Controversies in orthopaedic oncology.

Chondrosarcoma is the second most common surgically treated primary bone sarcoma. Despite a large number of scientific papers in the literature, there is still significant controversy about diagnostics, treatment of the primary tumour, subtypes, and complications. Therefore, consensus on its day-to-day treatment decisions is needed. In January 2024, the Birmingham Orthopaedic Oncology Meeting (BOOM) attempted to gain global consensus from 300 delegates from over 50 countries. The meeting focused on these critical areas and aimed to generate consensus statements based on evidence amalgamation and expert opinion from diverse geographical regions. In parallel, periprosthetic joint infection (PJI) in oncological reconstructions poses unique challenges due to factors such as adjuvant treatments, large exposures, and the complexity of surgery. The meeting debated two-stage revisions, antibiotic prophylaxis, managing acute PJI in patients undergoing chemotherapy, and defining the best strategies for wound management and allograft reconstruction. The objectives of the meeting extended beyond resolving immediate controversies. It sought to foster global collaboration among specialists attending the meeting, and to encourage future research projects to address unsolved dilemmas. By highlighting areas of disagreement and promoting collaborative research endeavours, this initiative aims to enhance treatment standards and potentially improve outcomes for patients globally. This paper sets out some of the controversies and questions that were debated in the meeting.

Extremity high-grade sarcomas in elderly patients, are they candidates for surgery? Experience in a sarcoma referral center.

The number of elderly patients diagnosed with cancer is increasing. However, knowledge regarding cancer in elderly patients is very scarce. The aim of this study is to analyze the differences in management and outcomes of high-grade extremity sarcomas between elderly and middle-aged patients. Two cohorts were made (> 70 and 30/50 years old) among patients treated in a multidisciplinary unit of a national reference center between 2011 and 2017 with a minimum of 2 years of follow-up. The management and outcomes between these two cohorts were compared. Seventy patients were included, 34 young patients and 36 elderly patients. The only difference between the treatment schemes was the chemotherapy used, 67.6% of the young patients received chemotherapy versus 16.7% of the elderly patients (p = 0.000015). There were no differences either in the overall survival or the progression-free survival between groups at 1 and 2-year follow-up. Deceases for other causes were nearly exclusive of elderly patients at a median of 45.57 months. Surgery is the treatment of choice for sarcomas in both elderly and young patients having similar results in terms of progression-free survival, overall survival, and surgery outcomes. The use of chemotherapy is the only difference in the treatment schemes between both groups. In the elderly patient with minimal or no comorbidity and good functional reserve, surgical curative treatment should be chosen. As for frail elderly patients, the therapeutic objectives must be focused mainly on quality of life and palliation of symptoms.

Is a greater degree of constraint really harmful? Clinical biomechanical comparative study between condylar constrained knee and rotating hinge prosthesis.

BACKGROUND: The real degree of constraint of rotating hinge knee and condylar constrained prostheses is a matter of discussion in revision knee arthroplasty. The objective of this study is to compare the tibial rotation between implants in the clinical settings. METHODS: An investigator blinded experimental study was designed including 20 patients: in 10 of them a rotating hinge knee prosthesis (Endomodel®, LINK) was implanted and in the remaining 10 a constrained condylar knee prosthesis (LCCK®, Zimmer) was used. A medial parapatellar approach was performed and implantation was performed according to conventional surgical technique. Tibial rotation was measured with two accelerometers in full extension and at 30°, 60° and 90° of flexion. Pre and postoperative Knee Injury and Osteoarthritis Outcome Score was recorded. FINDINGS: Both groups were homogenous in age (73.4 years in rotating hinge knee prosthesis vs 74 years in constrained condylar knee group), sex, laterality and preoperative Knee Injury and Osteoarthritis Outcome Score (p > 0.05). The postoperative Knee Injury and Osteoarthritis Outcome Score was significantly higher in the rotating hinge knee prosthesis group (80.98 vs 76.28). The degrees of tibial rotation measured by inertial sensors in the rotating hinge knee prosthesis group were also significantly higher than those measured in the constrained condylar knee group (5.66° vs 2.1°) with p = 0.001. INTERPRETATION: Rotating hinge knee prosthesis appears to represent a lower rotational constraint degree than constrained condylar knee systems in clinical practice and it may increase the clinical satisfaction. The clinical significance: Rotating hinge knee prosthesis appears to represent a lower constraint degree than constrained condylar knee systems in clinical practice.

HoloLens 1 vs. HoloLens 2: Improvements in the New Model for Orthopedic Oncological Interventions.

This work analyzed the use of Microsoft HoloLens 2 in orthopedic oncological surgeries and compares it to its predecessor (Microsoft HoloLens 1). Specifically, we developed two equivalent applications, one for each device, and evaluated the augmented reality (AR) projection accuracy in an experimental scenario using phantoms based on two patients. We achieved automatic registration between virtual and real worlds using patient-specific surgical guides on each phantom. They contained a small adaptor for a 3D-printed AR marker, the characteristic patterns of which were easily recognized using both Microsoft HoloLens devices. The newest model improved the AR projection accuracy by almost 25%, and both of them yielded an RMSE below 3 mm. After ascertaining the enhancement of the second model in this aspect, we went a step further with Microsoft HoloLens 2 and tested it during the surgical intervention of one of the patients. During this experience, we collected the surgeons' feedback in terms of comfortability, usability, and ergonomics. Our goal was to estimate whether the improved technical features of the newest model facilitate its implementation in actual surgical scenarios. All of the results point to Microsoft HoloLens 2 being better in all the aspects affecting surgical interventions and support its use in future experiences.

Improvement of surgical time and functional results after do-it-yourself 3D-printed model preoperative planning in acetabular defects Paprosky IIA-IIIB.

INTRODUCTION: The correct positioning of the implant in revision total hip arthroplasty (rTHA) is critical to obtaining substantial functional outcomes, and to avoiding complications. Current literature supports three-dimensional (3D)-printed models as potentially useful tools for preplanning, as well as the "do it yourself (DIY)" methodology to reduce both the time and costs of this procedure. However, no study has determined the efficacy of both methods combined in a cohort of patients with severe acetabular defects. In the lack of bibliography, we performed rTHA after preoperative planning by DIY-3D-printed models to evaluate its influence in: 1) the surgical time, 2) the functional scores, 3) the intra and postoperative complications, and 4) the reconstruction of the center of rotation (COR) of the hip. HYPOTHESIS: Preoperative planning through 3D-DIY printed models will both improve the accuracy of the implant positioning, and the surgical time, leading the latter to improved functional scores and reduced complications. MATERIALS & METHODS: A comparative study of 21 patients with Paprosky IIB to IIIB acetabular defects who underwent rTHA after 3D-printed model preoperative planning by the DIY method between 2016 and 2019 was conducted. A historical cohort of 24 patients served as the comparator. Surgical time, reconstruction of the COR, functional scores, and complications were analyzed. RESULTS: The mean follow-up was 32.4 (range, 12 to 60) months. All the patients showed significant improvement of the Harris hip score (HHS) after the operation (3D group: 26.58±10.73; control group 22.47±15.43 (p=0.00)). In the 3D-printed model preoperative planning group the mean operation time and the intraoperative complications were significantly lower (156.15±43.03min vs 187.5±54.38min (p=0.045); and 19% vs 62.5% (p=0.003), respectively), and the HHS and patient satisfaction score (PSS) were significantly greater (83.74±8.49 vs 75.59±11.46 (p=0.019); and 8.17±0.88 vs 7.36±1.17 (p=0.023), respectively). No differences were found in the postoperative complications, nor in the restoration of the COR as determined from the acetabular index, verticalization or horizontalization, although the acetabular index was closer to the intended one in the 3D-printed model planning group (46.67°±7.63 vs 49.22±8.1 (p=0.284)). CONCLUSION: Preoperative planning of severe acetabular defects through 3D-printed models shortens the surgical time, leading to a decrease in complications and thus to better functional outcomes and greater patient satisfaction. Moreover, the DIY philosophy could decrease both the time and costs of traditional 3D planning. LEVEL OF EVIDENCE: III, retrospective case matched study.

Augmented Reality as a Tool to Guide PSI Placement in Pelvic Tumor Resections.

Patient-specific instruments (PSIs) have become a valuable tool for osteotomy guidance in complex surgical scenarios such as pelvic tumor resection. They provide similar accuracy to surgical navigation systems but are generally more convenient and faster. However, their correct placement can become challenging in some anatomical regions, and it cannot be verified objectively during the intervention. Incorrect installations can result in high deviations from the planned osteotomy, increasing the risk of positive resection margins. In this work, we propose to use augmented reality (AR) to guide and verify PSIs placement. We designed an experiment to assess the accuracy provided by the system using a smartphone and the HoloLens 2 and compared the results with the conventional freehand method. The results showed significant differences, where AR guidance prevented high osteotomy deviations, reducing maximal deviation of 54.03 mm for freehand placements to less than 5 mm with AR guidance. The experiment was performed in two versions of a plastic three-dimensional (3D) printed phantom, one including a silicone layer to simulate tissue, providing more realism. We also studied how differences in shape and location of PSIs affect their accuracy, concluding that those with smaller sizes and a homogeneous target surface are more prone to errors. Our study presents promising results that prove AR's potential to overcome the present limitations of PSIs conveniently and effectively.

Conceptual evolution of 3D printing in orthopedic surgery and traumatology: from "do it yourself" to "point of care manufacturing".

BACKGROUND: 3D printing technology in hospitals facilitates production models such as point-of-care manufacturing. Orthopedic Surgery and Traumatology is the specialty that can most benefit from the advantages of these tools. The purpose of this study is to present the results of the integration of 3D printing technology in a Department of Orthopedic Surgery and Traumatology and to identify the productive model of the point-of-care manufacturing as a paradigm of personalized medicine. METHODS: Observational, descriptive, retrospective and monocentric study of a total of 623 additive manufacturing processes carried out in a Department of Orthopedic Surgery and Traumatology from November 2015 to March 2020. Variables such as product type, utility, time or materials for manufacture were analyzed. RESULTS: The areas of expertise that have performed more processes are Traumatology, Reconstructive and Orthopedic Oncology. Pre-operative planning is their primary use. Working and 3D printing hours, as well as the amount of 3D printing material used, vary according to the type of product or material delivered to perform the process. The most commonly used 3D printing material for manufacturing is polylactic acid, although biocompatible resin has been used to produce surgical guides. In addition, the hospital has worked on the co-design of customized implants with manufacturing companies. CONCLUSIONS: The integration of 3D printing in a Department of Orthopedic Surgery and Traumatology allows identifying the conceptual evolution from "Do-It-Yourself" to "POC manufacturing".

Point-of-care manufacturing: a single university hospital's initial experience.

BACKGROUND: The integration of 3D printing technology in hospitals is evolving toward production models such as point-of-care manufacturing. This study aims to present the results of the integration of 3D printing technology in a manufacturing university hospital. METHODS: Observational, descriptive, retrospective, and monocentric study of 907 instances of 3D printing from November 2015 to March 2020. Variables such as product type, utility, time, or manufacturing materials were analyzed. RESULTS: Orthopedic Surgery and Traumatology, Oral and Maxillofacial Surgery, and Gynecology and Obstetrics are the medical specialties that have manufactured the largest number of processes. Working and printing time, as well as the amount of printing material, is different for different types of products and input data. The most common printing material was polylactic acid, although biocompatible resin was introduced to produce surgical guides. In addition, the hospital has worked on the co-design of custom-made implants with manufacturing companies and has also participated in tissue bio-printing projects. CONCLUSIONS: The integration of 3D printing in a university hospital allows identifying the conceptual evolution to "point-of-care manufacturing."

Application of 3D printing and distributed manufacturing during the first-wave of COVID-19 pandemic. Our experience at a third-level university hospital.

BACKGROUND: 3D printing and distributed manufacturing represent a paradigm shift in the health system that is becoming critical during the COVID-19 pandemic. University hospitals are also taking on the role of manufacturers of custom-made solutions thanks to 3D printing technology. CASE PRESENTATION: We present a monocentric observational case study regarding the distributed manufacturing of three groups of products during the period of the COVID-19 pandemic from 14 March to 10 May 2020: personal protective equipment, ventilatory support, and diagnostic and consumable products. Networking during this period has enabled the delivery of a total of 17,276 units of products manufactured using 3D printing technology. The most manufactured product was the face shields and ear savers, while the one that achieved the greatest clinical impact was the mechanical ventilation adapters and swabs. The products were manufactured by individuals in 57.3% of the cases, and our hospital acted as the main delivery node in a hub with 10 other hospitals. The main advantage of this production model is the fast response to stock needs, being able to adapt almost in real time. CONCLUSIONS: The role of 3D printing in the hospital environment allows the reconciliation of in-house and distributed manufacturing with traditional production, providing custom-made adaptation of the specifications, as well as maximum efficiency in the working and availability of resources, which is of special importance at critical times for health systems such as the current COVID-19 pandemic.

Combining Augmented Reality and 3D Printing to Improve Surgical Workflows in Orthopedic Oncology: Smartphone Application and Clinical Evaluation.

During the last decade, orthopedic oncology has experienced the benefits of computerized medical imaging to reduce human dependency, improving accuracy and clinical outcomes. However, traditional surgical navigation systems do not always adapt properly to this kind of interventions. Augmented reality (AR) and three-dimensional (3D) printing are technologies lately introduced in the surgical environment with promising results. Here we present an innovative solution combining 3D printing and AR in orthopedic oncological surgery. A new surgical workflow is proposed, including 3D printed models and a novel AR-based smartphone application (app). This app can display the patient's anatomy and the tumor's location. A 3D-printed reference marker, designed to fit in a unique position of the affected bone tissue, enables automatic registration. The system has been evaluated in terms of visualization accuracy and usability during the whole surgical workflow. Experiments on six realistic phantoms provided a visualization error below 3 mm. The AR system was tested in two clinical cases during surgical planning, patient communication, and surgical intervention. These results and the positive feedback obtained from surgeons and patients suggest that the combination of AR and 3D printing can improve efficacy, accuracy, and patients' experience.

Patient-specific desktop 3D-printed guides for pelvic tumour resection surgery: a precision study on cadavers.

PURPOSE: 3D-printed patient-specific instruments have become a useful tool to improve accuracy in pelvic tumour resections. However, their correct placement can be challenging in some regions due to the morphology of the bone, so it is essential to be aware of the possible placement errors in each region. In this study, we characterize these errors in common pelvic osteotomies. METHODS: We conducted an experiment with 9 cadaveric specimens, for which we acquired a pre-operative computed tomography scan. Small PSIs were designed for each case following a realistic surgical approach for four regions of the pelvis: iliac crest (C), supra-acetabular (S), ischial (I), and pubic (P). Final surgical placement was based on a post-operative scan. The resulting positions were compared with pre-operative planning, obtaining translations, rotations, and maximum osteotomy deviations in a local reference frame defined based on the bone's morphology. RESULTS: Mean translations and rotations in the direction of the osteotomy plane were as follows: C = 5.3 mm, 6.7°; S = 1.8 mm, 5.1°; I = 1.5 mm, 3.4°; P = 1.8 mm, 3.5°. Mean translations in the remaining axes were below 2 mm. Maximum osteotomy deviations (75% of cases) were below 11.8 mm in C (7.8 mm for half-length), 7.8 mm in S (5.5 mm for half-length), 5.5 mm in I, and 3.7 mm in P. CONCLUSION: We have characterized placement errors for small PSIs in four regions of the pelvis. Our results show high errors in C and S PSIs in the direction of the resection plane's normal, and thus large osteotomy deviations. Deviations in short osteotomies in S, I and P and placement errors in the remaining directions were low. The PSIs used in this study are biocompatible and can be produced with a desktop 3D printer, thus minimizing manufacturing cost.

Intraoperative computed tomography imaging for dose calculation in intraoperative electron radiation therapy: Initial clinical observations.

In intraoperative electron radiation therapy (IOERT) the energy of the electron beam is selected under the conventional assumption of water-equivalent tissues at the applicator end. However, the treatment field can deviate from the theoretic flat irradiation surface, thus altering dose profiles. This patient-based study explored the feasibility of acquiring intraoperative computed tomography (CT) studies for calculating three-dimensional dose distributions with two factors not included in the conventional assumption, namely the air gap from the applicator end to the irradiation surface and tissue heterogeneity. In addition, dose distributions under the conventional assumption and from preoperative CT studies (both also updated with intraoperative data) were calculated to explore whether there are other alternatives to intraoperative CT studies that can provide similar dose distributions. The IOERT protocol was modified to incorporate the acquisition of intraoperative CT studies before radiation delivery in six patients. Three studies were not valid to calculate dose distributions due to the presence of metal artefacts. For the remaining three cases, the average gamma pass rates between the doses calculated from intraoperative CT studies and those obtained assuming water-equivalent tissues or from preoperative CT studies were 73.4% and 74.0% respectively. The agreement increased when the air gap was included in the conventional assumption (98.1%) or in the preoperative CT images (98.4%). Therefore, this factor was the one mostly influencing the dose distributions of this study. Our experience has shown that intraoperative CT studies are not recommended when the procedure includes the use of shielding discs or surgical retractors unless metal artefacts are removed. IOERT dose distributions calculated under the conventional assumption or from preoperative CT studies may be inaccurate unless the air gap (which depends on the surface irregularities of the irradiated volume and on the applicator pose) is included in the calculations.

Combining Augmented Reality and 3D Printing to Display Patient Models on a Smartphone.

Augmented reality (AR) has great potential in education, training, and surgical guidance in the medical field. Its combination with three-dimensional (3D) printing (3DP) opens new possibilities in clinical applications. Although these technologies have grown exponentially in recent years, their adoption by physicians is still limited, since they require extensive knowledge of engineering and software development. Therefore, the purpose of this protocol is to describe a step-by-step methodology enabling inexperienced users to create a smartphone app, which combines AR and 3DP for the visualization of anatomical 3D models of patients with a 3D-printed reference marker. The protocol describes how to create 3D virtual models of a patient's anatomy derived from 3D medical images. It then explains how to perform positioning of the 3D models with respect to marker references. Also provided are instructions for how to 3D print the required tools and models. Finally, steps to deploy the app are provided. The protocol is based on free and multi-platform software and can be applied to any medical imaging modality or patient. An alternative approach is described to provide automatic registration between a 3D-printed model created from a patient's anatomy and the projected holograms. As an example, a clinical case of a patient suffering from distal leg sarcoma is provided to illustrate the methodology. It is expected that this protocol will accelerate the adoption of AR and 3DP technologies by medical professionals.

Craniosynostosis surgery: workflow based on virtual surgical planning, intraoperative navigation and 3D printed patient-specific guides and templates.

Craniosynostosis must often be corrected using surgery, by which the affected bone tissue is remodeled. Nowadays, surgical reconstruction relies mostly on the subjective judgement of the surgeon to best restore normal skull shape, since remodeled bone is manually placed and fixed. Slight variations can compromise the cosmetic outcome. The objective of this study was to describe and evaluate a novel workflow for patient-specific correction of craniosynostosis based on intraoperative navigation and 3D printing. The workflow was followed in five patients with craniosynostosis. Virtual surgical planning was performed, and patient-specific cutting guides and templates were designed and manufactured. These guides and templates were used to control osteotomies and bone remodeling. An intraoperative navigation system based on optical tracking made it possible to follow preoperative virtual planning in the operating room through real-time positioning and 3D visualization. Navigation accuracy was estimated using intraoperative surface scanning as the gold-standard. An average error of 0.62 mm and 0.64 mm was obtained in the remodeled frontal region and supraorbital bar, respectively. Intraoperative navigation is an accurate and reproducible technique for correction of craniosynostosis that enables optimal translation of the preoperative plan to the operating room.

Augmented reality in computer-assisted interventions based on patient-specific 3D printed reference.

Augmented reality (AR) can be an interesting technology for clinical scenarios as an alternative to conventional surgical navigation. However, the registration between augmented data and real-world spaces is a limiting factor. In this study, the authors propose a method based on desktop three-dimensional (3D) printing to create patient-specific tools containing a visual pattern that enables automatic registration. This specific tool fits on the patient only in the location it was designed for, avoiding placement errors. This solution has been developed as a software application running on Microsoft HoloLens. The workflow was validated on a 3D printed phantom replicating the anatomy of a patient presenting an extraosseous Ewing's sarcoma, and then tested during the actual surgical intervention. The application allowed physicians to visualise the skin, bone and tumour location overlaid on the phantom and patient. This workflow could be extended to many clinical applications in the surgical field and also for training and simulation, in cases where hard body structures are involved. Although the authors have tested their workflow on AR head mounted display, they believe that a similar approach can be applied to other devices such as tablets or smartphones.

Biarticular total femur spacer for massive femoral bone loss: the mobile solution for a big problem.

Bone cement spacers loaded with antibiotic are the gold standard in septic revision. However, the management of massive bone defects constitutes a surgical challenge, requiring the use of different nails, expensive long stems, or cement-coated tumor prostheses for preparing the spacer. In most cases, the knee joint must be sacrificed. We describe a novel technique for preparing a biarticular total femur spacer with the help of a trochanteric nail coated with antibiotic loaded cement, allowing mobility of the hip and knee joints and assisted partial loading until second step surgery. This technique is helpful to maintain the length of the leg, prevent soft tissue contracture, and help eradicate the infection preserving the patient comfort and autonomy while waiting to receive total femoral replacement.

Metallisation of Biolox Delta® ceramic head: What's wrong?

INTRODUCTION: Since the recent failure of certain coating models, hybrid implants (coated acetabular inserts with conventional stems) and stems with modular necks, there has been growing interest in the consequences of the generation and release of metal particles at the prosthetic interfaces. The use of ceramic heads has recently been described as an option for reducing the production of metal ions and their consequences. CASE REPORT: The present case report describes the first complete metallisation of a ceramic head secondary to an excessive release of metal ions at the head-neck junction. CONCLUSIONS: We believe this to have occurred due to the use of 12/14 cones of different manufacturers.

Total femur arthroplasty for revision hip failure in osteogenesis imperfecta: limits of biology.

Osteogenesis imperfecta (OI) is a rare congenital disease characterized by alterations in bone quality, with susceptibility to fractures, instability, deformities, and osteoarthrosis. Prosthetic surgery in these patients is associated with an abnormally high rate of implant failures. On the other hand, abnormal bone fragility adds to the complexity of revision surgery in such individuals-thus representing a genuine challenge for the orthopaedic surgeon. We present a case of femoral reconstruction in a patient with OI and prosthetic loosening after reconstruction secondary to femoral septic pseudoarthrosis. Intramedullary total femoral reconstruction was carried out after exceeding the biological reconstruction limits. This is the first reported instance of the use of an intramedullary total femur arthroplasty as salvage technique in an OI patient. This technique should be considered when we have exceeded biological limits for femoral fixation.

Intraoperative radiotherapy for extremity soft-tissue sarcomas: can long-term local control be achieved?

BACKGROUND: Intraoperative electron-beam radiation therapy (IOERT) during limb-sparing surgery has the advantage of delivering a single high boost dose to sarcoma residues and surgical bed area near to radiosensitive structures with limited toxicity. Retrospective studies have suggested that IOERT may improve local control compared to standard radiotherapy and we aimed to demonstrate this theory. Therefore, we performed an observational prospective study to determine (1) if it is possible to achieve high local control by adding IOERT to external-beam radiation therapy (EBRT) in extremity soft-tissue sarcomas (STS), (2) if it is possible to improve long-term survival rates, and (3) if toxicity could be reduced with IOERT MATERIALS AND METHODS: From 1995-2003, 39 patients with extremity STS were treated with IOERT and postoperative radiotherapy. The median follow-up time was 13.2 years (0.7-19). Complications, locoregional control and survival rates were collected. RESULTS: Actuarial local control was attained in 32 of 39 patients (82%). Control was achieved in 88% of patients with primary disease and in 50% of those with recurrent tumors (p = 0.01). Local control was shown in 93% of patients with negative margins and in 50% of those with positive margins (p = 0.002). Limb-sparing was achieved in 32 patients (82%). The overall survival rate was 64%. 13% of patients had grade ≥3 acute toxicity, and 12% developed grade ≥3 chronic toxicity. CONCLUSION: IOERT used as a boost to EBRT provides high local control and limb-sparing rates in patients with STS of the extremities, with less toxicity than EBRT alone.