O emprego da moldagem digital na prática odontológica - relato de caso / The use of digital molding in dental practice ­ case report

O avanço da tecnologia de digitalização de imagens e desenvolvimento de dispositivos de fresagem possibilitaram a otimização de diversos processos na Odontologia. O emprego do escaneamento intraoral e do sistema CAD-CAM (CAD - Computer Aided Design; CAM - Computer Aided Manufacturing) aprimorou a realização de reabilitações protéticas, permitindo a obtenção de peças de alta qualidade em tempo reduzido. O objetivo deste trabalho é relatar um caso de reabilitação de um incisivo central inferior a partir de escaneamento intraoral, com scanner Omnicam (DentsplySirona Charlotte, NC, EUA) e aplicação do sistema CAD-CAM.

The advancement of image digitization technology and the development of milling devices have made it possible to optimize various processes in Dentistry. The use of intraoral scanning and the CAD-CAM system (CAD - Computer Aided Design; CAM - Computer Aided Manufacturing) has improved the performance of prosthetic rehabilitations, allowing the obtaining of high quality parts in a reduced time. The objective of this work is to report a case of rehabilitation of a lower central incisor using intraoral scanning, with an Omnicam scanner (Dentsply Sirona) and application of the CAD-CAM system.

Orientações de manutenção e higienização de prótese fixa total implantossuportada: revisão de literatura / Guidelines for maintenance and cleaning of implantssupported total fixed prosthesis: literature review

A evolução dos tratamentos em implantodontia possibilitou uma mudança nos tratamentos reabilitadores para pacientes edêntulos, tornando possível a colocação de próteses fixas, que proporcionam maior qualidade de vida para estes pacientes. Para que estas próteses tenham bom desempenho e longevidade satisfatórios é essencial que se mantenha um padrão adequado de higienização bucal e manutenção profissional. Assim, o objetivo deste trabalho foi realizar uma revisão de literatura a respeito dos principais recursos disponíveis para higienização e manutenção das próteses totais fixas sobre implante (protocolo de Branemark), tanto nos cuidados domiciliares dos pacientes quanto no atendimento profissional do cirurgião dentista. Foi realizada uma busca eletrônica, não sistemática, nas bases de dados Lilacs, Pubmed/Medline, Scielo e ScienceDirect, cruzando-se os seguintes descritores: "Higiene Oral"; "Implantes Dentários"; "Implantação Dentária"; "Manutenção"; "Prótese Dentária Fixada por Implante" e "Prótese Dentária". Foram consultados artigos de revisão de literatura, revisão sistemática, meta-análise, estudos clínicos randomizados, além de livros pertinentes ao assunto, publicados no período de 1995 a 2022.Verificou-se na literatura disponível que os principais instrumentos indicados para uso domiciliar são escova dental, fio dental, escova interdental, irrigador oral, dentifrício e enxaguatório. No atendimento profissional em consultório odontológico deve ser dispendida atenção especial às instruções passadas ao paciente e também fazer o possível para motivar e encorajar o seu engajamento na rotina de higienização, além do acompanhamento periodontal, possíveis substituições de parafusos e instalação de placa oclusal estabilizadora, quando necessário. Manter uma higiene oral adequada é essencial para o sucesso das próteses fixas sobre implantes e o cirurgião dentista desempenha um papel crucial não apenas ao realizar o acompanhamento periódico do paciente, mas também ao sugerir os instrumentos mais apropriados, instruir sobre a higiene oral adequada e motivar o paciente a manter a saúde bucal satisfatória(AU)

The evolution of treatments in implantology has enable a change in rehabilitation treatments for edentulous patients, making it possible to place fixed prostheses that provide a better quality of life for these patients. In order to ensure good performance and satisfactory longevity, it is essential to maintain an appropriate standard of oral hygiene and professional maintenance. Thus, the objective of this work was to conduct a literature review on the main resources available for cleaning and maintenance of complete fixed prostheses on implants (Branemark protocol), both in the patients' home care and in the professional care provided by the dentist. A nonsystematic electronic search was carried out in the Lilacs, Pubmed/Medline, Scielo, and ScienceDirect databases, crossing the following descriptors: "Oral Hygiene"; "Dental Implants"; "Dental Implantation"; "Maintenance"; "Dental Prosthesis, ImplantSupported"; and "Prosthodontics". Literature review articles, systematic reviews, meta-analyses, randomized clinical studies, and relevant books on the subject published from 1995 to 2022 were consulted. The literature available indicates that the main instruments recommended for home care are toothbrush, dental floss, interdental brush, oral irrigator, toothpaste, and mouthwash. In the professional dental office, special attention should be given to the instructions given to the patient, as well as to motivate and encourage their engagement in the hygiene routine, in addition to periodontal monitoring, possible screw replacements, and installation of an occlusal splint when necessary. Maintaining adequate oral hygiene is essential for the success of fixed prostheses on implants, and the dentist plays a crucial role, not only in providing periodic patient follow-up, but also in suggesting the most appropriate instruments, instructing on adequate oral hygiene, and motivating the patient to maintain satisfactory oral health(AU)

O acesso à prótese dentária na atenção primária no Brasil / Access to dental prosthesis in primary care in Brazil / Acceso a prótesis dental en atención primaria en Brasil

Este artigo tem como objetivo avaliar o acesso à prótese dentária na Atenção Primária em Saúde (APS) no Brasil. É um estudo transversal, em que foram utilizados dados do Programa de Melhoria do Acesso e da Qualidade Atenção Básica (PMAQ-AB), segundo e terceiro ciclos, com enfoque em saúde bucal e atendimento à prótese dentária por estado brasileiro. Ao comparar as Unidades Básicas de Saúde (UBS) que fazem instalações de prótese nos dois ciclos de avaliação, foi observada diferença estatisticamente significativa (teste Mann Whitney, p = 0,04), mostrando maior número de instalações no terceiro ciclo. O percentual de UBS que instalavam prótese dentária no segundo ciclo foi de 8,4% e no terceiro ciclo, 14,1%. Ao se avaliar os locais em que os pacientes fizeram a prótese dentária, verifica-se que a maioria fez suas próteses no serviço privado. Conclui-se, então, que a APS não consegue suprir a demanda por prótese dentária.

This cross-sectional study evaluates access to dental prosthesis in Primary Health Care (PHC) in Brazil. Data were obtained from the Access and Quality Improvement Program (PMAQ-AB), second and third cycles, focusing on oral health and dental care provided by the Brazilian State. Comparison of the Basic Health Units (BHU) that perform prosthesis installations in the two evaluation cycles (Mann Whitney test, p = 0.04) revealed a statistically significant difference, showing a greater number of installations in the third cycle. In the second and third cycles 8.4% and 14.1% of UBS, respectively, installed dental prostheses. When evaluating where patients acquired their dental prosthesis, most sought the private service. In conclusion, PHC cannot meet the demand for dental prosthesis.

Este artículo tuvo por objetivo evaluar el acceso a las prótesis dentales en la atención primaria de salud (APS) en Brasil. Se trata de un estudio transversal que utiliza datos del Programa de Mejoramiento del Acceso y Calidad de la Atención Primaria (PMAQ-AB, por sus siglas en portugués), segundo y tercer ciclo, con foco en salud bucal y atención con prótesis dental por estado brasileño. Al comparar las Unidades Básicas de Salud (UBS) que instalan prótesis en los dos ciclos de evaluación, se observó diferencia estadísticamente significativa (prueba de Mann Whitney, p = 0,04), con un mayor número de instalaciones en el tercer ciclo. El 8,4% de las UBS instalaron prótesis dental en el segundo ciclo, y el 14,1% en el tercer ciclo. En cuanto a los locales donde los pacientes hicieron su prótesis dental, la mayoría fue realizada por el servicio privado. Se concluye que la APS no logra satisfacer la demanda de prótesis dentales.

Trueness of different digital design methods for incisal guidance of maxillary anterior implant-supported single crowns / 北京大学学报(医学版)

Objective:To compare the trueness of incisal guidance of implant-supported single crowns designed by patient-specific motion(PSM)with that designed by average-value virtual articulator(AVA).Methods:The study had recruited 12 participants with complete dentition and stable incisal guidance.An intraoral scanner was used to scan digital casts and record two types of patient-specific mo-tion(data only including protrusive movement,and data including protrusive movement and lateral pro-trusive movement).The lingual surfaces of the maxillary incisors which guided the protrusive movement was selected and elevated to create a reference cast.A maxillary central incisor of original casts was vir-tually extracted and implanted to generate a working cast.The Dental system software program was used to design implant-supported single crowns with the anatomical coping design method.The incisal guidance was designed by different methods.The incisal guidance in control group was designed by the average-value virtual articulator.The incisal guidance in experiment groups was designed by the patient-specific motion only including protrusive movement(PSM1)and with the patient-specific motion including protru-sive movement and lateral protrusive movement(PSM2).The incisal guidance of prosthesis designed by these 3 methods were compared with the original incisal guidance in Geomagic Control 2015(3DSystem,America).The measurements included:Average of positive values,ratio of positive area and maximum value reflecting supra-occlusion;average of negative values,ratio of negative area and minimum value re-flecting over-correction;and root mean square reflecting overall deviation.Results:Statistical data were collected using the median(interquartile range)method.The average of positive values,ratio of positive area and average of negative values of the PSM2 group were smaller than those of the control group[8.0(18.8)μm vs.37.5(47.5)μm;0vs.7.2％(38.1％);-109.0(63.8)μm vs.-66.5(64.5)μm],and the ratio of negative area of PSM2 group was larger than those of the control group[52.9％(47.8％)vs.17.3％(45.3％)],with significant differences(P all＜0.05).The ratio of positive area[0.1％(7.0％)]and average of negative values[-97.0(61.5)μm]of PSM1 group,were smaller than those of the control group,and the ratio of negative area[40.7％(39.2％)]of the PSM1 group was larger than that of the control group,with significant differences(P＜0.05).The average of positive values[20.0(42.0)μm]and ratio of positive area of PSM1 group was larger than that of the PSM2 group with significant differences(P＜0.05).Conclusion:To establish the incisor guidance of implant-supported single crowns,compared with the average-value virtual articulator and the patient-specific motion only including protrusive movement,the patient-specific motion including protrusive movement and lateral protrusive movement is more conducive to reducing the protrusive interference of prosthesis and improving the occlusal fit.

Research advances in the accuracy of 3D printing prosthesis / 实用医学杂志

Prosthodontic dentures are used to treat tooth defects,dentition defects and dentition loss,which can restore the appearance and function of the patient's oral cavity.With the advent of the digital age,3D printing technologies have slowly gained widespread popularity.In the field of prosthodontics,3D printing can manufacture materials including resins,waxes,metals,and ceramics.Besides,it can produce fixed,movable,implant dentures and dental models required for dentures.3D printing can produce complicated things with a high material consump-tion rate,simplifying denture manufacture.In addition,the accuracy of 3D printed prosthesis is directly related to the comfort and durability.This article summarizes the process of accuracy of 3D printed dental prosthesis at home and abroad in recent years and provides clues for better 3D printing application.

Application of three-dimensional simulated osteotomy of the distal femur in total knee arthroplasty / 中国组织工程研究

BACKGROUND:Studies have shown that there are significant differences in the geometric morphology of the distal femur of different races and genders,and there are more short female patients in southern China,so the phenomenon of overhanging or insufficient coverage of imported knee prostheses often occurs during surgery. OBJECTIVE:To investigate the characteristics of distal femur bones in southern Chinese women and compare them with imported joint prostheses by simulating the three-dimensional reconstruction of the distal femur bone and matching the femoral side after osteotomy with common imported joint prostheses. METHODS:From January to December 2021,120 female volunteers underwent a CT scan of knee joints.The images were imported into Mimics 20.0 software in Dicom format for three-dimensional reconstruction and then imported into Magic 22.0 software to simulate osteotomy by posterior cruciate ligament preserved total knee arthroplasty and to conduct a matching study with a normal imported joint prosthesis. RESULTS AND CONCLUSION:(1)The functional anteroposterior dimension(fAP)of the distal femur and Persona matched prosthesis had a total overhang rate of 25%(30/120).The fAP≤47 mm group had an overhang than the other groups(P<0.05).The poor coverage rate of Triathlon prosthesis was 12.5%(15/120),and poor coverage was more likely in fAP>53 mm group than in fAP≤53 mm group(P<0.05).(2)The total poor coverage rate of femoral intercondylar width matching with Triathlon prosthesis was 27.5%(33/120).Therefore,the poor coverage rate of bone surface in the central region of the distal femur was more likely in the fAP≤47 mm group than in other groups(P<0.05).The overhang rate of Journey II was 21.6%(26/120),and the overhang rate was higher in the fAP>53 mm group than in the fAP≤53 mm group(P<0.05).(3)Journey II CR prosthesis had the largest difference with the length of the anterior mediolateral diameter of the femur,which was easy to hang out on the anterolateral side of the femoral prosthesis.The Persona CR prosthesis has the largest difference with the length of the posterior mediolateral diameter of the femur,which is easy to be poorly covered in the posterior medial part of the prosthesis.It is recommended to increase the femoral prosthesis with reduced mediolateral diameter in the fAP≤47 mm group and add wider and narrower sizes than the conventional size of intercondylar width,and optimize the anterolateral angular arc design of the femoral prosthesis to improve the matching of posterior cruciate ligament reserved knee prosthesis.

Role and significance of artificial intelligence preoperative planning in total hip arthroplasty / 中国组织工程研究

BACKGROUND:The preoperative planning of traditional X-ray films is often inaccurate,which can lead to some intraoperative and postoperative complications,increase the operation time and intraoperative blood loss,and to some extent affect the surgical outcome of total hip arthroplasty. OBJECTIVE:To investigate the accuracy and effectiveness of artificial intelligence preoperative planning in total hip arthroplasty. METHODS:Sixty patients who underwent primary total hip arthroplasty on the affected side were selected.30 of them used artificial intelligence 3D preoperative planning(trial group)and 30 used conventional X-ray film 2D preoperative planning(control group),and there were no statistically significant differences between the two groups in terms of gender,age,condition and other general data(P>0.05).The actual intraoperative prosthesis placement and preoperative planning prosthesis matching,intraoperative operation time,intraoperative blood loss,bilateral femoral eccentric distance difference,bilateral joint eccentric distance difference and bilateral lower limb length difference,and Harris score at 3 months after operation were compared between the two groups,and the accuracy and application effect of the two preoperative plans were analyzed. RESULTS AND CONCLUSION:(1)Patients in both groups were followed up for 4-6 months postoperatively.One patient in the control group had a posterior dislocation of the prosthesis at 5 days postoperatively,which recovered after performing manual repositioning without re-dislodgement.The rest of the patients did not have postoperative complications or postoperative death.(2)Complete matching rate of the prosthesis on the acetabular side and femoral side was significantly better in the trial group than that in the control group(P<0.05).(3)Operation time and intraoperative blood loss were significantly less in the trial group than those in the control group(P<0.05).(4)The difference in bilateral lower limb length between the two groups was statistically significant(P<0.05),and the difference in bilateral femoral eccentric distance and bilateral joint eccentric distance was not statistically significant(P>0.05).(5)Harris score of patients in the trial group was significantly higher than that in the control group 3 months after operation(P<0.05).(6)These results confirm that compared with traditional film planning,artificial intelligence preoperative planning can predict the prosthesis type more accurately,shorten the operation time,reduce intraoperative blood loss,diminish the occurrence of postoperative bilateral lower limb inequality,and accelerate postoperative recovery.

Accuracy and influencing factor of artificial intelligence planning system in patients undergoing total hip arthroplasty / 中国组织工程研究

BACKGROUND:Artificial intelligence planning system can automatically establish a three-dimensional model and generate planning schemes,but its accuracy in predicting the prosthesis size has not been fully verified. OBJECTIVE:To investigate the accuracy of artificial intelligence planning system in predicting prosthesis size before total hip arthroplasty and its influence on clinical prognosis,and further analyze the risk factors affecting the accuracy of planning. METHODS:Clinical data of patients with unilateral initial total hip arthroplasty who were admitted to the Department of Orthopedics of Affiliated Hospital of Xuzhou Medical University from January 2021 to June 2022 were prospectively collected.The patients were randomly divided into the artificial intelligence planning system group(n=80)and the conventional template group(n=79).Intraoperative use of prostheses and preoperative planning of prosthesis matching were compared between the two groups.Postoperative follow-up Harris scores and the occurrence of complications such as leg length discrepancy,dislocation and prosthesis loosening were recorded in both groups.The effects of demographic indicators,preoperative diagnosis,and Dorr typing on the accuracy of femoral stem planning were explored using univariate and multivariate Logistic regression analyses. RESULTS AND CONCLUSION:(1)The prediction of the prosthesis size on the acetabular side and femoral side was 50%(40/80)and 55%(44/80)in the artificial intelligence planning system group,compared to 34%(27/79)and 37%(29/79)in the conventional template group,with statistically significant differences(P＜0.05).(2)The artificial intelligence planning system group had an accuracy rate within one size difference for the acetabular and femoral side prostheses of 91%(73/80)and 86%(69/80),compared to 82%(65/79)and 72%(58/79)in the conventional template group,with differences statistically different only on the femoral side(P＜0.05).(3)No dislocation or prosthesis loosening occurred in the two groups during postoperative follow-up.The difference in lower limb length between the artificial intelligence planning system and conventional template groups was(3.56±2.32)mm and(3.52±2.41)mm.At the last follow-up,the Harris scores of the artificial intelligence planning system and conventional template groups were(92.74±3.08)and(91.81±3.52),respectively;there was no significant difference in the above differences(P＞0.05).(4)Univariate analysis results showed that preoperative diagnosis as developmental dysplasia of the hip and osteonecrosis of the femoral head,and Dorr type B and C femurs had a significant effect on the accuracy of predicted prosthesis size using an artificial intelligence planning system(P＜0.05).(5)Multivariate logistic regression analysis showed that preoperative diagnosis of developmental dysplasia of the hip(OR=18.233,95%CI:2.662-124.888)was an independent risk factor for the prediction of femoral stem size by artificial intelligence planning system.(6)The artificial intelligence planning system has a higher accuracy in predicting prosthetic size than traditional two-dimensional templates,and there is not a significant difference in the risk of postoperative complications or joint function.The accuracy of the artificial intelligence planning system in patients with developmental dysplasia of the hip was low due to anatomical deformities and acetabular anatomical position reconstruction.

Effect of tibial prosthesis riser length on knee biomechanics after unicompartmental knee arthroplasty / 中国组织工程研究

BACKGROUND:Unicompartmental knee arthroplasty can effectively treat severe unilateral knee osteoarthritis.It has been found that posterior tibial cortical fracture is prone to occur after unicompartmental knee arthroplasty.The fracture begins at the keel groove of tibial osteotomy.The tibial prosthesis riser length affects the biomechanical results of the knee joint after unicompartmental knee arthroplasty. OBJECTIVE:To investigate the effect of tibial prosthesis riser length on knee biomechanics in unicompartmental knee arthroplasty,and to find out the relationship between prosthesis riser length and anterior and posterior tibial diameters of patients. METHODS:Computed tomography image data and commonly used unicompartmental prostheses were selected from a 37-year-old healthy female with no history of knee disease.A natural knee joint model was established and a unicompartmental prosthesis model was built.Eight different lengths of tibial prosthesis risers were established,with a minimum length of 31 mm and a maximum length of 34.5 mm in 0.5 mm increments,for comparison with the commonly used hospital prosthesis riser length of 33.2 mm.The material of the femoral component and tibial disc was cobalt-chromium-molybdenum alloy,and the tibial spacer was ultra-high molecular weight polyethylene.The biomechanical changes of the knee joint were observed using finite element analysis software loaded with 1000 N over the femur. RESULTS AND CONCLUSION:(1)The tibial stress was minimal at a tibial prosthesis riser length of 33 mm;the anterior cruciate ligament stress was minimal;the lateral meniscus stress was minimal,and the femoral prosthesis stress was minimal.The remaining components were less stressful.(2)The subject's medial tibial plateau anterior-posterior diameter length was 53 mm,and by calculating the ratio,the optimal ratio of tibial prosthesis riser length to anterior-posterior tibial diameter should be about 62%.If it is lower than this value,aseptic loosening of the prosthesis may occur,and if it is higher than this value,fracture of the bone cortex at the anterior-posterior end of the tibia may occur.

Structural design of tibial intramedullary stem of artificial knee joint / 中国组织工程研究

BACKGROUND:With social progress,the incidence rate of knee osteoarthritis is getting higher and higher in the face of the rapidly developing aging problem in the social population,and the number of total knee replacement operations is gradually increasing. OBJECTIVE:To study the relationship between prosthesis size and stress shielding by improving the tibial prosthesis base. METHODS:A female patient with severe knee osteoarthritis was selected.Based on Mimics,through extracting the bone structure of the knee joint and simulating the total knee replacement surgery,osteotomy,positioning,and implantation operations were carried out to establish the geometric modeling of the total knee replacement prosthesis(including the femoral prosthesis,tibial bracket,and tibial pad),and improve the design of the tibial prosthesis base,analyze the effect of different tibial prosthesis bases on stress shielding of surrounding bone tissue. RESULTS AND CONCLUSION:(1)Compared with single-stem tibial intramedullary stem prosthesis,the design of four-post tibial intramedullary stem prosthesis created a certain degree of stress shielding around the short stem.However,compared with a thicker single long stem,this stress shielding effect was significantly reduced,and the load was evenly distributed among the four short stems,so there was no stress concentration at the bottom of the pile.(2)The design with a rectangular hole in the middle not only provided relatively good stability,but also helped to reduce stress shielding of cancellous bone to a certain extent,with a reduction rate of 77.5%.(3)Compared with a single-stem tibial intramedullary stem prosthesis,both the four-post tibial intramedullary stem prosthesis and the four-post tibial intramedullary stem prosthesis with a hole in the middle have good stability,which can reduce stress shielding to a certain extent without causing stress concentration,providing theoretical guidance for the design of the tibial intramedullary stem.

Effect of varus and valgus angles of tibial prosthesis on short-term outcome of fixed bearing unicompartmental knee arthroplasty / 中国组织工程研究

BACKGROUND:Previous studies on the effects of valgus and varus angles of tibial component on short-term postoperative outcomes after mobile bearing unicompartmental knee arthroplasty have been reported in and outside China.However,there are few reports on the effect of the valgus and varus angles of tibial component on short-term postoperative outcomes after fixed bearing unicompartmental knee arthroplasty. OBJECTIVE:To investigate the effect of valgus and varus angles of tibial component on short-term clinical outcomes in patients with medial knee osteoarthritis undergoing fixed bearing unicompartmental knee arthroplasty. METHODS:120 patients(122 knees)who underwent fixed bearing unicompartmental knee arthroplasty for medial knee osteoarthritis in Department of Orthopedic Surgery,Affiliated Hospital of Xuzhou Medical University from August 2020 to January 2023 were selected as the study subjects.Two physicians measured the varus angle of femoral prosthesis,valgus and varus angles of tibial prosthesis,flexion and extension angles of femoral prosthesis,and posterior inclination angle of tibial prosthesis after unicompartmental knee arthroplasty based on postoperative X-ray.After excluding the influence of the other three angles,the measurement results of the tibial component varus angle were divided into three groups:<-2°,-2° to 2°,>2°,which were denoted as groups 1,2,and 3,respectively.The range of knee motion,the hospital for special surgery knee score,the American knee society score,and forgotten joint score were recorded and compared before and after the operation. RESULTS AND CONCLUSION:(1)A total of 120 patients(122 knees)were enrolled in this study.They were divided into three groups according to the size of the valgus and varus angles of the tibial prosthesis after operation:37 patients in the first group,60 patients in the second group,and 23 patients in the third group.There was no significant difference between the three groups in terms of baseline information such as age,gender,and side of surgery(P>0.05).(2)Patients were followed up for 3-30 months after arthroplasty.(3)The hospital for special surgery knee score of the second group was higher than that of the first group(P=0.015)and the third group(P=0.012).The American knee society score of the second group was significantly higher than that of the first group(P=0.014)and the third group(P<0.001).The forgotten joint score of the second group was higher than that of the first group(P=0.033)and the third group(P=0.016).(4)After fixed bearing unicompartmental knee arthroplasty,when the valgus angle of tibial prosthesis was-2° to 2°,which can achieve better short-term clinical results,the degree of prosthesis self-realization is higher.

Design and finite element analysis of experimental device for simulating interface micro motion of bone trabecular prosthesis / 医疗卫生装备

Objective To design an experimental device for simulating the interface micro motion of bone trabecular prosthesis and carry out the finite element analysis.Methods The experimental device was composed of a screw-in cylinder with threads,a flexible hinge,a micro-motion rod,a trabecular prosthesis,a connecting rod and a fixation post.A model of the experimental device was constructed with SolidWorks software,and then imported into ABAQUS software to establish a finite element model.An axial displacement load was applied to the femur to analyze the effects of the position of the flexible hinge,the gap between the prosthesis and the femur and the length of the connecting rod on the micro motion.Results The interface micro motion produced by the experimental device increased with the distance of the flexible hinge from the lower end of the screwed-in cylinder;the gap between the prosthesis and the femur did not affect the interface micro motion when the gap was not lower than 20 μm;the interface micro motion rose with the length of the connecting rod.Conclusion The experimental device can accurately simulate the micro motion of different bone trabecular prosthesis interfaces,and can be used for studying the effect of the interface micro motion on osseointegration.[Chinese Medical Equipment Journal,2024,45(1):25-30]

Effect of Leaflet Pattering on Mechanical Valve Hydrodynamic Properties / 医学研究杂志

Objective To investigate the effects patterned structure located on the surface of mechanical valve leaflet exerted on the hydrodynamic properties of valve prostheses.Methods Bileaflet aortic mechanical valves of GKS 21A and 23 A were randomly selected as the control group,hydrodynamic performance of each valve were assessed,as per ISO5840 by calculating mean transvalvular pressure(MTP),regurgitation fraction(REG),effective orifice area(EOA)and effective orifice area(eLoss).Then,laser etching was applied to construct a parallel-groove array pattern on leaflet surface perpendicular to the direction of the blood flow.The valve was subjected a-gain to the same test,and the data obtained were recorded and analyzed.Results In the pulsating flow test,the MTP of the experimental group was smaller than that of the control group at the same flow rate and size.The RE in GKS 21A experimental group was smaller than that in control group,and the RE in GKS 23A experimental group was larger than that in control group.The EOA in the experimental group was larger than that in the control group at the same flow rate and size.The eLoss in the GKS 21A experimental group was smaller than that in the control group,and the eLoss in the GKS 23A experimental group was larger than that in the control group.Conclusion The parallel-groove array pattern on the surface of the leaflet affected the hemodynamic performance of the valve prostheses.

The current status and future of knee joint revision surgery / 中华骨科杂志

With enhanced recovery after surgery (ERAS), research and application of knee revision protheses and customized components or prostheses in the past decade, revision of total knee arthroplasty (TKA) is developing rapidly. However, periprosthetic joint infection (PJI) has always been a major clinical challenge. A comprehensive preoperative examination to find any potential infection sites should be conducted. The overall condition of the patients should be improved. Surgeons should evaluate the classification and degree of soft tissue and bone defects comprehensively and carefully select appropriate surgical approaches, bone reconstruction strategies, and revision prostheses to ultimately restore the alignment, stability, and the range of motion of the knee joint. In the future, efforts should be made to build a team of experts for the support of revisions of TKAs, including preoperative planning, 3D printing, surgical techniques, and ERAS. Nevertheless, primary TKAs protocols should always be firmly sticked to, which are a key to a low rate of revision surgeries. Prevention of PJIs and periprosthetic fractures, as well as establishing a high-quality follow-up system are of the same importance.

Treatment of polyethylene sleeve wear in rotating hinge knee joint with femoral component revision surgery / 中华骨科杂志

Objective:To investigate the clinical efficacy of femoral component revision surgery in addressing polyethylene sleeve wear in rotating hinge knee joints.Methods:A retrospective analysis was conducted on 21 patients who underwent treatment for polyethylene sleeve wear in rotating hinge knee joints at the Department of Orthopaedics, the Fourth Medical Center, PLA General Hospital, spanning from August 2008 to April 2023. There were 8 males and 13 females with a median age of 63(38, 76) years. Among them, 11 cases involved the left side, and 10 cases involved the right side. The average body mass index (BMI) was 25.0(22.5, 31.0) kg/m 2, and all cases underwent unilateral knee joint revision. The time interval from receiving the hinge knee joint prosthesis to revision was 10.5(6.0, 17.0) years, with 18 cases undergoing primary revision and 3 cases undergoing revision for the second time. Revision surgery of the femoral component sleeve was performed in all patients due to polyethylene sleeve wear. Visual analogue scale (VAS), range of motion (ROM) of the knee joint, changes in hip-knee-ankle angle (HKA), and Knee Society score (KSS) were collected and recorded to assess the surgical outcomes. Results:All patients were followed up for a median duration of 12.5(11.7, 13.4) months. Preoperatively, the VAS score was 5(3, 7) points, which significantly decreased to 0(0, 1) points at the last follow-up ( Z=5.721, P<0.001). At the last follow-up, the KSS scores decreased from 41.19±13.65 points preoperatively to 79.81±7.80 points, indicating a statistically significant difference ( t=12.560, P<0.001). HKA increased from 174.65°±5.20° preoperatively to 178.71°±2.79°, with a statistically significant difference ( t=5.533, P<0.001). Knee joint ROM increased from 69.05°±34.37° preoperatively to 110.00°±10.12°, also demonstrating a significant improvement ( t=5.960, P<0.001). Notably, patients exhibited knee joint stability with no passive flexion or extension laxity. Conclusion:Femoral component sleeve revision surgery effectively addresses polyethylene sleeve wear in rotating hinge knee joint prostheses, thereby mitigating the substantial loss of bone and soft tissue associated with overall revision procedures. The early postoperative clinical outcomes are promising and indicative of the efficacy of this surgical intervention.

Analysis of the causes of revision total knee arthroplasty / 中华骨科杂志

Objective:To assess causes for revision total knee arthroplasty (TKA) in China using the data of revision TKA in the past 15 years in our single center andcompare the differences in survival time, operation time and blood loss among different revision reasons.Methods:Data of 337 patients (345 knees) with revision TKAs at our institution from January 2007 to December 2021 (15 years) were retrospectively analyzed. The included population consists of 57 males and 288 females. The causes for first revision TKA were identified and compared according to the time of revision surgery as early (up to 2 years) and late revision (more than 2 years). The reason for revision before 2012 and after 2012 was also compared. Furthermore, the differences of survival time, operation time and blood loss among different revision reasons were compared.Results:The most common reasons for revision of knee joints in 345 cases were periprosthetic infection (133 knees, 38.6%), followed by aseptic loosening (97 knees, 28.1%) and joint instability (35 knees, 10.1%). Early revisions were performed in 171 knees (49.6%), while late revisions were performed in 174 knees (50.4%). Periprosthetic infection (96 knees, 56.1%) and aseptic loosening (86 knees, 49.4%) were the most common reasons for early and late revisions, respectively. There were 59 revisions performed before 2012 and 286 revisions performed after 2012, with periprosthetic infection being the main reason for revision in both groups. The percentage of revisions due to infection decreased from 64.4% before 2012 to 33.2% after 2012, and this difference was statistically significant (χ 2=18.790, P<0.001). The proportion of revisions due to aseptic loosening was 15.3% before 2012, which was significantly lower than the proportion of 30.8% after 2012 (χ 2=5.083, P=0.024). The median survival time of the prostheses in the included patients was 30 months, with shorter survival time observed in patients with stiffness, patellar complications, and periprosthetic infection, and longer survival time observed in patients with polyethylene wear and aseptic loosening. There were significant differences in operation time and blood loss among different reasons for revision ( P<0.001). Conclusion:In our specialized arthroplasty center periprosthesis infection was the most common reason for revision. Periprosthesis infection and aseptic loosening needed to be considered for early or late-stage revision. With the development of technique of total knee arthroplasty, the proportion of periprosthesis infection is decreasing, while the incidence of aseptic loosening is increasing.

The impact of constrained prostheses on the outcomes of two-stage revision for periprosthetic joint infection after total knee arthroplasty / 中华骨科杂志

Objective:To assess the clinical efficacy and infection control outcomes of two-stage revision in managing periprosthetic joint infection (PJI) following primary total knee arthroplasty (TKA) utilizing either a low or high constrained prosthesis.Methods:A retrospective analysis was performed on 40 patients who underwent revision TKA in the Sixth People's Hospital Affiliated to Shanghai Jiao Tong University from February 2019 to February 2022. According to the type of prosthesis selected in primary TKA, they were divided into low constrained prosthesis group and high constrained prosthesis group. There were 28 patients (28 knees) in the low constrained group, including 12 males and 16 females, aged 69.0(63.0, 74.0) years, with a body mass index of 25.18±0.55 kg/m 2. And there were 12 patients (12 knees) in the high-constrained group, including 5 males and 7 females, aged 66.5(65.0, 71.5) years, with a body mass index of 23.94±0.51 kg/m 2. All patients underwent two-stage revision surgery, with RHK used in 1 case and LCCK in 27 cases in the low-constrained prosthesis group. In the high-constrained prosthesis group, 3 patients were treated with RHK, 1 patient with PFC Sigma MBT, and 8 patients with LCCK. The preoperative and postoperative range of motion (ROM), Knee Society score (KSS), and postoperative infection control rate were compared between the two groups. Results:All patients were followed up. The follow-up time was 22.79±8.02 months in the low-constrained prosthesis group and 23.92±7.04 months in the high-constrained prosthesis group, with no significant difference between the two groups ( t=0.426, P=0.680). At the last follow-up, the KSS and ROM in the low-constrained prosthesis group were 77.96±9.74 and 93.48°±7.45°, respectively, significantly higher than 38.93±8.01 and 68.89°±9.44° before the operation ( P<0.05). The KSS score and ROM in the high-constrained prosthesis group were 67.83±8.31 and 80.08°±5.89° at the last follow-up, which were also significantly higher than those before operation (34.25±6.31 and 66.50°±10.48°, P<0.05). There was no significant difference in KSS and ROM between the two groups before operation ( P>0.05), but the KSS score and ROM in the low-constrained prosthesis group were significantly higher than those in the high-constrained prosthesis group at the last follow-up ( P<0.05). Bacterial culture results revealed that the primary infectious agents were coagulase-negative Staphylococcus and Staphylococcus aureus, with an overall infection control rate of 80% (32/40). The infection control rate was 89% (25/28) in the low-constrained prosthesis group and 58% (7/12) in the high-constrained prosthesis group, but the difference between the two groups was not statistically significant (χ 2=3.283, P=0.070). Conclusion:Two-stage revision effectively controls PJI, and the clinical outcomes of two-stage revision for PJI after primary TKA with a high-constrained prosthesis are inferior to those with a low-constrained prosthesis. Further exploration is needed to enhance efficacy.

3D printed metal augment or tibial prosthesis for reconstruction of large bone defects in total knee arthroplasty and revision surgery / 中华骨科杂志

Objective:To investigate the clinical efficacy of 3D printed metal augment or tibial prosthesis for reconstruction of large bone defects in total knee arthroplasty (TKA) and knee revision surgery.Methods:A total of 7 patients (7 knees) with TKA or knee revision who were admitted to the Department of Orthopaedics of the Second Affiliated Hospital of Zhejiang University School of Medicine with large bone defects from July 2018 to December 2023 were retrospectively analyzed, including 4 patients with TKA and 3 patients with knee revision. There were 3 males and 4 females, aged 58.7±7.6 years (range, 54-68 years), 3 patients with left knee and 4 patients with right knee. All the patients had bone defects in the knee joint (AORI type III), 2 cases had bone defects only in the femur, 4 cases had bone defects only in the tibia, and 1 case had bone defects in both the tibia and femur, which were treated with personalized reconstruction using 3D printing. Hip-knee-ankle angles, American Knee Society score (KSS) before and after surgery were compared, and postoperative complications were observed.Results:All patients successfully completed the operation, and the operation time was 189.3±35.5 min (range, 125-240 min). Complex TKA was performed in 4 cases with surgical times of 175, 195, 210, and 240 min, and revision surgery was performed in 3 cases with surgical times of 125, 180, and 200 min, respectively. Intraoperative blood loss was 114±24.4 ml (range, 100-150 ml). Five cases used 3D printed metal augment, and two used 3D printed one-piece tibial components. All patients were followed up for 2, 2, 5, 6, 7, 20, 57 months, respectively. The KSS of the five patients at 3 months postoperatively were 56, 61, 66, 56, and 56 points, respectively, greater than the preoperative scores of 35, 44, 36, 27, and 41 points. The KSS functional scores of the five patients at 3 months postoperatively were 45, 45, 45, 30, and 45 points, respectively, which were greater than the preoperative scores of 30, 30, 15, 20, and 20 points. The hip-knee-ankle angle was 181.8°±3.4° (range, 177.9° to 188.0°) at the final follow-up and 175.8°±12.4° (range, 153.3° to 192.1°) before surgery, with no significant difference ( t=-1.230, P=0.242). At the final follow-up, the 3D printed component was well integrated with the bone surface, the prosthesis was securely positioned, and the force lines of the lower limbs were normal. There were no postoperative complications such as poor wound healing, infection, fat liquefaction, nerve injury, deep vein thrombosis of lower limbs, knee joint stiffness, periprosthesis infection and loosening. Conclusion:Using 3D printed metal augment or tibial prosthesis to reconstruct the huge bone defect in TKA and revision has a satisfactory early clinical effect, satisfactory joint function and good surgical safety.

Finite element analysis of revision prostheses for tibial bone defects with different lengths of tibial stems / 中华骨科杂志

Objective:To evaluate the mechanical performance of customized metal prosthesis with tibia stems of varying lengths for tibial bone defects reconstruction.Methods:Morphologically matched postoperative finite element models of bone defect revision were developed, with three gradients (15 mm, 30 mm, and 45 mm) according to the degree of bone defect and were reconstructed with 3D printed tantalum metal prosthesis using three tibial stem lengths (80 mm, 120 mm, and 150 mm), respectively. Conventional static and dynamic (walking gait) loading was performed to analyze the peak tibial stress distribution and accumulated sliding distance at the prosthetic interface, and to assess the effects of the three tibial stems of different lengths on the stability of the customized tibial defect restorations and the internal tibial stress state.Results:The peak accumulated sliding distance of the dynamically loaded morphologically matched restorations ranged from 17.94 to 21.31 mm with static loading, which were 68% to 84.3% higher than those of 10.26 to 11.69 mm with static loading. The peak tibial stresses in the dynamically loaded model were greater than those in the statically loaded model, with an increase of 28%-49.2%, including 132.94-143.88 MPa in the statically loaded model and 170.41-200.14 MPa in the dynamically loaded model. The overall accumulated sliding distance of the tibia prosthetic model gradually decreased from the tibial osteotomy surface, and the accumulated peak sliding distances ranged from 10.26 to 11.69 mm for static loading, and from 17.94 to 21.31 mm for dynamic loading. The bone tissue stresses in the anterolateral and medial-posterior tibia increased gradually from top to bottom, and the maximum stress value in each section was in the posterior medial tibia (the maximum value was 200.14 MPa). The highest bone tissue stress in the lateral tibia was affected by the tibial stem length, which resulted in a different location, and it was the area most affected by stress shielding (maximum value of 170.65 MPa).Conclusion:For stability assessment of morphologically matched tantalum customized prosthesis, physiological gait dynamic loading studies are more reliable than static loading; the choice of tibial stem length depends on a combination of accumulated peak sliding distances and tibial bone stress distribution factors.

The role of four-generation Oxford nanopore sequencing technology in searching for pathogenic bacteria in periprosthetic infection / 中华骨科杂志

Objective:To explore the application value of Oxford nanopore technologies (ONT) in the diagnosis and treatment of periprosthetic joint infection (PJI).Methods:A prospective analysis was conducted on 32 patients with PJI admitted to the joint department of Xi'an Honghui Hospital from October 2021 to March 2023, who met the 2018 PJI diagnostic criteria of the American Skeletal Infection Society (MSIS), including 15 males and 17 females with an average age of 63.93±8.93 years. 32 revision patients who did not meet the 2018 MSIS PJI criteria during the same period were collected as controls (non PJI group), including 13 males and 19 females with an average age of 65.53±8.54 years. All patients underwent joint fluid puncture before or during surgery, and the specimens were tested by ONT, metagenomic next generation sequencing (mNGS), and general microbial culture. The receiver operating characteristic (ROC) curves were drawn for both groups, and the sensitivity, specificity, positive predictive value, negative predictive value, and Youden index of the three detection techniques were calculated and compared to evaluate the detection efficiency of different detection methods in PJI.Results:Among the 32 patients with PJI, 30 were positive for ONT, with a total of 30 pathogenic bacteria detected, and the detection time was 22.37±8.36 h. 31 were positive for mNGS, with a total of 33 bacterial species detected, and the detection time was 46.25±9.36 h. 17 were positive for microbial culture, with a total of 8 bacterial species detected, and the detection time was 96.23±15.62 h. Among the 32 patients with non PJI group, 1 was positive for ONT and 5 were positive for mNGS, with a total of 1 and 3 bacterial species detected, respectively. The results of microbial culture were all negative. The detection time and area under the curve (AUC) of ONT and mNGS were 22.37±8.36 h and 0.953[95% CI (0.901, 1.006)], 46.25±9.36 h and 0.906[95% CI (0.835, 0.977)], respectively, which were better than those of microbial culture 96.23±15.62 h and 0.766[95% CI (0.678, 0.853)], and the difference was statistically significant ( P<0.05). The sensitivity of ONT, mNGS, and microbial culture were 0.938, 0.969, and 0.531, respectively, and the specificity was 0.969, 0.844, and 1.000, respectively. The Jordan index was 0.906, 0.813, and 0.531, respectively. Conclusion:ONT testing has higher diagnostic efficacy than mNGS and microbial culture in the diagnosis of PJI, and also has advantages in detection time. It also suggests that some PJI are not caused by a single microbial infection.