Accuracy and Early Clinical Outcome of 3-Dimensional Planned and Guided Single-Cut Osteotomies of Malunited Forearm Bones

[Secondary defect coverage and functional reconstruction]

Secondary reconstruction in trauma surgery is crucial for restoring both functional and esthetic results in patients with complex defects. Established reconstructive techniques in plastic surgery offer a wide range of options for an effective treatment. This applies not only to covering large defects with free flaps but especially also for the functional reconstruction of bony, neural and musculotendinous impairments. Advances in the fields of microsurgery and 3D printing show innovative approaches to further improve the therapeutic options. A multidisciplinary approach, requiring close collaboration between trauma and plastic surgeons, is necessary to optimize treatment plans and outcomes. The effective management of complications and qualified postoperative care are essential for the success of reconstructive measures.

Dome versus single-cut osteotomies for correction of long bone deformities-technical considerations

Corrective osteotomy allows to improve joint loading, pain and function. In complex deformities, the biggest challenge is to define the optimal surgical solution, while considering anatomical, technical and biomechanical factors. While the single-cut osteotomy (SCOT) and focal dome osteotomy (FDO) are well-established treatment options, their mathematical relationship remain largely unclear. The aim of the study was (1) to describe the close mathematical relationship between the SCOT and FDO and (2) to analyze and introduce a novel technique-the stepped FDO-as a modification of the classic FDO. The mathematical background and relationship of SCOT and FDO are described for the example of a femoral deformity correction and visualized using a 3D surface model taking into account the benefits for the clinical application. The novel modifications of the stepped FDO are introduced and its technical and clinical feasibility demonstrated. Both, SCOT and FDO, rely on the same deformity axis that defines the rotation axis k for a 3D deformity correction. To achieve the desired correction using a SCOT, the resulting cutting plane is perpendicular to k, while using a FDO will result in a cylindrical cut with a central axis parallel to k. The SCOT and FDO demonstrate a strong mathematical relation, as both methods rely on the same deformity axis, however, resulting in different cutting planes. These characteristics enable a complementary use when defining the optimal type of osteotomy. This understanding enables a more versatile planning approach when considering factors as the surgical approach, biomechanical characteristics of fixation or soft tissue conditions. The newly introduced stepped FDO facilitates an exact reduction of the bone fragments and potentially expands the clinical applicability of the FDO.

Three cases of posttraumatic wrist problems solved with 3D-printed patient-specific guides

Symptomatic malunion of the wrist is one of the most common posttraumatic wrist problems. This study demonstrates three patients with complex malunions of the wrist who benefited from a corrective osteotomy using preplanned 3D-printed patient-specific guides, by experiencing improvement in their wrist function, grip strength and a reduction in pain.

Vascularized fibular flap and custom-made synthesis in post-traumatic ulnar diaphyseal pseudarthrosis: a case report

BACKGROUND

Although isolated fractures of the ulnar shaft are considered common and relatively benign injuries, numerous complications can arise especially in the context of suboptimal care pathways. For pediatric patients, however, there is no single indication of the surgical approach. In the context of the management of these complications, it is known that the vascularized fibular graft has numerous advantages and indications in the treatment of recurrent pseudarthrosis. However, in revision surgery the frequent occurrence of anatomical subversions requires the use of fixation means adapted to the individual patient. We present a clinical case of an adult patient suffering from post-traumatic ulnar pseudarthrosis treated with autologous vascularized fibula grafts and 3D-planned custom-made plate.

CASE PRESENTATION

A 38-year-old Ivorian woman came to our attention with a painful nonunion of the ulnar shaft and significant dysmorphism of the left forearm, with shortening and flexion of the limb as an outcome of unspecified road trauma in childhood. No alterations of the nerve compartment were reported. As far as detectable, she had undergone autologous bone grafting and implantation of questionable synthetic means, without acute treatment. Since we evaluated the patient (2012), we have performed two debridement surgeries, associated with autologous avascular bone graft from the iliac crest and plate fixation (2012 and 2014). In both cases, rupture of the fixation media was observed. In 2021, the pseudarthrosis was treated with a vascularized fibular bone graft. The subverted radius and ulna anatomy and poor bone quality required patient-specific reconstruction of the pseudarthrosic ulna from a 3D scan and the production of custom-made plate and screws, supported by the creation of special guides for drilling and by optimizing the positioning of screws with preoperative digital models. In the postoperative period, regular follow-up visits with X-rays evaluations were performed at 1, 3 and 6 months after surgery. No inflammatory reactions or local rejection were found. The fibula graft healed at the proximal ulnar junction six months after the operation while it took eight months to heal at the distal junction. Functionally, we observed a pain reduction and a range-of-motion preservation.

CONCLUSIONS

The multiple failures of diaphyseal reconstruction with avascular bone grafts have forced the indication to the vascularized fibular flap. This case is a unique experience but we believe that the association between vascularized bone graft and the potential for customization through 3D planning represents a valid surgical potentiality in complex cases of post-traumatic reconstruction.

[Malunion of the distal radius: 3D planning and performance of intra- and extra-articular corrective osteotomy]

OBJECTIVE

Restoration of the original anatomy with reduction of both current symptoms and risk of posttraumatic osteoarthritis.

INDICATIONS

Symptomatic intra- or extra-articular malunion due to limitation of movement and/or painful function, intra-articular step of > 1 mm, instability of the distal radioulnar joint.

CONTRAINDICATIONS

Minimal deformity. Pre-existing osteoarthritis Knirk and Jupiter II or higher. Simpler surgical alternative, e.g., ulna shortening osteotomy. Smoking or advanced age are not contraindications.

SURGICAL TECHNIQUE

Preoperative assessment and performance of a bilateral computed tomography (CT). Three-dimensional (3D) malposition analysis and calculation of the correction. Planning of the corrective osteotomy on the 3D model and creation of patient-specific drilling and sawing guides. Performing the 3D-guided osteotomy.

POSTOPERATIVE MANAGEMENT

Early functional unloaded mobilization with the splint for 8 weeks until consolidation control with CT.

RESULTS

Significant reduction of the step to < 1 mm (p ≤ 0.05) can be achieved with intra-articular corrections. In extra-articular corrective osteotomies, a mean residual rotational malalignment error of 2.0° (± 2.2°) and a translational malalignment error of 0.6 mm (± 0.2 mm) is achieved. Single-cut osteotomies in the shaft region can be performed to within a few degrees for rotation (e.g., pronation/supination 4.9°) and for translation (e.g., proximal/distal, 0.8 mm). After surgery, a mean residual 3D angle of 5.8° (SD 3.6°) was measured. Furthermore, surgical time for 3D-assisted surgery is significantly reduced compared to the conventional technique (140 ± 37 vs 108 ± 26 min; p < 0.05). Thus, the progression of osteoarthritis can be reduced in the medium term and improved mobility and grip strength are achieved. The clinical outcome parameters based on patient-rated wrist evaluation (PRWE) and the disabilities of the arm, shoulder and hand (DASH) scores are roughly comparable.

Automatic 3D Postoperative Evaluation of Complex Orthopaedic Interventions

In clinical practice, image-based postoperative evaluation is still performed without state-of-the-art computer methods, as these are not sufficiently automated. In this study we propose a fully automatic 3D postoperative outcome quantification method for the relevant steps of orthopaedic interventions on the example of Periacetabular Osteotomy of Ganz (PAO). A typical orthopaedic intervention involves cutting bone, anatomy manipulation and repositioning as well as implant placement. Our method includes a segmentation based deep learning approach for detection and quantification of the cuts. Furthermore, anatomy repositioning was quantified through a multi-step registration method, which entailed a coarse alignment of the pre- and postoperative CT images followed by a fine fragment alignment of the repositioned anatomy. Implant (i.e., screw) position was identified by 3D Hough transform for line detection combined with fast voxel traversal based on ray tracing. The feasibility of our approach was investigated on 27 interventions and compared against manually performed 3D outcome evaluations. The results show that our method can accurately assess the quality and accuracy of the surgery. Our evaluation of the fragment repositioning showed a cumulative error for the coarse and fine alignment of 2.1 mm. Our evaluation of screw placement accuracy resulted in a distance error of 1.32 mm for screw head location and an angular deviation of 1.1° for screw axis. As a next step we will explore generalisation capabilities by applying the method to different interventions.

3D-planned corrective osteotomy of metacarpal arch disruption after Motec® wrist prosthesis

We report two cases of metacarpal arch disruption after Motec® total wrist arthroplasty, with hyperextension of the third metacarpal and dorsal protrusion of the head. Correction osteotomies of the adjacent metacarpals using preoperative 3D surgical planning were successful. This report seeks to shed light on the origin of this deformation and to recommend some operative precautions. It is important that surgeons should be aware of the existence of this complication, as disruption of the transverse metacarpal arch affects both grasp and hand esthetics. LEVEL OF EVIDENCE: IV.

Application of 3D modeling in a personalized approach to bone osteosynthesis (A literature review)

Three-dimensional printing opens up many opportunities for use in traumatology and orthopedics, because it takes into account personal characteristics of the patients. Modern methods of high-resolution medical imaging can process data to create threedimensional images for printing physical objects. Today, three-dimensional printers are able to create a model of any complexity of shape and geometry. The article provides a review of the literature about three-dimensional digital modeling in shaping implants for osteosynthesis. Data search was carried out on the Scopus, Web of Scince, Pubmed, RSCI databases for the period 2012–2022. The effectiveness of three-dimensional printing for preoperative modeling of bone plates has been confirmed: implants perfectly corresponds with the unique anatomy of the patient, since the template for it is based on the materials of computed tomography. Individual templates can be useful when the geometry of patients' bones goes beyond the standard, and when improved results of surgery are expected due to better matching of implants to the anatomical needs of patients. 

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.

Intermediate-Term Outcome of 3-Dimensional Corrective Osteotomy for Malunited Distal Radius Fractures With a Mean Follow-Up of 6 Years

PURPOSE

Our study aimed to analyze the functional and radiological intermediate-term outcome of 3-dimensional-guided corrective osteotomies for malunited distal radius fractures and to evaluate the progression of osteoarthritis after this intervention.

METHODS

All patients with malunited distal radius fractures who underwent 3-dimensional-guided corrective osteotomies from October 2008 to January 2015 were included. Pre- and postoperative range of motion, grip strength, and postoperative patient-reported outcomes were assessed. Pre- and postoperative osteoarthritis grading was performed using conventional radiographs and the osteoarthritis grading system described by Knirk and Jupiter. Additionally, the evaluation of articular stepoff was performed using pre- and postoperative computed tomography.

RESULTS

Fifteen patients, with a mean follow-up of 6 years (range, 4.1-10.4 years), were included. According to rater 1, 8 cases had no postoperative osteoarthritis progression, 6 cases had progression of 1 grade, and 1 case had progression of 2 grades. According to rater 2, there was no progression in 11 cases, and there was progression of 1 grade in 2 cases and progression of 2 grades in 2 cases. Compared with before the surgery, the patients demonstrated a mean improvement of 14.8 kg (±12.6 kg) in grip strength after the surgery. At the last follow-up, the mean Patient-Rated Wrist Evaluation score was 11.8 (±12.0), the mean Disabilities of the Arm, Shoulder and Hand score was 11.1 (±11.4), and the mean residual pain score on the visual analog scale was 0.8 (±1.0).

CONCLUSIONS

The intermediate-term outcome of 3-dimensional-guided corrective osteotomies for distal radius intra-articular malunions showed excellent patient-reported outcomes and no clinically relevant progression of osteoarthritis.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Three-Dimensional Printing in Hand Surgery

The medical application of 3-dimensional printing technology has evolved in the last decade, with an increasing variety of uses in hand surgery. The ability for patient-specific design, rapid prototyping, and low cost of production of 3-dimensional printed materials has led to this rise in clinical applications, both for common procedures and complex reconstructions. Within hand surgery, 3-dimensional printing can be applied in several broad categories: to construct patient-specific models for preoperative planning, to design orthotics and prosthetics to meet specific patient demands, to create patient-specific aids for intraoperative use, to generate patient-specific hardware and prostheses for implantation, and for applications for trainee education.

SpineDepth: A Multi-Modal Data Collection Approach for Automatic Labelling and Intraoperative Spinal Shape Reconstruction Based on RGB-D Data

Computer aided orthopedic surgery suffers from low clinical adoption, despite increased accuracy and patient safety. This can partly be attributed to cumbersome and often radiation intensive registration methods. Emerging RGB-D sensors combined with artificial intelligence data-driven methods have the potential to streamline these procedures. However, developing such methods requires vast amount of data. To this end, a multi-modal approach that enables acquisition of large clinical data, tailored to pedicle screw placement, using RGB-D sensors and a co-calibrated high-end optical tracking system was developed. The resulting dataset comprises RGB-D recordings of pedicle screw placement along with individually tracked ground truth poses and shapes of spine levels L1-L5 from ten cadaveric specimens. Besides a detailed description of our setup, quantitative and qualitative outcome measures are provided. We found a mean target registration error of 1.5 mm. The median deviation between measured and ground truth bone surface was 2.4 mm. In addition, a surgeon rated the overall alignment based on 10% random samples as 5.8 on a scale from 1 to 6. Generation of labeled RGB-D data for orthopedic interventions with satisfactory accuracy is feasible, and its publication shall promote future development of data-driven artificial intelligence methods for fast and reliable intraoperative registration.

An image fusion system for corrective osteotomy of distal radius malunion

Background

To provide surgical support for corrective osteotomy, we developed an image fusion system for three-dimensional (3D) preoperative planning and fluoroscopy. To assess the utility of this image fusion system, we evaluated the reproducibility of preoperative planning for corrective osteotomy of dorsally angulated distal radius malunion using the system and compared reproducibility without using the system.

Methods

Ten wrists from 10 distal radius malunion patients who underwent corrective osteotomy were evaluated. 3D preoperative planning and the image fusion system were used for the image fusion group (n = 5). Only 3D preoperative planning was used for the control group (n = 5). 3D preoperative planning was performed for both groups in order to assess reduction, placement, and the choice of implants. In the image fusion group, the outline of the planned image was displayed on a monitor and overlapped with fluoroscopy images during surgery. Reproducibility was evaluated using preoperative plan and postoperative 3D images. Images were compared with the 3D coordinates of the radial styloid process (1), the volar and dorsal edges of the sigmoid notch (2) (3), and the barycentric coordinates of the three reference points. The reproducibility of the preoperative plan was evaluated by the distance of the coordinates between the plan and postoperative images for the reference points.

Results

The distances between preoperative planning and postoperative reduction in the image fusion group were 2.1 ± 1.1 mm, 1.8 ± 0.7 mm, 1.9 ± 0.9 mm, and 1.4 ± 0.7 mm for reference points (1), (2), (3), and the barycenter, respectively. The distances between preoperative planning and postoperative reduction in the control group were 3.7 ± 1.0 mm, 2.8 ± 2.0 mm, 1.7 ± 0.8 mm, and 1.8 ± 1.2 mm for reference points (1), (2), (3), and the barycenter, respectively. The difference in reference point (1) was significantly smaller in the image fusion group than in the control group (P < 0.05).

Conclusion

Corrective osteotomy using an image fusion system will become a new surgical support method for fracture malunion.

Trial registration Registered as NCT03764501 at ClinicalTrials.gov.

Augmented Reality in Orthopedic Surgery Is Emerging from Proof of Concept Towards Clinical Studies: a Literature Review Explaining the Technology and Current State of the Art

PURPOSE OF REVIEW

Augmented reality (AR) is becoming increasingly popular in modern-day medicine. Computer-driven tools are progressively integrated into clinical and surgical procedures. The purpose of this review was to provide a comprehensive overview of the current technology and its challenges based on recent literature mainly focusing on clinical, cadaver, and innovative sawbone studies in the field of orthopedic surgery. The most relevant literature was selected according to clinical and innovational relevance and is summarized.

RECENT FINDINGS

Augmented reality applications in orthopedic surgery are increasingly reported. In this review, we summarize basic principles of AR including data preparation, visualization, and registration/tracking and present recently published clinical applications in the area of spine, osteotomies, arthroplasty, trauma, and orthopedic oncology. Higher accuracy in surgical execution, reduction of radiation exposure, and decreased surgery time are major findings presented in the literature. In light of the tremendous progress of technological developments in modern-day medicine and emerging numbers of research groups working on the implementation of AR in routine clinical procedures, we expect the AR technology soon to be implemented as standard devices in orthopedic surgery.

Overview of In-Hospital 3D Printing and Practical Applications in Hand Surgery

Three-dimensional (3D) printing is spreading in hand surgery. There is an increasing number of practical applications like the training of junior hand surgeons, patient education, preoperative planning, and 3D printing of customized casts, customized surgical guides, implants, and prostheses. Some high-quality studies highlight the value for surgeons, but there is still a lack of high-level evidence for improved clinical endpoints and hence actual impact on the patient's outcome. This article provides an overview over the latest applications of 3D printing in hand surgery and practical experience of implementing them into daily clinical routine.

Inter-rater variability of three-dimensional fracture reduction planning according to the educational background

Background

Computer-assisted three-dimensional (3D) planning is increasingly delegated to biomedical engineers. So far, the described fracture reduction approaches rely strongly on the performance of the users. The goal of our study was to analyze the influence of the two different professional backgrounds (technical and medical) and skill levels regarding the reliability of the proposed planning method. Finally, a new fragment displacement measurement method was introduced due to the lack of consistent methods in the literature.

Methods

3D bone models of 20 distal radius fractures were presented to nine raters with different educational backgrounds (medical and technical) and various levels of experience in 3D operation planning (0 to 10 years) and clinical experience (1.5 to 24 years). Each rater was asked to perform the fracture reduction on 3D planning software.

Results

No difference was demonstrated in reduction accuracy regarding rotational (p = 1.000) and translational (p = 0.263) misalignment of the fragments between biomedical engineers and senior orthopedic residents. However, a significantly more accurate planning was performed in these two groups compared with junior orthopedic residents with less clinical experience and no 3D planning experience (p < 0.05).

Conclusion

Experience in 3D operation planning and clinical experience are relevant factors to plan an intra-articular fragment reduction of the distal radius. However, no difference was observed regarding the educational background (medical vs. technical) between biomedical engineers and senior orthopedic residents. Therefore, our results support the further development of computer-assisted surgery planning by biomedical engineers. Additionally, the introduced fragment displacement measure proves to be a feasible and reliable method.

Level of Evidence

Diagnostic Level II

Three-dimensional evaluations of preoperative planning reproducibility for the osteosynthesis of distal radius fractures

BACKGROUND

Three-dimensional preoperative planning was applied for the osteosynthesis of distal radius fractures. The objective of this study was to evaluate the reproducibility of three-dimensional preoperative planning for the osteosynthesis of distal radius fractures with three-dimensional reference points.

METHODS

Sixty-three wrists of 63 distal radius fracture patients who underwent osteosynthesis with three-dimensional preoperative planning were evaluated. After taking preoperative CT scans of the injured wrists, 3D images of the distal radius were created. Fracture reduction, implants choices, and placements simulation were performed based on the 3D images. One month after the surgery, postoperative CT images were taken. The reproducibility was evaluated with preoperative plan and postoperative 3D images. The images were compared with the three-dimensional coordinates of radial styloid process, volar and dorsal edges of sigmoid notch, and the barycentric coordinates of the three reference points. The reproducibility of the preoperative plan was evaluated by the distance of the coordinates between the plan and postoperative images for the reference points. The reproducibility of radial inclination and volar tilt on three-dimensional images were evaluated by intra-class correlation coefficient (ICC).

RESULTS

The distances between the preoperative plan and the postoperative reduction for each reference point were (1) 2.1±1.3 mm, (2) 1.9±1.2 mm, and (3) 1.9±1.2 mm, respectively. The distance between the preoperative plan and postoperative reduction for the barycentric coordinate was 1.3±0.8 mm. ICCs were 0.54 and 0.54 for the volar tilt and radial inclination, respectively (P<0.01).

CONCLUSIONS

Three-dimensional preoperative planning for the osteosynthesis of distal radius fracture was reproducible with an error of about 2 mm for each reference point and the correlations of reduction shapes were moderate. The analysis method and reference points may be helpful to understand the accuracy of reductions for the three-dimensional preoperative planning in the osteosynthesis of distal radius fractures.

TRIAL REGISTRATION

Registered as NCT02909647 at ClinicalTrials.gov.

Patient-specific plate for navigation and fixation of the distal radius: a case series

Purpose

Corrective osteotomy of a malunited distal radius conventionally relies on 2D imaging techniques for alignment planning and evaluation. However, this approach results in suboptimal bone repositioning, which is associated with poor patient outcomes. In this case series, we evaluate the use of novel patient-specific plates (PSPs), which feature navigation and fixation of bone segments as preoperatively planned in 3D.

Methods

Ten participants with distal radius malunion underwent CT scans for preoperative alignment planning. Patient-specific guides and plates were designed, 3D-printed, and sterilized for use in corrective surgery of the distal radius. Pre- and postoperative results were compared in regard to clinical, functional, and radiographic outcomes.

Results

The application of a PSP was successful in 7 of the 10 cases. After treatment, the residual alignment error was reduced by approximately 50% compared with conventional treatment. The use of PSPs reduced pain significantly. Pre- and postoperative results were pooled and demonstrated significant correlations between: (1) pain and malpositioning, (2) the range of pro- and supination motion, the MHOQ score, the EQ-5D-5L score and dorsovolar angulation, and (3) MHOQ score and proximodistal translation.

Conclusion

The correlation between malalignment and MHOQ score, EQ-5D-5L score, pain, and range of motion shows that alignment should be restored as well as possible. Compared to the conventional approach, which relies on 2D imaging techniques, corrective osteotomy based on 3D preoperative planning and intraoperative fixation with a PSP has been shown to improve bone alignment and reduce pain.

Level of evidence

IV.

Augmented Reality Based Surgical Navigation of Complex Pelvic Osteotomies—A Feasibility Study on Cadavers

Augmented reality (AR)-based surgical navigation may offer new possibilities for safe and accurate surgical execution of complex osteotomies. In this study we investigated the feasibility of navigating the periacetabular osteotomy of Ganz (PAO), known as one of the most complex orthopedic interventions, on two cadaveric pelves under realistic operating room conditions. Preoperative planning was conducted on computed tomography (CT)-reconstructed 3D models using an in-house developed software, which allowed creating cutting plane objects for planning of the osteotomies and reorientation of the acetabular fragment. An AR application was developed comprising point-based registration, motion compensation and guidance for osteotomies as well as fragment reorientation. Navigation accuracy was evaluated on CT-reconstructed 3D models, resulting in an error of 10.8 mm for osteotomy starting points and 5.4° for osteotomy directions. The reorientation errors were 6.7°, 7.0° and 0.9° for the x-, y- and z-axis, respectively. Average postoperative error of LCE angle was 4.5°. Our study demonstrated that the AR-based execution of complex osteotomies is feasible. Fragment realignment navigation needs further improvement, although it is more accurate than the state of the art in PAO surgery.

Computer-assisted open reduction internal fixation of intraarticular radius fractures navigated with patient-specific instrumentation, a prospective case series

BACKGROUND

Intra-articular fractures are associated with posttraumatic arthritis if inappropriately treated. Exact reduction of the joint congruency is the main factor to avoid the development of arthrosis. Aim of this study was to evaluate feasibility of computer-assisted surgical planning and 3D-printed patient-specific instrumentation (PSI) for treatment of distal intraarticular radius fractures.

METHOD

7 Patients who suffered a distal intraarticular radius fracture were enrolled in this prospective case series. Preoperative CT-scan was recorded, whereupon a 3D model was computed for surgical planning and design of PSI for surgical navigation. Postoperative accuracy and joint congruency were assessed. Patients were followed-up 3, 6 and 12 months postoperatively.

RESULTS

Mean follow-up was 16 months. Over all range of motion was restored and flexion, extension and pronation showed significant recovery, p < 0.05. Biggest intraarticular joint step-off and gap reduced from average 2.49 (± 1.04) to 0.8 mm (± 0.44), p < 0.05 and 6.12 mm (± 1.04) to 2.21 mm (± 1.16), p < 0.05. Average grip strength restored (3-16 months) from 20.33 kg (± 7.12) to 39.3 kg (± 19.55) p < 0.05, 100% of the healthy contralateral side. 3D-accuracy for guided fragments was 2.07 mm (± 0.64) and 8.59° (± 2.9) and 2.33 mm (± 0.69) and 12.86° (± 7.13), p > 0.05 for fragments reduced with ligamentotaxis.

CONCLUSION

Computer-assisted and PSI navigated intraarticular radius fracture treatment is feasible, safe and accurate. The benefits of this method, however, do not outstand the additional effort.

LEVEL OF EVIDENCE

IV.

Accuracy and Early Clinical Outcome After 3-Dimensional Correction of Distal Radius Intra-Articular Malunions Using Patient-Specific Instruments

PURPOSE

To investigate the residual articular incongruity on computed tomography image data and the early clinical outcome of 3-dimensional planned and navigated intra-articular osteotomies of the distal radius.

METHODS

We conducted a retrospective analysis of intra-articular osteotomies executed between 2008 and 2016. We identified 37 patients (aged 26-73 years) and performed a combined intra-articular and extra-articular osteotomy on 20 patients. A preoperative 3-dimensional plan with the superimposed bone of the contralateral healthy side was performed in each case to analyze and execute the osteotomy by intraoperative navigation. The residual articular incongruity was assessed by quantification of the maximal stepoff in the coronal or sagittal computed tomography scans. Clinical outcome, including range of motion, grip strength, and return to work, was assessed after a minimum follow-up of 12 months and compared with preoperative measurements.

RESULTS

On average, the preoperative intra-articular stepoff was 2.5 mm (±0.6 mm; range, 1.4-4.2 mm) and was significantly reduced to 0.8 mm (±0.2 mm) after surgery. After surgery, 30 patients had a stepoff less than 1 mm; in 7, a stepoff of 1.1 to 1.4 mm was measured. After 1 year, 22 had no pain, 9 had slight pain during heavy work, and 5 had moderate pain with no improvement compared with their preoperative status, although wrist strength and range of motion improved in all 37 patients. One patient underwent a secondary radioscapholunate arthrodeses owing to persistent pain despite a congruent joint with a small residual intra-articular stepoff (0.6 mm).

CONCLUSIONS

Intra-articular osteotomies of the distal radius treated by 3-dimensional preoperative planning and patient-specific guides are an accurate technique to reduce articular incongruity to an average stepoff of 0.8 mm (range, 0.3-1.4 mm). The early clinical outcomes demonstrated overall reduction in pain and improvement of range of motion and grip strength in 36 of 37 patients.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Patient-Specific Three-Dimensional-printed Instrumentation for Radius Lengthening Osteotomy by a Volar Approach in Epiphysiodesis Sequelae: A Case Report

Introduction:

Patient-specific guides are used in the correction of malunion sequelae in adult distal radius fractures. They allow a tridimensional correction of radial glenoid orientation. However, lengthening is small in those indications. Distal radius epiphysiodesis correction is much rarer and patient-specific guide after three-dimensional (3D) planning has never been reported for this indication in the literature.

Case Report:

We report the case of a 16-year-old teenager with a chronic painful wrist and an ulnar positive variance after a post-traumatic epiphysiodesis sequela of the radius. The radius was 11mm shorter than the ulna. An anatomic reconstruction was decided with a lengthening of the radius. Pre-operative planning and patient-specific guide allowed to control an important radial lengthening, to limit the morbidity of the iliac crest bone graft harvesting, to shape the graft precisely, and to maintain a correct radial glenoid orientation despite the important soft tissue tension. Clinical and radiological results at 6 months showed a complete disappearance of pain, optimal objective and subjective functional scores, and an improvement in the distal ulnar variance (7mm). The teenager went back to sport without limitation or pain.

Conclusion:

3Dplanning and intraoperative patient-specific guides in radial epiphysiodesis sequelae allow achieving 3D accurate measures of the graft and of the deformation, guiding the position and the orientation of the distal metaphysis cut of the radius, and limiting the morbidity of the iliac graft harvesting. In that case, it allowed restoring the full function of the wrist without remaining pain.

The Accuracy of Three-Dimensional Planned Bone Tumor Resection Using Patient-Specific Instrument

Introduction

Although treatment of bone tumors is multidisciplinary, the complete surgical resection of bone tumors remains the mainstay of the treatment. Patient-specific instruments (PSI) are personalized tools, which help the surgeon to perform tumor resections accurately. The aim of this study is to evaluate how precise the planned resection can be intraoperatively executed with the use of PSI.

Patients and Methods

Eleven patients who underwent a resection of bone tumor using PSI were analyzed. A preoperative model of the tumor and the affected bone was created from acquired CT scans and MRI. After defining the resection planes, PSI were produced by a 3D printer. The resected piece of bone was scanned and imported in the original planning model enabling the assessment of the distance between the planned resection plane and the realized osteotomy in every direction.

Results

In overall, the combined error of an osteotomy ranges from 0.74 ± 0.96 mm to 3.60 ± 2.46 mm. The average errors observed in situations with one resection plane (simple osteotomy) are lower than in complex curved osteotomies with multiple planes, in which we also found a greater variance.

Conclusion

3D planned bone tumor resections using PSI show promising results for precise resection at different anatomical regions. Even if the found error range in this series is slightly higher than reported, PSI remain a valuable tool to facilitate complex bone tumor resections.

Recent advances in the surgical treatment of malunions in hand and forearm using three-dimensional planning and patient-specific instruments

Malunions of the forearm and hand cause significant disability. Moreover, intraarticular deformities may contribute to early onset osteoarthritis. Such conditions require precise surgical correction in order to improve functional outcomes and prevent early or late complications. The purpose of this study was to describe the technical advantages of accurate anatomical reconstruction using 3D guided osteotomies and patient specific instruments (PSI) in multiple joints of the hand and forearm. Acquisition of three-dimensional (3D) datasets and surgical implementation of PSI was performed in a series of patients between December 2014 and July 2017. Patients had intra- or extra-articular malunions of the forearm, radiocarpal joint, trapeziometacarpal joint, or proximal interphalangeal joint. A previously described 3D surface model that incorporates CT data was used for segmentation (Mimics®, Materialise™, Belgium). For all the cases, CT scans of both forearms were acquired to use the contralateral uninjured side as the anatomic reconstruction template. Computer-assisted assessment of the deformity, the preoperative plan, and the design of PSI are described. Outcomes were determined by evaluating step-off correction, fusion, changes in range of motion (ROM) and grip strength. Six patients were included in the study; all achieved fusion. Improved clinical outcomes including pain reduction, better ROM and grip strength were obtained. Complete correction of intraarticular step-off was achieved in all cases with intraarticular malunions. 3D guided osteotomies are an established surgical treatment option for malunions of the hand and forearm. 3D analysis is a helpful diagnostic tool that provides detailed information about the underlying deformity. PSI can be developed and used for surgical correction with maximal accuracy for both intraarticular step-off and angular deformity.

Accuracy of manual and automatic placement of an anatomical coordinate system for the full or partial radius in 3D space

Accurate placement of a coordinate system on the radius is important to quantitatively report 3D surgical planning parameters or joint kinematics using 4D imaging techniques. In clinical practice, the scanned length of the radial shaft varies among scanning protocols and scientific studies. The error in positioning a radial coordinate system using a partially scanned radius is unknown. This study investigates whether the imaged length of the radius significantly affects the positioning of the coordinate system. For different lengths of the radius, the error of positioning a coordinate system was determined when placed automatically or manually. A total of 85 healthy radii were systematically shortened until 10% of the distal radius remained. Coordinate systems were placed automatically and manually at each shortening step. A linear mixed model was used to associate the positioning error with the length of the radial shaft. The accuracy and precision of radial coordinate system placement were compared between automatic and manual placement. For automatic placement of the radial coordinate system, an increasing positioning error was associated with an increased shortening of the radius (P = < 0.001). Automatic placement is superior to manual placement; however, if less than 20% of the radial shaft length remains, manual placement is more accurate.

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.

Image-Based Comparison Between the Bilateral Symmetry of the Distal Radii Through Established Measures

PURPOSE

Anthropometric assessment of bony structures in the body is important for preoperative computer-aided surgery, implant design, finite element modeling, and biomechanical studies investigating joint structure and function. The use of the contralateral limb in surgery and clinical practice relies on the assumption that the right and left limbs of an individual are symmetric. Therefore, the purpose of this study was to quantify the bilateral symmetry of the bony structures of the distal radius using 3-dimensional (3D) computed tomography.

METHODS

We collected computed tomography images of 37 paired, fresh-frozen, healthy cadaveric male upper limbs (aged 75.4 ± 8.3 years). Three-dimensional reconstructed models were created using semiautomatic segmentation. Using the 3D models, we measured 3D radial inclination, 3D volar tilt, 3D radial height, medial volar cortical angle, middle volar cortical angle, and lateral volar cortical angle and compared them between sides.

RESULTS

There were no statistically significant differences measured between right and left distal radius in 37 paired wrists. Mean radial height was 12.81 mm (SD, 1.74 mm) on the left and 12.88 mm (SD, 1.72 mm) on the right. Mean volar tilt was 10.74° (SD, 3.74°) and 10.77° (SD, 3.19°) and radial inclination was 24.05° (SD, 2.63°) and 24.18° (SD, 3.41°) on the left and right, respectively. Mean volar cortical angle across the radius was 140.9° (SD, 7.9°) on the left and 140.1° (SD, 7.9°) on the right.

CONCLUSIONS

Direct bilateral comparison of the distal radius and wrist joints is useful to predict normal anatomy of the injured radius, because bilateral similarities exist.

CLINICAL RELEVANCE

This article provides a comprehensive list of measurements of the distal radius compared bilaterally using a 3D model. From this study, we found that the contralateral radius can be used as a benchmark with which to compare fracture reduction and to manage malunions during the preoperative planning of corrective osteotomies. It can also be used to define normal anatomy.

3D printing in hand surgery

While 3D printing in hand surgery is still in its infancy, it offers new avenues in research, teaching, and personalized medicine. For these reasons, some surgeons may want to jump on the bandwagon of this trendy technology. But we cannot forget that its superiority over conventional techniques has not been demonstrated. Surgeons who want to work with 3D printed objects must master their use and the entire manufacturing process, otherwise they risk becoming dependent on engineers and/or medical device companies.

Complications during the treatment of missed Monteggia fractures with unilateral external fixation: a report on 20 patients in a 10-year period in a tertiary referral center

The treatment of a missed Monteggia (MM) fracture dislocation is still controversial. We describe our initial experience with ulnar osteotomy and progressive correction with unilateral external fixator in MM. We retrospectively evaluated 20 children undergoing ulnar osteotomy and progressive distraction angulation by unilateral external fixator to treat MM. Nine patients had closed reduction, whereas 11 patients had simultaneous open reduction, repair, or reconstruction of the annular ligament and K-wire stabilization of the radiocapitellar joint. Patients were followed for an average of 3 (1-11) years. Three children developed aseptic nonunion and one child had delayed union. A distal level of the osteotomy significantly increased the rate of nonunion or delayed union. At the final follow-up, eight children had complete reduction of the radial head, six children had partial reduction, whereas in six cases, the radial head remained dislocated. The angulation and the level of the osteotomy significantly influenced the relocation, whereas the open reduction had no significant effect on the final position of the radial head. At the final follow-up, the Kim's score averaged 93.25. The flexion-extension arc significantly improved postoperatively, and it was positively correlated with the angulation. The ulnar osteotomy and progressive traction-angulation by unilateral external fixator can achieve satisfactory results in MM, if a meticulous surgical technique is applied; care must be taken regarding the level of osteotomy and the progressive traction-angulation.

3D planning and surgical navigation of clavicle osteosynthesis using adaptable patient-specific instruments

Background

Preoperative three-dimensional planning and intraoperative navigation by patient-specific instruments is a promising method for the exact correction of bone deformities. Nevertheless, disadvantages of current concepts are the missing options of adapting the surgical plan intraoperatively. By providing the surgeons with a controlled length adjustment through the patient-specific instruments, the application area can usefully be expanded in the treatment of clavicle osteosyntheses.

Methods

In three cases, preoperative three-dimensional surgical planning with the intraoperative use of patient-specific instruments was applied. The computer-assisted assessments of clavicle deformities, the preoperative plan, and the design of patient-specific instruments were created on the basis of computed tomography data. Reduction guides for restoring length and rotation according to the mirrored healthy contralateral side were enhanced with adaptable length adjustment functions. The screw thread of the reduction guides enabled temporary distraction of the clavicle fracture fragments and a controlled compression of the optionally used interposed bone block between clavicle fragments.

Results

Navigated clavicle osteosyntheses by enhanced patient-specific instruments was executed uneventful in all three cases. The surgeon was able to adapt clavicle length in a planned axis intraoperatively as clinically desired.

Conclusion

Computer-assisted planning of clavicle osteosynthesis and surgical navigation with additional adaptable patient-specific instruments can usefully expand the previous application areas. By using guided length adjustments, the fragments and optionally the graft can be compressed along a planned axis as desired to ensure optimal bone healing.

Level of evidence

Basic science study, Surgical technique

Electronic supplementary material

The online version of this article (10.1186/s13018-019-1151-8) contains supplementary material, which is available to authorized users.

Pedicle screw navigation using surface digitization on the Microsoft HoloLens

PURPOSE

In spinal fusion surgery, imprecise placement of pedicle screws can result in poor surgical outcome or may seriously harm a patient. Patient-specific instruments and optical systems have been proposed for improving precision through surgical navigation compared to freehand insertion. However, existing solutions are expensive and cannot provide in situ visualizations. Recent technological advancement enabled the production of more powerful and precise optical see-through head-mounted displays for the mass market. The purpose of this laboratory study was to evaluate whether such a device is sufficiently precise for the navigation of lumbar pedicle screw placement.

METHODS

A novel navigation method, tailored to run on the Microsoft HoloLens, was developed. It comprises capturing of the intraoperatively reachable surface of vertebrae to achieve registration and tool tracking with real-time visualizations without the need of intraoperative imaging. For both surface sampling and navigation, 3D printable parts, equipped with fiducial markers, were employed. Accuracy was evaluated within a self-built setup based on two phantoms of the lumbar spine. Computed tomography (CT) scans of the phantoms were acquired to carry out preoperative planning of screw trajectories in 3D. A surgeon placed the guiding wire for the pedicle screw bilaterally on ten vertebrae guided by the navigation method. Postoperative CT scans were acquired to compare trajectory orientation (3D angle) and screw insertion points (3D distance) with respect to the planning.

RESULTS

The mean errors between planned and executed screw insertion were [Formula: see text] for the screw trajectory orientation and 2.77±1.46 mm for the insertion points. The mean time required for surface digitization was 125±27 s.

CONCLUSIONS

First promising results under laboratory conditions indicate that precise lumbar pedicle screw insertion can be achieved by combining HoloLens with our proposed navigation method. As a next step, cadaver experiments need to be performed to confirm the precision on real patient anatomy.

Physeal bar resection using a patient-specific guide with intramedullary endoscopic assistance for partial physeal arrest of the distal radius

The partial physeal arrest of the distal radius could result in progressive deformities and functional problems of the wrist. Despite being the most preferred surgical intervention, physeal bar resection (Langenskiöld procedure) is technically demanding. This manuscript aims to illustrate the technical tricks and present an illustrative case of premature physeal arrest of the distal radius managed with a novel method for the Langenskiöld procedure, involving complete removal of the bar using a patient-specific guide in combination with an intramedullary endoscopy technique that facilitated direct observation.