Laser and electron‐beam powder‐bed additive manufacturing of metallic implants: A review on processes,materials and designs

Additive manufacturing (AM), also commonly known as 3D printing, allows the direct fabrication of functional parts with complex shapes from digital models. In this review, the current progress of two AM processes suitable for metallic orthopaedic implant applications, namely selective laser melting (SLM) and electron beam melting (EBM) are presented. Several critical design factors such as the need for data acquisition for patient‐specific design, design dependent porosity for osteo‐inductive implants, surface topology of the implants and design for reduction of stress‐shielding in implants are discussed. Additive manufactured biomaterials such as 316L stainless steel, titanium‐6aluminium‐4vanadium (Ti6Al4V) and cobalt‐chromium (CoCr) are highlighted. Limitations and future potential of such technologies are also explored. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:369–385, 2016.     

Treatment of Die-Punch Fractures with 3D Printing Technology

ABSTRACT

Purpose: We evaluated the feasibility, accuracy and effectiveness of applying three-dimensional (3D) printing technology for preoperative planning for die-punch fractures. Methods: A total of 107 patients who underwent die-punch fracture surgery were enrolled in the study. They were randomly divided into two groups: 52 cases in the 3D model group and 55 cases in the routine group. A 3D digital model of each die-punch fracture was reconstructed in the 3D group. The 3D digital model was imported to a 3D printer to build the full solid model. The operation time, blood loss volume, and the number of intraoperative fluoroscopy were recorded. Follow-up was performed to evaluate the patients' surgical outcomes. Results: Treatment of die-punch fractures using the 3D printing approach reduced the number of intraoperative fluoroscopy, blood loss volume, and operation time, but did not improve wrist function compared to those in the routine group. The patients wanted the doctor to use the 3D model to introduce the condition and operative plan because it was easier for them to understand. The orthopedic surgeons thought that the 3D model was useful for communicating with their patients, but their satisfaction with the preoperative plan was much lower than the benefit of using the 3D model to communicate with their patients. Conclusions: 3D printing technology produced more accurate morphometric information for orthopedists to provide personalized surgical planning and communicate better with their patients. However, it is difficult to use widely in the department of orthopedics.     

A biomechanical comparison of fragment-specific fixation and augmented external fixation for intra-articular distal radius fractures

The biomechanical stability of an internal fixation system that uses low-profile modular implants to stabilize individual fracture components was studied in a validated cadaver fracture model that incorporated physiologic muscle forces and wrist motion. Fragment-specific fixation with immediate range of motion was compared with static augmented external fixation in simulated, unstable 3- and 4-part intra-articular distal radius fractures (n = 20). Fixation was applied and specimens were loaded via their major wrist tendons. Because the wrist joint was not constrained in the internal fixation group, full wrist motion occurred during load application in these specimens. A 3-dimensional motion tracking system calculated individual fracture fragment motion in both groups. In the 3-part fracture pattern fragment-specific fixation showed comparable stability to static augmented external fixation despite the full wrist range of motion that occurred during application of load in these specimens. In the 4-part fracture pattern fragment-specific fixation was shown to be significantly more stable when compared with static augmented external fixation in 4 of 6 axes of motion. Our findings confirm the stability of this low-profile plating system and support the consideration of early wrist motion when treating complex, intra-articular distal radius fractures with fragment-specific fixation.     

桡骨远端骨折畸形愈合与功能恢复的关系

畸形愈合是桡骨远端骨折治疗中常见的并发症之一。许多研究发现,畸形愈合是影响骨折预后的重要原因。本文总结了近年来国内外学者在生物力学分析及临床病例随访的研究资料,将骨折畸形愈合对腕关节功能恢复的影响进行综述。     

南京地区低能量骨折老年患者存在维生素 D缺乏的回顾性研究

目的研究评估南京地区老年低能量骨折(桡骨远端和髋部骨折)患者维生素D[Vitamin D,Vit D; 25 (OH) D]水平,以及补充活性Vitamin D是否可以有效提高血清25 (OH) D水平。方法回顾性研究南京鼓楼医院骨折联络服务(FLS)病例中90名老年(≥65岁)患者,桡骨远端骨折49名,髋部骨折41名,受伤后均给予口服活性Vitamin D治疗。分析受伤时和伤后4周的25 (OH) D水平。结果所有桡骨远端骨折的患者,受伤时血清25 (OH) D水平为14.83 ng/m L,伤后4周为21.23ng/m L;在髋部骨折患者受伤时血清25 (OH) D水平为9.92 ng/m L,伤后4周为18.96 ng/m L。结论桡骨远端以及髋部骨折老年患者的25 (OH) D水平较低,有可能使肌肉力量下降导致跌倒风险增加,Vitamin D的补充可以有效提高血清25(OH) D水平。     

Current applications of three-dimensional printing in urology

Three-dimensional (3D) printing or additive manufacturing is a new technology that has seen rapid development in recent years with decreasing costs. 3D printing allows the creation of customised, finely detailed constructs. Technological improvements, increased printer availability, decreasing costs, improved cell culture techniques, and biomaterials have enabled complex, novel and individualised medical treatments to be developed. Although the long-term goal of printing biocompatible organs has not yet been achieved, major advances have been made utilising 3D printing in biomedical engineering. In this literature review, we discuss the role of 3D printing in relation to urological surgery. We highlight the common printing methods employed and show examples of clinical urological uses. Currently, 3D printing can be used in urology for education of trainees and patients, surgical planning, creation of urological equipment, and bioprinting. In this review, we summarise the current applications of 3D-printing technology in these areas of urology.     

3D‐Printed Screw‐Rod Auxiliary System for Unstable Atlas Fractures: A Retrospective Analysis

ObjectiveTo develop and validate the efficacy of a 3D‐printed screw‐rod auxiliary system for unstable atlas fractures.MethodsThis research is a retrospective analysis, and a total of 14 patients, including 11 males and three females, were enrolled in our hospital from January 2017 to March 2019 who underwent occipitocervical fusion assisted by the 3D‐printed screw‐rod auxiliary system were reviewed, and with an average age of 53.21 ± 14.81 years, an average body mass index (BMI) of 23.61 ± 1.93 kg/m². The operation time, blood loss and radiation times during the operation were recorded. The maximum fracture displacement values of pre‐ and post‐operation were measured based on CT imaging. All screw grades were evaluated after surgery. The occipital‐cervical 2 (O‐C₂) angle and occipitocervical inclination (OCI) angle of pre‐operation, post‐operation and the last following‐up were measured. The dysphagia scale 3 months after surgery and at the last follow‐up, the Neck Disability Index (NDI) 3 months after surgery and at the last follow‐up were assessed.ResultsAll patients were completed the surgery successfully. There was no patient with severe dysphagia or aggravation of nerve injury. The follow‐up was from 12 to 14 months, and with an average of 12.5 months. The average surgery time, average blood loss and average radiation times for the 14 patients were 112.14 min, 171.43 mL and 5.07 times, respectively. There was a significant difference in maximum fracture displacement between pre‐ and post‐operation values (P < 0.05). A total of 56 screws were inserted in 14 patients, among them, three screws were classified as grade 1, and the other screws were classified as grade 0. There was a significant difference in the O‐C₂ between pre‐operation and 3 days after operation (P = 0.002); There was a significant difference in OCI angles between pre‐operation and 3 days after operation (P < 0.05); there was no significant difference in the O‐C₂ or OCI angle between 3 days after the operation and the last follow‐up (P = 0.079; P = 0.201). The dysphagia scales of two patients were assessed as mild at 3 months after surgery, and the others were assessed as normal at 3 months after surgery. All patients'' dysphagia scores returned to normal at the last follow‐up. The average NDI and average neck Visual Analogue Scale (VAS) scores at the last follow‐up were 2.53 and 8.41, respectively.ConclusionIt can objectively restore the OCI to normal with few post‐operative complications under the assistance of a screw‐rod auxiliary system to perform occipitocervical fusion for unstable atlas fractures and atlantooccipital joint instability.     

3D打印技术辅助双钢板个性化手术治疗AO-C型肱骨远端骨折

目的探讨3D打印技术辅助双钢板个性化手术治疗AO-C型肱骨远端骨折的临床疗效。方法回顾性分析自2014-01-2015-12诊治的60例AO-C型肱骨远端骨折,采用3D打印技术辅助双钢板个性化手术治疗30例(观察组),采用常规内固定手术治疗30例(对照组)。比较2组手术时间、术中出血量,以及末次随访时的肘关节功能Mayo评分。结果所有患者均获得随访,随访时间平均12.5(12.0~14.5)个月。观察组手术时间为(98.1±7.7)min,对照组为(143.0±13.0)min;观察组手术时间明显短于对照组,差异有统计学意义(P0.05)。观察组术中出血量为(140.7±21.3)ml,对照组为(394.3±43.9)ml;观察组术中出血量明显少于对照组,差异有统计意义(P0.05)。末次随访时根据肘关节功能Mayo评分标准评定疗效:观察组优22例,良6例,可2例,优良率93.3%;对照组优16例,良6例,可6例,差2例,优良率73.3%。观察组肘关节功能Mayo评分优于对照组,差异有统计学意义(P0.05)。结论采用3D打印技术辅助双钢板内固定治疗AO-C型肱骨远端骨折效果满意,可缩短手术时间,减少术中出血量,有利于患者术后早期功能恢复。     

The Correction of Systematic Error due to Plaster and Fiberglass Casts on HR-pQCT Bone Parameters Measured In Vivo at the Distal Radius

Due to difficulty assessing healing of distal radius fractures using conventional radiography, there is interest in using high resolution peripheral quantitative computed tomography (HR-pQCT) to track healing at the microarchitectural level. Unfortunately, the plaster-of-Paris and fiberglass casts used to immobilize fractures affect HR-pQCT measurements due to beam hardening, and increased noise. The challenge is compounded because casts have variable thickness, and an individual patient will often have their cast changed 2–3 times during the course of treatment. This study quantifies the effect of casts within a clinically relevant range of thicknesses on measured bone parameters at the distal radius, and establishes conversion equations to correct for systematic error in due to cast presence. Eighteen nonfractured participants were scanned by HR-pQCT in three conditions: no cast, plaster-of-Paris cast, and fiberglass cast. Measured parameters were compared between the baseline scan (no cast) and each cast scan to evaluate if systematic error exists due to cast presence. A linear regression model was used to determine an appropriate conversion for parameters that were found to have systematic error. Plaster-of-Paris casts had a greater range of thicknesses (3.2–9.5 mm) than the fiberglass casts (3.0–5.4 mm), and induced a greater magnitude of systematic error overall. Key parameters of interest were bone mineral density (total, cortical, and trabecular) and trabecular bone volume fraction, all of which were found to have systematic error due to presence of either cast type. Linear correlations between baseline and cast scans for these parameters were excellent (R² > 0.98), and appropriate conversions could be determined within a margin of error less than a ±6% for the plaster-of-Paris cast, and ±4% for the fiberglass cast. We have demonstrated the effects of cast presence on bone microarchitecture measurements, and presented a method to correct for systematic error, in support of future use of HR-pQCT to study fracture healing.     

Comparison of the Conventional Surgery and the Surgery Assisted by 3d Printing Technology in the Treatment of Calcaneal Fractures

ABSTRACT

Purpose: This study was aimed to compare conventional surgery and surgery assisted by 3D printing technology in the treatment of calcaneal fractures. In addition, we also investigated the effect of 3D printing technology on the communication between doctors and patients. Methods: we enrolled 75 patients with calcaneal fracture from April 2014 to August 2016. They were divided randomly into two groups: 35 cases of 3D printing group, 40 cases of conventional group. The individual models were used to simulate the surgical procedures and carry out the surgery according to plan in 3D printing group. Operation duration, blood loss volume during the surgery, number of intraoperative fluoroscopy and fracture union time were recorded. The radiographic outcomes Böhler angle, Gissane angle, calcaneal width and calcaneal height and final functional outcomes including VAS and AOFAS score as well as the complications were also evaluated. Besides, we made a simple questionnaire to verify the effectiveness of the 3D-printed model for both doctors and patients. Results: The operation duration, blood loss volume and number of intraoperative fluoroscopy for 3D printing group was 71.4 ± 6.8 minutes, 226.1 ± 22.6 ml and 5.6 ± 1.9 times, and for conventional group was 91.3 ± 11.2 minutes, 288.7 ± 34.8 ml and 8.6 ± 2.7 times respectively. There was statistically significant difference between the conventional group and 3D printing group (p < 0.05). Additionally, 3D printing group achieved significantly better radiographic results than conventional group both postoperatively and at the final follow-up (p < 0.05). However, No significant difference was noted in the final functional outcomes between the two groups. As for complications, there was no significant difference between the two groups. Furthermore, the questionnaire showed that both doctors and patients exhibited high scores of overall satisfaction with the use of a 3D printing model. Conclusion: This study suggested the clinical feasibility of 3D printing technology in treatment of calcaneal fractures.     

Repair of Critical‐Sized Long Bone Defects Using Dipyridamole‐Augmented 3D‐Printed Bioactive Ceramic Scaffolds

There are over two million long bone defects treated in the United States annually, of which ~5% will not heal without significant surgical intervention. While autogenous grafting is the standard of care in simple defects, a customized scaffold for large defects in unlimited quantities is not available. Recently, a three‐dimensionally (3D)‐printed bioactive ceramic (3DPBC) scaffold has been successfully utilized in the of repair critical‐sized (CSD) long bone defects in vivo. In this study, 3DPBC scaffolds were augmented with dipyridamole (DIPY), an adenosine A2A receptor (A_2AR) indirect agonist, because of its known effect to enhance bone formation. CSD full thickness segmental defects (~11 mm × full thickness) defects were created in the radial diaphysis in New Zealand white rabbits (n = 24). A customized 3DPBC scaffold composed of β‐tricalcium phosphate was placed into the defect site. Groups included scaffolds that were collagen‐coated (COLL), or immersed in 10, 100, or 1,000 μM DIPY solution. Animals were euthanized 8 weeks post‐operatively and the radii/ulna‐scaffold complex retrieved en bloc, for micro‐CT, histological, and mechanical analysis. Bone growth was assessed exclusively within scaffold pores and evaluated by microCT and advanced reconstruction software. Biomechanical properties were evaluated utilizing nanoindentation to assess the newly regenerated bone for elastic modulus (E) and hardness (H). MicroCT reconstructions illustrated bone in‐growth throughout the scaffold, with an increase in bone volume dependent on the DIPY dosage. The histological evaluation did not indicate any adverse immune response while revealing progressive remodeling of bone. These customized biologic 3DPBC scaffolds have the potential of repairing and regenerating bone. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2499–2507, 2019     

镜像3D打印技术在髋臼骨折手术治疗中的应用

2016年10月~2018年10月,我科采用镜像3D打印技术辅助手术治疗12例髋臼骨折患者,疗效满意,报道如下。1材料与方法1.1病例资料本组12例,男7例,女5例,年龄26~72岁。右侧髋臼7例,左侧髋臼5例。T形骨折2例,后柱伴后壁骨折5例,横断伴后壁骨折2例,前柱伴后半横断骨折1例,双柱骨折2例。伤后至手术时间5~12 d。1.2治疗方法术前行骨盆薄层CT+三维重建,将图像导入MAGICS医学软件系统行软件数据处理,将数据导入迈普医学SLA-JUPU420型3D打印机分别按1∶1比例打印镜像健侧髋臼及伤侧髋臼3D实体模型。     

采用3D打印技术辅助治疗陈旧髋臼骨盆骨折的疗效观察

目的 观察3D打印技术辅助治疗陈旧髋臼骨盆骨折的临床疗效.方法 2013年2月至2013年12月北京积水潭医院创伤骨科对20例陈旧髋臼骨盆患者进行了3D打印技术辅助的手术治疗.将所有患者骨盆打印为实体模型.使用多枚克氏针钻孔定位,进行截骨.然后进行模拟复位,塑形钢板进行固定.采用视觉疼痛模拟评分(VAS)对患者疼痛情况...