Reconstruction with 3D-printed pelvic endoprostheses after resection of a pelvic tumour

Surgical Site Infections Following Pelvic Sarcoma Reconstruction with 3D-Printed Implants: Current Concepts and Future Directions

Introduction: Surgical site infections (SSIs) are a major complication following pelvic sarcoma reconstruction using 3D-printed implants. Despite advances in anatomical matching and biomechanics, infection rates remain significantly higher than in conventional arthroplasty.To review and synthesize current evidence (2010-2025) on the incidence, microbiological characteristics, risk factors, prevention strategies, and treatment approaches of SSIs in patients undergoing pelvic reconstruction with 3D-printed implants. Methods: A narrative literature review was conducted using PubMed, MEDLINE, Scopus, and Web of Science databases. Studies focusing on pelvic reconstructions with 3D-printed implants and reporting infection outcomes were included. A total of 56 studies were selected after applying inclusion and exclusion criteria. Results: SSIs in 3D-printed pelvic reconstructions exhibit a high incidence (5-40%) and a unique polymicrobial, gram-negative-dominated microbiological profile. Key risk factors include extensive surgical resection, prolonged operative time, prior radiotherapy, and compromised immune status. Titanium alloy (Ti6Al4V) remains the standard material, although it poses infection risks due to bioinert properties. Preventive measures such as antibacterial coatings, improved surgical techniques, and high-pressure lavage are increasingly used. Treatment involves surgical debridement, targeted antibiotics, and in some cases, implant revision or removal. Conclusion: SSIs represent a critical barrier in optimizing outcomes for pelvic sarcoma reconstruction with 3D-printed implants. A multidisciplinary approach integrating surgical innovation, materials science, and infection control is essential. Further research is needed on antimicrobial technologies and long-term outcomes.

Clinical Application of 3D-Printed Custom Hemipelvic Prostheses With Negative Poisson's Ratio Porous Structures in Reconstruction After Resection of Pelvic Malignant Tumors

OBJECTIVES

Pelvic bone tumor resection and reconstruction present significant challenges due to complex anatomy and weight-bearing demands. 3D-printed hemipelvic prostheses, incorporating customized osteotomy guides and porous structures, offer a promising solution for enhancing osseointegration. This study evaluates the long-term outcomes of 3D-printed custom hemipelvic reconstruction with a focus on the integration of auxetic biomaterials with a negative Poisson's ratio to optimize mechanical properties.

METHODS

A retrospective analysis was conducted on 12 patients with primary pelvic malignancies who underwent reconstruction using 3D-printed hemipelvic prostheses between January 2018 and May 2023. Follow-up duration was 48 months (range, 29-64 months) Oncological, functional, surgical, pain control, and radiographic outcomes were assessed.

RESULTS

At the latest follow-up, 8 patients (66.7%) were disease-free, 3 (25%) had disease progression, and 1 (8.3%) died from metastatic complications. Functional outcomes improved significantly, with the MSTS-93 score increasing from 15 (range, 12-17) to 26 (range, 21-29). Pain scores decreased from 5 (range, 4-7) to 1 (range, 0-2). The median surgical duration was 270 min (range, 150-560 min), with intraoperative blood loss averaging 3200 mL (range, 1900-6300 mL). Complications included poor wound healing in 2 patients (16.7%), managed with VAC drainage. No mechanical failures, loosening, or fractures occurred. Accurate osteotomy, prosthesis implantation, and screw fixation were achieved. Successful osseointegration was observed in all cases, with no signs of bone absorption or osteolysis.

CONCLUSIONS

3D-printed custom hemipelvic prostheses with auxetic biomaterials offer an effective solution for pelvic reconstruction, providing promising oncological, functional, and radiographic outcomes. These findings support the use of 3D printing in complex pelvic defect reconstruction, optimizing both osteointegration and mechanical strength.

The rational design, biofunctionalization and biological properties of orthopedic porous titanium implants: a review

Porous titanium implants are becoming an important tool in orthopedic clinical applications. This review provides a comprehensive survey of recent advances in porous titanium implants for orthopedic use. First, the review briefly describes the characteristics of bone and the design requirements of orthopedic implants. Subsequently, the pore size and structural design of porous titanium alloy materials are presented, then we introduce the application of porous titanium alloy implants in orthopedic clinical practice, including spine surgery, joint surgery, and the treatment of bone tumors. Following that, we describe the surface modifications applied to porous titanium implants to obtain better biological functions. Finally, we discuss incorporating environmental responsive mechanisms into porous titanium alloy materials to achieve additional functionalities.

Patient-Specific 3-Dimensional-Printed Orthopedic Implants and Surgical Devices Are Potential Alternatives to Conventional Technology But Require Additional Characterization

Background

Three-dimensional (3D) printing allows anatomical models, guides, and implants to be easily customized to individual patients. Three-dimensional-printed devices can be used for a number of purposes in the medical field, yet there is a lack of data on the implementation of 3D-printed patient-specific implants and surgical guides in orthopedics. The objective of this review of the literature was to summarize the implementation of 3D printing in orthopedic surgery and identify areas that require more investigation.

Methods

PubMed and Scopus were used to perform a literature search. Articles that described 3D-printed patient-specific orthopedic implants or intraoperative guides were reviewed. Relevant articles were compiled and summarized to determine the role of personalized 3D-printed implants in orthopedic surgery.

Results

A total of 58 papers were selected. Overall, 3D-printed implants and surgical guides were shown to be effective in the selected cases. Patients with bone tumors benefitted from custom 3D-printed implants, which allow aggressive resection while preserving the function and mechanical stability of the limb. Eighty-one percent of devices were made using titanium, and 48% of articles reported the use of 3D printing in oncology. Some reported adverse events including wound dehiscence, periprosthetic infection, dislocation, and sequelae of malignancy. Regulations surrounding the use of 3D-printed surgical devices are ambiguous.

Conclusions

Three-dimensional-printed orthopedic implants and guides present an alternative to commercial devices, as they allow for customizability that is useful in cases of anatomic complexity. A variety of materials were surveyed across multiple subspecialties. Large controlled studies are necessary to compare patient-specific implants with the standard of care and evaluate their safety profiles over time.

Exploring the optimal reconstruction strategy for Enneking III defects in pelvis bone tumors: a finite element analysis

BACKGROUND

Controversy exists regarding the reconstruction of bone defects in Enneking III. This study aimed to use the finite element analysis (FEA) method to clarify (1) the utility of reconstructing the pelvis Enneking III region and (2) the optimal approach for this reconstruction.

METHODS

FEA models were generated for three types of Enneking III defects in the pelvis, replacing all the defect areas in region III with a sizable solid box for topology optimization (TO). Based on the defect location and TO results, three reconstruction schemes were designed for each type of defect. We subsequently conducted simulations of static FEA under natural walking loads using ANSYS software (version 2022R1, Canonsburg, Pennsylvania, USA).

RESULTS

Compared with Scheme A, reconstruction of the Enneking III region (Schemes B and C) led to a more uniform stress distribution and lower peak stress in the pelvis. Moreover, prostheses and screws exhibit decreased peak stress and deformation, with complex reconstruction schemes (C) outperforming simpler ones (B).

CONCLUSIONS

The FEA results suggest that reconstructing Enneking Zone III defects improves stress distribution and reduces peak stress in the pelvis compared to non-reconstruction, potentially enhancing stability and reducing fracture risks. Complex reconstruction schemes involving more contralateral pelvis regions demonstrate superior biomechanical performance. However, clinical decisions should be individualized, integrating biomechanical insights with comprehensive patient-specific factors.

Three-dimensional models demonstrate differences in correction depending on femoral derotational osteotomy site and may enhance the planning and precision in femoral derotational osteotomy - An observational study in eight femora and two surgeons

BACKGROUND

Increased femoral anteversion (FAV) is crucial in the genesis of anterior knee pain (AKP) and a femoral derotational osteotomy (FDO) has demonstrated good clinical results. It remains unclear at what level of the femur the osteotomy should be performed. Resulting degrees of FAV measured by Murphy's method do not always correspond to the degrees that had been planned after an FDO. The hypothesis of this study is that the femur rotation axis and the osteotomy rotation axis do not coincide. Three-dimensional (3D) technology is used to objectify the discrepancy between these two axes and to find solutions so that the two axes can coincide. The objective is to demonstrate the reliability and reproducibility of the 3D technique for osteotomy adjustment through an intraobserver and interobserver study.

METHODS

Images of eight computed tomography scans of the femur, corresponding to seven patients with a diagnosis of AKP and increased FAV, were selected. Two surgeons performed the FAV measurement and simulation of FDO on 3D biomodels. The femoral osteotomies were defined at three levels, at 10°, 20°, 30°. To determine interobserver agreement, measurements were performed independently by two surgeons. To evaluate intraobserver differences each surgeon repeated all measurements after 15 days.

RESULTS

Interobserver and intraobserver agreement: intraclass correlation coefficient 0.930 (95% confidence interval (CI) 0.799-0.975) and 0.986 (95% CI 0.959-0.995). Significant differences between the resulting values were observed when the osteotomy was performed at the intertrochanteric level.

CONCLUSIONS

The misalignment of the axes results in hypocorrection when the osteotomy is intertrochanteric. This phenomenon is not observed when the osteotomy is diaphyseal or supracondylar.

Using additive manufacturing for craniocervical reconstruction in traditionally challenging cases

Retrospective case series. The aim of this study was to evaluate the clinical outcomes and effectiveness of using 3D printed implants in upper cervical spine and occipitocervical junction surgery. C2 primary tumor patients who required axial en bloc resection and other patients who required partial bone decompression using customized 3D printed implants or fixation devices for surgery were included. Evaluate the stability and surgical outcomes of 3D printed implants through perioperative and follow-up period. Five tumor patients underwent reconstruction using customized 3D printed artificial vertebral bodies, while another five patients with atlantoaxial joint dislocation underwent reduction and decompression using customized 3D printed internal fixation devices. The postoperative imaging results showed that the 3D printed structures had good immediate stability and had no signs of displacement or subsidence. Follow up showed that all five cases of vertebral body reconstruction had achieved fusion. Only one patient died one month after surgery due to infection and respiratory difficulties. Other patients showed excellent improvement in neurological function in follow up. The use of 3D printed implants in surgery involving the occipitocervical area is a feasible and reliable alternative choice. It is a valuable attempt for complex atlantoaxial dislocation that cannot be treated with conventional instruments. 3D printed implants can improve the safety and accuracy of surgery, provide good immediate stability, have a low incidence of subsidence, fewer related complications during the follow-up period.

Innovations in three-dimensional-printed individualized bone prosthesis materials: revolutionizing orthopedic surgery: a review

The advent of personalized bone prosthesis materials and their integration into orthopedic surgery has made a profound impact, primarily as a result of the incorporation of three-dimensional (3D) printing technology. By leveraging digital models and additive manufacturing techniques, 3D printing enables the creation of customized, high-precision bone implants tailored to address complex anatomical variabilities and challenging bone defects. In this review, we highlight the significant progress in utilizing 3D-printed prostheses across a wide range of orthopedic procedures, including pelvis, hip, knee, foot, ankle, spine surgeries, and bone tumor resections. The integration of 3D printing in preoperative planning, surgical navigation, and postoperative rehabilitation not only enhances treatment outcomes but also reduces surgical risks, accelerates recovery, and optimizes cost-effectiveness. Emphasizing the potential for personalized care and improved patient outcomes, this review underscores the pivotal role of 3D-printed bone prosthesis materials in advancing orthopedic practice towards precision, efficiency, and patient-centric solutions. The evolving landscape of 3D printing in orthopedic surgery holds promise for revolutionizing treatment approaches, enhancing surgical outcomes, and ultimately improving the quality of care for orthopedic patients.

Short-to-Mid-Term Outcomes of Ipsilateral Femoral Head Autograft Combined with Uncemented Total Hip Replacement for Partial Periacetabular Defects Following Tumor Resection

OBJECTIVE

Periacetabular tumors, especially in young to middle-aged patients with invasive benign tumors or low-grade malignant tumors involving type II or II + III, present significant challenges due to their rarity and the complexity of the anatomical and biomechanical structures involved. The primary difficulty lies in balancing the need to avoid unfavorable oncological outcomes while maintaining postoperative hip joint function during surgical resection. This study aimed to evaluate the effectiveness and reliability of a surgical method involving partial weight-bearing acetabular preservation combined with the use of an uncontaminated femoral head autograft to reconstruct the segmental bone defect after intra-articular resection of the tumorous joint, providing a solution that ensures both oncological safety and functional preservation of the hip joint in these patients.

METHODS

We conducted a retrospective study with a follow-up period of at least 36 months. From January 2010 to October 2020, we reviewed 20 cases of patients under 60 year of age with periacetabular invasive benign tumors or primary low-grade malignant tumors. All patients underwent reconstruction of the tumorous joint using autologous femoral head grafts. Data collected included patient age, gender, tumor type, preoperative and postoperative visual analog scale (VAS) scores, Musculoskeletal Tumor Society (MSTS) scores, Harris Hip Scores (HHS), patient survival rates, postoperative tumor recurrence, and surgical complications. To analyze the data, we utilized various statistical methods, including descriptive statistics to summarize patient demographics and clinical characteristics, and paired sample t-tests to compare preoperative and postoperative scores.

RESULTS

The study included 20 patients, and a total median follow-up was 83 months. Their pathologic diagnoses comprised 13 giant cell tumors (GCTs), 5 chondrosarcomas, one chondroblastoma, and 1 leiomyosarcoma. Postoperatively, the median differences in vertical and horizontal center of rotation (COR) were 3.8 and 4.0 mm. Median limb length discrepancy (LLD) postoperatively was 5.7 mm (range, 2.3-17.8 mm). Two patients (10%) experienced delayed wound healing, resolved with antibiotics and early surgical debridement. One patient experienced dislocation 3 months postoperatively, which was promptly addressed under general anesthesia without further dislocation.

CONCLUSION

Through multiplanar osteotomy with limited margins, femoral head autograft, and uncemented total hip replacement for pelvic segmental bone defects in selected patients in type II or II + III appears to be an encouraging limb-sparing surgery worthy of consideration for carefully selected patients.

Mid-Term Clinical and Radiographic Results of Complex Hip Revision Arthroplasty Based on 3D Life-Sized Model: A Prospective Case Series

Background: The pre-operative three-dimensional (3D) assessment of acetabular bone defects may not be evaluated properly with conventional radiographic and computed tomography images. This paper reports mid-term clinical and radiographic outcomes of complex revision total hip arthroplasty (r-THA) based on a 3D life-sized printed model. Methods: Patients who underwent r-THA for septic or aseptic acetabular loosening with acetabular defects Paprosky types IIc, IIIa, and IIIb between 2019 and 2021 were included. The outcomes of the study were to determine clinical and radiographic assessment outcomes at the time of the last follow-up. Results: 25 patients with mean age of 62.9 ± 10.8 (18-83) years old were included. The mean Harris hip score improved from 34.8 ± 8.1 pre-operative to 81.6 ± 10.4 points (p < 0.001). The mean visual analog scale decreased from 6.7 ± 1.4 points pre-operative to 2.4 ± 1.0 points (p < 0.001). The mean limb length discrepancy improved from -2.0 ± 1.2 cm pre-operative to -0.6 ± 0.6 cm (p < 0.001). The mean vertical position of the center of rotation (COR) changed from 3.5 ± 1.7 cm pre-operative to 2.0 ± 0.7 cm (p < 0.05). The mean horizontal COR changed from 3.9 ± 1.5 cm pre-operative to 3.2 ± 0.5 cm (p < 0.05). The mean acetabular component abduction angle changed from 59.7° ± 29.6° pre-operative to 46° ± 3.9 (p < 0.05). Conclusions: A three-dimensional-printed model provides an effective connection between the pre-operative bone defects' evaluation and the intraoperative findings, enabling surgeons to select optimal surgical strategies.

Evaluation of finite element modeling methods for predicting compression screw failure in a custom pelvic implant

Introduction: Three-dimensional (3D)-printed custom pelvic implants have become a clinically viable option for patients undergoing pelvic cancer surgery with resection of the hip joint. However, increased clinical utilization has also necessitated improved implant durability, especially with regard to the compression screws used to secure the implant to remaining pelvic bone. This study evaluated six different finite element (FE) screw modeling methods for predicting compression screw pullout and fatigue failure in a custom pelvic implant secured to bone using nine compression screws. Methods: Three modeling methods (tied constraints (TIE), bolt load with constant force (BL-CF), and bolt load with constant length (BL-CL)) generated screw axial forces using functionality built into Abaqus FE software; while the remaining three modeling methods (isotropic pseudo-thermal field (ISO), orthotropic pseudo-thermal field (ORT), and equal-and-opposite force field (FOR)) generated screw axial forces using iterative physics-based relationships that can be implemented in any FE software. The ability of all six modeling methods to match specified screw pretension forces and predict screw pullout and fatigue failure was evaluated using an FE model of a custom pelvic implant with total hip replacement. The applied hip contact forces in the FE model were estimated at two locations in a gait cycle. For each of the nine screws in the custom implant FE model, likelihood of screw pullout failure was predicted using maximum screw axial force, while likelihood of screw fatigue failure was predicted using maximum von Mises stress. Results: The three iterative physics-based modeling methods and the non-iterative Abaqus BL-CL method produced nearly identical predictions for likelihood of screw pullout and fatigue failure, while the other two built-in Abaqus modeling methods yielded vastly different predictions. However, the Abaqus BL-CL method required the least computation time, largely because an iterative process was not needed to induce specified screw pretension forces. Of the three iterative methods, FOR required the fewest iterations and thus the least computation time. Discussion: These findings suggest that the BL-CL screw modeling method is the best option when Abaqus is used for predicting screw pullout and fatigue failure in custom pelvis prostheses, while the iterative physics-based FOR method is the best option if FE software other than Abaqus is used.

Research trends of bone tumor treatment with 3D printing technology from 2013 to 2022: a bibliometric analysis

OBJECTIVE

Bibliometrics was employed in this study to determine the research trends in the worldwide application of 3D printing technology to treat bone tumors over the previous 10 years.

METHODS

Published from 2013 to 2022, the papers related to bone tumors treated with 3D printing were located in Web of Science Core Collection (WoSCC), PubMed, and Scopus. The screened articles were included in this bibliometric study. From these papers in WoSCC, information on annual publications, journals, keywords, countries, authors, institutions, and cited references were extracted and visualized with CiteSpace (version 6.1.R6) software to investigate the state of bone tumor treatment using 3D printing as well as research hotspots. The Carrot2 online visualization tool and Vosviewer software (version 1.6.20) were employed to visualize the publications from PubMed and Scopus, respectively, in order to ascertain the most popular research topics from both databases.

RESULTS

A total of 606, 233, and 364 publications were obtained from WoSCC, PubMed, and Scopus, respectively, between the years 2013 and 2022. In WoSCC, the peak number of publications was found in 2021, with 145 publications published. Acta Biomaterialia (11 publications) and World Neurosurgery (10 publications) were the most prolific journals, and Biomaterials was the journal cited the most (244 times). Yong Zhou was the most productive author with 14 publications, while Kwok-Chuen Wong (69 citations) and William F Enneking, (69 citations) possessed the most citations. The country with the largest quantity of publications was China (207). Among all institutions, Shanghai Jiao Tong University produced the most publications (29). Rapid prototyping was the keyword with the strongest citation burst (4.73). 'Reconstruction', 'surgery', 'resection', and 'design' caught the significant attention of researchers. 3D-printed materials, pelvic reconstruction, mandibular reconstruction, computer-assisted surgical techniques, photothermal therapy, and in vitro experiments were recognized as hot subjects and trends in current research. The most frequently occurring topics in Scopus are not significantly different from those found in WoSCC. The most prevalent research areas in PubMed encompass implant, patient-specific, bioceramic, models, and pelvic.

Global research development of chondrosarcoma from 2003 to 2022: a bibliometric analysis

Background

Chondrosarcomas are common primary malignant bone tumors; however, comprehensive bibliometric analysis in this field has not yet been conducted. Therefore, this study aimed to explore the research hotspots and trends in the field of chondrosarcoma through bibliometric analysis to help researchers understand the current status and direction of research in the field.

Methods

Articles and reviews related to chondrosarcoma published between 2003 and 2022 were retrieved from the Web of Science. Countries, institutions, authors, journals, references, and keywords in this field were visualized and analyzed using CtieSpace and VOSviewer software.

Results

Between 2003 and 2022, 4,149 relevant articles were found. The number of articles published on chondrosarcoma has increased significantly annually, mainly from 569 institutions in China and the United States, and 81 in other countries. In total, 904 authors participated in the publication of studies related to chondrosarcomas. Over the past 20 years, articles on chondrosarcoma have been published in 958 academic journals, with Skeletal Radiology having the highest number of publications. Furthermore, keywords such as "gene expression," "radiotherapy," "experience," and "apoptosis" have been popular in recent years.

Conclusion

Over the past 20 years, the global trend in chondrosarcoma research has primarily been clinical research, with basic research as a supplement. In the future, communication and exchange between countries and institutions should be strengthened. Further, the future main research hotspots in the field of chondrosarcoma include mutated genes and signaling pathways, precision surgical treatment, proton therapy, radiation therapy, chemotherapy, immunotherapy, and other aspects.

Management of metastatic bone disease of the pelvis: current concepts

PURPOSE

Metastatic disease of the pelvis is frequently associated with severe pain and impaired ambulatory function. Depending on the patient's characteristics, primary tumor, and metastatic pelvic disease, the treatment choice may be varied. This study aims to report on the current management options of metastatic pelvic disease.

METHODS

We comprehensively researched multiple databases and evaluated essential studies about current concepts of managing a metastatic bone disease of the pelvis, focusing on specific indications as well as on the result of treatment.

RESULTS

Pelvic metastases not in the periacetabular region can be managed with modification of weight-bearing, analgesics, bisphosphonates, chemotherapy and/or radiotherapy. Minimally invasive approaches include radiofrequency ablation, cryoablation, embolization, percutaneous osteoplasty, and percutaneous screw placement. Pathological or impending periacetabular fracture, excessive periacetabular bone defect, radioresistant tumor, and persistent debilitating pain despite non-surgical treatment and/or minimally invasive procedures can be managed with different surgical techniques. Overall, treatment can be divided into nonoperative, minimally invasive, and operative based on specific indications, the expectations of the patient and the lesion.

CONCLUSION

Different treatment modalities exist to manage metastatic pelvic bone disease. Decision-making for the most appropriate treatment should be made with a multidisciplinary approach based on a case-by-case basis.

Advanced topology of triply periodic minimal surface structure for osteogenic improvement within orthopedic metallic screw

Metallic screws are one of the most common implants in orthopedics. However, the solid design of the screw has often resulted in stress shielding and postoperative loosening, substantially impacting its long-term fixation effect after surgery. Four additive manufacturing porous structures (Fischer-Koch S, Octet, Diamond, and Double Gyroid) are now introduced into the screw to fix those issues. Upon applying the four porous structures, elastic modulus in the screw decreased about 2∼15 times to reduce the occurrence of stress shielding, and bone regeneration effect on the screw surface increased about 1∼50 times to improve bone tissue regrowing. With more bone tissue regrowing on the inner surface of porous screw, a stiffer integration between screw and bone tissue will be achieved, which improves the long-term fixation of the screw tremendously. The biofunctions of the four topologies on osteogenesis have been fully explored, which provides an advanced topology optimization scheme for the screw utilized in orthopedic fixation.

Advanced Pelvic Girdle Reconstruction with three dimensional-printed Custom Hemipelvic Endoprostheses following Pelvic Tumour Resection

PURPOSE

Resection of pelvic bone tumours and subsequent pelvic girdle reconstruction pose formidable challenges due to the intricate anatomy, weight-bearing demands, and significant defects. 3D-printed implants have improved pelvic girdle reconstruction by enabling precise resections with customized guides, offering tailored solutions for diverse bone defect morphology, and integrating porous surface structures to promote osseointegration. Our study aims to evaluate the long-term efficacy and feasibility of 3D-printed hemipelvic reconstruction following resection of malignant pelvic tumours.

METHODS

A retrospective review was conducted on 96 patients with primary pelvic malignancies who underwent pelvic girdle reconstruction using 3D-printed custom hemipelvic endoprostheses between January 2017 and May 2022. Follow-up duration was median 48.1 ± 17.9 months (range, 6 to 76 months). Demographic data, imaging examinations, surgical outcomes, and oncological evaluations were extracted and analyzed. The primary endpoints included oncological outcomes and functional status assessed by the Musculoskeletal Tumor Society (MSTS-93) score. Secondary endpoints comprised surgical duration, intraoperative bleeding, pain control and complications.

RESULTS

In 96 patients, 70 patients (72.9%) remained disease-free, 15 (15.6%) had local recurrence, and 11 (11.4%) succumbed to metastatic disease. Postoperatively, function improved with MSTS-93 score increasing from 12.2 ± 2.0 to 23.8 ± 3.8. The mean operating time was 275.1 ± 94.0 min, and the mean intraoperative blood loss was 1896.9 ± 801.1 ml. Pain was well-managed, resulting in substantial improvements in VAS score (5.3 ± 1.8 to 1.4 ± 1.1). Complications occurred in 13 patients (13.5%), including poor wound healing (6.3%), deep prosthesis infection (4.2%), hip dislocation (2.1%), screw fracture (1.0%), and interface loosening (1.0%). Additionally, all patients achieved precise implantation of customized prosthetics according to preoperative plans. T-SMART revealed excellent integration at the prosthesis-bone interface for all patients.

CONCLUSION

The use of a 3D-printed custom hemipelvic endoprosthesis, characterized by anatomically designed contours and a porous biomimetic surface structure, offers a potential option for pelvic girdle reconstruction following internal hemipelvectomy in primary pelvic tumor treatment. Initial results demonstrate stable fixation and satisfactory mid-term functional and radiographic outcomes.

Clinical Consequences of Unreconstructed Pelvic Defect Caused by Osteosarcoma with Subsequent Progressive Scoliosis in a Pediatric Patient-Case Report

Osteosarcoma is the most common primary malignant bone tumor in children and adolescents. The standard and most effective treatment is wide resection of the tumor combined with neoadjuvant chemotherapy. Adolescent idiopathic scoliosis (AIS) is a genetically determined three-dimensional spinal deformity, which occurs in teenage patients and is mostly progressive. The basic management strategy is surgical treatment when the curve exceeds 50 degrees. However, the indications are different in oncologic patients. The aim of this study was to describe a case of adolescent scoliosis with osteosarcoma of the pelvis. The authors conducted a scoping review using PubMed and Embase to analyze the state of knowledge. The presented paper is the first report of pelvis osteosarcoma coexisting with adolescent idiopathic scoliosis. Treatment for this complex case finished with very good results, with no recurrence observed during the nine-year follow-up.

3D-Printed custom-made hemipelvic endoprosthetic reconstruction following periacetabular tumor resection: utilizing a novel classification system

BACKGROUND

Customized 3D-printed pelvic implants with a porous structure have revolutionized periacetabular pelvic defect reconstruction after tumor resection, offering improved osteointegration, long-term stability, and anatomical fit. However, the lack of an established classification system hampers implementation and progress.

METHODS

We formulated a novel classification system based on pelvic defect morphology and 3D-printed hemipelvis endoprostheses. It integrates surgical approach, osteotomy guide plate and prosthesis design, postoperative rehabilitation plans, and perioperative processes.

RESULTS

Retrospectively analyzing 60 patients (31 males, 29 females), we classified them into Type A (15 patients: Aa = 6, Ab = 9), Type B (27 patients: Ba = 15, Bb = 12), Type C (17 patients). All underwent customized osteotomy guide plate-assisted tumor resection and 3D-printed hemipelvic endoprosthesis reconstruction. Follow-up duration was median 36.5 ± 15.0 months (range, 6 to 74 months). The mean operating time was 430.0 ± 106.7 min, intraoperative blood loss 2018.3 ± 1305.6 ml, transfusion volume 2510.0 ± 1778.1 ml. Complications occurred in 13 patients (21.7%), including poor wound healing (10.0%), deep prosthesis infection (6.7%), hip dislocation (3.3%), screw fracture (1.7%), and interface loosening (1.7%). VAS score improved from 5.5 ± 1.4 to 1.7 ± 1.3, MSTS-93 score from 14.8 ± 2.5 to 23.0 ± 5.6. Implant osseointegration success rate was 98.5% (128/130), with one Type Ba patient experiencing distal prosthesis loosening.

CONCLUSION

The West China classification may supplement the Enneking and Dunham classification, enhancing interdisciplinary communication and surgical outcomes. However, further validation and wider adoption are required to confirm clinical effectiveness.

Biomechanical and clinical outcomes of 3D-printed versus modular hemipelvic prostheses for limb-salvage reconstruction following periacetabular tumor resection: a mid-term retrospective cohort study

BACKGROUND

Debates persist over optimal pelvic girdle reconstruction after acetabular tumor resection, with surgeons grappling between modular and 3D-printed hemipelvic endoprostheses. We hypothesize superior outcomes with 3D-printed versions, yet scarce comparative research exists. This study fills the gap, examining biomechanics and clinical results retrospectively.

METHODS

From February 2017 to June 2021, we retrospectively assessed 32 patients undergoing en bloc resection for malignant periacetabular tumors at a single institution.

PRIMARY OUTCOME

limb function.

SECONDARY OUTCOMES

implant precision, hip joint rotation center restoration, prosthesis-bone osteointegration, and complications. Biomechanical characteristics were evaluated through finite element analysis on pelvic defect models.

RESULTS

In the 3D-printed group, stress distribution mirrored a normal pelvis, contrasting the modular group with elevated overall stress, unstable transitions, and higher stress peaks. The 3D-printed group exhibited superior functional scores (MSTS: 24.3 ± 1.8 vs. 21.8 ± 2.0, p < 0.05; HHS: 79.8 ± 5.2 vs. 75.3 ± 3.5, p < 0.05). Prosthetic-bone interface osteointegration, measured by T-SMART, favored 3D-printed prostheses, but surgery time (426.2 ± 67.0 vs. 301.7 ± 48.6 min, p < 0.05) and blood loss (2121.1 ± 686.8 vs. 1600.0 ± 505.0 ml, p < 0.05) were higher.

CONCLUSIONS

The 3D-printed hemipelvic endoprosthesis offers precise pelvic ring defect matching, superior stress transmission, and function compared to modular endoprostheses. However, complexity, fabrication expertise, and challenging surgical implantation result in prolonged operation times and increased blood loss. A nuanced consideration of functional outcomes, complexity, and patient conditions is crucial for informed treatment decisions.

LEVEL OF EVIDENCE

Level III, therapeutic study (Retrospective comparative study).

Biomimetic design and clinical application of Ti-6Al-4V lattice hemipelvis prosthesis for pelvic reconstruction

OBJECTIVE

This study aims to biomimetic design a new 3D-printed lattice hemipelvis prosthesis and evaluate its clinical efficiency for pelvic reconstruction following tumor resection, focusing on feasibility, osseointegration, and patient outcomes.

METHODS

From May 2020 to October 2021, twelve patients with pelvic tumors underwent tumor resection and subsequently received 3D-printed lattice hemipelvis prostheses for pelvic reconstruction. The prosthesis was strategically incorporated with lattice structures and solid to optimize mechanical performance and osseointegration. The pore size and porosity were analyzed. Patient outcomes were assessed through a combination of clinical and radiological evaluations.

RESULTS

Multiple pore sizes were observed in irregular porous structures, with a wide distribution range (approximately 300-900 μm). The average follow-up of 34.7 months, ranging 26 from to 43 months. One patient with Ewing sarcoma died of pulmonary metastasis 33 months after surgery while others were alive at the last follow-up. Postoperative radiographs showed that the prosthesis's position was consistent with the preoperative planning. T-SMART images showed that the host bone was in close and tight contact with the prosthesis with no gaps at the interface. The average MSTS score was 21 at the last follow-up, ranging from 18 to 24. There was no complication requiring revision surgery or removal of the 3D-printed hemipelvis prosthesis, such as infection, screw breakage, and prosthesis loosening.

CONCLUSION

The newly designed 3D-printed lattice hemipelvis prosthesis created multiple pore sizes with a wide distribution range and resulted in good osteointegration and favorable limb function.

Strontium-loaded 3D intramedullary nail titanium implant for critical-sized femoral defect in rabbits

The treatment of critical-sized bone defects has long been a major problem for surgeons. In this study, an intramedullary nail shaped three-dimensional (3D)-printed porous titanium implant that is capable of releasing strontium ions was developed through a simple and cost-effective surface modification technique. The feasibility of this implant as a stand-alone solution was evaluated using a rabbit's segmental diaphyseal as a defect model. The strontium-loaded implant exhibited a favorable environment for cell adhesion, and mechanical properties that were commensurate with those of a rabbit's cortical bone. Radiographic, biomechanical, and histological analyses revealed a significantly higher amount of bone ingrowth and superior bone-bonding strength in the strontium-loaded implant when compared to an untreated porous titanium implant. Furthermore, one-year histological observations revealed that the strontium-loaded implant preserved the native-like diaphyseal bone structure without failure. These findings suggest that strontium-releasing 3D-printed titanium implants have the clinical potential to induce the early and efficient repair of critical-sized, load-bearing bone defects.

Clinical exploration of the international society of limb salvage classification of endoprosthetic failure using Henderson in the application of 3D-printed pelvic tumor prostheses

Background

The use of 3D-printed pelvic prosthesis for postoperative reconstruction after pelvic tumor resection has become one of the primary reconstruction methods the incidence of complications related to postoperative prosthesis reconstruction is high. Drawing on the failure of the type of bone tumor reconstruction in Henderson,the occurrence of postoperative complications was explored to take advantage of the design improvement of the 3D-printed prosthesis of subsequent pelvic tumors.

Methods

The data for patients who underwent 3D-printed pelvic tumor prostheses in the Department of Bone and Soft Tissue Surgery at the Affiliated Cancer Hospital of Guangxi Medical University from January 2019 to October 2022 were collected and analyzed.

Results

The median follow-up time for all patients was 15.99 months (1.33-31.16 months). At the most recent follow-up,all patients were alive,with an average Musculoskeletal Tumor Society (MSTS) score of 21.46 (17 to 26 points). Local recurrence occurred in two cases (15.3%), metastasis in four cases (30.7%), and complications in 10 cases (76.9%). Early complications after surgery were primarily local wound fissure, deep tissue infection, and postoperative neuralgia. Later complications included loose dissolution of internal fixation, postoperative prosthetic dislocation, and postoperative gluteal middle muscle gait.

Conclusion

3D printing personalized design pelvic tumor prosthesis is an effective way to reconstruct, and designing pelvic 3D printed tumor prosthesis with the help of Henderson's bone tumor reconstruction failure concept may help bone tumor surgeons develop better pelvic tumor prosthesis.

Pelvic-girdle reconstruction with three-dimensional-printed endoprostheses after limb-salvage surgery for pelvic sarcomas: current landscape

Resection of pelvic bone tumors and the subsequent reconstruction of the pelvic girdle pose challenges due to complex anatomy, load-bearing demands, and significant defects. 3D-printed implants have revolutionized pelvic girdle reconstruction by offering customized solutions, porous surface structures for precise resection with custom guides, and improved integration. Many tertiary medical centers have adopted 3Dprinted hemipelvic endoprostheses, leading to enhanced outcomes. However, most studies are limited to single centers, with a small number of cases and short follow-up periods. Additionally, the design of these implants often relies heavily on individual experience, resulting in a lack of uniformity and significant variation. To provide a comprehensive assessment of this technology, we conducted an analysis of existing literature, encompassing tumor resection classification, various types of prosthesis design, reconstruction concepts, and post-reconstruction functional outcomes.

Stress-shielding resistant design of custom pelvic prostheses using lattice-based topology optimization

Endoprosthetic reconstruction of the pelvic bone using 3D-printed, custom-made implants has delivered early load-bearing ability and good functional outcomes in the short term to individuals with pelvic sarcoma. However, excessive stress-shielding and subsequent resorption of peri‑prosthetic bone can imperil the long-term stability of such implants. To evaluate the stress-shielding performance of pelvic prostheses, we developed a sequential modeling scheme using subject-specific finite element models of the pelvic bone-implant complex and personalized neuromusculoskeletal models for pre- and post-surgery walking. A new topology optimization approach is introduced for the stress-shielding resistant (SSR) design of custom pelvic prostheses, which uses 3D-printable porous lattice structures. The SSR optimization was applied to a typical pelvic prosthesis to reconstruct a type II+III bone resection. The stress-shielding performance of the optimized implant based on the SSR approach was compared against the conventional optimization. The volume of the peri‑prosthetic bone predicted to undergo resorption post-surgery decreased from 44 to 18%. This improvement in stress-shielding resistance was achieved without compromising the structural integrity of the prosthesis. The SSR design approach has the potential to improve the long-term stability of custom-made pelvic prostheses.

Custom designed and 3D-printed titanium pelvic implants for acetabular reconstruction after tumour resection

BACKGROUND

Reconstructive procedure following resection of large pelvic tumours around the hip joint remains a complex challenge.

METHODS

This study presents a retrospective case series of patients presenting with benign or malignant pelvic tumour for which an internal hemipelvectomy including the hip joint and subsequent reconstruction with a custom designed 3-dimensional printed titanium pelvic implant (3DPPI) has been performed between August 2013 and January 2018.

RESULTS

15 consecutive patients with a median age of 33.9 years (IQR 26.4-72.2) and a median BMI of 20.7 kg/m2 (IQR 19.0-33.3) were reviewed after median follow-up of 33.8 months (IQR 24.0-78.1). The majority of patients presented with a malignant tumour as their principal diagnosis (n = 13, 86.7%). The median surgical time was 5.5 hours (IQR 4.5-8.5) and median peri-operative blood loss was 5000 ml (IQR 2000-10000). The median MSTS score at follow-up was 63.3% (IQR 51.7-86.7%). The median NRS in rest was 0.0 (IQR 0.0-5.0), the median NRS during activity was 2.0 (IQR 0.5-7.0) and the median HOOS-PS was 76.6% (IQR 67.9-91.0). 4 patients had implant-specific complications (n = 4, 26.6%); 1 hip dislocation (Henderson type 1a), 3 structural complications (type 3a), 1 deep infection (type 4a) and 1 local tumour recurrence (type 5b). At follow-up, 4 out of 15 implants were classified as a failure, resulting in an implant survival rate of 73.3%.

CONCLUSIONS

Acceptable peri-operative outcomes, functional results, complication rates and short-term implant survival can be achieved in a cohort of complex patients undergoing 3DPPI reconstruction after hemipelvectomy including the acetabulum.

3D printing metal implants in orthopedic surgery: Methods, applications and future prospects

Background

Currently, metal implants are widely used in orthopedic surgeries, including fracture fixation, spinal fusion, joint replacement, and bone tumor defect repair. However, conventional implants are difficult to be customized according to the recipient's skeletal anatomy and defect characteristics, leading to difficulties in meeting the individual needs of patients. Additive manufacturing (AM) or three-dimensional (3D) printing technology, an advanced digital fabrication technique capable of producing components with complex and precise structures, offers opportunities for personalization.

Methods

We systematically reviewed the literature on 3D printing orthopedic metal implants over the past 10 years. Relevant animal, cellular, and clinical studies were searched in PubMed and Web of Science. In this paper, we introduce the 3D printing method and the characteristics of biometals and summarize the properties of 3D printing metal implants and their clinical applications in orthopedic surgery. On this basis, we discuss potential possibilities for further generalization and improvement.

Results

3D printing technology has facilitated the use of metal implants in different orthopedic procedures. By combining medical images from techniques such as CT and MRI, 3D printing technology allows the precise fabrication of complex metal implants based on the anatomy of the injured tissue. Such patient-specific implants not only reduce excessive mechanical strength and eliminate stress-shielding effects, but also improve biocompatibility and functionality, increase cell and nutrient permeability, and promote angiogenesis and bone growth. In addition, 3D printing technology has the advantages of low cost, fast manufacturing cycles, and high reproducibility, which can shorten patients' surgery and hospitalization time. Many clinical trials have been conducted using customized implants. However, the use of modeling software, the operation of printing equipment, the high demand for metal implant materials, and the lack of guidance from relevant laws and regulations have limited its further application.

Conclusions

There are advantages of 3D printing metal implants in orthopedic applications such as personalization, promotion of osseointegration, short production cycle, and high material utilization. With the continuous learning of modeling software by surgeons, the improvement of 3D printing technology, the development of metal materials that better meet clinical needs, and the improvement of laws and regulations, 3D printing metal implants can be applied to more orthopedic surgeries.

The translational potential of this paper

Precision, intelligence, and personalization are the future direction of orthopedics. It is reasonable to believe that 3D printing technology will be more deeply integrated with artificial intelligence, 4D printing, and big data to play a greater role in orthopedic metal implants and eventually become an important part of the digital economy. We aim to summarize the latest developments in 3D printing metal implants for engineers and surgeons to design implants that more closely mimic the morphology and function of native bone.

A 3D-printed patient-specific modular implants for pelvic reconstruction of bone tumors involving the sacroiliac joint

Background: Current reconstruction methods of the pelvic ring after extensive resection of tumors involving the sacroiliac joint have a high incidence of failure. We aimed to study the effect of 3D-printed patient-specific implant reconstruction to show that this method is stable and has a low risk of failure. Methods: Between February 2017 and November 2021, six patients with bone tumors involving the sacroiliac joint (Enneking I + IV) who received 3D-printed patient-specific implants for pelvic reconstructive surgery were retrospectively analyzed. Two female and four male patients with a mean age of 41.83 years (range 25-65 years) were included. Two were osteosarcomas, two chondrosarcomas, one malignant fibrous histiocytoma, and one giant cell tumor of bone. For each patient, preoperative osteotomy guides were designed to ensure accurate tumor resection and individualized prostheses were designed to ensure a perfect fit of the bone defect. General, oncologic, and functional outcomes, implant status, and complications were retrospectively analyzed. The Visual Analog Scale (VAS) was used to assess pain and the Musculoskeletal Tumor Society (MSTS) score was used to assess hip function. Osseointegration was assessed by CT. Results: According to the preoperative design, complete resection of the entire tumor and reconstruction with a custom 3D-printed sacroiliac joint implant was completed without perioperative severe complications or deaths. Relatively satisfactory surgical margins were achieved. The mean operative time and intraoperative blood loss were 495 min (420-600 min) and 2533.33 mL (range, 1,200-3,500 mL), respectively. The mean follow-up was 49.83 months (range, 18-75 months). At the last follow-up, all four patients were disease-free, and the two patients who developed lung metastases were alive with tumors. All patients could walk unassisted. The mean VAS was 1.33 (range, 0-2). The mean MSTS score was 25.33 (range, 24-27). CT showed complete osseointegration of the implant to the ilium and sacrum. Conclusion: The 3D-printed custom prosthesis can effectively reconstruct pelvic stability after total sacroiliac joint resection with satisfactory clinical results.

An overview of 3D printed metal implants in orthopedic applications: Present and future perspectives

With the ability to produce components with complex and precise structures, additive manufacturing or 3D printing techniques are now widely applied in both industry and consumer markets. The emergence of tissue engineering has facilitated the application of 3D printing in the field of biomedical implants. 3D printed implants with proper structural design can not only eliminate the stress shielding effect but also improve in vivo biocompatibility and functionality. By combining medical images derived from technologies such as X-ray scanning, CT, MRI, or ultrasonic scanning, 3D printing can be used to create patient-specific implants with almost the same anatomical structures as the injured tissues. Numerous clinical trials have already been conducted with customized implants. However, the limited availability of raw materials for printing and a lack of guidance from related regulations or laws may impede the development of 3D printing in medical implants. This review provides information on the current state of 3D printing techniques in orthopedic implant applications. The current challenges and future perspectives are also included.

Performances of novel custom 3D-printed cutting guide in canine caudal maxillectomy: a cadaveric study

Introduction

Caudal maxillectomies are challenging procedures for most veterinary surgeons. Custom guides may allow the procedure to become more accessible.

Methods

A cadaveric study was performed to evaluate the accuracy and efficiency of stereolithography guided (3D-printed) caudal maxillectomy. Mean absolute linear deviation from planned to performed cuts and mean procedure duration were compared pairwise between three study groups, with 10 canine cadaver head sides per group: 3D-printed guided caudal maxillectomy performed by an experienced surgeon (ESG) and a novice surgery resident (NSG), and freehand procedure performed by an experienced surgeon (ESF).

Results

Accuracy was systematically higher for ESG versus ESF, and statistically significant for 4 of 5 osteotomies (p < 0.05). There was no statistical difference in accuracy between ESG and NSG. The highest absolute mean linear deviation for ESG was <2 mm and >5 mm for ESF. Procedure duration was statistically significantly longer for ESG than ESF (p < 0.001), and for NSG than ESG (p < 0.001).

Discussion

Surgical accuracy of canine caudal maxillectomy was improved with the use of our novel custom cutting guide, despite a longer duration procedure. Improved accuracy obtained with the use of the custom cutting guide could prove beneficial in achieving complete oncologic margins. The time increase might be acceptable if hemorrhage can be adequately controlled in vivo. Further development in custom guides may improve the overall efficacy of the procedure.

A systematic review of follow-up results of additively manufactured customized implants for the pelvic area

INTRODUCTION

While 3D printing of bone models for preoperative planning or customized surgical templating has been successfully implemented, the use of patient-specific additively manufactured (AM) implants is a newer application not yet well established. To fully evaluate the advantages and shortcomings of such implants, their follow-up results need to be evaluated.

AREA COVERED

This systematic review provides a survey of the reported follow-ups on AM implants used for oncologic reconstruction, total hip arthroplasty both primary and revision, acetabular fracture, and sacrum defects.

EXPERT OPINION

The review shows that Titanium alloy (Ti4AL6V) is the most common type of material system used due to its excellent biomechanical properties. Electron beam melting (EBM) is the predominant AM process for manufacturing implants. In almost all cases, porosity at the contact surface is implemented through the design of lattice or porous structures to enhance osseointegration. The follow-up evaluations show promising results, with only a small number of patients suffering from aseptic loosening, wear, or malalignment. The longest reported follow-up length was 120 months for acetabular cages and 96 months for acetabular cups. The AM implants have proven to serve as an excellent option to restore premorbid skeletal anatomy of the pelvis.

Study of the efficacy of 3D-printed prosthetic reconstruction after pelvic tumour resection

The purpose of this study is to explore the effect of using 3D printed pelvic prosthesis to reconstruct bone defect after pelvic tumor resection. From June 2018 to October 2021, a total of 10 patients with pelvic tumors underwent pelvic tumor resection and 3D printed customized hemipelvic prosthesis reconstruction in our hospital. Enneking pelvic surgery subdivision method was used to determine the degree of tumor invasion and the site of prosthesis reconstruction. 2 cases in Zone I, 2 cases in Zone II, 3 cases in Zone I + II, 2 cases in Zone II + III and 1 case in Zone I + II + III. Patients had preoperative VAS scores of 6.5 ± 1.3, postoperative VAS scores of 2.2 ± 0.9, preoperative MSTS-93 scores of 9.4 ± 5.3 and postoperative 19.4 ± 5.9(p < 0.05), all patients had improvement in pain after surgery; Postoperative complications included joint dislocation in 2 cases, myasthenia caused by Guillain-Barre syndrome in 1 case, delayed wound healing in 3 cases and wound infection in 2 cases. Postoperative wound-related complications and dislocations were associated with the extent of the tumor. Patients with tumor invasion of the iliopsoas and gluteus medius muscles had higher complication rates and worse postoperative MSTS scores (p < 0.05). The patients were followed up for 8 ∼ 28 months. During the follow-up period, 1 case recurred, 4 cases metastasized and 1 case died. All pelvic CTs reviewed 3-6 months after surgery showed good alignment between the 3D printed prosthesis and the bone contact, and tomography showed the growth of trabecular structures into the bone. Overall pain scores decreased and functional scores improved in patients after 3D printed prosthesis replacement for pelvic tumor resection. Long-term bone ingrowth could be seen on the prosthesis-bone contact surface with good stability.

The Possibilities of Personalized 3D Printed Implants-A Case Series Study

Background and Objectives: Following the most recent software and 3D printing developments, the use of personalized 3D printed orthopedic implants for treatment of complicated surgical cases has gained more popularity. Today, orthopedic problems that cannot be solved with standard implants may be effectively addressed using personalized prostheses. The aim of this study is to present the designing, modeling and production stages of four different personalized 3D printed prostheses and their application in clinical cases of patients who underwent treatment in various anatomical locations with a precisely specified indication for implantation. Materials and Methods: Based on computed tomography scanning, personalized 3D printed prostheses were designed, produced and used in four patients within a period of three to five days after injury or admission. Results: Early term follow-ups demonstrated good to excellent results. Conclusions: Personalized 3D printed prostheses offer an opportunity for a treatment of choice and provide good anatomical and functional results, shortened surgical time, less complications, and high satisfaction in patients with appropriate indications. The method should be considered primarily for patients with large bone defects, or such indicated for resection. Personalized 3D printed prostheses have the potential to become more common and beneficial in the future.

Complex geometry and integrated macro-porosity: Clinical applications of electron beam melting to fabricate bespoke bone-anchored implants

The last decade has witnessed rapid advancements in manufacturing technologies for biomedical implants. Additive manufacturing (or 3D printing) has broken down major barriers in the way of producing complex 3D geometries. Electron beam melting (EBM) is one such 3D printing process applicable to metals and alloys. EBM offers build rates up to two orders of magnitude greater than comparable laser-based technologies and a high vacuum environment to prevent accumulation of trace elements. These features make EBM particularly advantageous for materials susceptible to spontaneous oxidation and nitrogen pick-up when exposed to air (e.g., titanium and titanium-based alloys). For skeletal reconstruction(s), anatomical mimickry and integrated macro-porous architecture to facilitate bone ingrowth are undoubtedly the key features of EBM manufactured implants. Using finite element modelling of physiological loading conditions, the design of a prosthesis may be further personalised. This review looks at the many unique clinical applications of EBM in skeletal repair and the ground-breaking innovations in prosthetic rehabilitation. From a simple acetabular cup to the fifth toe, from the hand-wrist complex to the shoulder, and from vertebral replacement to cranio-maxillofacial reconstruction, EBM has experienced it all. While sternocostal reconstructions might be rare, the repair of long bones using EBM manufactured implants is becoming exceedingly frequent. Despite the various merits, several challenges remain yet untackled. Nevertheless, with the capability to produce osseointegrating implants of any conceivable shape/size, and permissive of bone ingrowth and functional loading, EBM can pave the way for numerous fascinating and novel applications in skeletal repair, regeneration, and rehabilitation. STATEMENT OF SIGNIFICANCE: Electron beam melting (EBM) offers unparalleled possibilities in producing contaminant-free, complex and intricate geometries from alloys of biomedical interest, including Ti6Al4V and CoCr. We review the diverse range of clinical applications of EBM in skeletal repair, both as mass produced off-the-shelf implants and personalised, patient-specific prostheses. From replacing large volumes of disease-affected bone to complex, multi-material reconstructions, almost every part of the human skeleton has been replaced with an EBM manufactured analog to achieve macroscopic anatomical-mimickry. However, various questions regarding long-term performance of patient-specific implants remain unaddressed. Directions for further development include designing personalised implants and prostheses based on simulated loading conditions and accounting for trabecular bone microstructure with respect to physiological factors such as patient's age and disease status.

Reconstruction with 3D-printed prostheses after type I + II + III internal hemipelvectomy: Finite element analysis and preliminary outcomes

Background: Prosthetic reconstruction after type I + II+ III internal hemipelvectomy remains challenging due to the lack of osseointegration and presence of giant shear force at the sacroiliac joint. The purpose of this study was to evaluate the biomechanical properties of the novel 3D-printed, custom-made prosthesis with pedicle screw-rod system and sacral tray using finite element analysis. Methods: Four models that included one intact pelvis were established for validation. Forces of 500 N and 2,000 N were applied, respectively, to simulate static bipedal standing and the most loaded condition during a gait cycle. Biomechanical analysis was performed, and the results were compared; the preliminary outcomes of four patients were recorded. Results: For the reconstructed hemipelvis, stress was mainly concentrated on the sacral screws, bone-prosthesis interface, and upper endplate of the L5 vertebra. The optimization of the design with the sacral tray structure could decrease the peak stress of the sacral screws by 18.6%, while the maximal stress of the prosthesis increased by 60.7%. The addition of the lumbosacral pedicle-rod system further alleviated stress of the sacral screws and prosthesis by 30.2% and 19.4%, respectively. The site of peak stress was contemporaneously transferred to the connecting rods within an elastic range. In the retrospective clinical study, four patients who had undergone prosthetic reconstruction were included. During a follow-up of 16.6 ± 7.5 months, the walking ability was found preserved in all patients who are still alive and no prosthesis-related complications had occurred except for one hip dislocation. The Musculoskeletal Tumor Society (MSTS) score was found to be 19.5 ± 2.9. Conclusion: The novel reconstructive system yielded favorable biomechanical characteristics and demonstrated promising preliminary outcomes. The method can be used as a reference for reconstruction after type I + II + III hemipelvectomy.

Early radiographic osseointegration of a novel highly porous 3D-printed titanium collar for megaprostheses compared to a previous generation smooth HA-coated collar

PURPOSE

Extracortical osseointegration at the collar-bone interface of megaprostheses is associated with improved implant stability, lower rates of stem fracture and loosening. The use of hydroxy-apatite (HA-) coated collars showed mixed results in previously published reports. A novel collar system has recently become available utilizing additive manufacturing technology to create a highly porous titanium collar with a calcium-phosphate coated surface. The aim of this study was to evaluate our early experience with this novel collar and compare it to the previously used HA-coated model.

METHODS

Twenty patients who underwent megaprostheses implantation utilizing the novel collar system were case matched to 20 patients who had previously undergone a HA-coated collar. A minimum radiological follow-up of three months was available in all included patients. Osseointegration was evaluated using postoperative plain radiographs in two planes based on a previously published semi-quantitative score.

RESULTS

Compared to the HA-coated collar the use of the novel highly porous collar was associated with a higher proportion of cases demonstrating osseointegration at the bone-collar interface (80% vs. 65%). Application of the highly porous collar led to a significantly shortened time to reach the final ongrowth score (173 ± 89 days vs. 299 ± 165 days, p < 0.05). At one year follow-up, 90% of the novel collars had reached their final osseoingration grade compared to 50% in the HA-coated collar group (p < 0.001). Radiological osseointegration was seen in 71% for highly porous collars where the indication was revision arthroplasty, compared to 27% in reported in the literature.

CONCLUSION

These results indicate more reliable and accelerated osseointegration at the bone-collar interface of a novel highly porous collar system compared to a previously used HA-coated collar. Further studies are warranted to confirm these findings.

The application of additive manufacturing technology in pelvic surgery: A bibliometrics analysis

With the development of material science, additive manufacturing technology has been employed for pelvic surgery, addressing the challenges, such as the complex structure of the pelvis, difficulty in exposing the operative area, and poor visibility, of the traditional pelvic surgery. However, only limited studies have been done to review the research hotspots and trends of the additive manufacturing technology applied for pelvic surgery. In this study, we comprehensively analyzed the literatures related to additive manufacturing technology in pelvic surgery by a bibliometrics analysis and found that additive manufacturing technology is widely used in several aspects of preoperative diagnosis, preoperative planning, intraoperative navigation, and personalized implants for pelvic surgery. Firstly, we searched and screened 856 publications from the Web of Science Core Collection (WoSCC) with TS = (3D printing OR 3D printed OR three-dimensional printing OR additive manufacturing OR rapid prototyping) AND TS = (pelvis OR sacrum OR ilium OR pubis OR ischium OR ischia OR acetabulum OR hip) as the search strategy. Then, 565 of these were eliminated by evaluating the titles and abstracts, leaving 291 pieces of research literature whose relevant information was visually displayed using VOSviewer. Furthermore, 10 publications with high citations were selected by reading all publications extensively for carefully evaluating their Titles, Purposes, Results, Limitations, Journal of affiliation, and Citations. Our results of bibliometric analysis demonstrated that additive manufacturing technology is increasingly applied in pelvic surgery, providing readers with a valuable reference for fully comprehending the research hotspots and trends in the application of additive manufacturing technology in pelvic surgery.

Less is better than more with resection of periacetabular tumors - A retrospective 16 years study and literature review

Introduction

Wide resections of periacetabular tumors create a sizeable bony defect that inevitably results in severe loss of function. Reconstruction of such defects usually requires using large metal implants, a feature associated with considerable surgery extension and complications. The aim of this study is to report resection with no reconstruction of the bony defect. In this retrospective study, we reviewed a consecutive series of 16 patients diagnosed with malignant periacetabular tumors and underwent en-bloc resection without reconstructing their remaining bone defect.

Methods

Records were reviewed of 16 consecutive patients diagnosed with malignant periacetabular tumors and underwent en-bloc resection without reconstructing their remaining bony defect. Measurements included: the duration of surgery, blood loss, hemoglobin levels and the need for blood transfusions, data on other hospitalization characteristics, and intraoperative and postoperative complications.

Results

Sixteen patients with malignant periacetabular bone tumors and extensive bone destruction underwent wide periacetabular tumor resection with a mean follow-up of 75 months and a mean age of 53 years. The average HOOS score was 46 (range: 20 to 76), and the mean MSTS score was 13% (range: 0 to 15). The mean operative time was 4.1 h, and the mean blood loss was 1200 ml. At their most recent follow-up, patients had a mean shortening of their operated extremity of 4.8 cm, and all could ambulate with assisting devices.

Conclusion

Wide resection of periacetabular tumors without reconstruction provides acceptable levels of function and was associated with shorter surgical time, less blood loss and fewer postoperative complications compared to resection with reconstruction. Therefore, this approach may be considered a viable surgical option in patients with an extensive malignant periacetabular.

Level III

Retrospective study.

Comparison of customized 3D-printed prosthesis and screw-rod-cage system reconstruction following resection of periacetabular tumors

Background and purpose

Various operative methods are used for reconstructing pelvic girdle after resection of primary malignant periacetabular tumor has been reported. The objective of this study was to evaluate the accuracy, effectiveness, and safety of customized three dimensional-printed prosthesis (3DP) in the reconstruction of bone defects compared with conventional reconstruction using the screw-rod-cage system.

Methods

A retrospective case–control analysis of 40 patients who underwent pelvic tumor resection and reconstruction with a customized 3D-printed prosthesis (3DP), or screw-rod-cage system (SRCS) between January 2010 and December 2019 was performed. The minimum follow-up time for patients alive was 2 years. Blood loss, operation time, complications, surgical margin, local recurrence, distant metastases, status at time of latest follow-up, MSTS-93 score, Harris hip score, and postoperative radiographic parameters were recorded. Moreover, overall survival, tumor-free survival, and prosthesis survival rates in both groups were compared.

Results

Customized 3DP reconstruction was performed in 15 patients, and SRCS reconstruction was done in 25 patients. The group of patients treated with customized 3DP reconstruction had significantly shorter operation time (323.7 ± 83.7 vs. 393.6 ± 98.8 min; P = 0.028) and more precise (all P < 0.05) radiographic reconstruction parameters than patients in the SRCS group. Fewer complications (P = 0.026), better MSTS score (P = 0.030), and better Harris hip score (P = 0.016) were achieved in the 3DP group. Furthermore, the survival rate of prosthesis was also significantly better in the 3DP group (P = 0.039). However, blood loss, surgical margin, local recurrence, distant metastases, and status at time of latest follow-up had no significant difference between two groups.

Conclusion

Compared with the screw-rod-cage system reconstruction, the customized 3D-printed prosthesis reconstruction is equally safe and effective, but it is more accurate and time-saving and is associated with fewer complications.

Application of 3-dimensional printing implants for bone tumors

Three-dimensional (3D) additive manufacturing has recently been used in various medical fields. Among them, orthopedic oncology is one that utilizes it most actively. Bone and tumor modeling for surgical planning, personalized surgical instrument fabrication, and implant fabrication are typical applications. The 3D-printed metal implants using titanium alloy powder have created a revolutionary change in bone reconstruction that can be customized to all body areas; however, bioprinting remains experimental and under active study. This review explores the practical applications of 3D printing in orthopedic oncology and presents a representative case. The 3D-printed implant can replace the conventional tumor prosthesis and auto/allobone graft, thereby personalizing bone reconstruction. Biologic bone reconstruction using biodegradable or bioprinted materials beyond metal may be possible in the future.

Long-term functional recovery in patients with custom-made 3D-printed anatomical pelvic prostheses following bone tumor excision

BACKGROUND

Anatomical custom-made prostheses make it possible to reconstruct complicated bone defects following excision of bone tumors, thanks to 3D-printed technology. To date, clinical measures have been used to report clinical-functional outcome and provide evidence for the effectiveness of this new surgical approach. However, there are no studies that quantified the achievable recovery during common activities by using instrumental clinical-functional evaluation in these patients.

RESEARCH QUESTION

What is the motor performance, functional outcome and quality of life in patients with custom-made 3D-printed pelvic prostheses following bone tumor?

METHODS

To analyze motor performance, six patients performed motion analysis during five motor activities at follow-up of 32 ± 18 months. Joint angles, ground reaction forces and joint moments of the operated and contralateral limbs were compared. On-off activity of lower-limb muscles were calculated from electromyography and compared to a healthy matched population. To analyze functional outcome and quality of life, differences in measured hip abductor strength between limbs were evaluated, as well as clinical-functional scores (Harris Hip Score, Barthel Index, Musculoskeletal Tumor Society score), and quality of life (SF-36 health survey).

RESULTS

We found only slight differences in joint kinematics when comparing operated and contralateral limb. The activity of gluteal muscles was normal, while hamstrings showed out-of-phase activities. Ground reaction forces and hip moments showed asymmetries between limbs, particularly in more demanding motor activities. We found a mean difference in hip abductor strength of 48 ± 82 N between limbs, good clinical-functional scores, and quality of life scores within normative.

SIGNIFICANCE

Our study showed optimal long-term results in functional recovery, mainly achieved through recovery of the gluteal function, although minor impairments were found, which may be considered for future improvement of this innovative surgery. The effect of a more loaded contralateral limb on internal loads and long-term performance of the implant remains unknown and deserves further investigation.

Computer-Aided Design and 3D Printing of Hemipelvic Endoprosthesis for Personalized Limb-Salvage Reconstruction after Periacetabular Tumor Resection

3D-printed hemipelvic endoprosthesis is an emerging solution for personalized limb-salvage reconstruction after periacetabular tumor resection. Further clinical studies are still required to report its surgical characteristics, outcomes, benefits and drawbacks. Sixteen consecutive patients underwent periacetabular tumor wide resection and pelvic reconstruction with a 3D-printed hemipelvic endoprosthesis from 2018 to 2021. The surgical characteristics and outcomes are described. The mean follow-up duration was 17.75 months (range, 6 to 46 months). Five patients underwent surgery for type I + II resection and reconstruction, seven for type II + III resection and reconstruction, three for type II resection and reconstruction, and one for type I + II + IV resection and reconstruction. The incidence of postoperative complication was 12.5% (2/16) for deep venous thrombosis (DVT), 12.5% (2/16) for pneumonia, and 12.5% (2/16) for would deep or superficial infection. During follow-up, two patients (12.5%) suffered hip dislocation and underwent revision surgery. CT demonstrated an obvious prosthetic porous structure–bone fusion after follow-up of at least 6 months. At the final follow-up, 12 lived with no evidence of disease while four lived with disease; no patients experienced pain; and 15 had independent ambulation, with a mean Musculoskeletal Tumor Society (MSTS) score of 85.8% (range, 26.7% to 100%). 3D-printed hemipelvic endoprosthesis facilitates wide resection of periacetabular tumor and limb-salvage reconstruction, thus resulting in good oncological and functional outcomes. The custom-made nature is able to well mimic the skeletal anatomy and microstructure and promote osseointegration. Perioperative complications and rehabilitation exercise still need to be stressed for this engineering technology-assisted major orthopedic surgery.

Feasibility and preliminary efficacy of tantalum components in the management of acetabular reconstruction following periacetabular oncologic resection in primary malignancies

Background

The aim of the study was to investigate the feasibility and preliminary efficacy of tantalum components utility in the reconstruction of acetabular defects following periacetabular oncologic resection of primary malignancies.

Methods

We prospectively collected a consecutive of 15 cases that were treated with tantalum components for acetabular reconstruction after periacetabular oncologic resection from January 2018 to December 2018. The cohort included 8 male and 7 female patients, with a mean age of 47.6 years (range, 33 to 67 years). Pathology types: chondrosarcoma (n = 9), malignant bone giant cell tumor (n = 3) and osteosarcoma (n = 3). Clinical outcomes, functional and radiographic results were recorded in detail for analysis.

Results

Patients received planned oncologic resection and tantalum components reconstruction without casualty; they were followed up with a mean of 39.7 months (35–45 months). The mean operation time was 4.0 h (3.0–6.0 h), and the mean blood loss was 1260 ml (800–2200 ml). Functional outcomes were assessed by MSTS-93 scale, with an average of 21.8 (12.0–26.0 scores), among which 3 cases were excellent, 11 were good and 1 was fair. The mean Harris Hip Score was 79.1scores (46.0–92.0 scores) at 1-year follow-up postoperatively. 3(3/15, 20.0%) cases experienced postoperative complications: 2 cases with hip dislocation received closed reduction under general anesthesia and were fixed with hip joint abduction braces for 6 weeks; one case had a superficial infection and received debridement with a delayed wound healing. Oncologic prognosis: one case relapsed at 8-month follow-up and received hemi-pelvic amputation; and another osteosarcoma patient experienced relapse with pulmonary metastasis and received further chemotherapy. No prosthetic loosening, displacement or fracture occurred during the follow-up period.

Conclusion

Preliminary results suggested that the use of tantalum components in the management of acetabular reconstruction following periacetabular oncologic resection provided reasonable improvement on functional outcomes and early stability of the prostheses. Porous tantalum components are conducive to bony ingrowth, which is a potential alternative to various existing reconstruction techniques to achieve better functional outcomes.

[Application of three-dimensional printing technology in treatment of limb bone tumors]

With the developing of three-dimensional (3D) printing technology, it is widely used in the treatment of bone tumors in the clinical orthopedics. Because of the great individual differences in the location of bone tumor, resection and reconstruction are difficult. Based on 3D printing technology, the 3D models can be prepared to show the anatomical part of the disease, so that the surgeons can create a patient-specific operational plans based on better understand the local conditions. At the same time, preoperative simulation can also be carried out for complex operations and patient-specific prostheses can be further designed and prepared according to the location and size of tumor, which may have more advantages in adaptability. In this paper, the domestic and international research progress of 3D printing technology in the treatment of limb bone tumors in recent years were reviewed and summarized.

[Pelvic limb-salvage surgery for malignant tumors: 30 years of progress in China]

This article reviews the development and progress in the field of limb salvage treatment, surgical techniques, and function reconstruction of pelvic malignant tumors in China in the past 30 years. Based on the surgical classification of pelvic tumor resection in different parts, the development of surgical techniques and bone defect repair and reconstruction methods were described in detail. In recent years, in view of the worldwide problem of biological reconstruction after pelvic tumor resection, Chinese researchers have systematically proposed the repair and reconstruction methods and prosthesis design for bone defects after resection of different parts for the first time in the world. In addition, a systematic surgical classification (Beijing classification) was first proposed for the difficult situation of pelvic tumors involving the sacrum, as well as the corresponding surgical plan and repair and reconstruction methods. Through unremitting efforts, the limb salvage rate of pelvic malignant tumors in China has reached more than 80%, which has preserved limbs and restored walking function for the majority of patients, greatly reduced surgical complications, and achieved internationally remarkable results.

Low-Cost Cranioplasty-A Systematic Review of 3D Printing in Medicine

The high cost of biofabricated titanium mesh plates can make them out of reach for hospitals in low-income countries. To increase the availability of cranioplasty, the authors of this work investigated the production of polymer-based endoprostheses. Recently, cheap, popular desktop 3D printers have generated sufficient opportunities to provide patients with on-demand and on-site help. This study also examines the technologies of 3D printing, including SLM, SLS, FFF, DLP, and SLA. The authors focused their interest on the materials in fabrication, which include PLA, ABS, PET-G, PEEK, and PMMA. Three-dimensional printed prostheses are modeled using widely available CAD software with the help of patient-specific DICOM files. Even though the topic is insufficiently researched, it can be perceived as a relatively safe procedure with a minimal complication rate. There have also been some initial studies on the costs and legal regulations. Early case studies provide information on dozens of patients living with self-made prostheses and who are experiencing significant improvements in their quality of life. Budget 3D-printed endoprostheses are reliable and are reported to be significantly cheaper than the popular counterparts manufactured from polypropylene polyester.

Efficacy and safety of a 3D-printed arthrodesis prosthesis for reconstruction after resection of the proximal humerus: preliminary outcomes with a minimum 2-year follow-up

Background

The purpose of this study was to investigate the feasibility of using a three-dimensional (3D)-printed arthrodesis prosthesis for reconstruction of the proximal humeral defect after tumor resection.

Methods

A novel proximal humeral prosthesis was designed to restore bone continuity and shoulder arthrodesis and was fabricated via 3D printing technology. Ten patients with primary malignancies in the proximal humerus underwent intra-articular resection and replacement with this prosthesis from 2017 to 2019. Baseline and operative data, oncological and prosthetic survival, and functional status were summarized.

Results

This cohort consisted of 9 males and 1 female with a mean age of 32.1 ± 16.1 years. Diagnoses included 5 cases of osteosarcoma, 3 cases of chondrosarcoma and 1 each case of undifferentiated pleomorphic sarcoma and malignant myoepithelioma. The mean operative duration, intraoperative hemorrhage and postoperative length of hospitalization were 151.5 ± 61.0 min, 410.0 ± 353.4 ml and 5.3 ± 1.9 d, respectively. The mean follow-up duration was 29.3 ± 6.4 months, with a minimum of 24 months for the surviving patients. Two patients experienced local recurrence, and four patients developed distant metastases. Detachment of the taper occurred in two patients. One was managed conservatively, and the other received amputation due to concurrent tumor recurrence. The mean MSTS-93 and ASES scores and ranges of forwards flexion and abduction were 24.9 ± 3.1, 79.4 ± 8.3, 71.3 ± 19.4°, and 61.3 ± 16.4°, respectively. The functional outcomes were independent of the preservation of the axillary nerve. Histological study of the glenoid component showed evidence of bone ingrowth at the bone-prosthesis porous interface.

Conclusion

Application of the 3D-printed arthrodesis prosthesis might be a safe and efficacious method for functional reconstruction in patients who underwent resection of the proximal humerus, especially for those without preservation of the axillary nerve.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05581-6.

Reconstruction of Tumor-Induced Pelvic Defects With Customized, Three-Dimensional Printed Prostheses

Background

Reconstruction of pelvis girdle stability after tumor-induced hemipelvectomy remains challenging. We surgically treated 13 patients with custom-made, three-dimensional printed hemipelvic prostheses. We aim to identify the preliminary outcomes for patients who have been managed with more mixed regions of prosthetic pelvic reconstruction and the feasibility of two reconstructive systems.

Methods

Seven male patients and 6 female patients treated at our center between January 2019 and May 2021 were included. There were 11 primary sarcomas and 2 solitary bone metastases. After en bloc tumor resection, two types of personalized, three-dimensional printed prostheses were fixed to restore the stability and rebuild the load transfer. The position of the reconstructed hemipelvis was evaluated on an anteroposterior plain radiograph. The complications and outcomes were traced. One amputation specimen was discovered through histological analysis of the porous structure.

Results

The operative duration was 467 ± 144 min, and the blood loss was 3,119 ± 662 ml. During a follow-up of 22.4 ± 8.5 months, two patients had delayed wound healing and one had a second-stage flap transfer. One patient with osteosarcoma died of pulmonary metastasis 27 months after surgery. Two patients with marginal resection suffered from local recurrence and had extra surgeries. One patient had traumatic hip dislocation 2 months after surgery and manipulative reduction was performed. The acetabular inclination of the affected side was 42.2 ± 4.3°, compared with 42.1 ± 3.9° on the contralateral side. The horizontal distance between the center of the femoral head and the middle vertical line was 10.4 ± 0.6 cm, while the reconstructed side was 9.8 ± 0.8 cm. No significant difference in acetabular position after surgery was found (p > 0.05). The amputation specimen harvested from one patient with local recurrence demonstrated bone and soft tissue ingrowth within the three-dimensional printed trabecular structure. Walking ability was preserved in all patients who are still alive and no prosthesis-related complications occurred. The MSTS score was 22.0 ± 3.7.

Conclusions

Both types of custom-made, three-dimensional printed prostheses manifested excellent precision, mechanical stability, and promising functional rehabilitation. The porous structure exhibited favorable histocompatibility to facilitate the ingrowth of bone and soft tissue.

A novel limb-salvage reconstruction strategy with a custom hemipelvic endoprosthesis and preserved femoral head following the resection of periacetabular tumors: A preliminary study

The treatment of periacetabular malignancy frequently challenges surgeons. To simplify the surgical procedure, we performed a novel reconstruction strategy preserving the femoral head for patients with periacetabular malignancies. We retrospectively reviewed 14 patients who underwent total en bloc resection of a periacetabular tumor and reconstruction of the hip joint with an individualized hemipelvic endoprosthesis and remaining femoral head from July 2015 to January 2019 at our center. Regions of pelvic resection: region II-4 (28.6%), region I + II-5 (35.7%), region II + III-2 (14.3%) and region I + II + III-3 (21.4%). The oncological outcomes were that 13 patients survived without disease and one patient survived with lung metastasis. None of the patients experienced local recurrence (range: 20-62 months; mean: 32 months). The incidence of postoperative complications was 35.7%, including delayed wound healing and deep venous thrombosis. No prosthesis-related complications occurred until the last follow-up in this study (range: 20-62 months; mean: 32 months). The mean Musculoskeletal Tumor Society functional outcome score was 23.2. The mean Toronto Extremity Salvage Score of the patients was 75.7 points, with a mean limb discrepancy of 1.51 cm (range: 0.5-3.2 cm). Reconstruction with preservation of the femoral head showed acceptable early functional and oncological outcomes, and it had an acceptable complication rate.

Elbow hemiarthroplasty with a 3D-printed megaprosthesis for defects of the distal humerus or proximal ulna after tumour resection : a preliminary report

AIMS

The aim of this study was to investigate the feasibility of application of a 3D-printed megaprosthesis with hemiarthroplasty design for defects of the distal humerus or proximal ulna following tumour resection.

METHODS

From June 2018 to January 2020, 13 patients with aggressive or malignant tumours involving the distal humerus (n = 8) or proximal ulna (n = 5) were treated by en bloc resection and reconstruction with a 3D-printed megaprosthesis with hemiarthroplasty, designed in our centre. In this paper, we summarize the baseline and operative data, oncological outcome, complication profiles, and functional status of these patients.

RESULTS

Preparation of the prosthesis was a mean of 8.0 days (SD 1.5), during which time no patients experienced tumour progression. The mean operating time and intraoperative blood loss were 158.1 minutes (SD 67.6) and 176.9 ml (SD 187.8), respectively. All of the prostheses were implanted successfully. During a mean follow-up of 25.7 months (SD 7.8), no patients died, but four had complications (two superficial wound problems, one temporary palsy of radial nerve, and one dislocation). No aseptic loosening, structural failure, infection, heterotopic ossification, or degenerative arthritis was seen in this study. The mean flexion of the elbow was 119.6° (SD 15.9°) and the mean extension lag was 11.9° (SD 13.8°). The mean Musculoskeletal Tumor Society 93 score and Mayo Elbow Performance Score were 28.4 (SD 0.9) and 97.7 (SD 4.4), respectively.

CONCLUSION

The custom-made, 3D-printed megaprosthesis with hemiarthroplasty is a feasible option for functional reconstruction after resection of a tumour in the distal humerus or proximal ulna. Cite this article: Bone Joint J 2022;104-B(6):747-757.