Factors affecting anophthalmic socket reconstruction outcomes using autologous oral mucosal graft.

BACKGROUND: Limited studies have reported surgical outcomes that are defined by strict criteria following grade 2 or 3 socket reconstruction using an oral mucosal graft (OMG). We aimed to determine factors influencing surgical outcomes of anophthalmic socket reconstruction using OMG in patients with grade 2 or 3 socket contractures. METHODS: Thirty-seven patients who underwent socket reconstruction with autologous OMG between January 2007 and December 2017 were retrospectively analyzed. The successful outcome was defined as an eye prosthesis wearing without experiencing displacement and the absence of any re-operations or additional surgeries following socket reconstruction. Factors affecting surgical outcomes were identified using multivariate analysis. RESULTS: A total of 15 male and 22 female patients (mean age: 40.2 ± 17.2 years) were included. The median duration of socket contracture was 21.5 years. Grade 2 and 3 socket contractures, based on Tawfik's classification, were reported in 20 and 17 patients, respectively. Twenty-eight and eight patients underwent socket reconstruction using OMG alone and OMG combined with a hard palate graft, respectively. The success rates of grades 2 and 3 socket contracture reconstruction were 80.0% and 52.9%, respectively. Multivariate analysis demonstrated that only grade 3 contractures were predictive of worse outcomes. At the final visit (mean follow-up: 6.3 years), 34 patients (91.9%) could wear their eye prostheses. CONCLUSIONS: Socket reconstruction using autologous OMG can provide acceptable results in grade 2 and 3 contractures; however, satisfactory results were more significantly reported in grade 2 than in grade 3 contractures.

An in vitro study using confocal laser scanning microscopy to evaluate the marginal misfits of different implant-supported frameworks.

PURPOSE: This study aimed to develop and evaluate a simple, non-destructive method for assessing the misfit and passivity of implant-retained prostheses frameworks. MATERIALS AND METHODS: To simulate the rehabilitation of a mandible posterior partially edentulous area using 3-unit screw-retained frameworks supported by two implants were fabricated and divided into the following five groups (n = 10 in each group): OP = one-piece framework cast in Co-Cr with the conventional method (control-group); Co-Cr frameworks sectioned and welded by laser (=LAS) or tungsten inert gas (=TIG); Co-Cr CAD-CAM = milled Co-Cr framework; Zir CAD-CAM = milled zirconia framework. The horizontal |X| and vertical |Y| misfits were measured using confocal laser scanning microscopy with one or both screws tightened. Data were analyzed by a two-way ANOVA with repeated measures and Bonferroni correction (α = 0.05). RESULTS: The greatest |X| misfit was observed in the OP group with both screws tightened (290 µm) and one screw tightened (388 and 340 µm). The conventional casting groups sectioned and welded by laser or TIG had lower mean values (235.35 µm, both screws tightened; and 275 µm, one screw tightened) than the OP framework. However, these values still exceeded those of the milled Co-Cr and zirconia frameworks (190 and 216 µm with both screws tightened). Across all reading conditions, every framework subjected to testing consistently maintained vertical |Y| misfit levels below the threshold of 53 µm; however, the milled frameworks exhibited higher vertical misfits than the frameworks obtained by the conventional cast method. CONCLUSIONS: The frameworks, whether cast and sectioned with laser welding or milled from Co-Cr, exhibit improved marginal misfit and enhanced passive fit when compared to other fabrication methods. Additionally, the use of confocal laser scanning microscopy is highly effective for passivity and misfit analysis.

Measurement of proximal contact of single crowns to assess interproximal relief: A pilot study.

Background: It is common for dental technicians to adjust the proximal surface of adjacent teeth on casts when fabricating single crowns. However, whether the accuracy of the proximal contact is affected if this step is eliminated is unclear. Objective: To evaluate the accuracy of the proximal contact of single crowns for mandibular first molars fabricated from four different restorative materials, without adjustment of the proximal surface of the adjacent teeth by the laboratory/dental technician. Methods: This study was in vitro; all the clinical procedures were conducted on a dentoform. The mandibular first molar tooth on the dentoform was prepared using diamond burs and a high speed handpiece. Twenty single crowns were fabricated, five for each group (monolithic zirconia, lithium disilicate, metal ceramic, and cast gold). No proximal surface adjacent to the definitive crowns was adjusted for tight contact in the dental laboratory. Both the qualitative analyses, using dental floss and shimstock, and the quantitative analyses, using a stereo microscope, were performed to evaluate the accuracy of the proximal contact of the restoration with the adjacent teeth. In the quantitative analysis, one-way analysis of variance was used to compare mean values at a significance level of 0.05. Results: In quantitative analysis, the differences between the proximal contact tightness of the four groups was not statistically significant (P = 0.802 for mesial contacts, P = 0.354 for distal contacts). In qualitative analysis, in most crowns, dental floss passed through the contact with tight resistance and only one film of shimstock could be inserted between the adjacent teeth and the restoration. However, one specimen from the cast gold crown had open contact. Conclusions: Even without proximal surface adjustment of the adjacent teeth during the crown fabrication process, adequate proximal contact tightness between the restoration and adjacent teeth could be achieved.

Using human-in-the-loop optimization for guiding manual prosthesis adjustments: a proof-of-concept study.

Introduction: Human-in-the-loop optimization algorithms have proven useful in optimizing complex interactive problems, such as the interaction between humans and robotic exoskeletons. Specifically, this methodology has been proven valid for reducing metabolic cost while wearing robotic exoskeletons. However, many prostheses and orthoses still consist of passive elements that require manual adjustments of settings. Methods: In the present study, we investigated if human-in-the-loop algorithms could guide faster manual adjustments in a procedure similar to fitting a prosthesis. Eight healthy participants wore a prosthesis simulator and walked on a treadmill at 0.8 ms-1 under 16 combinations of shoe heel height and pylon height. A human-in-the-loop optimization algorithm was used to find an optimal combination for reducing the loading rate on the limb contralateral to the prosthesis simulator. To evaluate the performance of the optimization algorithm, we used a convergence criterium. We evaluated the accuracy by comparing it against the optimum from a full sweep of all combinations. Results: In five out of the eight participants, the human-in-the-loop optimization reduced the time taken to find an optimal combination; however, in three participants, the human-in-the-loop optimization either converged by the last iteration or did not converge. Discussion: Findings from this study show that the human-in-the-loop methodology could be helpful in tasks that require manually adjusting an assistive device, such as optimizing an unpowered prosthesis. However, further research is needed to achieve robust performance and evaluate applicability in persons with amputation wearing an actual prosthesis.

Biomechanical effects of fixed-bearing femoral prostheses with different coronal positions in medial unicompartmental knee arthroplasty.

BACKGROUND: To study the biomechanical effects of femoral prostheses at different coronal positions using finite element analysis and provide a clinical reference for unicompartmental knee arthroplasty (UKA). METHODS: A normal knee joint model was established and verified, establishing 13 working conditions for the femoral prosthesis: the standard position, varus and valgus angles of 3°, 6° and 9° and medial and lateral translations of 1 mm, 3 mm and 5 mm. The stress changes at different positions were analysed, including the polyethylene (PE) insert upper surface, the surface of lateral compartment cartilage and the surface of cancellous bone under tibial prosthesis. RESULTS: The stresses on the PE insert upper surface and the cancellous bone surface increased with increasing femoral prosthesis valgus/varus, and the stress increased gradually during medial to lateral translation. The stress change is more significant during valgus and lateral translation. However, the stress on the cartilage surface decreases in the process of varus to valgus and medial translation to lateral translation. CONCLUSION: The fixed-bearing femoral prosthesis of the medial UKA should avoid translation or varus/valgus tilt on the coronal plane as much as possible. The obvious misalignment of the femoral prosthesis will significantly affect the stress on the internal structure of the knee joint, especially the PE insert and cartilage surface. A femoral prosthesis coronal tilt of more than 6° may significantly increase the stress on the PE surface, and varus of more than 6° may significantly increase the stress on the cartilage surface. For the femoral prosthesis position at the distal end of the femoral condyle, it is recommended to be placed in the centre.

Fitting transtibial and transfemoral prostheses in persons with a severe flexion contracture: problems and solutions - a systematic review.

PURPOSE: In persons with a hip or knee flexion contracture ≥25°, fitting a prosthesis is said to be difficult. This systematic review aims to assess the evidence for fitting of a prosthesis in persons with a severe contracture (≥25°) after a lower limb amputation. METHOD: PubMed, Embase, Scopus, CINAHL, and Orthotics & Prosthetics Virtual Library databases were searched from inception to December 2019, using database specific search terms related to amputation, prosthesis, and contracture. Reference lists of included studies were checked for relevant studies. Quality of the included studies was assessed using the critical appraisal checklist for case reports (Joanna Briggs Institute). RESULTS: In total, 13 case studies provided evidence for fitting of a prosthesis in more than 63 persons with a transtibial amputation and three with a transfemoral amputation, all of whom had a hip or knee flexion contracture ≥25°. Some studies found a reduction in contractures after prosthesis use. CONCLUSIONS: Several techniques for fitting a prosthesis in case of a flexion contracture ≥25° were found. Contracture reduction occurred in some cases and was possibly related to prosthesis use. Fitting a transtibial or transfemoral prosthesis in persons with a lower limb amputation with a severe flexion contracture is possible.IMPLICATIONS FOR REHABILITATIONThis study provides information on prosthesis prescriptions and adaptations for persons with a transfemoral and transtibial amputation with a flexion contracture ≥25°.The fitting of bent prostheses is not limited by prosthetic components and techniques.Parallel to the use of bent prostheses, it is also important to treat the contracture.

Fixed vs Measured Length of Stapes Prosthesis in Stapes Surgery.

Aims The aim of this study is to assess the relationship between the prosthesis length and the outcome of the primary stapes surgery in patients with otosclerosis. Material and Methods This was a retrospective cohort study. We reviewed medical records of 218 patients between January 2015 and August 2020 in two different referral centers. It was conducted in two hospitals by two different well experienced otologic surgeons that one of them believes in fixed length (4.75 mm) of stapes prosthesis (group A) and, the other one believes in measuring the distance between the footplate and incus long process to choose the proper length of prosthesis (group B). The surgery success rates and complications between these two groups were compared 3 months postoperatively. Results Mean age, preoperative bone conduction (BC) audiometric threshold and air-bone gap, postoperative BC and air-bone gap were similar in both groups (All p > 0.05). Vertigo frequency was not significantly different between the two groups (p = 0.303). There were no significant differences regarding the number of favorable postoperative outcomes between group A and B (70 (97.2%) vs. 142(97.3%) respectively) (p = 0.632). Conclusion This study found no significant difference regarding the hearing outcomes between fixed length vs measured length of stapes prosthesis.

Preservation of Residual Limb Length with Antibiotic-loaded Bone Cement Implantation to Treat Femoral Periprosthetic Infection: A Case Report.

BACKGROUND: : Fitting a femoral prosthesis in a transfemoral amputee with a very short amputation stump is challenging. This case report aimed to introduce an effective and simple method that can preserve the residual limb length by the implantation of antibiotic-loaded bone cement for the treatment of a patient with femoral periprosthetic infection. CASE: : A 30-year-old man who had osteosarcoma at the age of 13 years underwent transfemoral amputation 17 years after the initial surgery because of periprosthetic infection. Antibiotic-loaded bone cement was inserted into the infected bone marrow to control the residual infection and to preserve the stump length. The infection resolved, and the patient regained functional gait using a femoral prosthesis. DISCUSSION: : This case report demonstrates the usefulness of antibiotic-loaded cement in preserving the length of residual limbs and for femoral prosthesis fitting after periprosthetic infection. Maintaining the residual bone length is crucial in amputees for the functional fitting of femoral prostheses. The use of antibiotic-loaded bone cement has potential as a simple and useful surgical option in amputees after periprosthetic infection.

Validade e confiabilidade da versão brasileira da Trinity Amputation and Prosthesis Experience Scales - Revised (TAPES-R) / Validity and reliability of the brazilian version of Trinity Amputation and Prosthesis Experience Scales ­ Revised (TAPES-R)

Objetivo: Avaliar a validade e confiabilidade da versão brasileira da TAPES-R em uma população com amputação de membro inferior. Método: Participaram deste estudo transversal 102 pessoas com amputação de membro inferior, usuárias de prótese. Foram avaliadas as propriedades psicométricas (validade concorrente, grau de concordância (Índice de Kappa) e confiabilidade (ICC) intra e interobservador, além da consistência interna dos itens pelo alfa de Cronbach) da versão brasileira da TAPES-R. Para avaliação da validade concorrente foi utilizado o Prosthesis Evaluation Questionnaire (PEQ). Resultados: A TAPES-R se correlacionou com o PEQ, com exceção das subescalas de ajuste social e geral. O ICC interobservador variou de 0,38 a 0,88 na parte 1 e de 0,27 a 0,88 na parte 2, já o ICC intraobservador variou de 0,63 a 0,83 na parte 1 e de 0,27 a 0,79 na parte 2. O índice de Kappa variou de 0,18 a 0,66 na análise interobservador e de 0,25 a 0,69 na análise intraobservador. O Alfa de Cronbach variou de 0,75 a 0,89. Conclusão: A avaliação das propriedades psicométricas permite concluir que a TAPES-R é válida, confiável e apresenta uma boa consistência interna para ser aplicada em adultos brasileiros amputados de membro inferior.

Objective: Evaluate the validity and reliability of the Brazilian version of TAPES-R in people with lower limb amputation. Method: 102 people with lower limb amputation who used a prosthesis participated in this cross-sectional study. The psychometric properties (concurrent validity, degree of agreement (Kappa Index) and intra and interobserver reliability (ICC), in addition to the internal consistency of the items by Cronbach's alpha) of the Brazilian version of TAPES-R were evaluated. To assess concurrent validity, the Prosthesis Evaluation Questionnaire (PEQ) was used. Results: TAPES-R was correlated with PEQ, except for the subscales of social and general adjustment. The inter-observer ICC ranged from 0.38 to 0.88 in part 1 and from 0.27 to 0.88 in part 2, whereas the intra-observer ICC ranged from 0.63 to 0.83 in part 1 and 0.27 to 0.79 in part 2. The Kappa index varied from 0.18 to 0.66 in the inter-observer analysis and from 0.25 to 0.69 in the intra-observer analysis. Cronbach's alpha ranged from 0.75 to 0.89. Conclusion: The evaluation of psychometric properties allows us to verify that a TAPES-R is valid, reliable and has a good internal consistency to be applied to Brazilian adults with lower limb amputations.

Utilidad del sistema Myo Plus en pacientes amputados transradiales / Use of the Myo Plus system in transradial amputation patients

Las amputaciones de miembro superior son infrecuentes pero provocan una gran discapacidad. Suelen ser de etiología traumática y en varones jóvenes menores de 40 años y activos. La frecuencia de la amputación de nivel transradial es del 35% de los casos, siendo la prótesis mioeléctrica la que aporta mayor funcionalidad. Un 25% de los pacientes abandona el uso de la prótesis, siendo la complejidad de su uso, mediante 2 electrodos convencionales, una de las causas más frecuentes del abandono. El sistema Myo Plus, con 8 canales de electromiografía, facilita al paciente el control protésico utilizando el miembro fantasma y consiguiendo los patrones de cierre, apertura y pronosupinación de la mano en un tiempo menor al convencional y más fácilmente. Además, conlleva un menor tiempo de rehabilitación, disminuyendo los costes y los desplazamientos innecesarios, sin incrementar el tiempo de fabricación del encaje (AU)

Upper limb amputations are uncommon but cause severe disability. It is usually of traumatic origin and in young males less than 40 years-old, and active. The frequency of amputation at transradial level is around 35% of cases, with the myoelectric prosthesis achieving greater functionality. Around 25% of the patients give up using of the prosthesis, due to its complexity of use by means of 2 conventional electrodes, one of the most common causes for giving up. The Myo Plus system with an 8-channel electromyograph helps the patient to control the prosthesis using the phantom limb and achieving the closing, opening, and pronation-supination patterns of the hand in a time less than the conventional one and more easily. It also leads to less rehabilitation time, decreasing costs and unnecessary travel, without increasing the time for the manufacture of the socket (AU)

[Use of the Myo Plus system in transradial amputation patients]. / Utilidad del sistema Myo Plus en pacientes amputados transradiales.

Upper limb amputations are uncommon but cause severe disability. It is usually of traumatic origin and in young males less than 40 years-old, and active. The frequency of amputation at transradial level is around 35% of cases, with the myoelectric prosthesis achieving greater functionality. Around 25% of the patients give up using of the prosthesis, due to its complexity of use by means of 2 conventional electrodes, one of the most common causes for giving up. The Myo Plus system with an 8-channel electromyograph helps the patient to control the prosthesis using the phantom limb and achieving the closing, opening, and pronation-supination patterns of the hand in a time less than the conventional one and more easily. It also leads to less rehabilitation time, decreasing costs and unnecessary travel, without increasing the time for the manufacture of the socket.

Lower limb prosthetic interfaces: Clinical and technological advancement and potential future direction.

The human-prosthesis interface is one of the most complicated challenges facing the field of prosthetics, despite substantive investments in research and development by researchers and clinicians around the world. The journal of the International Society for Prosthetics and Orthotics, Prosthetics and Orthotics International, has contributed substantively to the growing body of knowledge on this topic. In celebrating the 50th anniversary of the International Society for Prosthetics and Orthotics, this narrative review aims to explore how human-prosthesis interfaces have changed over the last five decades; how research has contributed to an understanding of interface mechanics; how clinical practice has been informed as a result; and what might be potential future directions. Studies reporting on comparison, design, manufacturing and evaluation of lower limb prosthetic sockets, and osseointegration were considered. This review demonstrates that, over the last 50 years, clinical research has improved our understanding of socket designs and their effects; however, high-quality research is still needed. In particular, there have been advances in the development of volume and thermal control mechanisms with a few designs having the potential for clinical application. Similarly, advances in sensing technology, soft tissue quantification techniques, computing technology, and additive manufacturing are moving towards enabling automated, data-driven manufacturing of sockets. In people who are unable to use a prosthetic socket, osseointegration provides a functional solution not available 50 years ago. Furthermore, osseointegration has the potential to facilitate neuromuscular integration. Despite these advances, further improvement in mechanical features of implants, and infection control and prevention are needed.

Optimizing P2 Neochordal Length and Stability in Mitral Valve Repair With Use of a Polypropylene Loop.

Determining the optimal length of artificial chordae tendineae and then effectively securing them is a major challenge in mitral valve repair. Our technique for measuring and stabilizing neochordae involves tying a polypropylene suture loop onto the annuloplasty ring. We used this method in 4 patients who had moderate-to-severe mitral regurgitation from degenerative posterior leaflet (P2) prolapse and flail chordae. Results of intraoperative saline tests and postoperative transesophageal echocardiography revealed only mild insufficiency. One month postoperatively, echocardiograms showed trivial regurgitation in all 4 patients. We think that this simple, precise method for adjusting and stabilizing artificial chordae will be advantageous in mitral valve repair.

Fit of cobalt-chromium copings fabricated by the selective laser melting technology and casting method: A comparative evaluation using a profilometer.

BACKGROUND: This study aimed to assess the marginal adaptation and internal fit of cobalt-chromium copings fabricated by the selective laser melting (SLM) and conventional techniques using a profilometer. MATERIALS AND METHODS: In this in vitro study sample size was calculated to be a total of 10 in two groups (n = 5). A brass model was used that had a circular cross-section with a round shoulder margin with 0.5 mm thickness and axial walls with 10 mm length and 6° taper. The copings fabricated with both techniques (SLM and casting method) were placed on the model, and vertical marginal gap was measured using a profilometer. The internal fit of copings was assessed by weighing the light-body addition silicone applied inside them, which simulated the cement. Data were analyzed through parametric (Independent t-test) and nonparametric (Mann-Whitney U-test, Bootstrap, Spearman, and Pearson Correlation) analysis. All analyses were performed at a significant level (α = 0.05) using SPSS. RESULTS: The mean marginal gap in the casting group (132.93 ± ) was significantly higher than that in the SLM group (67.14 ± 15.67 µm) (P < 0.05). The mean weight of light-body silicone was 9.60 ± in the SLM and 8.70 ± 1.21 mg in the casting group. No significant difference was noted between the two groups regarding the internal fit (P > 0.05). CONCLUSION: The copings fabricated by the SLM technique showed a smaller vertical marginal gap compared to the casting group. However, the two groups were not significantly different in terms of internal fit.

Perceived Effect of Socket Fit on Major Lower Limb Prosthetic Rehabilitation: A Clinician and Amputee Perspective.

OBJECTIVES: To determine the perspectives of amputees and rehabilitation clinicians on the effect of socket fit and issues caused by ill-fitting sockets throughout lower limb prosthetic rehabilitation. DESIGN: A survey was developed to identify rehabilitation factors and issues for prosthesis wearers and rehabilitation clinicians. Participants opted to participate in a further telephone interview. SETTING: Online and across the United Kingdom. PARTICIPANTS: Lower limb prosthetic wearers and clinicians who are part of a lower limb prosthetic rehabilitation team (N=94). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: A survey and an interview to measure the perceived effect of socket fit on lower limb rehabilitation. RESULTS: Issues related to socket fit were identified as the biggest factor affecting rehabilitation by 48.0% of amputees and 65.7% of clinicians. Amputee interviewees focused on the effect of fit on quality of life and the ability to complete daily tasks, whereas clinicians focused on the lack of widespread ability to adjust the socket and gait re-education. CONCLUSIONS: Socket fit has a large effect on and is a large source of frustration to amputees and their clinical teams throughout rehabilitation. From the interviews, it became clear that the interpretation of socket fit is different for each person; thus, "socket fit" does not mean the same for all patients.

Finite element analysis of optimization on placement of medial fixed-bearing unicompartmental knee arthroplasty / 中华骨科杂志

Objective@#To investigate the influence of displacement of femoral and tibial components on the biomechanics of femoral or tibial bone in coronal view.@*Methods@#A series of CT and MRI of the left knee joint of a Han male volunteer was taken and a three-dimensional finite element model of the healthy knee joint was established. The femoral component and the tibial component were designed with varus 6°, varus 3°, 0°, valgus 3°, and valgus 6°, and were combined into 25 three-dimensional finite element model (FEM) of medial unicompartmental knee arthroplasty. A 1 000 N load was applied along the femoral mechanical axis. The von Mises cloud stress distribution was observed. Moreover, the lateral compartment load ratio, the high contact stress of cancellous bone and medial cortical bone below the tibial component, the upper surface of the polyethylene liner, and the femoral cartilage in the lateral compartment was measured. The statistically significant indicators compared with the neutral position (0° varus or valgus of the tibia and the femoral prosthesis, and 5° posterior slope of tibia prosthesis) were identified by scatter plots to find the dense and sparse areas of point items. The optimal position of the femoral component and the tibial component was determined by the number of items with statistical significance in the sparse area.@*Results@#When the femoral component was placed at 0° position, there was no significant difference in the high contact stress of cancellous bone below the tibial component in the five groups. When the femoral component was placed at 0° position, the tibial component was 6° varus or 6° valgus and the stress was increased by 9.21±3.38 MPa and 9.08±4.13 MPa (P<0.05), respectively. With the changes of femoral and tibial components from 6° varus to 6° valgus, the high contact stress of the medial cortical bone below the tibia was gradually decreased (P<0.05). When the femoral component was placed at 0°, the tibial component changes from 6° varus to 6° valgus without significant difference in the high contact stress on the upper surface of each group of polyethylene gasket. Compared with the neutral position group, the high contact stress of the 6° varus or 6° valgus group were increased by 2.88±2.53 MPa and 3.47±2.86 MPa, respective ly (P<0.05). The lateral compartment load ratio and the high contact stress of lateral compartment femoral cartilage was gradually decreased (P<0.05), when the femoral and tibial components changed from 6° varus to 6° valgus. The number (2.8%, 1/36) of indicators in the sparse area (the combination of all combinations of femur or tibia from 3° varus to 3° valgus) was less than that (57.8%, 37/64) in the dense area (set of all combinations except sparse area), and the difference was significant (χ2=29.61, P<0.001).@*Conclusion@#It is suggested that the position of the femoral component and the tibial component in fixed medial unicompartmental arthroplasty should not exceed 3° varus or valgus in patients with standard lower limb alignment.

Finite element analysis of optimization on placement of medial fixed-bearing unicompartmental knee arthroplasty / 中华骨科杂志

Objective To investigate the influence of displacement of femoral and tibial components on the biomechanics of femoral or tibial bone in coronal view.Methods A series of CT and MRI of the left knee joint of a Han male volunteer was taken and a three-dimensional finite element model of the healthy knee joint was established.The femoral component and the tibial component were designed with varus 6°,varus 3°,0°,valgus 3°,and valgus 6°,and were combined into 25 three-dimensional finite element model (FEM) of medial unicompartmental knee arthroplasty.A 1 000 N load was applied along the femoral mechanical axis.The von Mises cloud stress distribution was observed.Moreover,the lateral compartment load ratio,the high contact stress of cancellous bone and medial cortical bone below the tibial component,the upper surface of the polyethylene liner,and the femoral cartilage in the lateral compartment was measured.The statistically significant indicators compared with the neutral position (0° varus or valgus of the tibia and the femoral prosthesis,and 5° posterior slope of tibia prosthesis) were identified by scatter plots to find the dense and sparse areas of point items.The optimal position of the femoral component and the tibial component was determined by the number of items with statistical significance in the sparse area.Results When the femoral component was placed at 0° position,there was no significant difference in the high contact stress of cancellous bone below the tibial component in the five groups.When the femoral component was placed at 0° position,the tibial component was 6° varus or 6° valgus and the stress was increased by 9.21±3.38 MPa and 9.08±4.13 MPa (P＜0.05),respectively.With the changes of femoral and tibial components from 6° varus to 6° valgus,the high contact stress of the medial cortical bone below the tibia was gradually decreased (P＜ 0.05).When the femoral component was placed at 0°,the tibial component changes from 6° varus to 6° valgus without significant difference in the high contact stress on the upper surface of each group of polyethylene gasket.Compared with the neutral position group,the high contact stress of the 6° varus or 6° valgus group were increased by 2.88±2.53 MPa and 3.47±2.86 MPa,respectively (P＜0.05).The lateral compartment load ratio and the high contact stress of lateral compartment femoral cartilage was gradually decreased (P＜0.05),when the femoral and tibial components changed from 6° varus to 6° valgus.The number (2.8％,1/36) of indicators in the sparse area (the combination of all combinations of femur or tibia from 3° varus to 3° valgus) was less than that (57.8％,37/64) in the dense area (set of all combinations except sparse area),and the difference was significant (x2=29.61,P＜ 0.001).Conclusion It is suggested that the position of the femoral component and the tibial component in fixed medial unicom partmental arthroplasty should not exceed 3° varus or valgus in patients with standard lower limb alignment.

Adaptación de pilares rectos sobre implantes con conexión hexagonal interna y externa por microscopía electrónica de barrido / Adaptation of straight pillars on implants with internal and external hexagonal connection by scanning electronic mi-croscopy / Adaptação de pilares retos em implantes com conexão hexagonal interna e externa por microscopia eletrônica de varredura

En implantología oral, ha sido motivo de investigación y constante evolución la interfase implante-pilar, princi-palmente desde el punto de vista biomecánico y biológico. Objetivo: Valorar el espacio o "gap" en la interfase implante-pilar en implantes de conexión hexagonal interna y externa por medio de microscopía electrónica de barrido (MEB). Materiales y Métodos: Estudio in vitro en 24 implantes (Bionnovation®) divididos en dos gru-pos (n=12): conexión hexagonal interna y externa. Para el experimento, se atornillaron pilares rectos con 30N de torque. A su vez 6 implantes por grupo se sometieron a 500000 ciclos de carga dinámica; posteriormente, se evaluó por MEB el espacio de la interfase implante pilar en 3 puntos de todas las muestras, las medias de los resultados de cada espécimen se respaldaron en tablas de Excel y se analizaron en el programa BioEstat 5.3. Resultados: Mediante test T para muestras independientes, con una significancia del 95%, se encontró una diferencia muy significativa luego de la aplicación de la carga dinámica en los implantes de hexágono ex-terno (p= 0.0002). En los implantes de hexágono interno también existió diferencia estadística (p= 0.03). Entre los implantes de hexágono externo e interno existieron diferencias muy significativas en la precisión del ajuste en la interfase implante pilar antes y después de la aplicación de las cargas dinámicas (p= <0.0001 y p= 0.0003 respectivamente). Conclusiones: Las cargas dinámicas aumentaron significativamente la discrepan-cia en la conexión implante-pilar de los implantes de hexágono externo e interno (p= < 0.05); adicionalmente, la distancia del "gap" fue mayor para los implantes de hexágono externo en contraste con los implantes de Hexágono Interno antes y después de la carga dinámica, siendo muy significativo (p= < 0.0003).

In oral implantology, the implant-pillar interface has been a subject of research and constant evolution, mainly from the biomechanical and biological point of view. Objective: To assess the gap in the implant-abutment interface in internal and external hexagonal connection implants by means of scanning electron microscopy (SEM). Materials and Methods: In vitro study in 24 implants (Bionnovation®) divided into two groups (n = 12): internal and external hexagonal connection. For the experiment, straight pillars with 30N of torque were screwed. In turn, 6 implants per group underwent 500,000 cycles of dynamic loading; Subsequently, the space of the pillar implant interface at 3 points of all samples was evaluated by MEB, the means of the results of each specimen were supported in Excel tables and analyzed in the BioEstat 5.3 program. Results: Using a T test for independent samples, with a significance of 95%, a very significant difference was found after the application of the dynamic load in the external hexagon implants (p = 0.0002). In the internal hexagon implants there was also a statistical difference (p = 0.03). Between the external and internal hexagon implants there were very significant differences in the accuracy of the adjustment in the abutment implant interface before and after the application of the dynamic loads (p = <0.0001 and p = 0.0003 respectively). Conclusions: Dynamic loads significantly increased the discrepancy in the implant-abutment connection of the external and internal hexa-gon implants (p = <0.05); additionally, the gap distance was greater for external hexagon implants in contrast to Internal Hexagon implants before and after dynamic loading, being very significant (p = <0.0003).

Na implantologia oral, a interface implante-pilar tem sido objeto de pesquisa e evolução constante, principal-mente do ponto de vista biomecânico e biológico. Objetivo: Avaliar o espaço ou "gap" na interface implan-te-pilar em implantes de conexão hexagonal interna e externa por meio de microscopia eletrônica de varre-dura (MEV). Materiais e Métodos: Estudo in vitro em 24 implantes (Bionnovation®) divididos em dois grupos (n = 12): conexão hexagonal interna e externa. Para o experimento, pilares retos com 30N de torque foram parafusados. Por sua vez, 6 implantes por grupo passaram por 500.000 ciclos de carregamento dinâmico; posteriormente, o espaço da interface do implante de pilar em 3 pontos de todas as amostras foi avaliado pelo MEV, as médias dos resultados de cada amostra foram suportadas em tabelas Excel e analisadas no programa BioEstat 5.3. Resultados: Usando um teste T para amostras independentes, com significância de 95%, foi encontrada uma diferença muito significativa após a aplicação da carga dinâmica nos implantes hexagonais externos (p = 0,0002). Nos implantes hexagonais internos também houve diferença estatística (p = 0,03). Entre os implantes hexágono externo e interno, houve diferenças muito significativas na precisão do ajuste na interface do implante de pilar antes e após a aplicação das cargas dinâmicas (p = <0,0001 ep = 0,0003, respectivamente). Conclusões: As cargas dinâmicas aumentaram significativamente a discrepância na conexão implante-pilar dos implantes hexágono externo e interno (p = <0,05); além disso, a distância do gap foi maior para os implantes hexagonais externos, em contraste com os implantes de hexágono interno antes e após o carregamento dinâmico, sendo muito significativa (p = <0,0003).

Bionic Upper Limb Reconstruction: A Valuable Alternative in Global Brachial Plexus Avulsion Injuries-A Case Series.

Global brachial plexopathies including multiple nerve root avulsions may result in complete upper limb paralysis despite surgical treatment. Bionic reconstruction, which includes the elective amputation of the functionless hand and its replacement with a mechatronic device, has been described for the transradial level. Here, we present for the first time that patients with global brachial plexus avulsion injuries and lack of biological shoulder and elbow function benefit from above-elbow amputation and prosthetic rehabilitation. Between 2012 and 2017, forty-five patients with global brachial plexus injuries approached our centre, of which nineteen (42.2%) were treated with bionic reconstruction. While fourteen patients were amputated at the transradial level, the entire upper limb was replaced with a prosthetic arm in a total of five patients. Global upper extremity function before and after bionic arm substitution was assessed using two objective hand function tests, the action research arm test (ARAT), and the Southampton hand assessment procedure (SHAP). Other outcome measures included the DASH questionnaire, VAS to assess deafferentation pain and the SF-36 health survey to evaluate changes in quality of life. Using a hybrid prosthetic arm mean ARAT scores improved from 0.6 ± 1.3 to 11.0 ± 6.7 (p = 0.042) and mean SHAP scores increased from 4.0 ± 3.7 to 13.8 ± 9.2 (p = 0.058). After prosthetic arm replacement mean DASH scores improved from 52.5 ± 9.4 to 31.2 ± 9.8 (p = 0.003). Deafferentation pain decreased from mean VAS 8.5 ± 1.0 to 6.7 ± 2.1 (p = 0.055), while the physical and mental component summary scale as part of the SF-36 health survey improved from 32.9 ± 6.4 to 40.4 ± 9.4 (p = 0.058) and 43.6 ± 8.9 to 57.3 ± 5.5 (p = 0.021), respectively. Bionic reconstruction can restore simple but robust arm and hand function in longstanding brachial plexus patients with lack of treatment alternatives.

Dimensional Changes of 3-Unit Implant-Supported Zirconia Frameworks of Two CAD/CAM Systems from Scanning to Sintering.

OBJECTIVES: Internal fit of implant frameworks is an important factor determining the long-term success of dental implant restorations. This in-vitro study aimed to evaluate dimensional changes of implant-supported zirconia frameworks fabricated by two computer-aided design/computer-aided manufacturing (CAD/CAM) systems from scanning to sintering. MATERIALS AND METHODS: A master model of a three-unit fixed partial denture was fabricated with two implant abutments. In each CAD/CAM system (AmannGirrbach and Zirkonzahn), the master model was scanned 12 times, and data were saved as Standard Transformation Language files (scanning groups). Using semi-sintered zirconia, 12 real-size frameworks (milling groups) and 12 enlarged frameworks, were sintered (sintering groups) and made by each system. Dimensions of the master model and frameworks in each phase were measured. Dimensional changes (compared to the master model) were calculated. Data were analyzed using repeated measures analysis of variance, independent t-test, and paired sample t-test (α=0.05). RESULTS: Comparison of the two systems revealed that although dimensional changes were greater in the milling phase of Zirkonzahn, they were larger in the sintering phase of the AmannGirrbach system. Evaluation of fabrication phases revealed greater dimensional changes in the milling phase compared to the other phases in the Zirkonzahn system (P<0.05). However, in the AmannGirrbach system, the values were not significantly different between milling and sintering phases (P>0.05). CONCLUSION: Within the limitations of this study, the results showed that fabrication phases, CAD/CAM system type and abutment size had significant effects on dimensional changes.