND EAR TRAUMA

Objective To explore the value of computed tomography virtual endoscopy(VE) in assessing ossicular chain disruption in temporal bone fracture and ear trauma with intact tympanum. Methods High resolution spiral computerized tomography(CT) was completed in 35 cases of temporal bone fracture and 5 cases of tympanum trauma, all with intact or healed tympanum. Three-dimensional reconstruction was completed using a virtual endoscopy software. Audiological tests were conducted in all patients and evaluation of facial nerve injury in patients with facial paralysis. Patients with mild conductive deafness, ossicular chain subluxation on VE, and no facial paralysis were treated conservatively for 4-12 weeks with repeated hearing evaluation; those with facial paralysis underwent surgery if no recovery after 4- 8 weeks of conservative treatment. Patients with moderate to severe conductive hearing loss or mixed hearing loss, incus long process fracture or dislocation on VE and facial paralysis, underwent ossicular chain reconstruction and facial nerve decompression after conservative treatment for 4-8 weeks, or exploratory tympanotomy only if no facial paralysis. VE, audiological tests and facial nerve function tests were repeated in 3-6 months after surgery. Results Of the 6 cases with mild conductive hearing loss, ossicular chain subluxation and no facial paralysis, 3recovered to normal hearing spontaneously and 3 showed no significant improvement, after 4-12 weeks of conservative treatment. After conservative treatment for 4-8 weeks, 3 of the 12 cases with mild conductive deafness, ossicular chain dislocation on VE and facial paralysis recovered to normal hearing and HouseBrackmann(HB) grade I facial function from HB grade II,4 showed facial function recovery to HB grade I(n=2) or II(n=2) from HB grade III but no hearing recovery, and 5 gained no recovery and went on to receive exploratory tympanotomy and facial nerve decompression. The 11 cases with moderate to severe conductive deafness, incus long process fracture or dislocation on VE and facial paralysis all received ossicular chain reconstruction and facial nerve decompression after 4-8 weeks of conservative treatment. The 7 cases with moderate to severe conductive deafness, dislocated or fallen incus on VE but no facial paralysis received ossicular chain reconstruction after conservative treatment. The 4 cases with mixed hearing loss, dislocated or fallen incus on VE and no facial paralysis received ossicular chain repair via the intact canal wall epitympanum approach after conservative treatment. Pharmacological therapies continued postoperatively in these patients to treat sensorineural deafness. Although temporal bone CT scans displayed the fracture line and malleus/incus abnormalities, VE provided additional detailed information on dislocation of incudomalleal and incudostapedial joints, incus dislocation or fracture, separation between crus longum incudis and stapes, and incus shifting. These were all confirmed during surgery. VE results and surgery findings were 100% consistent in patients with ossicular chain disruption. Conclusion VE can provide reliable visual evidence for accurate assessment of traumatic ossicular chain disruption, timing of surgery and individualizing surgical strategies and postoperative follow-up.

DEGRADATION AND PROCESSING OF PLA AND ITS APPLICATION IN FIXATION OF BONE FRACTURE

PLA is presently considered as the most attractive compound for temporarytherapeutic application in the biomedical field. In this paper we give an overview of thepresent knowledge on the degradation behavior,processing technology of PLA and itsapplication in the fixation of bone fracture.

The Effects of Absorbable Materials in the Treatment for Non-Weight-Bearing Bone Fractures of Extremities

Objective:To study the effects of absorbable materials in non-weight-bearing bone fractures of extremities.Methods:After 66 patients with nonweight-bearing bone fractures of extremities were selected,absorbable materials were used in the observation group and metal materials were used in the control group.Results:After treatment,the bone healing in the observation group was significantly improved(P<0.05).Conclusion:the application of absorbable materials in non-weight-bearing bone fractures of extremities is effective.

Regulation of metabolic microenvironment with a nanocomposite hydrogel for improved bone fracture healing

Bone nonunion poses an urgent clinical challenge that needs to be addressed.Recent studies have revealed that the metabolic microenvironment plays a vital role in fracture healing.Macrophages and bone marrow-derived mesenchymal stromal cells(BMSCs)are important targets for therapeutic interventions in bone fractures.Itaconate is a TCA cycle metabolite that has emerged as a potent macrophage immunomodulator that limits the inflammatory response.During osteogenic differentiation,BMSCs tend to undergo aerobic glycolysis and metabolize glucose to lactate.Copper ion(Cu^(2+))is an essential trace element that participates in glucose metabolism and may stimulate glycolysis in BMSCs and promote osteogenesis.In this study,we develop a 4-octyl itaconate(4-OI)@Cu@Gel nanocomposite hydrogel that can effectively deliver and release 4-OI and Cu^(2+)to modulate the metabolic microenvironment and improve the functions of cells involved in the fracture healing process.The findings reveal that burst release of 4-OI reduces the inflammatory response,promotes M2 macrophage polarization,and alleviates oxidative stress,while sustained release of Cu^(2+)stimulates BMSC glycolysis and osteogenic differentiation and enhances endothelial cell angiogenesis.Consequently,the 4-OI@Cu@Gel system achieves rapid fracture healing in mice.Thus,this study proposes a promising regenerative strategy to expedite bone fracture healing through metabolic reprogramming of macrophages and BMSCs.

Systemic modulation of skeletal mineralization by magnesium implant promoting fracture healing: Radiological exploration enhanced with PCA-based machine learning in a rat femoral model

The clinical application of magnesium(Mg)and its alloys for bone fractures has been well supported by in vitro and in vivo trials.However,there were studies indicating negative effects of high dose Mg intake and sustained local release of Mg ions on bone metabolism or repair,which should not be ignored when developing Mg-based implants.Thus,it remains necessary to assess the biological effects of Mg implants in animal models relevant to clinical treatment modalities.The primary purpose of this study was to validate the beneficial effects of intramedullary Mg implants on the healing outcome of femoral fractures in a modified rat model.In addition,the mineralization parameters at multiple anatomical sites were evaluated,to investigate their association with healing outcome and potential clinical applications.Compared to the control group without Mg implantation,postoperative imaging at week 12 demonstrated better healing outcomes in the Mg group,with more stable unions in 3D analysis and high-mineralized bridging in 2D evaluation.The bone tissue mineral density(TMD)was higher in the Mg group at the non-operated femur and lumbar vertebra,while no differences between groups were identified regarding the bone tissue volume(TV),TMD and bone mineral content(BMC)in humerus.In the surgical femur,the Mg group presented higher TMD,but lower TV and BMC in the distal metaphyseal region,as well as reduced BMC at the osteotomy site.Principal component analysis(PCA)-based machine learning revealed that by selecting clinically relevant parameters,radiological markers could be constructed for differentiation of healing outcomes,with better performance than 2D scoring.The study provides insights and preclinical evidence for the rational investigation of bioactive materials,the identification of potential adverse effects,and the promotion of diagnostic capabilities for fracture healing.

Beyond the imaging evaluation of fractures of the lateral process of the talus:Let’s not forget concomitant injuries

Fractures of the lateral process of the talus(FLPT)are uncommon fractures that represent a clinical challenge.Traditional radiological classification systems rely predominantly on radiographic findings.However,due to the high rate of FLPT misdiagnosis and the limited accuracy in evaluating concomitant talar injuries through plain radiographs,novel imaging classification systems have been developed that aim to enhance the diagnosis of concomitant talar injuries,thereby optimizing patient management and reducing the incidence of long-term complications.

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.

Biodegradable metals for bone fracture repair in animal models: a systematic review

Biodegradable metals hold promises for bone fracture repair.Their clinical translation requires pre-clinical evaluations including animal studies,which demonstrate the safety and performance of such materials prior to clinical trials.This evidence-based study investigates and analyzes the performance of bone fractures repair as well as degr adation properties of biodegradable metals in animal models.Data were carefully collected after identification of population,interventions,com-parisons,outcomes and study design,as well as inclusion criteria combining biodegradable metals and animal study.Twelve publications on pure Mg,Mg alloys and Zn alloys were finally included and reviewed after extraction from a collected database of 2122 publications.Compared to controls of traditional non-degradable metals or resorbable polymers,biodegradable metals showed mixed or contradictory outcomes of fracture repair and degradation in animal models.Although quantita-tive meta-analysis cannot be conducted because of the data heterogeneity,this systematic review revealed that the quality of evidence for biodegradable metals to repair bone fractures in animal models is'very low'.Recommendations to standardize the animal studies of biodegradable metals were proposed.Evidence based biomaterials research could help to both identify reliable scientific evidence and ensure future clinical translation of biodegradable metals for bone fracture repair.

Orthopedic implants and devices for bone fractures and defects:Past,present and perspective

Bone is a unique tissue that is capable of repairing itself after damage.However,there are certain instances of fractures and defects that require clinical intervention for proper alignment and healing.As with any implant,careful consideration of the material used to create the implants to treat these problems is needed.If the incorrect material is chosen,the implants themselves can lead to bone fractures or defects,or bone healing may not take place at all.All three classes of biomaterials-metals,ceramics,and polymers-have been used in the treatment of both bone fractures and bone defects,and each has its own unique benefits and limitations for its applications.Furthermore,composites of these different materials have also been created to try to take advantage of all the different benefits offered by each different material.This review highlights different materials that have been used for the development of internal fixators and bone graft substitutes to treat fracture and bone defects as well as their limitations and needed future research.

Bone Fracture Reduction Surgery-aimed Bone Connection Robotic Hand

Bone connection with robot is an important topic in the research of robot assisted fracture reduction surgery.With the method to achieve bone-robot connection in current robots,requirements on reliability and low trauma can not be satisfied at the same time.In this paper,the design,manufacturing,and experiments of a novel Bone Connection Robotic Hand(BCRH)with variable stiffness capability are carried out through the bionics research on human hand and the principle of particle jamming.BCRH’s variable stiffness characteristic is a special connection between“hard connection”and“soft connection”,which is different from the existing researches.It maximizes the reliability of bone-robot connection while minimizes trauma,meets the axial load requirement in clinical practice,and effectively shortens the operating time to less than 40 s(for mode 1)or 2 min(for mode 2).Meanwhile,a theoretical analysis of bone-robot connection failure based on particle jamming is carried out to provide references for the research in this paper and other related studies.

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.

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

Rotary self-locking intramedullary nail for long tubular bone fractures

Background Intramedullary nails had been widely used in the treatment of long-bone fractures because of less interference of fractures and center bearing biomechanical advantage. However, it had been also found many shortcomings such as broken nails, delayed healing and was modified in order to achieve better efficacy and reduce complications. The aim of the present study is to compare the efficacy of rotary self-locking intramedullary nails （RSIN） with that of interlocking intramedullary nails （IIN） in the treatment of long-bone fractures.

Biodegradable Zn-2Cu-0.5Zr alloy promotes the bone repair of senile osteoporotic fractures via the immune-modulation of macrophages

Delayed bone-healing of senile osteoporotic fractures remains a clinical challenge due to the alterations caused by aging in bone and immune systems.The novel biomaterials that address the deficiencies in both skeletal cells and immune systems are required to effectively treat the bone injuries of older patients.Zinc(Zn)has shown promise as a biodegradable material for use in orthopedic implants.To address the bone-healing deficiencies in elderly patients with bone injuries,we developed a biodegradable Zn-based alloy(Zn-2Cu-0.5Zr)with enhanced mechanical properties,including a yield strength of 198.7 MPa and ultimate tensile strength of 217.6 MPa,surpassing those of pure Zn and Zn-2Cu alloys.Cytotoxicity tests conducted on bone marrow mesenchymal stem cells(BMSCs)and MC3T3-E1 cells demonstrated that the extracts from Zn-2Cu-0.5Zr alloy exhibited no observable cytotoxic effects.Furthermore,the extracts of Zn-2Cu-0.5Zr alloy exhibited significant anti-inflammatory effects through regulation of inflammation-related cytokine production and modulation of macrophage polarization.The improved immune-osteo microenvironment subsequently contributed to osteogenic differentiation of BMSCs.The potential therapeutic application of Zn-2Cu-0.5Zr in senile osteoporotic fracture was tested using a rat model of age-related osteoporosis.The Zn-2Cu-0.5Zr alloy met the requirements for load-bearing applications and accelerated the healing process in a tibial fracture in aged rats.The imaging and histological analyses showed that it could accelerate the bone-repair process and promote the fracture healing in senile osteoporotic rats.These findings suggest that the novel Zn-2Cu-0.5Zr alloy holds potential for influencing the immunomodulatory function of macrophages and facilitating bone repair in elderly individuals with osteoporosis.

Usage of buttress plate internal fixation associated with autografting of fibula and iliac bone for the treatment of distal femoral C_3 type fracture

To assess the effect of using buttress plate associated with antografting of fibula and iliac bone for the treatment of distal femoral C3 type fracture.Methods Seventeen cases of distal femoral C3 type fracture using buttress plate associated with antografting of fibula and iliac bone were analyzed retrospectively.Results All cases were followed up for an average of 24 months（8～55 months）.The average time of octets bridge forming were 4 months（3～5 months） while the average time for bone union were 8 months （6～14 months）.According to Shelbourne rating system,result of all 18 cases were excellent and no malunion,infection were found.Conclusion Buttress plate associated with antografting of fibula and iliac bone is an effective alternative for the treatment of distal femoral C3 type fracture.It can provide more stable fixation to the bone and earlier functional exercises can be achieved.5 refs,3 figs,1 tab.

Role of fibroblast growth factor receptor 1 in the bone development and skeletal diseases

Accumulating data suggest that FGFs/FGFR1 plays essential roles in the bone development and human skeletal diseases. Conditional inactivation of fgfrl caused different phenotypes displaying in different cells or specific organs and revealed some novel functions of FGFR1 in bone development. Fgfrl mutation mainly induced 2 types of human skeletal diseases, craniosynostosis syndrome and dysplasias. Similar mutation of fgfrl in mouse model just mimicked the phenotype that happened in human. These fa- cilitate the investigation on the underlying mechanism of the diseases. Here we mainly focused on the ad- vance of FGFR1 function in the bone development and its mutation caused skeletal diseases.