Corrective osteotomies using patient-specific 3D-printed guides: a critical appraisal

3D-assisted corrective osteotomies of the distal radius: a comparison of pre-contoured conventional implants versus patient-specific implants

PURPOSE

There is a debate whether corrective osteotomies of the distal radius should be performed using a 3D work-up with pre-contoured conventional implants (i.e., of-the-shelf) or patient-specific implants (i.e., custom-made). This study aims to assess the postoperative accuracy of 3D-assisted correction osteotomy of the distal radius using either implant.

METHODS

Twenty corrective osteotomies of the distal radius were planned using 3D technologies and performed on Thiel embalmed human cadavers. Our workflow consisted of virtual surgical planning and 3D printed guides for osteotomy and repositioning. Subsequently, left radii were fixated with patient-specific implants, and right radii were fixated with pre-contoured conventional implants. The accuracy of the corrections was assessed through measurement of rotation, dorsal and radial angulation and translations with postoperative CT scans in comparison to their preoperative virtual plan.

RESULTS

Twenty corrective osteotomies were executed according to their plan. The median differences between the preoperative plan and postoperative results were 2.6° (IQR: 1.6-3.9°) for rotation, 1.4° (IQR: 0.6-2.9°) for dorsal angulation, 4.7° (IQR: 2.9-5.7°) for radial angulation, and 2.4 mm (IQR: 1.3-2.9 mm) for translation of the distal radius, thus sufficient for application in clinical practice. There was no significant difference in accuracy of correction when comparing pre-contoured conventional implants with patient-specific implants.

CONCLUSION

3D-assisted corrective osteotomy of the distal radius with either pre-contoured conventional implants or patient-specific implants results in accurate corrections. The choice of implant type should not solely depend on accuracy of the correction, but also be based on other considerations like the availability of resources and the preoperative assessment of implant fitting.

Radial head replacement with the 3D-printed patient-specific titanium prosthesis: Preliminary results of a multi-centric prospective study

PURPOSE

To report preliminary clinical results and safety of 3D-printed patient-specific titanium radial head (RH) prosthesis in treatment of the irreparable RH fractures.

MATERIAL AND METHODS

This multi-centric prospective study included 10 patients (6 men and four women, mean age 41 years (range, 25-64 years)). Three cases were classified as Mason type III and 7 cases as type IV. Patients were assessed preoperatively, intraoperatively, and at 1, 6, 12, 24, 36, and 48 weeks postoperatively. Range of motion (ROM), visual analog scale (VAS) score, Disabilities of the Arm, Shoulder and Hand (DASH) score, Mayo Elbow Performance Score (MEPS), radiology imaging, and laboratory blood and urine testing were evaluated.

RESULTS

The prostheses were implanted utilizing cemented stems in 5 patients and cementless stems in 5 patients. Intraoperatively, well congruency of a prosthesis with capitellum and radial notch of ulna was observed in all cases. All patients had improvement of ROM, VAS score, DASH score, and MEPS during the postoperative follow-ups. At the final follow-up, mean elbow extension was 6.5° (range, 0°-30°), flexion 145° (range, 125°-150°), supination 79° (range, 70°-80°), and pronation 73.5° (range, 45°-80°). Mean VAS score was 0.3 (range, 0-3), DASH score was 12.35 (range, 1.7-23.3), and MEPS was 99.5 (range, 95-100). Postoperative radiographs demonstrated heterotopic ossification in 2 cases, periprosthetic radiolucency in 2 cases, and proximal radial neck resorption in 2 cases. No one had the evidence of capitellar erosion, implant failure, malpositioning, overstuffing, or symptomatic stem loosening. There was no significant alteration of laboratory results or adverse events related to the 3D-printed prosthesis implantation.

CONCLUSION

The preliminary results demonstrated that implantation of the 3D-printed patient-specific titanium RH prosthesis is safe and may be a potential treatment option for irreparable RH fracture.

Proximal humerus fracture sequelae: are corrective osteotomies still a taboo? The role of three-dimensional preoperative planning and patient-specific surgical guides for proximal humerus corrective osteotomy in combination with reverse shoulder arthroplasty

Background

Symptomatic proximal humeral fracture sequelae (PHFS) represent a surgical challenge due to the altered bone and soft tissue morphology. The purpose of this study was to report the outcome of Multiplanar Corrective Humeral Osteotomies (MCHOs) in combination with reverse total shoulder arthroplasty (rTSA) performed following a three-dimensional (3D) preoperative planning and using a 3D-printed patient-specific surgical instrumentation (PSI) in type 1C, 1D, and 4 PHFS.

Methods

In this prospective monocentric study, we enrolled patients affected by symptomatic PHFS type 1C, 1D, or 4 of Boileau's classification, treated between 2018 and 2019 with rTSA associated to MCHO and followed-up at 12 and 24 mo. The preoperative and postoperative Constant Score (CS), visual analog scale, and Disabilities of the Arm, Shoulder and Hand (DASH) score were recorded. All patients underwent a preoperative computed tomography, then a dedicated software was used to run a segmentation algorithm on computed tomography images. Metaphyseal bone cuts were virtually performed before surgery in all patients, and a 3D-printed PSI was used to reproduce the planned osteotomies in vivo.

Results

Twenty patients completed a 2-y follow-up. The mean (± standard deviation) CS, visual analog scale, and DASH values improve from 24.3 (± 8.8), 6.5 (± 1.3), 60.7 (± 9.6) preoperatively, to 67.7 (± 11.4), 1.6 (± 0.8), 24.1 (± 13.1) points after surgery, respectively. The minimally clinical important difference for CS and DASH score was achieved in 95% of patients. No major complication was observed. One patient showed an unexplained worsening of clinical scores between the 12 and the 24-mo follow-up, while in one patient bone resorption of the greater tuberosity was observed on radiographs at 2 y, with no clinical impact.

Conclusion

The combination of preoperative 3D planning and intraoperative use of 3D-printed PSI to perform MCHO as concurrent procedure in the context of rTSA in the treatment of Boileau type 1C, 1D, and 4 PHFS may lead to a satisfactory clinical outcome at 2 y of follow-up.

3D planning and patient-specific surgical guides in forearm osteotomy in children: Radiographic accuracy and clinical morbidity

INTRODUCTION

Three-dimensional (3D) planning and patient-specific surgical guides are increasingly used in the treatment of skeletal deformities. The present study hypothesis was that they are reliable in forearm osteotomy in children, with low morbidity.

MATERIAL AND METHODS

Twenty-there children with one or several osteotomies to correct forearm deformities were retrospectively included: 9 (20 osteotomies) with surgical guide (G+), and 14 (28 osteotomies) without (G-). Etiologies comprised 8 cases of Madelung disease (3G+, 5G-) and 15 of post-traumatic malunion (6G+, 9G-). Mean age at surgery was 14.8±1.9 years. The patient-specific 3D-printed polyamide guides were produced from 3D virtual models based on 3D CT reconstruction. Mean follow-up was 22.1±13.6 months.

RESULTS

Mean correction error was 5.3°±4.1 and 4.2°±4.1 in the frontal and sagittal planes respectively in G+ (p=0.6). Surgery time was significantly shorter in G+, by a mean 42min (p=0.02). Mean total radiation dose (preoperative CT+intraoperative fluoroscopy) was significantly higher in G+ (p<0.0001). Complications rates were similar between groups. Improvement in PRWE score was significantly greater in G+.

CONCLUSION

The present preliminary results were encouraging. 3D planning and patient-specific surgical guides can be used in the treatment of forearm deformity in children.

LEVEL OF EVIDENCE

III; retrospective cohort study.

A Two-Step Approach for 3D-Guided Patient-Specific Corrective Limb Osteotomies

Background: Corrective osteotomy surgery for long bone anomalies can be very challenging since deformation of the bone is often present in three dimensions. We developed a two-step approach for 3D-planned corrective osteotomies which consists of a cutting and reposition guide in combination with a conventional osteosynthesis plate. This study aimed to assess accuracy of the achieved corrections using this two-step technique. Methods: All patients (≥12 years) treated for post-traumatic malunion with a two-step 3D-planned corrective osteotomy within our center in 2021 were prospectively included. Three-dimensional virtual models of the planned outcome and the clinically achieved outcome were obtained and aligned. Postoperative evaluation of the accuracy of performed corrections was assessed by measuring the preoperative and postoperative alignment error in terms of angulation, rotation and translation. Results: A total of 10 patients were included. All corrective osteotomies were performed according to the predetermined surgical plan without any complications. The preoperative deformities ranged from 7.1 to 27.5° in terms of angulation and 5.3 to 26.1° in terms of rotation. The achieved alignment deviated on average 2.1 ± 1.0 and 3.4 ± 1.6 degrees from the planning for the angulation and rotation, respectively. Conclusions: A two-step approach for 3D-guided patient-specific corrective limb osteotomies is reliable, feasible and accurate.

Clinical applications and prospects of 3D printing guide templates in orthopaedics

Background

With increasing requirements for medical effects, and huge differences among individuals, traditional surgical instruments are difficult to meet the patients' growing medical demands. 3D printing is increasingly mature, which connects to medical services critically as well. The patient specific surgical guide plate provides the condition for precision medicine in orthopaedics.

Methods

In this paper, a systematic review of the orthopedic guide template is presented, where the history of 3D-printing-guided technology, the process of guides, and basic clinical applications of orthopedic guide templates are described. Finally, the limitations of the template and possible future directions are discussed.

Results

The technology of 3D printing surgical templates is increasingly mature, standard, and intelligent. With the help of guide templates, the surgeon can easily determine the direction and depth of the screw path, and choose the angle and range of osteotomy, increasing the precision, safety, and reliability of the procedure in various types of surgeries. It simplifies the difficult surgical steps and accelerates the growth of young and mid-career physicians. But some problems such as cost, materials, and equipment limit its development.

Conclusions

In different fields of orthopedics, the use of guide templates can significantly improve surgical accuracy, shorten the surgical time, and reduce intraoperative bleeding and radiation. With the development of 3D printing, the guide template will be standardized and simplified from design to production and use. 3D printing guides will be further sublimated in the application of orthopedics and better serve the patients.

The translational potential of this paper

Precision, intelligence, and individuation are the future development direction of orthopedics. It is more and more popular as the price of printers falls and materials are developed. In addition, the technology of meta-universe, digital twin, and artificial intelligence have made revolutionary effects on template guides. We aim to summarize recent developments and applications of 3D printing guide templates for engineers and surgeons to develop more accurate and efficient templates.

Three-Dimensional Printing of Medical Devices Used Directly to Treat Patients: A Systematic Review

Until recently, three-dimensional (3D) printing/additive manufacturing has not been used extensively to create medical devices intended for actual clinical use, primarily on patient safety and regulatory grounds. However, in recent years there have been advances in materials, printers, and experience, leading to increased clinical use. The aim of this study was to perform a structured systematic review of 3D-printed medical devices used directly in patient treatment. A search of 13 databases was performed to identify studies of 3D-printed medical devices, detailing fabrication technology and materials employed, clinical application, and clinical outcome. One hundred and ten papers describing one hundred and forty medical devices were identified and analyzed. A considerable increase was identified in the use of 3D printing to produce medical devices directly for clinical use in the past 3 years. This is dominated by printing of patient-specific implants and surgical guides for use in orthopedics and orthopedic oncology, but there is a trend of increased use across other clinical specialties. The prevailing material/3D-printing technology used were titanium alloy/electron beam melting for implants, and polyamide/selective laser sintering or polylactic acid/fused deposition modeling for surgical guides and instruments. A detailed analysis across medical applications by technology and materials is provided, as well as a commentary regarding regulatory aspects. In general, there is growing familiarity with, and acceptance of, 3D printing in clinical use.

Custom 3D-Printed Cutting Guides for Femoral Osteotomy in Rotational Malalignment Due to Diaphyseal Fractures: Surgical Technique and Case Series

Femoral shaft fractures are one of the most common injuries in trauma patients. The gold standard treatment consists of closed reduction and intramedullary nailing, providing a high fracture healing rate and allowing early mobilization. However, rotational malalignment is a well-known complication following this procedure, and excessive femoral anteversion or femoral retroversion can trigger functional complaints. In order to achieve the ideal degree of femoral rotation, a 3D planning and printing cutting guides procedure was developed to correct femoral malrotation. A patient series with malalignment after a femoral diaphyseal fracture was operated on with the customized guides and evaluated in this study. Computed tomography scans were performed to accurately determine the number of degrees of malrotation, allowing the design of specific and personalized surgical guides to correct these accurately. Once designed, they were produced by 3D printing. After surgery with the customized guides to correct femoral malrotation, all patients presented a normalized anteversion angle of the femur (average −10.3°, range from −5° to −15°), according to their contralateral limb. These data suggest that the use of customized cutting guides for femoral osteotomy is a safe and reproducible surgical technique that offers precise results when correcting femoral malrotation.

Are the common sterilization methods completely effective for our in-house 3D printed biomodels and surgical guides?

INTRODUCTION

In-hospital 3D printing is being implemented in orthopaedic departments worldwide, being used for additive manufacturing of fracture models (or even surgical guides) which are sterilized and used in the operating room. However, to save time and material, prints are nearly hollow, while 3D printers are placed in non-sterile rooms. The aim of our study is to evaluate whether common sterilization methods can sterilize the inside of the pieces, which would be of utmost importance in case a model breaks during a surgical intervention.

MATERIAL AND METHOD

A total of 24 cylinders were designed and printed with a 3D printer in Polylactic Acid (PLA) with an infill density of 12%. Manufacturing was paused when 60% of the print was reached and 20 of the cylinders were inoculated with 0.4 mL of a suspension of S epidermidis ATTCC 1228 in saline solution at turbidity 1 McFarland. Printing was resumed, being all the pieces completely sealed with the inoculum inside. Posteriorly, 4 groups were made according to the chosen sterilization method: Ethylene Oxide (EtO), Gas Plasma, Steam Heat or non-sterilized (positive control). Each group included 5 contaminated cylinders and 1 non-contaminated cylinder as a negative control. After sterilization, the inside of the cylinders was cultured during 7 days.

RESULTS

We observed bacterial growth of just a few Forming Colony Units (FCU) in 4 out of 5 positive controls and in 2 out of 5 contaminated cylinders sterilized with Gas Plasma. We could not assess any bacterial growth in any of the EtO or Steam Heat samples or in any of the negative controls. Pieces sterilized under Steam Heat resulted completely deformed.

CONCLUSIONS

High temperatures reached during the procedure of additive manufacturing can decrease the bacterial load of the biomodels. However, there is a potential risk of contamination during the procedure. We recommend sterilization with EtO for in-hospital 3D-printed PLA hollow biomodels or guides. Otherwise, in case of using Gas Plasma, an infill of 100% should be applied.

Three-dimensional Printing in Orthopaedic Surgery: Current Applications and Future Developments

Three-dimensional (3D) printing is an exciting form of manufacturing technology that has transformed the way we can treat various medical pathologies. Also known as additive manufacturing, 3D printing fuses materials together in a layer-by-layer fashion to construct a final 3D product. This technology allows flexibility in the design process and enables efficient production of both off-the-shelf and personalized medical products that accommodate patient needs better than traditional manufacturing processes. In the field of orthopaedic surgery, 3D printing implants and instrumentation can be used to address a variety of pathologies that would otherwise be challenging to manage with products made from traditional subtractive manufacturing. Furthermore, 3D bioprinting has significantly impacted bone and cartilage restoration procedures and has the potential to completely transform how we treat patients with debilitating musculoskeletal injuries. Although costs can be high, as technology advances, the economics of 3D printing will improve, especially as the benefits of this technology have clearly been demonstrated in both orthopaedic surgery and medicine as a whole. This review outlines the basics of 3D printing technology and its current applications in orthopaedic surgery and ends with a brief summary of 3D bioprinting and its potential future impact.

An Easy and Economical Way to Produce a Three-Dimensional Bone Phantom in a Dog with Antebrachial Deformities

Simple Summary

Accurate planning, for corrective surgeries in case of bone cutting, is necessary to obtain a precise coordination of the skeleton and to achieve the owner’s satisfaction. The present experiment displays a simple and cost-effective technique for surgical planning, utilizing a 3-D bone phantom model in a dog with foreleg deformity.

Abstract

3-D surgical planning for restorative osteotomy is costly and time-consuming because surgeons need to be helped from commercial companies to get 3-D printed bones. However, practitioners can save time and keep the cost to a minimum by utilizing free software and establishing their 3-D printers locally. Surgical planning for the corrective osteotomy of antebrachial growth deformities (AGD) is challenging for several reasons (the nature of the biapical or multiapical conformational abnormalities and lack of a reference value for the specific breed). Pre-operative planning challenges include: a definite description of the position of the center of rotation of angulation (CORA) and proper positioning of the osteotomies applicable to the CORA. In the present study, we demonstrated an accurate and reproducible bone-cutting technique using patient-specific instrumentations (PSI) 3-D technology. The results of the location precision showed that, by using PSIs, the surgeons were able to accurately replicate preoperative resection planning. PSI results also indicate that PSI technology provides a smaller standard deviation than the freehand method. PSI technology performed in the distal radial angular deformity may provide good cutting accuracy. In conclusion, the PSI technology may improve bone-cutting accuracy during corrective osteotomy by providing clinically acceptable margins.

Digitalization of the IOM: A comprehensive cadaveric study for obtaining three-dimensional models and morphological properties of the forearm's interosseous membrane

State-of-the-art of preoperative planning for forearm orthopaedic surgeries is currently limited to simple bone procedures. The increasing interest of clinicians for more comprehensive analysis of complex pathologies often requires dynamic models, able to include the soft tissue influence into the preoperative process. Previous studies have shown that the interosseous membrane (IOM) influences forearm motion and stability, but due to the lack of morphological and biomechanical data, existing simulation models of the IOM are either too simple or clinically unreliable. This work aims to address this problematic by generating 3D morphological and tensile properties of the individual IOM structures. First, micro- and standard-CT acquisitions were performed on five fresh-frozen annotated cadaveric forearms for the generation of 3D models of the radius, ulna and each of the individual ligaments of the IOM. Afterwards, novel 3D methods were developed for the measurement of common morphological features, which were validated against established optical ex-vivo measurements. Finally, we investigated the individual tensile properties of each IOM ligament. The generated 3D morphological features can provide the basis for the future development of functional planning simulation of the forearm.

An automatic genetic algorithm framework for the optimization of three-dimensional surgical plans of forearm corrective osteotomies

Three-dimensional (3D) computer-assisted corrective osteotomy has become the state-of-the-art for surgical treatment of complex bone deformities. Despite available technologies, the automatic generation of clinically acceptable, ready-to-use preoperative planning solutions is currently not possible for such pathologies. Multiple contradicting and mutually dependent objectives have to be considered, as well as clinical and technical constraints, which generally require iterative manual adjustments. This leads to unnecessary surgeon efforts and unbearable clinical costs, hindering also the quality of patient treatment due to the reduced number of solutions that can be investigated in a clinically acceptable timeframe. In this paper, we propose an optimization framework for the generation of ready-to-use preoperative planning solutions in a fully automatic fashion. An automatic diagnostic assessment using patient-specific 3D models is performed for 3D malunion quantification and definition of the optimization parameters' range. Afterward, clinical objectives are translated into the optimization module, and controlled through tailored fitness functions based on a weighted and multi-staged optimization approach. The optimization is based on a genetic algorithm capable of solving multi-objective optimization problems with non-linear constraints. The framework outputs a complete preoperative planning solution including position and orientation of the osteotomy plane, transformation to achieve the bone reduction, and position and orientation of the fixation plate and screws. A qualitative validation was performed on 36 consecutive cases of radius osteotomy where solutions generated by the optimization algorithm (OA) were compared against the gold standard solutions generated by experienced surgeons (Gold Standard; GS). Solutions were blinded and presented to 6 readers (4 surgeons, 2 planning engineers), who voted OA solutions to be better in 55% of the time. The quantitative evaluation was based on different error measurements, showing average improvements with respect to the GS from 20% for the reduction alignment and up to 106% for the position of the fixation screws. Notably, our algorithm was able to generate feasible clinical solutions which were not possible to obtain with the current state-of-the-art method.