Analysis of the Mechanical Behavior of Porcine Graft Fixation in a Polyurethane Block Using a 3D-printed PLA Interference Screw / Análise do comportamento mecânico da fixação do enxerto suíno em um bloco de poliuretano usando um parafuso de interferência PLA impresso em 3D

Abstract Objective The interest in using 3D printing in the healthcare field has grown over the years, given its advantages and potential in the rapid manufacturing of personalized devices and implants with complex geometries. Thus, the aim of the present study was to compare the mechanical fixation behavior of a 3D-printed interference screw, produced by fused deposition modeling of polylactic acid (PLA) filament, with that of a titanium interference screw. Methods Eight deep flexor porcine tendons, approximately 8 mm wide and 9 cm long, were used as graft and fixed to a 40 pounds-per-cubic-foot (PCF) polyurethane block at each of its extremities. One group was fixed only with titanium interference screws (group 1) and the other only with 3D-printed PLA screws (BR 20 2021 018283-6 U2) (group 2). The tests were conducted using an EMIC DL 10000 electromechanical universal testing machine in axial traction mode. Results Group 1 (titanium) obtained peak force of 200 ± 7 N, with mean graft deformation of 8 ± 2 mm, and group 2 (PLA) obtained peak force of 300 ± 30 N, and mean graft deformation of 7 ± 3 mm. Both the titanium and PLA screws provided good graft fixation in the polyurethane block, with no slippage or apparent deformation. In all the samples, the test culminated in graft rupture, with around 20 mm of deformation in relation to the initial length. Conclusion The 3D-printed PLA screw provided good fixation, similar to that of its titanium counterpart, producing satisfactory and promising results.

Resumo Objetivo O interesse em utilizar a impressão 3D na área da saúde tem crescido ao longo dos anos, dadas as suas vantagens e o seu potencial na rápida fabricação de dispositivos e implantes personalizados com geometrias complexas. Assim, o objetivo do presente estudo foi comparar o comportamento de fixação mecânica de um parafuso de interferência impresso em 3D, produzido pela modelagem fundida de deposição do filamento de ácido polilático (PLA), com o de um parafuso de interferência de titânio. Métodos Oito tendões suínos flexores profundos, de aproximadamente 8 mm de largura e 9 cm de comprimento, foram utilizados como enxerto e fixados em um bloco de poliuretano de 40 PCF em cada uma de suas extremidades. Um grupo foi fixado apenas com parafusos de interferência de titânio (grupo 1) e o outro apenas com parafusos PLA impressos em 3D (BR 20 2021 018283-6 U2) (grupo 2). Os testes foram realizados utilizando uma máquina de teste universal eletromecânica EMIC DL 10.000 no modo de tração axial. Resultados O grupo 1 (titânio) obteve força máxima de 200 ± 7 N com deformação média do enxerto de 8 ± 2 mm, e a força máxima do grupo 2 (PLA) foi de 300 ± 30 N e deformação média do enxerto de 7 ± 3 mm. Ambos os parafusos de titânio e PLA forneceram boa fixação de enxerto no bloco de poliuretano, sem deslizamento ou deformação aparente. Em todas as amostras o teste culminou na ruptura do enxerto, com cerca de 20 mm de deformação em relação ao comprimento inicial. Conclusão O parafuso PLA impresso em 3D proporcionou boa fixação, semelhante à de sua contraparte de titânio, produzindo resultados satisfatórios e promissores.

Effectiveness in Sterilization of Objects Produced by 3D Printing with Polylactic Acid Material: Comparison Between Autoclave and Ethylene Oxide Methods / Eficácia na esterilização de objetos produzidos pela impressão 3D com material ácido polilático: Comparação entre os métodos autoclave e óxido de etileno

Abstract Objective Due to the popularity of 3D technology, surgeons can create specific surgical guides and sterilize them in their institutions. The aim of the present study is to compare the efficacy of the autoclave and ethylene oxide (EO) sterilization methods for objects produced by 3D printing with polylactic acid (PLA) material. Methods Forty cubic-shaped objects were printed with PLA material. Twenty were solid and 20 were hollow (printed with little internal filling). Twenty objects (10 solid and 10 hollow) were sterilized in autoclave, forming Group 1. The others (10 solid and 10 hollow) were sterilized in EO, composing Group 2. After sterilization, they were stored and referred to culture. Hollow objects of both groups were broken during sowing, communicating the dead space with the culture medium. The results obtained were statistically analyzed (Fisher exact test and residue analysis). Results In group 1 (autoclave), there was bacterial growth in 50% of solid objects and in 30% of hollow objects. In group 2 (EO), growth occurred in 20% of hollow objects, with no bacterial growth in solid objects (100% of negative samples). The bacteria isolated in the positive cases was non-coagulase-producing Staphylococcus Gram positive. Conclusions Sterilization by both autoclave and EO was not effective for hollow printed objects. Solid objects sterilized by autoclave did not demonstrate 100% of negative samples and were not safe in the present assay. Complete absence of contamination occurred only with solid objects sterilized by EO, which is the combination recommended by the authors.

Resumo Objetivo Devido à popularidade da tecnologia 3D, cirurgiões podem criar guias cirúrgicos específicos e esterilizá-los nas suas instituições. O objetivo do presente estudo é comparar a eficácia dos métodos de esterilização por autoclave e óxido de etileno (OE) de objetos produzidos pela impressão 3D com material ácido polilático (PLA, na sigla em inglês). Métodos Quarenta objetos em formato cúbico foram impressos com material de PLA. Vinte eram sólidos e 20 eram ocos (impressos com pouco enchimento interno). Vinte objetos (10 sólidos e 10 ocos) foram esterilizados em autoclave, formando o Grupo 1. Os demais (10 sólidos e 10 ocos) foram esterilizados em OE, compondo o Grupo 2. Após a esterilização, os objetos foram armazenados e encaminhados para cultura. Objetos ocos de ambos os grupos foram quebrados durante a semeadura, comunicando o espaço morto com o meio de cultura. Os resultados obtidos foram analisados estatisticamente (teste exato de Fisher e análise de resíduo). Resultados No grupo 1 (autoclave) houve crescimento bacteriano em 50% dos objetos sólidos e em 30% dos objetos ocos. No grupo 2 (OE) o crescimento ocorreu em 20% dos objetos ocos, com ausência de crescimento bacteriano nos objetos sólidos (100% de amostras negativas). A bactéria isolada nos casos positivos foi Staphylococcus Gram positivo não produtor de coagulase. Conclusões A esterilização tanto em autoclave quanto pelo OE não foi eficaz para objetos impressos no formato oco. Objetos sólidos esterilizados em autoclave não demonstraram 100% de amostras negativas, não sendo seguro no presente ensaio. Ausência completa de contaminação ocorreu apenas com objetos sólidos esterilizados pelo OE, sendo a combinação recomendada pelos autores.

Application of 3D Printing Technology in the Treatment of Hoffa's Fracture Nonunion / Aplicação da tecnologia de impressão 3D no tratamento da pseudartrose da fratura de Hoffa

Abstract Objective To evaluate a proposed three-dimensional (3D) printing process of a biomodel developed with the aid of fused deposition modeling (FDM) technology based on computed tomography (CT) scans of an individual with nonunion of a coronal femoral condyle fracture (Hoffa's fracture). Materials and Methods Thus, we used CT scans, which enable the evaluation of the 3D volumetric reconstruction of the anatomical model, as well as of the architecture and bone geometry of sites with complex anatomy, such as the joints. In addition, it enables the development of the virtual surgical planning (VSP) in a computer-aided design (CAD) software. This technology makes it possible to print full-scale anatomical models that can be used in surgical simulations for training and in the choice of the best placement of the implant according to the VSP. In the radiographic evaluation of the osteosynthesis of the Hoffa's fracture nonunion, we assessed the position of the implant in the 3D-printed anatomical model and in the patient's knee. Results The 3D-printed anatomical model showed geometric and morphological characteristics similar to those of the actual bone. The position of the implants in relation to the nonunion line and anatomical landmarks showed great accuracy in the comparison of the patient's knee with the 3D-printed anatomical model. Conclusion The use of the virtual anatomical model and the 3D-printed anatomical model with the additive manufacturing (AM) technology proved to be effective and useful in planning and performing the surgical treatment of Hoffa's fracture nonunion. Thus, it showed great accuracy in the reproducibility of the virtual surgical planning and the 3D-printed anatomical model.

Resumo Objetivo Avaliar uma proposta de processo de impressão tridimensional (3D) de um biomodelo preparado com o auxílio da tecnologia de modelagem por deposição de material fundido (fused deposition modeling, FDM, em inglês) a partir de imagens de tomografia computadorizada (TC) de um indivíduo com pseudartrose de fratura coronal do côndilo femoral (fratura de Hoffa). Materiais e Métodos Para tanto, utilizamos imagens de TC, que permitem estudar a reconstrução volumétrica 3D do modelo anatômico, além da arquitetura e geometria óssea de sítios de anatomia complexa, como as articulações. Também permite o planejamento cirúrgico virtual (PCV) em um programa de desenho assistido por computador (computer-aided design, CAD, em inglês). Essa tecnologia possibilita a impressão de modelos anatômicos em escala real que podem ser utilizados em simulações cirúrgicas para o treinamento e a escolha do melhor posicionamento do implante de acordo com o PCV. Na avaliação radiográfica da osteossíntese da pseudartrose de Hoffa, verificou-se a posição do implante no modelo anatômico impresso em 3D e no joelho do paciente. Resultados O modelo anatômico impresso em 3D apresentou características geométricas e morfológicas semelhantes às do osso real. O posicionamento dos implantes em relação à linha de pseudartrose e pontos anatômicos foram bastante precisos na comparação do joelho do paciente com o modelo anatômico impresso em 3D. Conclusão A utilização do modelo anatômico virtual e do modelo anatômico impresso em 3D com a tecnologia de manufatura aditiva (MA) foi eficaz e auxiliou o planejamento e a realização do tratamento cirúrgico da pseudartrose da fratura de Hoffa. Desta forma, foi bastante preciso na reprodutibilidade do planejamento cirúrgico tanto virtual quanto no modelo anatômico impresso em 3D.

Effectiveness of disinfectant solutions associated or not with brushing on the biofilm control of a 3D printed-denture base resin

Abstract The formation of biofilm on denture bases is a recurrent clinical problem that favors the development of denture stomatitis. The effectiveness of a hygiene protocol in a 3D-printed denture base resin is still uncertain. Objective To evaluate of the effectiveness of immersion, associated or not with brushing in a soap solution, on the biofilm control of a 3D-printed denture base resin. Methodology Specimens of denture base resins [Cosmos Denture (COS) and Classico (CLA/control)] were contaminated in vitro with Candida albicans and immersed in sodium hypochlorite 0.25% (SH, alkaline peroxide) AP, chlorhexidine digluconate 2% (CD or PBS-Control), associated or not with brushing with 0.78% Lifebuoy soap. Roughness was evaluated before and after brushing and immersion. The effectiveness of the protocols was assessed by CFU/mL, cellular metabolism (XTT), scanning electron microscopy (SEM), and confocal scanning laser microscopy. Data were analyzed by T student, ANOVA/Welch, and Tukey/Gomes-Howell pos-hoc tests (α = 0.05). Results CLA showed greater roughness than COS. CFU/mL and XTT were higher in COS resin with a higher hyphae formation. Immersion in SH and CD eliminated CFU/mL and reduced XTT for both resins, associated or not with brushing. AP reduced CFU/mL only when associated with brushing. Conclusions The biofilm on the 3D-printed resin was thicker and presumably more pathogenic, regardless of its smoother surface. Immersions in SH 0.25% and CD 2% are effective hygiene protocols for both resins, associated or not with brushing. AP should be recommended when associated with brushing with a Lifebuoy 0.78% solution.

Efficacy of 3D-printed guide plate assisted versus freehand placement of cannulated screws for the treatment of Sanders type II and III calcaneal fractures / 中华创伤杂志

Objective:To compare the efficacy of 3D-printed guide plate assisted versus freehand placement of cannulated screws for the treatment of Sanders type II and III calcaneal fractures.Methods:A retrospective cohort study was conducted to analyze the clinical data of 29 patients with Sanders type II and III calcaneal fractures admitted to Chonggang General Hospital from June 2020 to October 2022. Among them, there were 18 males and 11 females, with an age range of 22-69 years [(40.1±11.5)years]. Nineteen patients were treated with individualized 3D-printed guide plate assisted placement of cannulated screws (3D-printed group) and 10 were treated with freehand placement of cannulated screws (freehand group). The surgical time, fluoroscopy times, postoperative 6-month calcaneal morphology (length, width, height, B?hler angle and Gissane angle), and American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score and Maryland functional score assessed at 3, 6 months after operation and at the final follow-up were compared between the two groups. The incision healing and complications were observed.Results:The patients were followed up for 6-24 months [(11.3±2.5)months]. The surgical time and fluoroscopy times in the 3D-printed group were (53.4±9.1)minutes and (7.3±1.1)times, respectively, which were shorter than (90.2±16.0)minutes and (16.0±3.2)times in the freehand group (all P<0.01). At 6 months after operation, there was no significant difference in calcaneal length between the two groups ( P>0.05); the calcaneal width, height, B?hler angle and Gissane angle in the 3D-printed group [(34.0±1.8)mm, (47.2±1.6)mm, (27.8±1.0)°, (129.2±2.8)°] were superior than those in the freehand group [(37.5±2.0)mm, (43.0±2.7)mm, (25.8±1.5)°, (125.9±2.5)°] (all P<0.01). At 3, 6 months after operation and at the final follow-up, the values of AOFAS ankle-hindfoot score in the 3D-printed group [(72.2±2.3)points, (79.7±2.3)points, (86.5±4.4)points] were higher than those in the freehand group [(64.2±6.9)points, (73.4±4.2)points, (81.8±3.1)points] (all P<0.05); the values of Maryland score in the 3D-printed group [(71.4±7.7)points, (84.7±2.6)points, (91.5±2.5)points] were higher than those in the freehand group [(65.2±5.6)points, (79.1±3.8)points, (87.1±2.9)points] (all P<0.05). All surgical incisions were healed in stage I. In the 3D-printed group, there were no complications regarding infection, iatrogenic vascular or nerve injury, or fixation failure after surgery. In the freehand group, one patient with lateral sural cutaneous nerve injury was resolved spontaneously without specific treatment. Conclusion:Compared with freehand placement of cannulated screws, 3D-printed guide plate assisted placement of percutaneous placement has the advantages of shorter surgical time, fewer fluoroscopy times, lower reduction loss, better ankle joint function recovery, and less complications in treating Sanders type II and III calcaneal fractures.

3D printed guide plate assisted and C-arm X-ray fluoroscopic positioning for femoral tunnel reconstruction of medial patellofemoral ligament in treating recurrent patellofemoral dislocation: a comparison of efficacies / 中华创伤杂志

Objective:To compare the efficacies of 3D printed guide plate assisted positioning and C-arm X-ray machine fluoroscopic positioning for femoral tunnel reconstruction of medial patellofemoral ligament in treating recurrent patellofemoral dislocation.Methods:A retrospective cohort study was performed on the clinical data of 60 patients with recurrent patellar dislocation admitted to the First Affiliated Hospital of Kunming Medical University from January 2018 to December 2022. The patients included 29 males and 31 females, with age range of 14-40 years [(28.6±7.6)years]. The 3D printed guide plate was used to locate the femoral tunnel in 30 patients for medial patellofemoral ligament reconstruction (3D guide group), and C-arm X-ray machine was used for another 30 patients (conventional group). (1) CT data of the knee joint were collected before surgery and at 7 days after surgery. Mimics 19.0 software was introduced to measure the distance between the center of femoral tunnel and Sch?ttle point after surgery. (2) Knee Lysholm score and Kujala score were used to evaluate the knee function before and at 3, 6, 9 and 12 months after surgery. (3) At the same time points, Opti-Knee TM 3D knee kinematics analysis system was used to collect the forward and backward displacement, up and down displacement, internal and external displacement, internal and external flipping angle, internal and external rotation angle, and flexion and extension angle of the affected knee joint. The range of each freedom degree was calculated and 6 freedom degree items of 30 healthy people were subjected to knee kinematics analysis. Results:All patients were followed up for 12-15 months [(12.3±0.7)months]. (1) The distance between the center of femoral tunnel and Sch?ttle point in the 3D guide group was (5.5±2.3)mm, smaller than that in the conventional group [(7.6±2.5)mm] ( P<0.01). (2) The Lysholm score and Kujala score of the 3D guide group and conventional gruop gradually increased after surgery (all P<0.01). There were no significant differences in the Lysholm score or Kujala score between the 3D guide group and conventional gruop before surgery and at 12 months after surgery (all P>0.05). At 3, 6 and 9 months after surgery, the Lysholm score of the 3D guide group [(70.4±4.5)points, (86.4±3.1)points, (91.2±3.2)points] and Kujala score [(74.2±5.3)points, (80.9±3.5)points, (85.2±3.2)points] were higher than those of the conventional group [Lysholm score: (67.3±5.2)points, (81.8±2.5)points, (86.2±1.9)points; Kujala score: (69.8±5.2)points, (77.6±2.1)points, (82.7±2.6)points] ( P<0.05 or 0.01). (3) Before surgery, the forward and backward displacement in the 3D guide group and conventional group [(0.6±0.1)cm, (0.6±0.2)cm], up and down displacement [(0.5±0.1)cm, (0.6±0.0)cm], internal and external displacement [(0.7±0.1)cm, (0.6±0.2)cm], and flexion and extension angle [(50.6±10.3)°, (51.6±8.5)°] were less than those in the healthy controls [(1.6±0.3)cm, (1.7±0.5)cm, (1.0±0.4)cm, (63.2±5.1)°] (all P<0.05), while the internal and external flipping angle [(17.5±4.0)°, (17.1±3.8)°] and internal and external rotation angle [(17.9±1.9)°, (17.5±1.5)°] were greater than those in the healthy controls [(11.8±3.6)°, (15.8±4.9)°] (all P<0.05). At other time points, the results of front and back displacement, up and down displacement, internal and external displacement, internal and external rotation angle in the 3D guide group and conventional group were not significantly different compared with the healthy controls (all P>0.05). The flexion and extension angle in the 3D guide group and conventional gruop were smaller than those in the healthy controls at 3 months after surgery (all P<0.05). At 6 and 9 months after surgery, the flexion and extension angle in the conventional group [(55.0±3.7)°, (57.7±4.8)°] were smaller than those in the healthy controls [(63.2±5.1)°, (63.2±5.1)°] (all P<0.05), but no significant difference was found between the 3D guide group [(61.0±4.8)°, (61.8±4.9)°] and the healthy controls (all P>0.05). The flexion and extension angle in the 3D guide group and conventional gruop was similar with that in the healthy controls at 12 months after surgery (all P>0.05). Conclusions:Compared with the C-arm X-ray machine, the 3D printed guide plate assisted positioning of femoral tunnel is more simple and accurate for the medial patellofemoral ligament reconstruction in treating recurrent patellofemoral dislocation, together with better early knee function recovery, better satisfaction of the patients, and better and faster restoration of the flexion and extension angle of knee joint kinematic function.

Effect of 3D-printed nano-β-tricalcium phosphate in repairing seawater-soaked tibial defects in rabbits / 中华创伤杂志

Objective:To explore the repairing effects of 3D-printed nano-β-tricalcium phosphate (β-TCP) scaffolds loaded with vancomycin and bone morphogenetic protein-2 (BMP-2) for seawater -soaked tibial bone defects in rabbits. Methods:A total of 27 male New Zealand White rabbits were assigned to the normal group using a random number table method, with each group consisting of 9 rabbits. The rabbit tibial bone defect model was created using the osteotomy surgical method. Eight hours after operation, the wounds in the control group and seawater group were immersed in seawater for 2 hours, and those in the normal group were not immersed. After an observation period of 5-7 days, no significant redness or purulent discharge was observed in the wound appearance, then debridement was performed followed by corresponding implantations: the control group with gelatin sponges loaded with vancomycin and BMP-2, and the other two groups with 3D-printed nano-β-TCP scaffolds loaded with vancomycin and BMP-2. After filling the bone defects with the respective materials, all groups underwent layer-by-layer suturing of the wound, followed by disinfection with iodine and injection of gentamicin to prevent infection. The affected limbs were then immobilized using a plaster cast. The affected limbs were imaged using anteroposterior X-ray at 4, 8 and 16 weeks after operation, and the repair effects were evaluated using the Lane-Sandhu X-ray scoring system. At 16 weeks after operation, the bone defect tissues were collected for HE staining to observe bone tissue growth.Results:At 4 weeks after operation, the Lane-Sandhu X-ray score in the control group was significantly lower than that in the normal group [(2.8±1.1)points vs. (1.1±0.9)points] ( P<0.05), and that in the seawater group [(2.2±1.0)points] was not significantly different from those in the other two groups (all P>0.05). At 8 weeks after operation, the seawater group [(6.1±0.9)points] and the control group [(2.8±1.0)points] exhibited lower Lane-Sandhu X-ray score compared to the normal group [(8.2±1.0)points] (all P<0.05), and the seawater group showed a higher score compared to the control group ( P<0.05). At 16 weeks after operation, the control group [(3.8±1.0)points] exhibited a lower Lane-Sandhu X-ray score compared to the normal group [(10.0±1.3)points] and the seawater group [(9.3±1.2)points] (all P<0.05), while no significant difference was noted between the latter two ( P>0.05). At 16 weeks after operation, histological observations revealed varying degrees of bone tissue formation in three groups, with the normal group showing the best bone defect repair effect, followed by the seawater group. Conclusion:The 3D-printed nano-β-TCP scaffolds loaded with vancomycin and BMP-2 are effective for the treatment of seawater -soaked bone defects, which can promote bone tissue repair.

The role and value of surgeon-engineer interaction during preoperative planning of patient-specific instrumentation assisted total knee arthroplasty / 中华骨科杂志

Objective:To investigate the significance and importance of the interaction between surgeons and engineers during the preoperative planning phase of total knee arthroplasty (TKA) when utilizing patient-specific instrumentation (PSI).Methods:A retrospective review was conducted on 202 knees of PSI-assisted TKA performed on 178 patients between June 2018 and August 2022. The patients' mean age was 68.4±6.2 years, ranging from 53 to 86 years. Among the participants, there were 149 females and 29 males, 93 left knees and 109 right knees. The study involved 171 patients of osteoarthritis (193 knees) and 7 patients of rheumatoid arthritis (9 knees), with 194 knees presenting varus knees and 8 knees with valgus knees. The preoperative plan documents, from the initial engineer-designed plan to the final plan approved by the surgeon, were analyzed to assess the frequency, parameters, and reasons for adjustments made during the planning process.Results:The planning of the 202 PSI-assisted TKA was subjected to at least one round of surgeon-engineer interaction. Among the 202 TKA planning, 117 knees (57.9%) underwent modifications after discussion, with most plans (100 knees, 49.5%) being confirmed after one round of modification. Two rounds of modifications were performed on 10 knees (5.0%), and three rounds on 5 knees (2.5%). A maximum of four rounds of modifications were made on two knees (0.9%). Furthermore, in the case of the remaining 85 knees (42.1%), the surgeons promptly consented to the engineers' initial planning following the discussions. Specific adjustments were made in 106 knees (52.5%) regarding femoral parameters, 57 knees (28.2%) concerning tibial parameters, and 46 knees (22.8%) requiring adjustments to both femoral and tibial parameters. Notably, the most frequently adjusted parameter was the osteotomy thickness of the posterior femoral condyles, which was modified in 94 knees (80.3%). The reasons for adjusting femoral or tibial parameters were summarized, revealing the main factors as follows: 1) Discrepancy between the mediolateral and anteroposterior diameters of the femoral condyle; 2) Twisted deformity of the proximal tibia; 3) Severe flexion contracture deformity of the knee; 4) Collapse of the medial or lateral tibial plateau; 5) Evident anterior arch deformity of the femur.Conclusion:The interaction between surgeons and engineers plays a pivotal role in the preoperative phase of PSI-assisted TKA. Effective collaboration allows surgeons to accurately analyze the unique anatomical characteristics and pathological changes of each patient in a three-dimensional perspective, facilitating the formulation of individualized surgical plans.

Application of three-dimensional printed endoprosthesis for reconstruction after metaphysis-involved intercalary tumor resection / 中华骨科杂志

Objective:To describe the design, manufacture and use of three-dimensional (3D)-printed endoprosthesis for reconstruction after metaphysis-involved intercalary tumor resection and to evaluate its outcome.Methods:Forty-three patients who received metaphysis-involved intercalary tumor resection followed by 3D-printed endoprosthetic reconstruction in Musculoskeletal Tumor Center, Peking University People's Hospital between January 2018 and December 2021 were retrospectively reviewed. There were 25 males and 18 males with an average age of 20.1±15.2 years (range, 4-58 years). The pathological diagnosis included 24 cases of osteosarcomas, 6 cases of Ewing sarcomas, 5 cases of chondrosarcomas, 2 cases of pleomorphic undifferentiated sarcomas, 3 cases of soft-tissue sarcomas (liposarcoma, synovial sarcoma, malignant peripheral nerve sheath tumor for each) and 3 others (adamantinoma, recurrent aneurysmal bone cyst and recurrent osteofibrous dysplasia for each). The tumors located at femur in 25 patients (58%), including 14 lesions involving distal femoral metaphysis and 11 lesions involving both proximal and distal metaphysis; the tumors located at tibia in 11 patients (26%), including 4 lesions involving distal tibial metaphysis, 5 lesions involving proximal tibial metaphysis and 2 lesions involving both proximal and distal tibial metaphysis; the tumors located at humerus in 7 patients (16%), including 1 lesion involving distal humeral metaphysis, 3 lesions involving proximal humeral metaphysis and 3 lesions involving both proximal and distal humeral metaphysis. The endoprosthesis was designed in a semi-modular fashion and consisted of three parts: a diaphysis-fixing component, a semi-modular lap joint component, and a custom-made 3D-printed metaphysis-fixing component which was designed as two types with 3D-printed porous bone-contacting surfaces according to the osteotomy plane (Type I on meta-diaphyseal region, Type II on meta-epiphyseal region). The functional outcome was assessed using Musculoskeletal Tumor Society (MSTS) 93 system.Results:All surgeries were accomplished sucessfully. The median resection length and the distance from osteotomy plane to adjacent joint was 16.0 (13.0, 22.0) cm and 4.5 (3.5, 6.0) cm, respectively. 59 metaphysis-fixing components were installed in 43 patients. Type I components were used in single and dual ends of endoprosthesis in 12 and 6 cases respectively. Type II components were used in single and dual ends in 15 and 5 cases respectively. Hybrid endoprosthesis with Type I and II components were used in 5 cases. The mean follow-up time was 26.0 (17, 37) months (range, 12-54 months). The mean MSTS 93 score was 29.0 (28.0, 30.0) points (range, 21-30 points). Implant failures were found in 5 patients, including 2 cases of aseptic loosening (loosening was observed in the cementing diaphysis-fixing stems while no evidence of loosening in metaphysis-fixing components) and 3 cases of local tumor progression. The 2-year implant survival rate was 90.3% (95% CI: 0.81, 0.99). Conclusion:Using 3D-printed intercalary endoprosthesis for reconstruction after intercalary resection of metaphysis-involved bone tumor shows satisfactory functional outcome and implant survival. Moreover, by assembling endoprosthetic components according to the different osteotomy plane, the semi-modularized endoprosthesis also provids a comprehensive and individualized reconstruction for patients with metaphysis-involved intercalary tumor.

Application of newly designed modular hinged ankle prosthesis in the reconstruction of defect after surgical treatment of malignant tumor at the distal tibia / 中华骨科杂志

Objective:To investigate the outcome of surgical treatment of malignant tumor at the distal tibial after reconstruction with modular hinged ankle prosthesis.Methods:The data of 9 patients with malignant tumor at the distal tibia at Musculoskeletal Tumor Center of PKUPH from June 2020 to November 2021 were analyzed retrospectively. They were male patients with age of 17 (14, 24) years (range 11-56 years). There were five tumors at the left sides and four at the right sides. There were eight patients with osteosarcoma who received the neo-chemotherapy. Among eight osteosarcomas, one was Enneking IIA and seven Enneking IIB. Furthermore, there was only one patient with renal carcinama and with solitary metastatic lesion at the distal tibia. After the resection of tumor at the distal tibia, talus cartilage was removed and talus component was fixed by lag screws. The proper tibia component was used to restore the defect of tibia and the reduction of tibia and talus components were performed. The following clinical data were collected: baseline demographic features, surgical and follow-up data. The baseline demographic features included gender, age, side, lung or/and other metastasis at initial diagnosis, Enneking stage or systematic progression for renal carcinama, histological type. The surgical data included: surgery time, blood loss, length of bone involved by the tumor, prosthesis type. Monitoring data was also recorded: complications (ankle pain when loading, talar collapse, component loosing, infection and wound dehiscence), local recurrence, pulmonary and systematic metastasis, radiological image and the function at the last follow-up (MSTS and VAS evaluation).Results:Among these nine patients, the average blood loss was 245.6±103.9 ml (range 100-400 ml) and the mean surgery time was 178.9±56.9 mins (range 120-300 min). No patient was lost during the follow-up period and the average follow-up was 21.4±5.6 months (range 12.5-27.2 months). The excision length of tibia was 14 (11, 17) cm (range 11-28 cm). There were one case with 2# prosthetic base, three cases with 3# and five cases with 4#. Five had cement fixation of prosthetic stem and four had the pressing fixation. No pulmonary and other organ metastasis occurred among eight patients with osteosarcoma and one patient with distal tibia matastasis of renal carcinama. One patient with OShad the local recurrence and received the resection. One sustained the deep infection after four months and received the removal of prosthesis and spacer implant. At the final follow-up, except one with deep infection and receiving the removal of prosthesis and spacer implant, eight patients were assessed for the function. The average MSTS was 97.1%±3.3% (range 93%-100%). The VAS of all patients was 0. One patient with prosthesis removal had no functional evaluation. At the final follow-up, all patients walked without crutch. No breakage and loosening of prosthetic stem, talar collapse, prosthetic sinking and ankle pain occurred at the final follow-up.Conclusion:The early satisfactory outcome can be obtained for patients with segmental defect after resection of malignant tumor at the distal tibia, who received the newly designed modular hinged ankle prosthesis. Meanwhile, it's worth promoting in the reconstruction of large segmental defect at the distal tibia.

A new 3D-printed ankle fusion prosthesis for the treatment of osteosarcoma in the distal tibia: a case report / 中华骨科杂志

To report the short-term clinical outcome of three cases of distal tibial osteosarcoma treated with a novel 3D-printed ankle fusion prosthesis for limb preservation. The patients were admitted to the Department of Bone Tumor, Shanghai General Hospital from January 2020 to June 2021, with one male and two female cases, aged 18, 12, and 14 years, respectively, all diagnosed with distal tibial osteosarcoma (Ennecking stage IIb). A new self-designed ankle fusion prosthesis was used to perform osteosarcoma resection and prosthetic reconstruction of the distal tibia. The operation time, blood loss, postoperative American Orthopedic Foot and Ankle Society Score (AOFAS) and ankle range of motion were recorded. All the 3 patients successfully completed the operation and were followed up for 22 months, 18 months and 12 months, respectively. The operation time was 140 min, 110 min and 200 min, and the blood loss was 200 ml, 200 ml and 350 ml, respectively. At the last follow-up, the AOFAS were 86, 90 and 95 points, and the range of motion of ankle flexion and extension were 30°, 15° and 30°. There was no local recurrence or lung metastasis at the last follow-up. The novel 3D-printed ankle fusion prosthesis in the distal tibia is safe and effective for the reconstruction of bone defects after resection of osteosarcoma in the distal tibia, and the early postoperative function is satisfactory.

Mid-term efficacy of surface knee prosthesis combined with bionic block in joint reconstruction after resection of giant cell tumor in proximal tibia / 中华骨科杂志

A total of 6 patients were treated with surface knee joint prosthesis combined with 3D-printed customized bionic tibial block for reconstruction of bone defect after giant cell tumor (GCT) in proximal tibia (1 male and 5 females, aged 50, 40, 68, 53, 35, 42, respectively). 3 patients with primary and 3 patients with recurrence of GCT. After resection of the tumor, the bone defect was filled with 3D-printed block combined with surface knee prosthesis, the surrounding ligaments were reconstructed with microporous structure and artificial mesh. All cases were followed up for 60, 90, 60, 60, 75, and 50 months, respectively. During the follow-up, there was no local recurrence, no radiolucent lines around prosthesis, and no signs of loosening. The clinical scores of the American Knee Society Score (KSS) were 87, 92, 85, 90, 95 and 78. The functional scores were 70, 100, 70, 100, 100 and 80 respectively. Musculoskeletal Tumor Society Score (MSTS) were 27, 28, 26, 26, 26, 27, respectively. Surface knee prosthesis combined with bionic block can effectively fill the bone defect after resection of GCT in proximal tibia, achieve anatomical and functional reconstruction of knee joint.

Three-dimensional printing technology in reverse shoulder arthroplasty after resection of proximal humeral tumors / 中华骨科杂志

Objective:To analyze the efficacy of the reconstruction of the proximal humerus by reverse shoulder arthroplasty with three-dimensional (3D) printing technology after tumor rescetion.Methods:A retrospective analysis was conducted on the data of eight patients undergoing semi-constrained reverse shoulder arthroplasty with 3D printing technology after the resection of bone tumors in proximal humeri at the Affiliated Wuxi People's Hospital of Nanjing Medical University from December 2017 to January 2021. There were four males and four females with an average age of 55.1 (range, 31-73) years, all of whom had unilateral onset, 2 on the left and 6 on the right. There was one case of leiomyosarcoma (Enneking IIB), two cases of chondrosarcomas (one Enneking IA and one Enneking IB), four cases of Campanacci grade 3 giant cell tumor of bone, and one case of bone metastasis of lung adenocarcinoma. Individualized prosthesis and implantation protocol were completed preoperatively in all patients. The glenoid baseplate was manufactured using 3D printing technology. During the surgery, Malawer type I tumor resection and semi-constrained reverse shoulder arthroplasty were performed, with 6 cases simultaneously using allograft-prosthetic composite reconstruction. The follow-up was scheduled, and the patient received X-ray examination of the shoulder. The range of motion of the shoulder was measured, the Constant-Murley score and musculoskeletal tumor society (MSTS) score were recorded.Results:All 8 patients successfully completed the surgery, with a surgical time of 173.8±46.7 min (range, 130-260 min), intraoperative blood loss of 487.5±334.6 ml (range 200-1,200 ml), and proximal humeral resection of 9.9±4.6 cm (range, 4.5-19.0 cm). All patients were followed up for a period of 45.6±12.5 months (range, 24-60 months). At the last follow-up, the abduction ranges of motion of the affected shoulders increased from 27.5°±14.4° pre-operatively to 106.3°±21.8° post-operatively, with a statistically significant difference ( t=11.37, P<0.001). The forward flexion ranges increased from 28.1°±12.8° pre-operatively to 115.6°±24.0° post-operatively, with a statistically significant difference ( t=11.49, P<0.001). The Constant-Murley score was improved from 40.5±14.3 pre-operatively to 79.3±11.2 post-operatively, with a statistically significant difference ( t=9.58, P<0.001). The MSTS score was 25.6±2.2 (range, 23-28), including 6 excellent cases and 2 good cases. At 2 weeks after surgery, one patient experienced joint dislocation that was successfully reduced manually. Up to the final follow-up, all patients had survived without local tumor recurrence, metastasis, prosthesis infection and loosening. Conclusion:3D printing technology assisted shoulder arthroplasty is helpful for effective reconstruction and shoulder joint function recovery after resection of proximal humeral tumors, with satisfactory outcomes in the early and middle stages.

Research and progress of three-dimensional printing in the field of hepatopancreatobiliary surgery / 中华肝胆外科杂志

Three-dimensional (3D) printing is an additive manufacturing technology, which is widely used in automobile, aerospace, food, medicine and other fields. 3D printing technology brings novel solutions for precision medicine. In the field of hepatopancreatobiliary surgery, 3D printing is used in medical education, surgical simulation, patient-specific liver models printing in hepatectomy and liver transplantation. In the future, with the discovery and application of high-tech materials, 3D printing technology will be further developed in hepatopancreatobiliary surgery, and hepatobiliary surgery will usher in a new spring. This paper will review the application and future prospects of 3D printing technology in hepatopancreatobiliary surgery.

Biomechanical evaluation of four surgical techniques for ventral stabilization of the atlantoaxial joint in dogs

ABSTRACT Purpose: This study compared, through biomechanical evaluation under ventral flexion load, four surgical techniques for ventral stabilization of the atlantoaxial joint in dogs. Methods: In total, 28 identical atlantoaxial joint models were created by digital printing from computed tomography images of a dog, and the specimens were divided into four groups of seven. In each group, a different technique for ventral stabilization of the atlantoaxial joint was performed: transarticular lag screws, polyaxial screws, multiple screws and bone cement (polymethylmethacrylate-PMMA), and atlantoaxial plate. After the stabilization technique, biomechanical evaluation was performed under ventral flexion load, both with a predefined constant load and with a gradually increasing load until stabilization failure. Results: All specimens, regardless of stabilization technique, were able to support the predefined load without failing. However, the PMMA method provided significant more rigidity (p ≤ 0.05) and also best resisted the gradual increase in load, supporting a significantly higher maximum force (p ≤ 0.05). There was no statistical difference in flexural strength between the transarticular lag screws and plate groups. The polyaxial screws method was significantly less resistant to loading (p ≤ 0.05) than the other groups. Conclusions: The PMMA technique had biomechanical advantages in ventral atlantoaxial stabilization over the other evaluated methods.

Percutaneous kyphoplasty assisted by three dimensional printing percutaneous guide plate for the treatment of osteoporotic vertebral compression fractures / 中国骨伤

OBJECTIVE@#To verify the safety of three dimensional printing percutaneous guide plate assisted percutaneous kyphoplasty(PKP) in the treatment of osteoporotic vertebral compression fractures(OVCFs).@*METHODS@#The clinical data of 60 patients with OVCFs treated by PKP from November 2020 to August 2021 were retrospectively analyzed. There were 24 males and 36 females, aged from 72 to 86 years old with an average of (76.5±7.9) years. Routine percutaneous kyphoplasty was performed in 30 cases (conventional group) and three dimensional printing percutaneous guide plate assisted PKP was performed in 30 cases (guide plate group). Intraoperative pedicle puncture time (puncture needle to posterior vertebral body edge) and number of fluoroscopy, total operation time, total number of fluoroscopy, amount of bone cement injection, and complication (spinal canal leakage of bone cement) were observed. The visual analogue scale (VAS) and the anterior edge compression rate of the injured vertebra were compared before operation and 3 days after operation between two groups.@*RESULTS@#All 60 patients were successfully operated without complication of spinal canal leakage of bone cement. In the guide plate group, the pedicle puncture time was(10.23±3.15) min and the number of fluoroscopy was(4.77±1.07) times, the total operation time was (33.83±4.21) min, the total number of fluoroscopy was(12.27±2.61) times;and in the conventional group, the pedicle puncture time was (22.83±3.09) min and the number of fluoroscopy was (10.93±1.62) times, the total operation time was(44.33±3.57) min, the total number of fluoroscopy was(19.20±2.67) times. There were statistically significant differences in the pedicle puncture time, intraoperative number of fluoroscopy, the total operation time, and the total number of fluoroscopy between the two groups(P<0.05). There was no significant difference in amount of bone cement injection between the two groups(P>0.05). There were no significant differences in VAS and the anterior edge compression rate of the injured vertebra at 3 days after operation between two groups(P>0.05).@*CONCLUSION@#Three dimensional printing percutaneous guide plate assisted percutaneous kyphoplasty is safe and reliable, which can reduce the number of fluoroscopy, shorten the operation time, and decrease the radiation exposure of patients and medical staff, and conforms to the concept of precise orthopaedic management.

Low-fidelity simulation models in urology resident's microsurgery training

Purpose: To evaluate the gain of microsurgical skills and competencies by urology residents, using low-fidelity experimental models. Methods: The study involved the use of training boards, together with a low-fidelity microsurgery simulator, developed using a 3D printer. The model consists in two silicone tubes, coated with a resin, measuring 10 cm in length and with internal and external diameters of 0.5 and 1.5 mm. The support for the ducts is composed by a small box, developed with polylactic acid. The evaluation of the gain of skills and competencies in microsurgery occurred throughout a training course consisting of five training sessions. The first sessions (S1-S4) took place at weekly intervals and the last session (S5) was performed three months after S4. During sessions, were analyzed: the speed of performing microsurgical sutures in the pre and post-training and the performance of each resident through the Objective Structure Assessment of Technical Skill (OSATS) and Student Satisfaction Self-Confidence tools in Learning (SSSCL). Results: There was a decrease in the time needed to perform the anastomosis (p=0.0019), as well as a progressive increase in the score in the OSATS over during sessions S1 to S4. At S5, there was a slightly decrease in performance (p<0.0001), however, remaining within the expected plateau for the gain of skills and competences. The SSSCL satisfaction scale showed an overall approval rating of 96.9%, with a Cronback alpha coefficient of 83%. Conclusions: The low-fidelity simulation was able to guarantee urology residents a solid gain in skills and competencies in microsurgery.

Técnica de clonación 3D aplicada en planificación quirúrgica para craneosinostosis sagital en Latinoamérica-Perú: reporte de caso

La craneosinostosis sagital es el cierre prematuro de la sutura sagital, ocasionando alteraciones funcionales y estructurales. El tratamiento es quirúrgico, y actualmente se cuenta con diversas técnicas, las cuales requieren de una planificación y entrenamiento para lograr óptimos resultados. Se presenta el caso de un varón de 1 año presenta crecimiento anteroposterior anormal del cráneo, indicándose tomografía cerebral sin contraste evidenciando una sinostosis sagital. Se realiza la planificación quirúrgica de la técnica a desarrollar mediante modelo 3D personalizado a escala real. Paciente cursa con buena evolución y es dado de alta. Finalmente, la tecnología de clonación 3D esencial para la educación y desarrollo neuroquirúrgico permitiendo acceder a modelos táctiles de alta precisión y bajo costo que mejoran la calidad del manejo de craneosinostosis.

Sagittal craniosynostosis is the premature closure of the sagittal suture, causing functional and structural alterations. The treatment is surgical, and there are currently various techniques, which require planning and training to achieve optimal results. We present the case of a 1-year-old male with abnormal anteroposterior growth of the skull, indicating brain tomography without contrast, showing sagittal synostosis. Surgical planning of the technique to be developed is carried out using a real-scale personalized 3D model. The patient progresses well and is discharged. Finally, essential 3D cloning technology for neurosurgical education and development allows access to high-precision, low-cost tactile models that improve the quality of craniosynostosis management.

Three-dimensional printing of orbital computed tomography scan images for use in ophthalmology teaching / Impressão tridimensional de imagens médicas de tomografia computadorizada para uso no ensino de oftalmologia

ABSTRACT Introduction: The use of tridimensional (3D) printing in healthcare has contributed to the development of instruments and implants. The 3D printing has also been used for teaching future professionals. In order to have a good 3D printed piece, it is necessary to have high quality images, such as the ones from Computerized Tomography (CT scan) exam, which shows the anatomy from different cuts and allows for a good image reconstruction. Purpose: To propose a protocol for creating digital files from computerized tomography images to be printed in 3D and used as didactic material in the ophthalmology field, using open-source software, InVesalius®, Blender® and Repetier-Host©. Methods: Two orbit CT scan exam images in the DICOM format were used to create the virtual file to be printed in 3D. To edit the images, the software InVesalius® (Version 3.1.1) was used to delimit and clean the structure of interest, and also to convert to STL format. The software Blender® (Version 2.80) was used to refine the image. The STL image was then sent to the Repetier-Host© (Version 2.1.3) software, which splits the image in layers and generates the instructions to print the piece in the 3D printer using the polymer polylactic acid (PLA). Results: The printed anatomical pieces printed reproduced most structures, both bone and soft structures, satisfactorily. However, there were some problems during printing, such as the loss of small bone structures, that are naturally surrounded by muscles due to the lack of support. Conclusion: Despite the difficulties faced during the production of the pieces, it was also possible to reproduce the anatomical structures adequately, which indicates that this protocol of 3D printing from medical images is viable.

RESUMO Introdução: O uso de impressão em 3-D na área da saúde tem contribuído para o desenvolvimento de instrumentos e próteses. A impressão 3-D tem sido usada para o ensino de futuros profissionais. Para se alcançar uma boa peça em 3-D, é necessário ter imagens de alta qualidade, como aquelas geradas pelo exame de Tomografia Computadorizada (TC), que mostra a anatomia sob diferentes cortes e permite uma boa reconstrução de imagem. Objetivo: Propor um protocolo para a criação de arquivos digitais a partir de imagens de tomografia computadorizada a serem impressas em 3-D e usadas como modelo de material didático oftalmológico usando software de código aberto, InVesalius®, Bender® e Repetier-Host©. Métodos: Foram utilizadas imagens em formato DICOM provenientes de dois exames de tomografia computadorizada de órbitas para a impressão tridimensional. Para manuseio das imagens, foram utilizados o InVesalius®, versão 3.1.1, para delimitar e limpar a estrutura de interesse e também para converter em formato STL. O Blender®, versão 2.80 foi usado para refinamento. A imagem em STL foi então enviada para o programa Repetier-Host, versão 2.1.3, que divide a imagem em camadas e gera as instruções para impressão da peça em ácido polilático na impressora tridimensional. Resultados: As peças anatômicas impressas reproduziram de forma satisfatória a maioria das estruturas ósseas e musculares. No entanto, houve dificuldade durante a impressão das estruturas ósseas menores, como perda de estrutura óssea pequena, que não possuíam sustentação, por serem envoltas pelo músculo. Conclusão: Apesar das dificuldades encontradas na produção dessas peças de estudo, foi possível reproduzir estruturas com fidelidade, indicando que o protocolo proposto viabiliza a impressão de imagens oriundas da tomografia computadorizada para impressão tridimensional.

A study comparing patient satisfaction and retention of CAD/CAM milled complete dentures and 3D printed CAD/CAM complete dentures versus conventional complete dentures: a randomized clinical trial / Um estudo comparando a satisfação do paciente e a retenção de próteses totais fresadas em CAD/CAM e próteses totais 3D impressas com tecnologia CAD/CAM versus próteses totais convencionais: um ensaio clínico randomizado

Objective: To compare the three different methods of complete denture fabrication assessing patient satisfaction and retention after insertion for six months' follow-up period. Material and Methods: The study was conducted in the Prosthodontic Department where a total of forty-eight patients were recruited from the outpatient clinics fulfilling the inclusion criteria. This study was designed as a randomized controlled clinical trial. All patients followed the steps of complete denture construction till jaw relation record. Then, all eligible patients were randomized to intervention and control groups. For intervention groups digital scanning, designing, manufacturing of complete dentures was done; 3D printing for first and milling for second intervention. For the comparator group, complete dentures were manufactured the conventional way. After 2 weeks of delivery of the dentures, patients received a patient satisfaction questionnaire, retention was measured by retention force gauge. Both readings were also recorded after 3 months and at 6 months. The mean and standard deviation values were calculated for each group in each test. The significance level was set at P≤ 0.05. Results: No statistical difference was found in terms of patient satisfaction and retention between the three groups at different time intervals. Conclusion: The manufacturing technique seemed to have no influence on patient satisfaction and retention with milled showing the least results.(AU)

Objetivo: Comparar três métodos diferentes de fabricação de prótese total avaliando a satisfação do paciente e a retenção após a inserção por um período de acompanhamento de seis meses. Material e Métodos: O estudo foi conduzido no departamento de Prótese onde um total de quarenta e oito pacientes foram recrutados das clínicas ambulatoriais atendendo os critérios de inclusão. Este estudo foi designado como um ensaio clínico randomizado controlado. Todos os pacientes seguiram as mesmas etapas de confecção de prótese total até o registro da relação maxilo-mandibular. Então, todos os pacientes qualificados foram divididos de forma aleatória nos grupos de intervenção e grupo controle. Para os grupos de intervenção foram realizados escaneamento digital, projeto e fabricação de próteses totais; Impressão 3D para o primeiro e fresagem para o segundo grupo de intervenção. Para o grupo de comparação, próteses totais foram feitas com o método convencional. Depois de 2 semanas após a entrega das próteses os pacientes receberam um questionário de satisfação e a retenção foi mensurada com um medidor de força de retenção. Ambas as leituras também foram registradas após 3 e 6 meses. Os valores de média e desvio padrão foram calculados para cada grupo em cada teste. O nível de significância foi estabelecido em P ≤ 0,05. Resultados: Nenhuma diferença estatística foi encontrada em termos de satisfação do paciente e retenção entre os três grupos em diferentes intervalos de tempo. Conclusão: A técnica de fabricação pareceu não ter influência na satisfação do paciente e retenção da prótese, com o grupo fresado apresentando o mínimo de resultados.(AU)