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.

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.

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.

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.

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.

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

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.

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.

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.

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.

Length unstable femoral fractures:A misnomer?

BACKGROUND Flexible intramedullary nailing(FIMN)is relatively contraindicated for pediatric length unstable femoral fractures.AIM To evaluate FIMN treatment outcomes for pediatric diaphyseal length unstable femoral fractures in patients aged 5 to 13 years.METHODS This retrospective study includes pediatric patients(age range 5-13 years)who received operative treatment for a diaphyseal femoral fracture at a single institution between 2013 and 2019.Length unstable femur fractures treated with FIMN were compared to treatment with other fixation methods[locked intramedullary nailing(IMN),submuscular plating(SMP),and external fixation]and to length stable fractures treated with FIMN.Exclusion criteria included patients who had an underlying predisposition for fractures(e.g.,pathologic fractures or osteogenesis imperfecta),polytrauma necessitating intensive care unit care and/or extensive management of other injuries,incomplete records,or no follow-up visits.Patients who had a length stable femoral fracture treated with modalities other than FIMN were excluded as well.RESULTS Ninety-five fractures from ninety-two patients were included in the study and consists of three groups.These three groups are length unstable fractures treated with FIMN(n=21),length stable fractures treated with FIMN(n=45),and length unstable fractures treated with either locked IMN,SMP,or external fixator(n=29).P values<0.05 were considered statistically significant.Patient characteristic differences that were statistically significant between the groups,length unstable with FIMN and length unstable with locked IMN,SMP,or external fixator,were average age(7.4 years vs 9.3 years,respectively),estimated blood loss(29.2 mL vs 98 mL,respectively)and body mass(27.8 kg vs 35.1 kg,respectively).All other patient characteristic differences were statistically insignificant.Regarding complications,length unstable with FIMN had 9 total complications while length unstable with locked IMN,SMP,or external fixator had 10.Grouping these complications into minor or major,length unstable with locked IMN,SMP,or external fixator had 6 major complication while length unstable with FIMN had 0 major complications.This difference in major complications was statistically significant.Lastly,when comparing patient characteristics between the groups,length unstable with FIMN and length stable with FIMN,all characteristics were statistically similar except time to weight bearing(39 d vs 29 d respectively).When analyzing complication differences between these two groups(9 total complications,0 major vs 20 total complications,4 major),the complication rates were considered statistically similar.CONCLUSION FIMN is effective for length unstable fractures,having a low rate of complications.FIMN is a suitable option for length stable and length unstable femur fractures alike.

Waders(Scolopacidae)surviving despite malaligned leg fractures in the wild:kinematics of bipedal locomotion

Background: Bone fracture frequencies and survival rates are essential parameters in skeleton evolution, but information on the functional consequences of naturally healed fractures is scarce. No leg bone fracture healing in the wild has been reported so far from long-legged Charadriiformes(waders), which depend on bipedal locomotion for feeding.Methods: We documented a healed but malaligned tarsometatarsus fracture in a wild Willet(Tringa [Catoptrophorus]semipalmata), and a malaligned tibiotarsus fracture in a Curlew(Numenius arquata) skeleton from a museum collection. Functional consequences of the malalignments were evaluated by kinematic analyses of videos(Willet) and in silico 3D modeling(Curlew).Results: The Willet's left tarsometatarsus exhibited an angular malalignment of 70°, resulting in a limping gait that was less pronounced at high than at low walking speed. The bird seemed unable to club the toes of the left foot together, apparently a secondary effect of the deformity. The Curlew's tibiotarsus showed an angular and an axial malalignment, causing the foot to rotate outwards when the intertarsal joint was flexed. Despite the severe effects of their injuries, the birds had survived at least long enough for the fractures to heal completely.Conclusions: Somewhat unexpectedly, leg fractures are not necessarily fatal in long-legged waders, even if deformities occur in the healing process. Bipedal locomotion on vegetated grounds must have been impeded due to the bone malalignments in both analyzed cases. The birds probably alleviated the impact of their handicaps by shifting a larger proportion of their activities to vegetation-free habitats.

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.

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.

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.

鼻内镜下同期行鼻骨骨折复位加鼻中隔创伤处理

鼻骨骨折是耳鼻咽喉科最为常见的外伤之一。随着鼻内镜及螺旋CT三维重建的应用,鼻骨骨折的诊断已经不局限于外鼻畸形,鼻中隔骨折、鼻中隔软骨脱位、鼻中隔血肿等原因所致的鼻中隔严重偏曲常合并存在,这就使得同期改善鼻腔的通气引流成为必须。我科于2001年7月-2010年11月，对25例鼻骨骨折同时伴有鼻中隔偏曲患者行鼻骨骨折复位并同期处理鼻中隔创伤，效果满意，报道如下。

形状记忆合金环抱器在骨折中的应用(英文)

Objective:To evaluate the effect of encircled fixer of shape memory alloy on bone fracture. Methods:A total of twenty patients with eighteen males and two females was studied. There were three patients with fractares in the upper one third of thighbone, five with fractures in the middle part of thighbone, six with humeral fractures, three with collarbone fractures,one with ulna fracture and two with thighbone fractures as complication of artificial hipbone arthroplasty. After exposure and fixation of fracture ends, prepared encircled fixer was inserted into 0～4℃ normal reline(NS) to lower its temperature, then pulled out with a clamp. Encircled fixer was put on the tersile side of the fractured bone(center pointed to fracture line), restored and stabilized after raising temperature in 40℃ NS. Results: Encircled fixers of shape memory alloy were used to treat twenty patients with bone fracture.Clinical concrescence was obtained in 1.5 to 3 months after operation,and the joint gained its normal function without complication. Conclusion:Encircled fixer of shape memory alloy has features as exerting vertical pressure continoulsy, little stress shield effect and convenient manipulation, especially adapt to stem fracture after artificial arthroplasty.

Experimental Study and Preliminary Clinical Application of Miniinvasive Percutaneous Internal Screw Fixation for Scaphoid Fracture under the Guidance of a 3D-printed Guide Plate

This study explored the feasibility of employing computer-aided design(CAD)and 3 dimensional(3D)-printed personalized guide plate for the mini-invasive percutaneous internal screw fixation of fractured scaphoid.The study consisted of two parts:(1)experimentation on upper limbs from corpses and(2)preliminary clinical application.Corpse experiments involved upper limbs of 6 adult corpses.The specimens of upper limbs were subjected to plain CT scan.Then the CT data were input into computer to conduct 3D reconstruction of wrist region.The direction and depth of the guide wire and screw were designed on the basis of the principle that screw should lie at the center of scaphoid and the long axis of the screw should be aligned with that of the scaphoid.The carpal bone model and the guide plate were designed and 3D-printed.By using the guide plates,the guide wire was placed and the cannulated compression screw was inserted.The wrist region was examined by X-ray and CT to observe the location of the screw in the scaphoid.The scaphoid was longitudinally excised to grossly observe the location and evaluate the result of screw insertion.For clinical application,the guide plate was employed in 4 patients with fresh scaphoid fracture using the aforementioned operative technique.Our results showed that,in the 6 corpse limbs,the guide plate well fitted the skin surface and the guide wire and screw were accurately put in place in one session.X-ray examination and gross observation confirmed that the screw was satisfactorily positioned and the result met the requirements of the preoperative design.For 4 patients,the guide wire and screw were all precisely inserted into place in one session.The operation time and X-ray exposure times were apparently reduced.The imaging examination exhibited satisfactory results and the hand functioned well.It was concluded that the operative guide plate used for the mini­invasive percutaneous internal screw fixation of fractured scaphoid not only can assist in accurate placement of screw but also shorten operation time and reduce insertion and X-ray exposure times,thereby reducing the radiation injury and damage to the substance and the blood circulation of carpal bone.Its use can also improve the learning curve of surgeons.