BACKGROUND Pedicle screw instrumentation is a critical technique in spinal surgery,offering effective stabilization for various spinal conditions.However,the impact of intraoperative imaging quality—specifically the ...BACKGROUND Pedicle screw instrumentation is a critical technique in spinal surgery,offering effective stabilization for various spinal conditions.However,the impact of intraoperative imaging quality—specifically the use of both anteroposterior(AP)and lateral views—on surgical outcomes remains insufficiently studied.Evaluating whether the adequacy of these imaging modalities affects the risk of unplanned returns to theatre(URTT)within 90 days due to screw malplacement is essential for refining surgical practices and improving patient care.AIM To evaluate how intraoperative imaging adequacy influences unplanned returnto-theatre rates,focusing on AP and lateral fluoroscopic views.METHODS This retrospective cohort study analyzed 1335 patients who underwent thoracolumbar and sacral pedicle screw instrumentation between January 2013 and December 2022.Data on intraoperative imaging adequacy,screw placement,and URTT events were collected and statistically analyzed using IBM SPSS v23.Imaging adequacy was assessed based on the presence of both AP and lateral views,and outcomes were compared between imaging groups.RESULTS A total of 9016 pedicle screws were inserted,with 82 screws identified as malplaced in 52 patients.Of these,46 patients required URTT due to screw malplacement,with 37 returning within 90 days(URTT90).Patients with both AP and lateral imaging saved intraoperatively had significantly lower URTT90 rates compared to those with only lateral imaging saved,demonstrating the critical role of imaging adequacy in improving surgical outcomes.CONCLUSION This study underscores that comprehensive intraoperative imaging with both AP and lateral views reduces unplanned returns,improves outcomes,enhances precision,and offers a cost-effective approach for better spinal surgery results.展开更多
BACKGROUND Bioabsorbable interference screws are a widely used option for graft fixation in anterior cruciate ligament(ACL)reconstruction.Their ability to degrade over time and avoid secondary hardware removal makes t...BACKGROUND Bioabsorbable interference screws are a widely used option for graft fixation in anterior cruciate ligament(ACL)reconstruction.Their ability to degrade over time and avoid secondary hardware removal makes them advantageous.However,complications such as breakage and intra-articular migration of screws can cause significant clinical issues,including joint pain,swelling,and cartilage damage.Early diagnosis and management are critical in such cases.CASE SUMMARY A 26-year-old male presented with knee pain and swelling one year after ACL reconstruction using a hamstring graft and bioabsorbable tibial interference screw.The patient had been engaged in rigorous physical activity as part of military training.Clinical examination revealed mild effusion without instability,and imaging showed screw breakage with intra-articular migration.Therapeutic arthroscopy confirmed intact graft tension,and broken screw fragments were removed successfully.The patient resumed normal activity two weeks after surgery.CONCLUSION This case highlights the potential complications associated with bioabsorbable screws,emphasizing the need for meticulous surgical technique,postoperative monitoring,and timely intervention.A comprehensive review of the literature illustrates the mechanisms,risk factors,and preventive strategies associated with screw-related complications.展开更多
BACKGROUND Retrograde pubic ramus screw placement is an effective technique but requires substantial surgical expertise and specialized equipment.The management of osteoporotic anterior pelvic ring injuries remains ch...BACKGROUND Retrograde pubic ramus screw placement is an effective technique but requires substantial surgical expertise and specialized equipment.The management of osteoporotic anterior pelvic ring injuries remains challenging due to technical difficulties and a high risk of complications.AIM To introduce a novel and simplified surgical approach that utilizes a custom-designed handheld pelvic alignment guide(HPAG)in combination with a 6.0 mm hollow screw,aiming to enhance the accuracy,efficiency,and safety of retrograde pubic ramus screw fixation in osteoporotic pelvic fragility fractures.METHODS The HPAG and 6.0 mm hollow screw were employed during surgical treatment.A 2.0-3.0 cm incision was made to expose the optimal screw entry point.Intraop-erative pelvic inlet and obturator oblique views were used to monitor fracture reduction and guide screw insertion.Clinical outcomes and fracture reduction quality were evaluated using Matta,visual analog scale,and Majeed scores during follow-ups.A representative case is presented to demonstrate the surgical procedure in detail.RESULTS No perioperative complications were observed.The mean operative time was 35.2±6.97 minutes,with a screw insertion time of 7.25±1.86 minutes,an average incision length of 2.8±0.67 cm,and mean blood loss of 43.25±15.64 mL.At one-year follow-up,seven patients achieved excellent Majeed scores and three achieved good scores.CONCLUSION No perioperative complications were observed.The mean operative time was 35.2±6.97 minutes,with a screw insertion time of 7.25±1.86 minutes,an average incision length of 2.8±0.67 cm,and mean blood loss of 43.25±15.64 mL.At one-year follow-up,seven patients achieved excellent Majeed scores and three achieved good scores.展开更多
BACKGROUND Comminuted calcaneal fractures present significant treatment challenges.Open reduction and internal fixation carries risks such as infection and skin necrosis,while minimally invasive techniques may comprom...BACKGROUND Comminuted calcaneal fractures present significant treatment challenges.Open reduction and internal fixation carries risks such as infection and skin necrosis,while minimally invasive techniques may compromise reduction stability.Conservative management is generally limited to minimally displaced fractures.Traditional Chinese manual bone-setting has a long history in fracture treatment and is renowned globally for achieving functional reduction.It offers distinct advantages including lower cost,minimal soft tissue trauma,and the avoidance of expensive reduction equipment or internal fixation materials.CASE SUMMARY A 60-year-old female presented with left foot pain and limited mobility following a fall.Computed tomography scan revealed a Sanders type IV calcaneal fracture with a Böhler angle of 0°.A standardized,stepwise Traditional Chinese manual bone-setting was initially performed,followed by percutaneous screw fixation through several mini-incisions after satisfactory alignment was confirmed under fluoroscopy.The Visual Analog Scale score decreased from 5 on postoperative day 1 to 3 by day 3.The American Orthopaedic Foot and Ankle Society score improved from 73 at 6 weeks to 90 at 3 months,indicating rapid functional recovery and high patient satisfaction.At 7 months postoperatively,the American Orthopaedic Foot and Ankle Society score reached 95,prompting removal of internal fixation.At the 6-year follow-up,reduction remained well maintained,with the Böhler angle preserved at 22°.CONCLUSION The combination of Traditional Chinese manual bone-setting and percutaneous screw fixation achieved satisfactory functional reduction for comminuted calcaneal fractures.展开更多
The aim of this study was to assess the potential of surgical guides as a complementary tool to augmented reality(AR)in enhancing the safety and precision of pedicle screw placement in spinal surgery.Four trainers wer...The aim of this study was to assess the potential of surgical guides as a complementary tool to augmented reality(AR)in enhancing the safety and precision of pedicle screw placement in spinal surgery.Four trainers were divided into the AR navigation group using surgical guides and the free-hand group.Each group consisted of a novice and an experienced spine surgeon.A total of 80 pedicle screws were implanted.First,the AR group reconstructed the 3D model and planned the screw insertion route according to the computed tomography data of L2 lumbar vertebrae.Then,the Microsoft HoloLens™2 was used to identify the vertebral model,and the planned virtual path was superimposed on the real cone model.Next,the screw was placed according to the projected trajectory.Finally,Micron Tracker was used to measure the deviation of screws from the preoperatively planned trajectory,and pedicle screws were evaluated using the Gertzbein-Robbins scale.In the AR group,the linear deviations of the experienced doctor and the novice were(1.59±0.39)mm and(1.73±0.52)mm respectively,and the angle deviations were 2.72°±0.61°and 2.87°±0.63°respectively.In the free-hand group,the linear deviations of the experienced doctor and the novice were(2.88±0.58)mm and(5.25±0.62)mm respectively,and the angle deviations were 4.41°±1.18°and 7.15°±1.45°respectively.Both kinds of deviations between the two groups were significantly different(P<0.05).The screw accuracy rate was 95%in the AR navigation group and 77.5%in the free-hand group.The results of this study indicate that the integration of surgical guides and AR is an innovative technique that can substantially enhance the safety and precision of spinal surgery and assist inexperienced doctors in completing the surgery.展开更多
Objective To compare the clinical outcomes of retrograde pubic ramus intramedullary nail(RPRIN)and percutaneous cannulated screw(PCS)in the treatment of anterior pelvic ring fractures(APRFs).Methods This retrospective...Objective To compare the clinical outcomes of retrograde pubic ramus intramedullary nail(RPRIN)and percutaneous cannulated screw(PCS)in the treatment of anterior pelvic ring fractures(APRFs).Methods This retrospective cohort study included 45 patients with APRFs treated between February 2019 and October 2022 in our trauma center.Patients were divided into two groups based on the surgical method:20 received RPRIN fixation,and 25 received PCS fixation.Key variables including operation time,fluoroscopic time,blood loss,and postoperative complications were analyzed.Fracture reduction quality was assessed using the Matta score system,and pelvic functional recovery was evaluated using the Majeed score system at the final follow-up.Quantitative variables were compared using the independent sample t test,while categorical variables were analyzed using Chisquare and Fisher’s exact tests.Results The RPRIN group had significantly shorter operation time(36.3±5.6 min vs.49.5±6.9 min,P<0.01),fluoroscopic time(32.0±2.8 s vs.48.4±3.6 s,P<0.01),and less blood loss(20.4±7.6 mL vs.34.0±5.7 mL,P<0.01)than the PCS group.Fracture reduction quality(Matta outcome)and pelvic functional recovery(Majeed outcome)were comparable between the two groups(P>0.05).No significant complications were reported in either group.Conclusions Both RPRIN and PCS are effective for treating APRFs.However,RPRIN offers distinct advantages by reducing operation time,fluoroscopic time,and blood loss,making it a more efficient and less invasive option.Further multicenter studies and biomechanical analyses are warranted to confirm these findings.展开更多
Objective:To observe and study the actual effects of percutaneous pedicle screw minimally invasive surgery in the treatment of spinal fractures and its impact on spinal function.Methods:This study included 48 patients...Objective:To observe and study the actual effects of percutaneous pedicle screw minimally invasive surgery in the treatment of spinal fractures and its impact on spinal function.Methods:This study included 48 patients with spinal fractures admitted between May 2023 and May 2024.The patients were divided into a control group and an experimental group based on treatment differences,with 24 patients in each group.The control group underwent open internal fixation surgery,while the experimental group received percutaneous pedicle screw minimally invasive surgery.Clinical index improvements,cervical dysfunction index,Japanese Orthopaedic Association scores,and pain level improvements were compared between the two groups.Results:The intraoperative blood loss,incision length,operation time,and hospitalization duration in the experimental group were(88.63±18.85),(6.32±1.05),(73.42±4.05),and(12.58±2.56),respectively,compared to(279.95±17.32),(12.89±1.36),(89.93±4.79),and(22.41±2.87)in the control group.Significant differences were observed between the groups,with the experimental group showing superior improvements across all metrics(P<0.05).Conclusion:Percutaneous pedicle screw minimally invasive surgery shows more significant effects in treating spinal fractures,particularly in improving cervical and lumbar spine function,enhancing treatment efficacy and safety,reducing pain levels,and shortening recovery time.Clinical application and promotion are recommended.展开更多
BACKGROUND The pedicle screw technique is widely employed for vertebral body fixation in the treatment of spinal disorders.However,traditional screw placement methods require the dissection of paraspinal muscles and t...BACKGROUND The pedicle screw technique is widely employed for vertebral body fixation in the treatment of spinal disorders.However,traditional screw placement methods require the dissection of paraspinal muscles and the insertion of pedicle screws at specific transverse section angles(TSA).Larger TSA angles require more force to pull the muscle tissue,which can increase the risk of surgical trauma and ischemic injury to the lumbar muscles.AIM To study the feasibility of zero-degree TSA vertical pedicle screw technique in the lumbosacral segment.METHODS Finite element models of vertebral bodies and pedicle screw-rod systems were established for the L4-S1 spinal segments.A standard axial load of 500 N and a rotational torque of 10 N/m were applied.Simulated screw pull-out experiment was conducted to observe pedicle screw resistance to pull-out,maximum stress,load-displacement ratio,maximum stress in vertebral bodies,load-displacement ratio in vertebral bodies,and the stress distribution in pedicle screws and vertebral bodies.Differences between the 0-degree and 17-degree TSA were compared.RESULTS At 0-degree TSA,the screw pull-out force decreased by 11.35%compared to that at 17-degree TSA(P<0.05).At 0-degree and 17-degree TSA,the stress range in the screw-rod system was 335.1-657.5 MPa and 242.8-648.5 MPa,separately,which were below the fracture threshold for the screw-rod system(924 MPa).At 0-degree and 17-degree TSA,the stress range in the vertebral bodies was 68.45-78.91 MPa and 39.08-72.73 MPa,separately,which were below the typical bone yield stress range for vertebral bodies(110-125 MPa).At 0-degree TSA,the load-displacement ratio for the vertebral bodies and pedicle screws was slightly lower compared to that at 17-degree TSA,indicating slightly lower stability(P<0.05).CONCLUSION The safety and stability of 0-degree TSA are slightly lower,but the risks of screw-rod system fracture,vertebral body fracture,and rupture are within acceptable limits.展开更多
BACKGROUND Among the most frequent hip fractures are trochanteric fractures,which usually occur from low-energy trauma like minor falls,especially in older people with osteoporotic bones.AIM To evaluate the treatment ...BACKGROUND Among the most frequent hip fractures are trochanteric fractures,which usually occur from low-energy trauma like minor falls,especially in older people with osteoporotic bones.AIM To evaluate the treatment efficacy of dynamic condylar screws(DCS)and proximal femoral nails(PFN)for unstable intertrochanteric fractures.METHODS To find pertinent randomized controlled trials and retrospective observational studies comparing PFN with DCS for the management of unstable femoral intertrochanteric fractures,a thorough search was carried out.For research studies published between January 1996 and April 2024,PubMed,EMBASE,Scopus,Web of Science,Cochrane Library,and Google Scholar were all searched.The complete texts of the papers were retrieved,vetted,and independently examined by two investigators.Disputes were settled by consensus,and any disagreements that persisted were arbitrated by a third author.RESULTS This study included six articles,comprising a total of 173 patients.Compared to the DCS,the PFN had a shorter operation time[mean difference(MD):-41.7 min,95%confidence interval(95%CI):-63.04 to-20.35,P=0.0001],higher success rates with closed reduction techniques[risk ratio(RR):34.05,95%CI:11.12-104.31,P<0.00001],and required less intraoperative blood transfusion(MD:-1.4 units,95%CI:-1.80 to-1.00,P<0.00001).Additionally,the PFN showed shorter fracture union time(MD:-6.92 wk,95%CI:-10.27 to-3.57,P<0.0001)and a lower incidence of reoperation(RR:0.37,95%CI:0.17-0.82,P=0.01).However,there was no discernible variation regarding hospital stay,implant-related complications,and infections.CONCLUSION Compared to DCS,PFN offers shorter operative times,reduces the blood transfusions requirements,achieves higher closed reduction success,enables faster fracture healing,and lowers reoperation incidence.展开更多
Bone screws are devices used to fix implants or bones to bones.However,conventional screws are mechanically fixed with thread and often face long-term failure due to poor osseointegration.To improve osseointegration,s...Bone screws are devices used to fix implants or bones to bones.However,conventional screws are mechanically fixed with thread and often face long-term failure due to poor osseointegration.To improve osseointegration,screws are evolving from solid and smooth to porous and rough.Additive manufacturing(AM)offers a high degree of manufacturing freedom,enabling the preparation of predesigned screws that are porous and rough.This paper provides an overview of the problems currently faced by bone screws:long-term loosening and screw breakage.Next,advances in osseointegrated screws are summarized hierarchically(sub-micro,micro,and macro).At the sub-microscale level,we describe surface-modification techniques for enhancing osseointegration.At the micro level,we summarize the micro-design parameters that affect the mechanical and biological properties of porous osseointegrated screws,including porosity,pore size,and pore shape.In addition,we highlight three promising pore shapes:triply periodic minimal surface,auxetic structure with negative Poisson ratio,and the Voronoi structure.At the macro level,we outline the strategies of graded design,gradient design,and topology optimization design to improve the mechanical strength of porous osseointegrated screws.Simultaneously,this paper outlines advances in AM technology for enhancing the mechanical properties of porous osseointegrated screws.AM osseointegrated screws with hierarchical design are expected to provide excellent long-term fixation and the required mechanical strength.展开更多
The horizontal bearing capacity of the screw pile and monopile was analyzed by model tests.Results showed that the horizontal bearing capacity of the screw pile was significantly greater than that of the monopile unde...The horizontal bearing capacity of the screw pile and monopile was analyzed by model tests.Results showed that the horizontal bearing capacity of the screw pile was significantly greater than that of the monopile under the same loading conditions.With the increase in horizontal loading speed,the ultimate horizontal bearing capacity of the two piles also increases,and the difference decreases gradually.Moreover,the influence of vertical loading on the horizontal bearing capacity of screw pile and monopile is studied at the horizontal loading speed of 2 mm s-1.The findings indicate that vertical load evidently affects the horizontal bearing capacity of common piles,but slightly influences the horizontal bearing capacity of screw piles.展开更多
Objective:Robot-assisted pedicle screw insertion has recently emerged as an alternative to the traditional free-hand technique.However,discrepancies in the accuracy of screw placement between the 2 methods have been h...Objective:Robot-assisted pedicle screw insertion has recently emerged as an alternative to the traditional free-hand technique.However,discrepancies in the accuracy of screw placement between the 2 methods have been highlighted by some comparative studies.This meta-analysis was conducted to synthesize evidence comparing these techniques.Methods:Searches were conducted in 5 electronic databases adhering to specific eligibility criteria for randomized and observational studies.The data were analyzed using RevMan software and the results are presented as odds ratios(ORs),mean differences,or standard mean differences(SMDs)with 95%confidence intervals(CIs).Our analysis included 12 studies(7 randomized trials and 5 observational studies,involving 883 patients and 4903 screws).Results:The results demonstrated a higher rate of Grade A Gertzbein and Robbins pedicle placement score(OR:1.77;95%CI:1.10e2.87),a lower rate of revision surgeries(OR:0.21;95%CI:0.09e0.52),and a shorter radiation exposure duration(SMD?1.38,95%CI:2.32 to0.44)in the robot-assisted group compared with the free-hand group.Nonetheless,the length of hospital stay,volume of intraoperative blood loss,postoperative visual analogue scale scores for back pain,and rate of wound infection were similar between the 2 groups.Significant heterogeneity was observed in some outcomes.Conclusion:Compared with the free-hand method,the robot-assisted technique provides greater accuracy and reduced radiation exposure.The efficacy of the robot-assisted technique is expected to improve further as experience with its use in surgery grows.展开更多
We are developing a speed reducer that can be considered a transformation of a worm gear reducer: the worm is replaced by an inverted roller screw, and the gear is replaced by a threaded chain drive. This configuratio...We are developing a speed reducer that can be considered a transformation of a worm gear reducer: the worm is replaced by an inverted roller screw, and the gear is replaced by a threaded chain drive. This configuration lessens wear, increases load capacity, and improves efficiency. The threaded chain consists of nut-shaped links. This paper presents the results of tests carried out on a prototype with a reduction ratio of 46.展开更多
Objective: To evaluate the radiological and functional results of patients treated with dynamic screw plates (DHS) for trochanteric fractures in the Orthopedics-Traumatology Department of the Donka National Hospital. ...Objective: To evaluate the radiological and functional results of patients treated with dynamic screw plates (DHS) for trochanteric fractures in the Orthopedics-Traumatology Department of the Donka National Hospital. Methodology: This was a five (05)-year continuous retrospective study from January 1, 2019, to December 31, 2023. We used the Watson-Jones pathway without an image intensifier. Patients were evaluated according to the Postel-Merle D’Aubigné evaluation criteria. Results: A total of 25 trochanteric fractures were recorded. The patients were 16 men and 9 women, with a sex ratio of 1.77 and an average age of 63.5 years, with extremes of 31 and 96 years. The average fracture management time was 4.04 days. Etiologies were dominated by road traffic accidents (52.00%), followed by domestic accidents (falls) (44.00%). Merchants and housewives were the most affected (32.00%). According to the Ender classification, type III fractures (n = 15;60.00%) were the most common, followed by type VII (n = 4;16.00%). The procedure was performed 23 times (92.00%) under spinal anesthesia, 2 times (8.00%) under general anesthesia. The average hospital stay was 9.6 days. The mean operative time was 105.6 min, with extremes ranging from 90 to 120 min. The mean time to consolidation was 14.88 weeks, with extremes of twelve and twenty weeks. Comorbidities included hypertension and diabetes. The majority of patients (76.00%) had good anterior autonomy according to the Parker index. The mean index was 8.2 [standard deviation ±1.8]. We noted three cases of post-operative death (12.00%). We evaluated nineteen patients with a mean follow-up of 24 months, and the functional results according to Postel and Merle d’Aubigné scores were excellent in 42.10% (n = 8), good in 52.63% (n = 10), and fair in 5.2% (n = 1). Conclusion: The DHS dynamic screw-plate has enabled us to achieve good radiological and functional results, enabling us to resume daily activities as quickly as possible. It appears to be a reliable solution for trochanteric fractures. It can be performed without an image intensifier, provided we are aware of its limitations.展开更多
For effective anterior cruciate ligament(ACL)reconstruction,an interference screw(IFS)is employed to force transplantation of the ligament into the bone tunnel.In this study,IFSs were successfully designed and pre-par...For effective anterior cruciate ligament(ACL)reconstruction,an interference screw(IFS)is employed to force transplantation of the ligament into the bone tunnel.In this study,IFSs were successfully designed and pre-pared,and the top tooth width,thread depth,and drive structure were parameterized with a forming accuracy of 80.0±21.1μm using SLA-3D printing technology.To improve the initial stability of ACL reconstruction,a biomechanical model was established,and the results were optimized through insertion torque and tensile test-ing.Consequently,the IFS with the top tooth width of 0.4 mm,thread depth of 0.8 mm,and hexagon drive,matching with theΦ8 mm bone tunnel,exhibits the best mechanical properties(maximum insertion torque of 1.064±0.117 N m,ultimate load of 446.126±37.632 N,stiffness of 66.33±27.48 N/mm).Additionally,the ZrO_(2)/PDA/RGD/Zn^(2+)bioactive coating was found to significantly improve the surface bioactivity of zirconia IFS.In conclusion,this study has significant implications for ACL reconstruction.展开更多
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 20...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.展开更多
Unifying the models for topology design and kinematic analysis has long been a desire for the research of parallel kinematic machines(PKMs). This requires that analytical description, formulation and operation for bot...Unifying the models for topology design and kinematic analysis has long been a desire for the research of parallel kinematic machines(PKMs). This requires that analytical description, formulation and operation for both finite and instantaneous motions are performed by the same mathematical tool. Based upon finite and instantaneous screw theory, a unified and systematic approach for topology design and kinematic analysis of PKMs is proposed in this paper. Using the derivative mapping between finite and instantaneous screws built in the authors’ previous work, the finite and instantaneous motions of PKMs are analytically described by the simple and non?redundant screws in quasi?vector and vector forms. And topological and parametric models of PKMs are algebraically formulated and related. These related topological and parametric models are ready to do type synthesis and kinematic analysis of PKMs under the unified framework of screw theory. In order to show the validity of the proposed approach, a kind of two?translational and three?rotational(2T3R)5?axis PKMs is taken as example. Numerous new structures of the 2T3R PKMs are synthe?sized as the results of topology design, and their Jacobian matrix is obtained easily for parameter optimization and performance evaluation. Some of the synthesized PKMs have outstanding capabilities in terms of large workspaces and flexible orientations, and have great potential for industrial applications of machining and manufacture. Among them, METROM PKM is a typical example which has attracted a lot of attention from global companies and already been developed as commercial products. The approach is a general and unified approach that can be used in the innovative design of different kinds of PKMs.展开更多
The 3 D non isothermal flow of non Newtonian viscous polymer melt in a co rotating twin screw extruder is modeled. The distributions of the velocity, temperature, pressure and the viscous dissipation in the fl...The 3 D non isothermal flow of non Newtonian viscous polymer melt in a co rotating twin screw extruder is modeled. The distributions of the velocity, temperature, pressure and the viscous dissipation in the flow domain are presented by using a fluid dynamics analysis package (Polyflow). The numerical results show that the temperatures are high in the intermeshing region and on the screw surface, the maximum pressure and the minimum pressure occur in the intermeshing region, and the flow rate is almost proportional to the screw speed.展开更多
COREX shaft furnace（SF）is a typical screw feeder with a storage container coupled with eight screw casings and screws.The structure of screw casing plays an important role in the moving behavior of burdens,stress di...COREX shaft furnace（SF）is a typical screw feeder with a storage container coupled with eight screw casings and screws.The structure of screw casing plays an important role in the moving behavior of burdens,stress distribution,abrasive wear of screws,and energy consumption during the operation of SF.Therefore,a three-dimensional semi-cylindrical model of actual size of COREX-3000 SF was established based on discrete element method to investigate the influences of screw casing structure.The results show that the increase in the gap between the outside of screw flight and screw casing is beneficial for the smooth operation of SF,resulting in uniform descending velocity along the radius of SF in the lower part,decreasing the size of recirculation region,and alleviating stress concentration in the screw casing.Moreover,raising the gap appropriately is also beneficial to weaken screw abrasive wear,decrease energy consumption,and then prolong the service life of the screws.However,enlarging the gap also leads to more undesired high temperature reduction gas into the SF from melter gasifier,thereby deteriorating the operation of SF.Thus,an ideal distance exists between the outside of the screw flight and the screw casing,which is suggested to be equal to the average of particle diameter.展开更多
BACKGROUND Whether it’s better to adopt unilateral pedicle screw(UPS)fixation or to use bilateral pedicle screw(BPS)one for lumbar degenerative diseases is still controversially undetermined.AIM To make a comparison ...BACKGROUND Whether it’s better to adopt unilateral pedicle screw(UPS)fixation or to use bilateral pedicle screw(BPS)one for lumbar degenerative diseases is still controversially undetermined.AIM To make a comparison between UPS and BPS fixation as to how they work efficaciously and safely in patients suffering from lumbar degenerative diseases.METHODS We have searched a lot in the databases through 2020 with index terms such as“unilateral pedicle screw fixation”and“bilateral pedicle screw fixation.”Only randomized controlled trials and some prospective cohort studies could be found,yielding 15 studies.The intervention was unilateral pedicle screw fixation;Primarily We’ve got outcomes of complications and fusion rates.Secondarily,we’ve achieved outcomes regarding total blood loss,operative time,as well as length of stay.Softwares were installed and utilized for subgroup analysis,analyzing forest plots,sensitivity,heterogeneity,forest plots,publication bias,and risk of bias.RESULTS Fifteen previous cases of study including 992 participants have been involved in our meta-analysis.UPS had slightly lower effects on fusion rate[relative risk(RR)=0.949,95%CI:0.910 to 0.990,P=0.015],which contributed mostly to this metaanalysis,and similar complication rates(RR=1.140,95%CI:0.792 to 1.640,P=0.481),Δvisual analog scale[standard mean difference(SMD)=0.178,95%CI:-0.021 to 0.378,P=0.080],andΔOswestry disability index(SMD=-0.254,95%CI:-0.820 to 0.329,P=0.402).In contrast,an obvious difference has been observed inΔJapanese Orthopedic Association(JOA)score(SMD=0.305,95%CI:0.046 to 0.563,P=0.021),total blood loss(SMD=-1.586,95%CI:-2.182 to-0.990,P=0.000),operation time(SMD=-2.831,95%CI:-3.753 to-1.909,P=0.000),and length of hospital stay(SMD=-0.614,95%CI:-1.050 to-0.179,P=0.006).CONCLUSION Bilateral fixation is more effective than unilateral fixation regarding fusion rate after lumbar interbody fusion.However,JOA,operation time,total blood loss,as well as length of stay were improved for unilateral fixation.展开更多
文摘BACKGROUND Pedicle screw instrumentation is a critical technique in spinal surgery,offering effective stabilization for various spinal conditions.However,the impact of intraoperative imaging quality—specifically the use of both anteroposterior(AP)and lateral views—on surgical outcomes remains insufficiently studied.Evaluating whether the adequacy of these imaging modalities affects the risk of unplanned returns to theatre(URTT)within 90 days due to screw malplacement is essential for refining surgical practices and improving patient care.AIM To evaluate how intraoperative imaging adequacy influences unplanned returnto-theatre rates,focusing on AP and lateral fluoroscopic views.METHODS This retrospective cohort study analyzed 1335 patients who underwent thoracolumbar and sacral pedicle screw instrumentation between January 2013 and December 2022.Data on intraoperative imaging adequacy,screw placement,and URTT events were collected and statistically analyzed using IBM SPSS v23.Imaging adequacy was assessed based on the presence of both AP and lateral views,and outcomes were compared between imaging groups.RESULTS A total of 9016 pedicle screws were inserted,with 82 screws identified as malplaced in 52 patients.Of these,46 patients required URTT due to screw malplacement,with 37 returning within 90 days(URTT90).Patients with both AP and lateral imaging saved intraoperatively had significantly lower URTT90 rates compared to those with only lateral imaging saved,demonstrating the critical role of imaging adequacy in improving surgical outcomes.CONCLUSION This study underscores that comprehensive intraoperative imaging with both AP and lateral views reduces unplanned returns,improves outcomes,enhances precision,and offers a cost-effective approach for better spinal surgery results.
文摘BACKGROUND Bioabsorbable interference screws are a widely used option for graft fixation in anterior cruciate ligament(ACL)reconstruction.Their ability to degrade over time and avoid secondary hardware removal makes them advantageous.However,complications such as breakage and intra-articular migration of screws can cause significant clinical issues,including joint pain,swelling,and cartilage damage.Early diagnosis and management are critical in such cases.CASE SUMMARY A 26-year-old male presented with knee pain and swelling one year after ACL reconstruction using a hamstring graft and bioabsorbable tibial interference screw.The patient had been engaged in rigorous physical activity as part of military training.Clinical examination revealed mild effusion without instability,and imaging showed screw breakage with intra-articular migration.Therapeutic arthroscopy confirmed intact graft tension,and broken screw fragments were removed successfully.The patient resumed normal activity two weeks after surgery.CONCLUSION This case highlights the potential complications associated with bioabsorbable screws,emphasizing the need for meticulous surgical technique,postoperative monitoring,and timely intervention.A comprehensive review of the literature illustrates the mechanisms,risk factors,and preventive strategies associated with screw-related complications.
基金Supported by Shanghai Tongren Hospital,Shanghai Jiaotong University School of Medicine,No.TRYJ2024 LC16the National Natural Science Foundation of China,No.82102577the Laboratory Open Fund of Key Technology and Materials in Minimally Invasive Spine Surgery,No.2024JZWC-YBA05.
文摘BACKGROUND Retrograde pubic ramus screw placement is an effective technique but requires substantial surgical expertise and specialized equipment.The management of osteoporotic anterior pelvic ring injuries remains challenging due to technical difficulties and a high risk of complications.AIM To introduce a novel and simplified surgical approach that utilizes a custom-designed handheld pelvic alignment guide(HPAG)in combination with a 6.0 mm hollow screw,aiming to enhance the accuracy,efficiency,and safety of retrograde pubic ramus screw fixation in osteoporotic pelvic fragility fractures.METHODS The HPAG and 6.0 mm hollow screw were employed during surgical treatment.A 2.0-3.0 cm incision was made to expose the optimal screw entry point.Intraop-erative pelvic inlet and obturator oblique views were used to monitor fracture reduction and guide screw insertion.Clinical outcomes and fracture reduction quality were evaluated using Matta,visual analog scale,and Majeed scores during follow-ups.A representative case is presented to demonstrate the surgical procedure in detail.RESULTS No perioperative complications were observed.The mean operative time was 35.2±6.97 minutes,with a screw insertion time of 7.25±1.86 minutes,an average incision length of 2.8±0.67 cm,and mean blood loss of 43.25±15.64 mL.At one-year follow-up,seven patients achieved excellent Majeed scores and three achieved good scores.CONCLUSION No perioperative complications were observed.The mean operative time was 35.2±6.97 minutes,with a screw insertion time of 7.25±1.86 minutes,an average incision length of 2.8±0.67 cm,and mean blood loss of 43.25±15.64 mL.At one-year follow-up,seven patients achieved excellent Majeed scores and three achieved good scores.
基金Supported by Jin-Wen Liu Academic Experience Heritage Studio Special Fund of National Famous Traditional Chinese Medicine,No.75.
文摘BACKGROUND Comminuted calcaneal fractures present significant treatment challenges.Open reduction and internal fixation carries risks such as infection and skin necrosis,while minimally invasive techniques may compromise reduction stability.Conservative management is generally limited to minimally displaced fractures.Traditional Chinese manual bone-setting has a long history in fracture treatment and is renowned globally for achieving functional reduction.It offers distinct advantages including lower cost,minimal soft tissue trauma,and the avoidance of expensive reduction equipment or internal fixation materials.CASE SUMMARY A 60-year-old female presented with left foot pain and limited mobility following a fall.Computed tomography scan revealed a Sanders type IV calcaneal fracture with a Böhler angle of 0°.A standardized,stepwise Traditional Chinese manual bone-setting was initially performed,followed by percutaneous screw fixation through several mini-incisions after satisfactory alignment was confirmed under fluoroscopy.The Visual Analog Scale score decreased from 5 on postoperative day 1 to 3 by day 3.The American Orthopaedic Foot and Ankle Society score improved from 73 at 6 weeks to 90 at 3 months,indicating rapid functional recovery and high patient satisfaction.At 7 months postoperatively,the American Orthopaedic Foot and Ankle Society score reached 95,prompting removal of internal fixation.At the 6-year follow-up,reduction remained well maintained,with the Böhler angle preserved at 22°.CONCLUSION The combination of Traditional Chinese manual bone-setting and percutaneous screw fixation achieved satisfactory functional reduction for comminuted calcaneal fractures.
基金the National Natural Science Foundation of China(No.11502146)the 1 Batch of 2021 MOE of PRC Industry University Collaborative Education Program(No.202101042008)。
文摘The aim of this study was to assess the potential of surgical guides as a complementary tool to augmented reality(AR)in enhancing the safety and precision of pedicle screw placement in spinal surgery.Four trainers were divided into the AR navigation group using surgical guides and the free-hand group.Each group consisted of a novice and an experienced spine surgeon.A total of 80 pedicle screws were implanted.First,the AR group reconstructed the 3D model and planned the screw insertion route according to the computed tomography data of L2 lumbar vertebrae.Then,the Microsoft HoloLens™2 was used to identify the vertebral model,and the planned virtual path was superimposed on the real cone model.Next,the screw was placed according to the projected trajectory.Finally,Micron Tracker was used to measure the deviation of screws from the preoperatively planned trajectory,and pedicle screws were evaluated using the Gertzbein-Robbins scale.In the AR group,the linear deviations of the experienced doctor and the novice were(1.59±0.39)mm and(1.73±0.52)mm respectively,and the angle deviations were 2.72°±0.61°and 2.87°±0.63°respectively.In the free-hand group,the linear deviations of the experienced doctor and the novice were(2.88±0.58)mm and(5.25±0.62)mm respectively,and the angle deviations were 4.41°±1.18°and 7.15°±1.45°respectively.Both kinds of deviations between the two groups were significantly different(P<0.05).The screw accuracy rate was 95%in the AR navigation group and 77.5%in the free-hand group.The results of this study indicate that the integration of surgical guides and AR is an innovative technique that can substantially enhance the safety and precision of spinal surgery and assist inexperienced doctors in completing the surgery.
基金supported by Clinical Application-oriented Medical Innovation Foundation from National Clinical Research Center for Orthopedics,Sports Medicine&Rehabilitation and Jiangsu China-Israel Industrial Technical Research Institute Foundation(No.2021-NCRC-CXJJ-ZH-24)National Key R&D Plan of the 14th Five-Year Plan(No.2022YFC2504303).
文摘Objective To compare the clinical outcomes of retrograde pubic ramus intramedullary nail(RPRIN)and percutaneous cannulated screw(PCS)in the treatment of anterior pelvic ring fractures(APRFs).Methods This retrospective cohort study included 45 patients with APRFs treated between February 2019 and October 2022 in our trauma center.Patients were divided into two groups based on the surgical method:20 received RPRIN fixation,and 25 received PCS fixation.Key variables including operation time,fluoroscopic time,blood loss,and postoperative complications were analyzed.Fracture reduction quality was assessed using the Matta score system,and pelvic functional recovery was evaluated using the Majeed score system at the final follow-up.Quantitative variables were compared using the independent sample t test,while categorical variables were analyzed using Chisquare and Fisher’s exact tests.Results The RPRIN group had significantly shorter operation time(36.3±5.6 min vs.49.5±6.9 min,P<0.01),fluoroscopic time(32.0±2.8 s vs.48.4±3.6 s,P<0.01),and less blood loss(20.4±7.6 mL vs.34.0±5.7 mL,P<0.01)than the PCS group.Fracture reduction quality(Matta outcome)and pelvic functional recovery(Majeed outcome)were comparable between the two groups(P>0.05).No significant complications were reported in either group.Conclusions Both RPRIN and PCS are effective for treating APRFs.However,RPRIN offers distinct advantages by reducing operation time,fluoroscopic time,and blood loss,making it a more efficient and less invasive option.Further multicenter studies and biomechanical analyses are warranted to confirm these findings.
文摘Objective:To observe and study the actual effects of percutaneous pedicle screw minimally invasive surgery in the treatment of spinal fractures and its impact on spinal function.Methods:This study included 48 patients with spinal fractures admitted between May 2023 and May 2024.The patients were divided into a control group and an experimental group based on treatment differences,with 24 patients in each group.The control group underwent open internal fixation surgery,while the experimental group received percutaneous pedicle screw minimally invasive surgery.Clinical index improvements,cervical dysfunction index,Japanese Orthopaedic Association scores,and pain level improvements were compared between the two groups.Results:The intraoperative blood loss,incision length,operation time,and hospitalization duration in the experimental group were(88.63±18.85),(6.32±1.05),(73.42±4.05),and(12.58±2.56),respectively,compared to(279.95±17.32),(12.89±1.36),(89.93±4.79),and(22.41±2.87)in the control group.Significant differences were observed between the groups,with the experimental group showing superior improvements across all metrics(P<0.05).Conclusion:Percutaneous pedicle screw minimally invasive surgery shows more significant effects in treating spinal fractures,particularly in improving cervical and lumbar spine function,enhancing treatment efficacy and safety,reducing pain levels,and shortening recovery time.Clinical application and promotion are recommended.
基金the institutional review board of Mingzhou Hospital of Ningbo(No.202208501).
文摘BACKGROUND The pedicle screw technique is widely employed for vertebral body fixation in the treatment of spinal disorders.However,traditional screw placement methods require the dissection of paraspinal muscles and the insertion of pedicle screws at specific transverse section angles(TSA).Larger TSA angles require more force to pull the muscle tissue,which can increase the risk of surgical trauma and ischemic injury to the lumbar muscles.AIM To study the feasibility of zero-degree TSA vertical pedicle screw technique in the lumbosacral segment.METHODS Finite element models of vertebral bodies and pedicle screw-rod systems were established for the L4-S1 spinal segments.A standard axial load of 500 N and a rotational torque of 10 N/m were applied.Simulated screw pull-out experiment was conducted to observe pedicle screw resistance to pull-out,maximum stress,load-displacement ratio,maximum stress in vertebral bodies,load-displacement ratio in vertebral bodies,and the stress distribution in pedicle screws and vertebral bodies.Differences between the 0-degree and 17-degree TSA were compared.RESULTS At 0-degree TSA,the screw pull-out force decreased by 11.35%compared to that at 17-degree TSA(P<0.05).At 0-degree and 17-degree TSA,the stress range in the screw-rod system was 335.1-657.5 MPa and 242.8-648.5 MPa,separately,which were below the fracture threshold for the screw-rod system(924 MPa).At 0-degree and 17-degree TSA,the stress range in the vertebral bodies was 68.45-78.91 MPa and 39.08-72.73 MPa,separately,which were below the typical bone yield stress range for vertebral bodies(110-125 MPa).At 0-degree TSA,the load-displacement ratio for the vertebral bodies and pedicle screws was slightly lower compared to that at 17-degree TSA,indicating slightly lower stability(P<0.05).CONCLUSION The safety and stability of 0-degree TSA are slightly lower,but the risks of screw-rod system fracture,vertebral body fracture,and rupture are within acceptable limits.
文摘BACKGROUND Among the most frequent hip fractures are trochanteric fractures,which usually occur from low-energy trauma like minor falls,especially in older people with osteoporotic bones.AIM To evaluate the treatment efficacy of dynamic condylar screws(DCS)and proximal femoral nails(PFN)for unstable intertrochanteric fractures.METHODS To find pertinent randomized controlled trials and retrospective observational studies comparing PFN with DCS for the management of unstable femoral intertrochanteric fractures,a thorough search was carried out.For research studies published between January 1996 and April 2024,PubMed,EMBASE,Scopus,Web of Science,Cochrane Library,and Google Scholar were all searched.The complete texts of the papers were retrieved,vetted,and independently examined by two investigators.Disputes were settled by consensus,and any disagreements that persisted were arbitrated by a third author.RESULTS This study included six articles,comprising a total of 173 patients.Compared to the DCS,the PFN had a shorter operation time[mean difference(MD):-41.7 min,95%confidence interval(95%CI):-63.04 to-20.35,P=0.0001],higher success rates with closed reduction techniques[risk ratio(RR):34.05,95%CI:11.12-104.31,P<0.00001],and required less intraoperative blood transfusion(MD:-1.4 units,95%CI:-1.80 to-1.00,P<0.00001).Additionally,the PFN showed shorter fracture union time(MD:-6.92 wk,95%CI:-10.27 to-3.57,P<0.0001)and a lower incidence of reoperation(RR:0.37,95%CI:0.17-0.82,P=0.01).However,there was no discernible variation regarding hospital stay,implant-related complications,and infections.CONCLUSION Compared to DCS,PFN offers shorter operative times,reduces the blood transfusions requirements,achieves higher closed reduction success,enables faster fracture healing,and lowers reoperation incidence.
基金supported by the National Natural Science Foundation of China(Nos.82272504 and 82072456)the National Key R&D Program of China(No.2018YFB1105100)+4 种基金the Department of Science and Technology of Jilin Province,China(Nos.20200404202YY,20200403086SF,20210101321JC,20210204104YY,20200201453JC,20220204119YY,202201ZYTS131,202201ZYTS129,20220401084YY,202201ZYTS505,and YDZJ202301ZYTS076)the Department of Finance of Jilin Province,China(No.2020SCZT037)the Jilin Provincial Development and Reform Commission,China(Nos.2018C010 and 2022C043-5)the Interdisciplinary Integration and Cultivation Project of Jilin University(No.JLUXKJC2020307)the Central University Basic Scientific Research Fund(No.2023-JCXK-04).
文摘Bone screws are devices used to fix implants or bones to bones.However,conventional screws are mechanically fixed with thread and often face long-term failure due to poor osseointegration.To improve osseointegration,screws are evolving from solid and smooth to porous and rough.Additive manufacturing(AM)offers a high degree of manufacturing freedom,enabling the preparation of predesigned screws that are porous and rough.This paper provides an overview of the problems currently faced by bone screws:long-term loosening and screw breakage.Next,advances in osseointegrated screws are summarized hierarchically(sub-micro,micro,and macro).At the sub-microscale level,we describe surface-modification techniques for enhancing osseointegration.At the micro level,we summarize the micro-design parameters that affect the mechanical and biological properties of porous osseointegrated screws,including porosity,pore size,and pore shape.In addition,we highlight three promising pore shapes:triply periodic minimal surface,auxetic structure with negative Poisson ratio,and the Voronoi structure.At the macro level,we outline the strategies of graded design,gradient design,and topology optimization design to improve the mechanical strength of porous osseointegrated screws.Simultaneously,this paper outlines advances in AM technology for enhancing the mechanical properties of porous osseointegrated screws.AM osseointegrated screws with hierarchical design are expected to provide excellent long-term fixation and the required mechanical strength.
基金funded by the National Natural Science Foundation of China(No.51779171)。
文摘The horizontal bearing capacity of the screw pile and monopile was analyzed by model tests.Results showed that the horizontal bearing capacity of the screw pile was significantly greater than that of the monopile under the same loading conditions.With the increase in horizontal loading speed,the ultimate horizontal bearing capacity of the two piles also increases,and the difference decreases gradually.Moreover,the influence of vertical loading on the horizontal bearing capacity of screw pile and monopile is studied at the horizontal loading speed of 2 mm s-1.The findings indicate that vertical load evidently affects the horizontal bearing capacity of common piles,but slightly influences the horizontal bearing capacity of screw piles.
基金the Human Research Ethics Committee,Faculty of Medicine Ramathibodi Hospital,Mahidol University,IRB No.(COA.MURA2020/1934).
文摘Objective:Robot-assisted pedicle screw insertion has recently emerged as an alternative to the traditional free-hand technique.However,discrepancies in the accuracy of screw placement between the 2 methods have been highlighted by some comparative studies.This meta-analysis was conducted to synthesize evidence comparing these techniques.Methods:Searches were conducted in 5 electronic databases adhering to specific eligibility criteria for randomized and observational studies.The data were analyzed using RevMan software and the results are presented as odds ratios(ORs),mean differences,or standard mean differences(SMDs)with 95%confidence intervals(CIs).Our analysis included 12 studies(7 randomized trials and 5 observational studies,involving 883 patients and 4903 screws).Results:The results demonstrated a higher rate of Grade A Gertzbein and Robbins pedicle placement score(OR:1.77;95%CI:1.10e2.87),a lower rate of revision surgeries(OR:0.21;95%CI:0.09e0.52),and a shorter radiation exposure duration(SMD?1.38,95%CI:2.32 to0.44)in the robot-assisted group compared with the free-hand group.Nonetheless,the length of hospital stay,volume of intraoperative blood loss,postoperative visual analogue scale scores for back pain,and rate of wound infection were similar between the 2 groups.Significant heterogeneity was observed in some outcomes.Conclusion:Compared with the free-hand method,the robot-assisted technique provides greater accuracy and reduced radiation exposure.The efficacy of the robot-assisted technique is expected to improve further as experience with its use in surgery grows.
文摘We are developing a speed reducer that can be considered a transformation of a worm gear reducer: the worm is replaced by an inverted roller screw, and the gear is replaced by a threaded chain drive. This configuration lessens wear, increases load capacity, and improves efficiency. The threaded chain consists of nut-shaped links. This paper presents the results of tests carried out on a prototype with a reduction ratio of 46.
文摘Objective: To evaluate the radiological and functional results of patients treated with dynamic screw plates (DHS) for trochanteric fractures in the Orthopedics-Traumatology Department of the Donka National Hospital. Methodology: This was a five (05)-year continuous retrospective study from January 1, 2019, to December 31, 2023. We used the Watson-Jones pathway without an image intensifier. Patients were evaluated according to the Postel-Merle D’Aubigné evaluation criteria. Results: A total of 25 trochanteric fractures were recorded. The patients were 16 men and 9 women, with a sex ratio of 1.77 and an average age of 63.5 years, with extremes of 31 and 96 years. The average fracture management time was 4.04 days. Etiologies were dominated by road traffic accidents (52.00%), followed by domestic accidents (falls) (44.00%). Merchants and housewives were the most affected (32.00%). According to the Ender classification, type III fractures (n = 15;60.00%) were the most common, followed by type VII (n = 4;16.00%). The procedure was performed 23 times (92.00%) under spinal anesthesia, 2 times (8.00%) under general anesthesia. The average hospital stay was 9.6 days. The mean operative time was 105.6 min, with extremes ranging from 90 to 120 min. The mean time to consolidation was 14.88 weeks, with extremes of twelve and twenty weeks. Comorbidities included hypertension and diabetes. The majority of patients (76.00%) had good anterior autonomy according to the Parker index. The mean index was 8.2 [standard deviation ±1.8]. We noted three cases of post-operative death (12.00%). We evaluated nineteen patients with a mean follow-up of 24 months, and the functional results according to Postel and Merle d’Aubigné scores were excellent in 42.10% (n = 8), good in 52.63% (n = 10), and fair in 5.2% (n = 1). Conclusion: The DHS dynamic screw-plate has enabled us to achieve good radiological and functional results, enabling us to resume daily activities as quickly as possible. It appears to be a reliable solution for trochanteric fractures. It can be performed without an image intensifier, provided we are aware of its limitations.
基金supported by National Key Research and Development Program of China(Grant No.2022YFB4601400)Major Basic Research Projects of Shandong Province of China(Grant No.ZR2023ZD24).
文摘For effective anterior cruciate ligament(ACL)reconstruction,an interference screw(IFS)is employed to force transplantation of the ligament into the bone tunnel.In this study,IFSs were successfully designed and pre-pared,and the top tooth width,thread depth,and drive structure were parameterized with a forming accuracy of 80.0±21.1μm using SLA-3D printing technology.To improve the initial stability of ACL reconstruction,a biomechanical model was established,and the results were optimized through insertion torque and tensile test-ing.Consequently,the IFS with the top tooth width of 0.4 mm,thread depth of 0.8 mm,and hexagon drive,matching with theΦ8 mm bone tunnel,exhibits the best mechanical properties(maximum insertion torque of 1.064±0.117 N m,ultimate load of 446.126±37.632 N,stiffness of 66.33±27.48 N/mm).Additionally,the ZrO_(2)/PDA/RGD/Zn^(2+)bioactive coating was found to significantly improve the surface bioactivity of zirconia IFS.In conclusion,this study has significant implications for ACL reconstruction.
文摘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.
基金Supported by National Natural Science Foundation of China(Grant No.51675366)Tianjin Research Program of Application Foundation and Advanced Technology(Grant Nos.16JCYBJC19300,15JCZDJC38900)
文摘Unifying the models for topology design and kinematic analysis has long been a desire for the research of parallel kinematic machines(PKMs). This requires that analytical description, formulation and operation for both finite and instantaneous motions are performed by the same mathematical tool. Based upon finite and instantaneous screw theory, a unified and systematic approach for topology design and kinematic analysis of PKMs is proposed in this paper. Using the derivative mapping between finite and instantaneous screws built in the authors’ previous work, the finite and instantaneous motions of PKMs are analytically described by the simple and non?redundant screws in quasi?vector and vector forms. And topological and parametric models of PKMs are algebraically formulated and related. These related topological and parametric models are ready to do type synthesis and kinematic analysis of PKMs under the unified framework of screw theory. In order to show the validity of the proposed approach, a kind of two?translational and three?rotational(2T3R)5?axis PKMs is taken as example. Numerous new structures of the 2T3R PKMs are synthe?sized as the results of topology design, and their Jacobian matrix is obtained easily for parameter optimization and performance evaluation. Some of the synthesized PKMs have outstanding capabilities in terms of large workspaces and flexible orientations, and have great potential for industrial applications of machining and manufacture. Among them, METROM PKM is a typical example which has attracted a lot of attention from global companies and already been developed as commercial products. The approach is a general and unified approach that can be used in the innovative design of different kinds of PKMs.
文摘The 3 D non isothermal flow of non Newtonian viscous polymer melt in a co rotating twin screw extruder is modeled. The distributions of the velocity, temperature, pressure and the viscous dissipation in the flow domain are presented by using a fluid dynamics analysis package (Polyflow). The numerical results show that the temperatures are high in the intermeshing region and on the screw surface, the maximum pressure and the minimum pressure occur in the intermeshing region, and the flow rate is almost proportional to the screw speed.
基金supported by the National Key Technology Research and Development Program of China (Grant No.2011BAE04B02)National Natural Science Foundation of China(Grant No.51174053)
文摘COREX shaft furnace（SF）is a typical screw feeder with a storage container coupled with eight screw casings and screws.The structure of screw casing plays an important role in the moving behavior of burdens,stress distribution,abrasive wear of screws,and energy consumption during the operation of SF.Therefore,a three-dimensional semi-cylindrical model of actual size of COREX-3000 SF was established based on discrete element method to investigate the influences of screw casing structure.The results show that the increase in the gap between the outside of screw flight and screw casing is beneficial for the smooth operation of SF,resulting in uniform descending velocity along the radius of SF in the lower part,decreasing the size of recirculation region,and alleviating stress concentration in the screw casing.Moreover,raising the gap appropriately is also beneficial to weaken screw abrasive wear,decrease energy consumption,and then prolong the service life of the screws.However,enlarging the gap also leads to more undesired high temperature reduction gas into the SF from melter gasifier,thereby deteriorating the operation of SF.Thus,an ideal distance exists between the outside of the screw flight and the screw casing,which is suggested to be equal to the average of particle diameter.
基金Supported by the Health Science and Technology of Tianjin Municipality,No.RC20204Tianjin Institute of Orthopedics,No.2019TJGYSKY03the National Natural Science Foundation of China,No.818717771177226。
文摘BACKGROUND Whether it’s better to adopt unilateral pedicle screw(UPS)fixation or to use bilateral pedicle screw(BPS)one for lumbar degenerative diseases is still controversially undetermined.AIM To make a comparison between UPS and BPS fixation as to how they work efficaciously and safely in patients suffering from lumbar degenerative diseases.METHODS We have searched a lot in the databases through 2020 with index terms such as“unilateral pedicle screw fixation”and“bilateral pedicle screw fixation.”Only randomized controlled trials and some prospective cohort studies could be found,yielding 15 studies.The intervention was unilateral pedicle screw fixation;Primarily We’ve got outcomes of complications and fusion rates.Secondarily,we’ve achieved outcomes regarding total blood loss,operative time,as well as length of stay.Softwares were installed and utilized for subgroup analysis,analyzing forest plots,sensitivity,heterogeneity,forest plots,publication bias,and risk of bias.RESULTS Fifteen previous cases of study including 992 participants have been involved in our meta-analysis.UPS had slightly lower effects on fusion rate[relative risk(RR)=0.949,95%CI:0.910 to 0.990,P=0.015],which contributed mostly to this metaanalysis,and similar complication rates(RR=1.140,95%CI:0.792 to 1.640,P=0.481),Δvisual analog scale[standard mean difference(SMD)=0.178,95%CI:-0.021 to 0.378,P=0.080],andΔOswestry disability index(SMD=-0.254,95%CI:-0.820 to 0.329,P=0.402).In contrast,an obvious difference has been observed inΔJapanese Orthopedic Association(JOA)score(SMD=0.305,95%CI:0.046 to 0.563,P=0.021),total blood loss(SMD=-1.586,95%CI:-2.182 to-0.990,P=0.000),operation time(SMD=-2.831,95%CI:-3.753 to-1.909,P=0.000),and length of hospital stay(SMD=-0.614,95%CI:-1.050 to-0.179,P=0.006).CONCLUSION Bilateral fixation is more effective than unilateral fixation regarding fusion rate after lumbar interbody fusion.However,JOA,operation time,total blood loss,as well as length of stay were improved for unilateral fixation.
