3-Dimensional prebent plate fixation in corrective osteotomy of malunited upper extremity fractures using a real-sized plastic bone model prepared by preoperative computer simulation

Accuracy Analysis of 3D Bone Fracture Models: Effects of Computed Tomography (CT) Imaging and Image Segmentation

The introduction of three-dimensional (3D) printed anatomical models has garnered interest in pre-operative planning, especially in orthopedic and trauma surgery. Identifying potential error sources and quantifying their effect on the model dimensional accuracy are crucial for the applicability and reliability of such models. In this study, twenty radii were extracted from anatomic forearm specimens and subjected to osteotomy to simulate a defined fracture of the distal radius (Colles' fracture). Various factors, including two different computed tomography (CT) technologies (energy-integrating detector (EID) and photon-counting detector (PCD)), four different CT scanners, two scan protocols (i.e., routine and high dosage), two different scan orientations, as well as two segmentation algorithms were considered to determine their effect on 3D model accuracy. Ground truth was established using 3D reconstructions of surface scans of the physical specimens. Results indicated that all investigated variables significantly impacted the 3D model accuracy (p < 0.001). However, the mean absolute deviation fell within the range of 0.03 ± 0.20 to 0.32 ± 0.23 mm, well below the 0.5 mm threshold necessary for pre-operative planning. Intra- and inter-operator variability demonstrated fair to excellent agreement for 3D model accuracy, with an intra-class correlation (ICC) of 0.43 to 0.92. This systematic investigation displayed dimensional deviations in the magnitude of sub-voxel imaging resolution for all variables. Major pitfalls included missed or overestimated bone regions during the segmentation process, necessitating additional manual editing of 3D models. In conclusion, this study demonstrates that 3D bone fracture models can be obtained with clinical routine scanners and scan protocols, utilizing a simple global segmentation threshold, thereby providing an accurate and reliable tool for pre-operative planning.

Indications for Nonbiological Reconstruction of Posttraumatic Bone Defects About the Knee

SUMMARY

3D printing and modeling has continued to grow in popularity over the past decade because the technology has matured and become more affordable and widely available. The main indications for nonbiological reconstruction of large bone defects are principally those patients where the candidate is unlikely to be successful if reconstructed by other means. Bespoke, custom, patient-specific implants can be designed to very effectively address bone loss, incorporating design elements that are particular to the needs of any given unique clinical condition. These implants are generally designed as titanium scaffolds that encourage bony incorporation at the host implant junction both proximal and distal. These scaffolds are typically considered a cellular solid, with high porosity that also promotes bone ingrowth directly into the substance of the body of the implant. Titanium scaffolds of this type have become a useful treatment alternative for large segmental bone defects around the knee, especially distal femoral defects. These are often adult patients with local or systemic compromise, or instead they may be too young to be considered candidates for reconstruction using a megaprosthesis. The process requires careful evaluation of individual patients, then matching that patient with the best treatment option, while recognizing the expectations and demands specific to that particular patient. Several cases are presented here to illustrate the variety of indications that can be successfully addressed with this technology, highlighting the quality of the clinical outcome that can be achieved despite the complexity of the pathology encountered.

Preoperative simulated surgery on 3D model assists osteotomy feasibility verification and surgical guidance for patients with cubitus valgus/varus deformity: a retrospective observational study

BACKGROUND

As the common delayed complication of supracondylar fractures in children, cubitus valgus/varus deformity might lead to pain and loss of motion of the elbow. The current corrective treatment might not be accurate enough and even contribute to postoperative deformity. This study retrospectively analyzed the clinical value of preoperative simulated surgery on 3D model-assisted osteotomy feasibility verification and surgical guidance for cubitus valgus/varus deformity.

METHODS

Seventeen patients were selected from October 2016 to November 2019. Deformities were analyzed from imaging data and 3D models and corrected after the simulated operations. The radiographic evaluation comprised osseous union, carrying angle, and anteversion angle of the distal humerus. The clinical evaluation was performed according to the Hospital for Special Surgery (HSS) scoring system.

RESULTS

All patients underwent the operation successfully and had no postoperative deformity. The carrying angle was significantly improved postoperatively (P < 0.001). The anteversion angle of the distal humerus did not change significantly (P > 0.05). The HSS score rose after surgery (P < 0.001). The function of the elbow joint was excellent in seven cases and good in ten cases.

CONCLUSION

Simulated surgery on 3D model plays an important role in osteotomy plan and surgical guidance, contributing to good surgical efficacy.

The Flipping-Wedge Osteotomy: How 3D Virtual Surgical Planning (VSP) Suggested a Simple and Promising Type of Osteotomy in Pediatric Post-Traumatic Forearm Deformity

(1) Background: The application of computer-aided planning in the surgical treatment of post-traumatic forearm deformities has been increasingly widening the range of techniques over the last two decades. We present the “flipping-wedge osteotomy”, a promising geometrical approach to correct uniapical deformities defined during our experience with virtual surgical planning (VSP); (2) Methods: a case of post-traumatic distal radius deformity (magnitude 43°) treated with a flipping-wedge osteotomy in an 11-year-old girl is reported, presenting the planning rationale, its geometrical demonstration, and the outcome of the procedure; (3) Results: surgery achieved correction of both the angular and rotational deformities with a neutral ulnar variance; (4) Conclusions: flipping-wedge osteotomy may be a viable option to achieve correction in forearm deformities, and it deserves further clinical investigation.

Clinical Applications of Three-Dimensional Printing in Upper Extremity Surgery: A Systematic Review

Three-dimensional printing for medical applications in surgery of the upper extremity has gained in popularity as reflected by the increasing number of publications. This systematic review aims to provide an overview of the clinical use of 3D printing in upper extremity surgery.

METHODS

We searched the databases PubMed and Web of Science for clinical studies that described clinical application of 3D printing for upper extremity surgery including trauma and malformations. We evaluated study characteristics, clinical entity, type of clinical application, concerned anatomical structures, reported outcomes, and evidence level.

RESULTS

We finally included 51 publications with a total of 355 patients, of which 12 were clinical studies (evidence level II/III) and 39 case series (evidence level IV/V). The types of clinical applications were for intraoperative templates (33% of a total of 51 studies), body implants (29%), preoperative planning (27%), prostheses (15%), and orthoses (1%). Over two third of studies were linked to trauma-related injuries (67%).

CONCLUSION

The clinical application of 3D printing in upper extremity surgery offers great potential for personalized approaches to aid in individualized perioperative management, improvement of function, and ultimately help to benefit certain aspects in the quality of life.

Accuracy of 3D Corrective Osteotomy for Pediatric Malunited Both-Bone Forearm Fractures

Re-displacement of a pediatric diaphyseal forearm fracture can lead to a malunion with symptomatic impairment in forearm rotation, which may require a corrective osteotomy. Corrective osteotomy with two-dimensional (2D) radiographic planning for malunited pediatric forearm fractures can be a complex procedure due to multiplanar deformities. Three-dimensional (3D) corrective osteotomy can aid the surgeon in planning and obtaining a more accurate correction and better forearm rotation. This prospective study aimed to assess the accuracy of correction after 3D corrective osteotomy for pediatric forearm malunion and if anatomic correction influences the functional outcome. Our primary outcome measures were the residual maximum deformity angle (MDA) and malrotation after 3D corrective osteotomy. Post-operative MDA > 5° or residual malrotation > 15° were defined as non-anatomic corrections. Our secondary outcome measure was the gain in pro-supination. Between 2016−2018, fifteen patients underwent 3D corrective osteotomies for pediatric malunited diaphyseal both-bone fractures. Three-dimensional corrective osteotomies provided anatomic correction in 10 out of 15 patients. Anatomic corrections resulted in a greater gain in pro-supination than non-anatomic corrections: 70° versus 46° (p = 0.04, ANOVA). Residual malrotation of the radius was associated with inferior gain in pro-supination (p = 0.03, multi-variate linear regression). Three-dimensional corrective osteotomy for pediatric forearm malunion reliably provided an accurate correction, which led to a close-to-normal forearm rotation. Non-anatomic correction, especially residual malrotation of the radius, leads to inferior functional outcomes.

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.

Malunion of Pediatric Forearm Shaft Fractures: Management Principles and Techniques

PURPOSE OF REVIEW

Clinically significant malunion of forearm diaphyseal fractures is an uncommon but potentially disabling condition amongst children and adolescents. We present the preoperative evaluation, including imaging, and discuss surgical indications and contemporary approaches to manage such patients, including an illustrative case.

RECENT FINDINGS

While advances in three-dimensional (3D) simulation, modeling, and patient-specific instrumentation have expanded the surgical armamentarium, their impact on long-term outcomes compared to traditional methods remains unknown. Successful outcome following surgical correction of malunion following a both-bone forearm fracture can be achieved with careful patient selection, appropriate indications, and a well-planned surgical execution.

Outcomes of 3-D corrective osteotomies for paediatric malunited both-bone forearm fractures

Closed treatment of paediatric diaphyseal forearm fractures carries the risk of re-displacement, which can lead to symptomatic malunions. This is because growth will not correct angulation deformity as it does in metaphyseal fractures. The purpose of this prospective cohort study was to evaluate the outcomes after 3-D-planned corrective osteotomy with patient-specific surgical guides for paediatric malunited forearm fractures causing impaired pro-supination. Our primary outcome measure was the gain in pro-supination at 12 months follow-up. Fifteen patients with a mean age at trauma of 9.6 years and time until osteotomy of 5.9 years were included. Preoperatively, patients displayed a mean pro-supination of 67° corresponding to 44% of the contralateral forearm. At final follow-up, this improved to 128°, achieving 85% of the contralateral side. Multivariate linear regression analysis revealed that predictors of greater functional gain after 3-D corrective osteotomy are severe preoperative impairment in pro-supination, shorter interval until 3-D corrective osteotomy and greater angulation of the radius.Level of evidence: III.

Smart Technology and Orthopaedic Surgery: Current Concepts Regarding the Impact of Smartphones and Wearable Technology on Our Patients and Practice

PURPOSE OF REVIEW

While limited to case reports or small case series, emerging evidence advocates the inclusion of smartphone-interfacing mobile platforms and wearable technologies, consisting of internet-powered mobile and wearable devices that interface with smartphones, in the orthopaedic surgery practice. The purpose of this review is to investigate the relevance and impact of this technology in orthopaedic surgery.

RECENT FINDINGS

Smartphone-interfacing mobile platforms and wearable technologies are capable of improving the patients' quality of life as well as the extent of their therapeutic engagement, while promoting the orthopaedic surgeons' abilities and level of care. Offered advantages include improvements in diagnosis and examination, preoperative templating and planning, and intraoperative assistance, as well as postoperative monitoring and rehabilitation. Supplemental surgical exposure, through haptic feedback and realism of audio and video, may add another perspective to these innovations by simulating the operative environment and potentially adding a virtual tactile feature to the operator's visual experience. Although encouraging in the field of orthopaedic surgery, surgeons should be cautious when using smartphone-interfacing mobile platforms and wearable technologies, given the lack of a current academic governing board certification and clinical practice validation processes.

3D printing-assisted extended lateral approach for displaced intra-articular calcaneal fractures: a systematic review and meta-analysis

BACKGROUND

Three-dimensional (3D) printing technology has developed rapidly in orthopaedic surgery and effectively achieves precise and personalized surgery. The purpose of this meta-analysis was to assess the efficacy of 3D printing technology in the management of displaced intra-articular calcaneal fractures (DICFs) by extended lateral approach (ELA).

METHODS

We searched PubMed, Web of Science, Embase, Cochrane Library, CNKI, VIP, and VANFUN databases were searched up to October 2020. All clinical studies comparing traditional surgery and 3D printing-assisted surgery in the management of DICFs were obtained, evaluating the quality of the included studies and extracting data. For each study, we assessed odds ratios (ORs), standard mean difference (SMD), and 95% confidence interval (95% CI) to assess and synthesize the outcomes.

RESULTS

Three RCTs and nine retrospective studies involving 732 patients were included met our inclusion criteria with 366 patients in the 3D group and 366 patients in the conventional group. The meta-analysis showed that there were significant differences of the operative time in the 3D group [SMD =  - 1.86, 95% CI (- 2.23, - 1.40), P < 0.001], intraoperative blood loss [SMD =  - 1.26, 95% CI (- 1.82, - 0.69), P < 0.001], the number of intraoperative X-ray exposures [SMD =  - 0.66, 95% CI (- 1.20, - 0.12), P < 0.001], postoperative complications [OR = 0.49, 95% CI (0.31, 0.79), P < 0.001], excellent and good rate of calcaneal fracture outcome [OR = 4.09, 95% CI (2.03, 8.22), P < 0.001].

CONCLUSION

The current study indicates that 3D printing-assisted ELA surgery showed a better rate of excellent and good outcome, shorter operation time, less intraoperative blood loss, fewer intraoperative fluoroscopies, fewer complications. Besides, there is still a need for large-sample, high-quality, long-term randomized controlled trials to confirm the conclusion.

Three-dimensional printing technology for patient-matched instrument in treatment of cubitus varus deformity: A case report

BACKGROUND

Recently, medical three-dimensional printing technology (3DPT) has demonstrated potential benefits for the treatment of cubitus varus deformity (CVD) by improving accuracy of the osteotomy through the use of an osteotomy guide, with or without a patient-mated plate. Here, we present an interesting CVD case, involving a patient who was treated with corrective biplanar chevron osteotomy using an innovative customized osteotomy guide and a newly designed patient-matched monoblock crosslink plate created with 3DPT.

CASE SUMMARY

A 32-year-old female presented with a significant CVD from childhood injury. A computer simulation was processed using images from computerized tomography scans of both upper extremities. The biplanar chevron osteotomy was designed to create identical anatomy between the mirror image of the contralateral distal humerus and the osteotomized distal humerus. Next, the customized osteotomy guide and patient-matched monoblock crosslink plate were designed and printed. A simulation osteotomy was created for the real-sized bone model, and the operation was performed using the posterior paratricipital approach with k-wire positioning from the customized osteotomy guide as a predrilled hole for screw fixation to achieve immediate control of the reduction after osteotomy. Our method allowed for successful treatment of the CVD case, significantly improving the patient’s radiographic and clinical outcomes, with satisfactory result.

CONCLUSION

3DPT-created patient-matched osteotomy guide and instrumentation provides accurate control during CVD correction.

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.

Corrective Osteotomy of Upper Extremity Malunions Using Three-Dimensional Planning and Patient-Specific Surgical Guides: Recent Advances and Perspectives

Malunions of the upper extremity can result in severe functional problems and increase the risk of osteoarthritis. The surgical reconstruction of complex malunions can be technically challenging. Recent advances in computer-assisted orthopedic surgery provide an innovative solution for complex three-dimensional (3-D) reconstructions. This study aims to evaluate the clinical applicability of 3-D computer-assisted planning and surgery for upper extremity malunions. Hence, we provide a summary of evidence on this topic and highlight recent advances in this field. Further, we provide a practical implementation of this therapeutic approach based on three cases of malunited forearm fractures treated with corrective osteotomy using preoperative three-dimensional simulation and patient-specific surgical guides. All three cases, one female (56 years old) and two males (18 and 26 years old), had painful restrictions in range of motion (ROM) due to forearm malunions and took part in clinical and radiologic assessments. Postoperative evaluation of patient outcomes showed a substantial increase in range of motion, reduction of preoperatively reported pain, and an overall improvement of patients' satisfaction. The therapeutic approach used in these cases resulted in an excellent anatomical and functional reconstruction and was assessed as precise, safe, and reliable. Based on current evidence and our results, the 3-D preoperative planning technique could be the new gold standard in the treatment of complex upper extremity malunions in the future.

A Review on 3D-Printed Templates for Precontouring Fixation Plates in Orthopedic Surgery

This paper is a systematic review of the literature on 3D-printed anatomical replicas used as templates for precontouring the fixation plates in orthopedic surgery. Embase, PubMed, Cochrane, Scopus and Springer databases were consulted for information on design study, fracture anatomical location, number of patients, surgical technique, virtual modeling approach and 3D printing process. The initial search provided a total of 496 records. After removing the duplicates, the title and abstract screening, and applying exclusion criteria and citations searching, 30 papers were declared eligible and included in the final synthesis. Seven studies were identified as focusing on retrospective non-randomized series of clinical cases, while two papers presented randomized case control studies. Two main approaches were highlighted in developing 3D-printed anatomical models for precontouring fixation plates: (a.) medical reconstruction, virtual planning and fracture reduction followed by 3D printing the model; (b.) medical reconstruction followed by 3D printing the model of the mirrored uninjured side. Revised studies reported advantages such as surgical time and blood loss reduction, while the reduction quality is similar with that of the conventional surgery. During the last couple of years there was an increase in the number of studies focused on precontouring orthopedic plates using 3D printing technology. Three-dimensionally-printed templates for plate precontouring were mostly used for acetabular fractures. Knowledge on medical virtual modeling and reconstruction is mandatory.

An innovative strategy to treat large metaphyseal segmental femoral bone defect using customized design and 3D printed micro-porous prosthesis: a prospective clinical study

Five patients with segmental irregular-shaped bone defect of the femur were recruited in this study from 2017.12 to 2018.11. All patients were treated by customized design and 3D printed micro-porous prosthesis. And the procedure was divided into stages: radical debridement and temporary fixation (the first stage); the membrane formation and virtual surgery (intervening period for 6-8 weeks); definite reconstruction the defects (the second stage). Routine clinical follow-up and radiographic evaluation were done to assess bone incorporation and complications of internal fixation. The weight-bearing time and the joint function of the patients were recorded. The patients were followed up for an average of 16.4 months. The average length of bone defect and the distal residual bone was 12 cm and 6.5 cm. The average time of partial weight-bearing and full weight-bearing was 12.7 days and 2.6 months. X-ray demonstrated good osseous integration of the implant/bone interface. No complications occurred such as implant loosening, subsidence, loss of correction and infection. At the last follow-up, Harris score of hip joint was excellent in 2 cases, good in 2 cases, fair in 1 case; HSS score of knee joint was good in 4 cases, middle in 1 case. From our study, we concluded that meticulous customized design 3D printed micro-porous prosthesis combined with intramedullary nail may be a promising and an alternative strategy to treat metaphyseal segmental irregular-shaped femoral bone defect, especially for cases with massive juxta-articular bone loss.

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.

A personalized preoperative modeling system for internal fixation plates in long bone fracture surgery-A straightforward way from CT images to plate model

BACKGROUND

Long bone fractures are a type of physical damage with high incidence rates that have serious impacts on the normal lives of humans.

AIMS

How to obtain a preoperative internal fixation plate model before cutting muscle has become a critical issue.

MATERIALS AND METHODS

In this paper, we present a new personalized modeling system for internal fixation plates in long bone fracture surgery. This system can achieve straight semi-automatic processing from CT images to 3D models. First, broken bones are separated in CT images. Second, the axes of long broken bones are extracted using 3D models. Third, the vertices on the broken bone cross-sections are segmented. Fourth, rough alignment and fine registration are implemented.

RESULTS

An internal fixation plate is reconstructed for a long bone fracture.

DISCUSSION

Three validations indicate that this method framework is reasonable and feasible.

CONCLUSION

This system can provide technical support for the personalized, minimally invasive and accurate operation on long bone fractures.

Are Three-Dimensional Printed Models Useful for Preoperative Planning of Tibial Plafond Fractures?

Computed tomography (CT) scans with 3-dimensional (3D) reconstruction are the gold standard of imaging for complex fractures. However, visualising CT imaging can be challenging. With increasing access to 3D printing, we postulate that life-sized 3D models can better assist in visualising CT images, aiding preoperative planning of tibial plafond fractures. 3D models of 3 tibial plafond fractures of differing complexities were printed. We approached surgeons in our institution who manage tibial plafond fractures to complete a questionnaire on preoperative planning of the cases based on CT scans. We then examined whether analysing the 3D models after that changed the plan. This included ratings on the usefulness, accuracy, and ease of use of the models. Six surgeons participated in the study. In the simple fracture model, median usefulness was graded as 4.5 (range minimum to maximum: 0 to 7), accuracy 8 (4 to 10), and ease of use 9 (7 to 10) with 0 being the lowest and 10 being the upper limit of how useful, accurate, or easy to use the models were. For the intermediate fracture, median usefulness was 6.5 (2 to 8), accuracy 7.5 (3 to 10), and ease of use 8.5 (7 to 10). For the complex fracture, median usefulness was 6 (1 to 9), accuracy 7.5 (1 to 9), and ease of use 8.5 (0 to 9). We attribute these poorer scores to difficulty in processing the scans, resulting in less accurate printing of the many fragments in complex impacted fractures. In conclusion, 3D-printed models are easy to use and accurate in preoperative planning of tibial plafond fractures. Most surgeons believe that 3D models and CT scans combined were more useful than CT scans alone.

Three-Dimensional Corrective Osteotomy for Malunited Fractures of the Upper Extremity Using Patient-Matched Instruments: A Prospective, Multicenter, Open-Label, Single-Arm Trial

BACKGROUND

Medical image processing has facilitated simulation of 3-dimensional (3-D) corrective osteotomy, and 3-D rapid prototyping technology has further enabled the manufacturing of patient-matched surgical guides and implants (patient-matched instruments, or PMIs). However, 3-D corrective osteotomy using these technologies has not been the standard procedure. We aimed to prospectively verify the efficacy and safety of PMIs in corrective osteotomy for deformities of the upper extremity.

METHODS

We enrolled 16 patients with a total of 17 bone deformities in the upper extremity. Eight patients had distal radial malunion; 5, distal humeral malunion; and 3, forearm diaphyseal malunion. All cases underwent 3-D corrective osteotomy with PMIs. The primary end point was the residual maximum deformity angle (MDA), which was calculated from 2 deformity angles-1 on the anteroposterior and 1 on the lateral postoperative radiograph. Secondary end points included the deformity angle on radiographs, 3-D error between the preoperative planning model and the postoperative result, range of motion, grip strength, pain measured with a visual analog scale (VAS), patient satisfaction, and Disabilities of the Arm, Shoulder and Hand (DASH) score.

RESULTS

The average MDA significantly improved from 25.5° preoperatively to 3.3° at the final follow-up (p < 0.001). The angular deformity was within 5° in all cases, except for 1 with distal radial malunion who had a higher angle on the anteroposterior radiograph. The error between the correction seen on the postoperative 3-D bone model and the planned correction was <1° and <1 mm. Flexion and extension of the wrist and pronation of the forearm of the patients treated for distal radial malunion improved significantly, and pronation improved for those treated for forearm diaphyseal malunion. The average VAS score, grip strength, and DASH score significantly improved as well. Of the 16 patients, 15 were very satisfied or satisfied with the outcomes.

CONCLUSIONS

Corrective osteotomy using PMIs achieved accurate correction and good functional recovery in the upper extremity. Although our study was limited to cases without any deformity on the contralateral side, 3-D corrective osteotomy using PMIs resolved treatment challenges for complex deformities in upper extremities.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Implementation of a semiautomatic method to design patient-specific instruments for corrective osteotomy of the radius

PURPOSE

3D-printed patient-specific instruments (PSIs), such as surgical guides and implants, show great promise for accurate navigation in surgical correction of post-traumatic deformities of the distal radius. However, existing costs of computer-aided design and manufacturing process prevent everyday surgical use. In this paper, we propose an innovative semiautomatic methodology to streamline the PSIs design.

METHODS

The new method was implemented as an extension of our existing 3D planning software. It facilitates the design of a regular and smooth implant and a companion guide starting from a user-selected surface on the affected bone. We evaluated the software by designing PSIs starting from preoperative virtual 3D plans of five patients previously treated at our institute for corrective osteotomy. We repeated the design for the same cases also with commercially available software, with and without dedicated customization. We measured design time and tracked user activity during the design process of implants, guides and subsequent modifications.

RESULTS

All the designed shapes were considered valid. Median design times ([Formula: see text]) were reduced for implants (([Formula: see text]) = 2.2 min) and guides (([Formula: see text]) = 1.0 min) compared to the standard (([Formula: see text]) = 13 min and ([Formula: see text]) = 8 min) and the partially customized (([Formula: see text]) = 6.5 min and ([Formula: see text]) = 6.0 min) commercially available alternatives. Mouse and keyboard activities were reduced (median count of strokes and clicks during implant design (([Formula: see text]) = 53, and guide design (([Formula: see text]) = 27) compared to using standard software (([Formula: see text]) = 559 and ([Formula: see text]) = 380) and customized commercial software (([Formula: see text]) = 217 and ([Formula: see text]) = 180).

CONCLUSION

Our software solution efficiently streamlines the design of PSIs for distal radius malunion. It represents a first step in making 3D-printed PSIs technology more accessible.

Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): guidelines for medical 3D printing and appropriateness for clinical scenarios

Medical three-dimensional (3D) printing has expanded dramatically over the past three decades with growth in both facility adoption and the variety of medical applications. Consideration for each step required to create accurate 3D printed models from medical imaging data impacts patient care and management. In this paper, a writing group representing the Radiological Society of North America Special Interest Group on 3D Printing (SIG) provides recommendations that have been vetted and voted on by the SIG active membership. This body of work includes appropriate clinical use of anatomic models 3D printed for diagnostic use in the care of patients with specific medical conditions. The recommendations provide guidance for approaches and tools in medical 3D printing, from image acquisition, segmentation of the desired anatomy intended for 3D printing, creation of a 3D-printable model, and post-processing of 3D printed anatomic models for patient care.

A Novel Method for the Approximation of Humeral Head Retrotorsion Based on Three-Dimensional Registration of the Bicipital Groove

BACKGROUND

The accurate restoration of premorbid anatomy is key for the success of reconstructive surgeries of the proximal part of the humerus. The bicipital groove has been proposed as a landmark for the prediction of humeral head retrotorsion. We hypothesized that a novel method based on bilateral registration of the bicipital groove yields an accurate approximation of the premorbid anatomy of the proximal part of the humerus.

METHODS

Three-dimensional (3D) triangular surface models were created from computed tomographic data of 100 paired humeri (50 cadavers). Segments of the distal part of the humerus and the humeral shaft of prespecified lengths were defined. A surface registration algorithm was applied to superimpose the models onto the mirrored contralateral humeral model based on the defined segments. We evaluated the 3D proximal humeral contralateral registration (p-HCR) errors, defined as the difference in 3D rotation of the humeral head between the models when superimposed. For comparison, we quantified the landmark-based retrotorsion (LBR) error, defined as the intra-individual difference in retrotorsion, measured with a landmark-based 3D method.

RESULTS

The mean 3D p-HCR error using the most proximal humeral shaft (bicipital groove) segment for the registration was 2.8° (standard deviation [SD], 1.5°; range, 0.6° to 7.4°). The mean LBR error of the reference method was 6.4° (SD, 5.9°; range, 0.5° to 24.0°).

CONCLUSIONS

Bilateral 3D registration of the bicipital groove is a reliable method for approximating the premorbid anatomy of the proximal part of the humerus.

CLINICAL RELEVANCE

The accurate approximation of the premorbid anatomy is a key for the successful restoration of the premorbid anatomy of the proximal part of the humerus.

Rotational Corrective Osteotomy for Malunited Distal Diaphyseal Radius Fractures in Children and Adolescents

PURPOSE

To report our method of computer-planned rotational corrective osteotomy for malunited distal diaphyseal radius fractures in children and adolescents using a custom jig and to review the results of 4 cases.

METHODS

Four patients (mean age, 13 years; range, 11-16 years) underwent computer-planned rotational corrective osteotomy for malunited distal diaphyseal radius fracture using a custom jig. We retrospectively evaluated their radiographic and clinical data.

RESULTS

In patients who had marked restriction of forearm supination before osteotomy, the mean arc of forearm supination improved from 5° before surgery to 79° after surgery. Angular deformity on x-ray, range of forearm rotation, and grip strength all improved after surgery. Mild and moderate pain reported by 1 and 2 patients, respectively, was resolved after surgery.

CONCLUSIONS

Computer-planned rotational corrective osteotomy for malunited distal diaphyseal radius fracture in children and adolescents using a custom jig is a strategy that facilitates the surgical procedure by accurately correcting both rotational and angular deformities on 1 plane in a single procedure.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.

Preoperative Computer Simulation and Patient-specific Guides are Safe and Effective to Correct Forearm Deformity in Children

BACKGROUND

Posttraumatic and congenital forearm deformities in children can be difficult to appreciate in all planes. In cases of distal radioulnar joint instability and loss of forearm rotation, surgical correction is challenging. Advances in 3-dimensional printing allow creation of custom guides at a reasonable cost, enabling precise correction of the deformity in all planes.

METHODS

Nineteen children with deformity of the forearm had corrective osteotomies performed using preoperative 3-dimensional computer modeling and patient-specific surgical guides. Surgicase software was used for 3-dimensional planning of the corrective osteotomy, by superimposing a mirror image of the unaffected side as a template. Based upon this planning, patient-specific surgical guides were manufactured. Radiographic and clinical outcomes were assessed.

RESULTS

Three patients had a diagnosis of multiple hereditary exostoses, and one of Madelung's deformity. The remaining 15 patients had a diagnosis of fracture malunion. Average preoperative angulation of both the radius and ulna was 23 degrees. For the patients with fracture malunions, the time from injury to surgery ranged from 6 months to 8 years. Twelve patients underwent osteotomies of both the radius and ulna, 5 had osteotomies of the radius alone, and 2 had a single osteotomy of the ulna only. All osteotomies went on to unite and no patient lost range of motion. Preoperative arc of forearm rotation averaged 101 degrees (range 0 to 180 degrees). Postoperatively, this improved to 133 degrees (range 85 to 180 degrees). Eight patients had distal radioulnar instability preoperatively, all of which normalized after surgery. There were 4 complications: 1 hypertrophic scar, 1 subject with extensor pollicis longus weakness, and 2 transient sensory losses in the superficial radial nerve distribution.

CONCLUSIONS

This case series demonstrates that 3-dimensional computer modeling permits complex and multiple osteotomies to be done safely to achieve deformity correction in children. Limitations in forearm rotation and distal radioulnar malalignment can be reliably improved using this technique.

LEVEL OF EVIDENCE

Level IV-retrospective case series.

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

INTRODUCTION

Over the last decade, the technique of 3D planning has found its way into trauma surgery. The use of this technique in corrective osteotomies for treatment of malunions provides the trauma surgeon with a powerful tool. However, this technique is not entirely straightforward. We aimed to define potential pitfalls of this technique and possible solutions to overcome these shortcomings.

MATERIALS AND METHODS

Ten patients with either a uni-, bi- or triplanar malunion of the long bones were included in this study. These patients were divided into three groups: a weight-bearing group and a non-weight-bearing group, the latter was divided into the humerus group and the forearm group, subsequently. 2D correction parameters were defined and compared within every group, as well as the interpretations of 3D visualization.

RESULTS

The weight-bearing group revealed an undercorrection for almost all clinical measurements of the femur and tibia, while there was adequate matching of the osteotomies and of screw entry points in all cases. In the humerus group, coronal correction angles were nearly perfect in all cases, while axial and sagittal correction rates, however, differed substantially. Screw entry points and osteotomies were all at the level as planned. The forearm group showed undercorrection in multiple planes while there were good matching entry points for the screw trajectories.

DISCUSSION

Four major pitfalls were encountered using the 3D printing technique: (1) careful examination of the planned guide positioning is mandatory, since suboptimal intra-operative guide positioning is most likely the main cause of the incomplete correction; (2) the use of pre-drilled screw holes do not guarantee adequate screw positioning; (3) translation of bone fragments over the osteotomy planes in case of an oblique osteotomy is a potential hazard; (4) the depth of the osteotomy is hard to estimate, potentially leading to extensive cartilage damage.

Factors determining outcome of corrective osteotomy for malunited paediatric forearm fractures: a systematic review and meta-analysis

The aim of this study was to identify predictors of a superior functional outcome after corrective osteotomy for paediatric malunited radius and both-bone forearm fractures. We performed a systematic review and meta-analysis of individual participant data, searching databases up to 1 October 2016. Our primary outcome was the gain in pronosupination seen after corrective osteotomy. Individual participant data of 11 cohort studies were included, concerning 71 participants with a median age of 11 years at trauma. Corrective osteotomy was performed after a median of 12 months after trauma, leading to a mean gain of 77° in pronosupination after a median follow-up of 29 months. Analysis of variance and multiple regression analysis revealed that predictors of superior functional outcome after corrective osteotomy are: an interval between trauma and corrective osteotomy of less than 1 year, an angular deformity of greater than 20° and the use of three-dimensional computer-assisted techniques.

LEVEL OF EVIDENCE

II.

Corrective Osteotomy for Malunited Diaphyseal Forearm Fractures Using Preoperative 3-Dimensional Planning and Patient-Specific Surgical Guides and Implants

PURPOSE

Three-dimensional planning based on computed tomography images of the malunited and the mirrored contralateral forearm allows preoperative simulations of corrective osteotomies, the fabrication of patient-specific osteotomy guides, and custom-made 3-dimensional printed titanium plates. This study aims to assess the precision and clinical outcome of this technique.

METHODS

This was a prospective pilot study with 5 consecutive patients. The mean age at initial injury was 11 years (range, 4-16 years), and the mean interval from the time of injury to the time of corrective surgery was 32 months (range, 7-107 months). Patient-specific osteotomy guides and custom-made plates were used for multiplanar corrective osteotomies of both forearm bones at the distal level in 1 patient and at the middle-third level in 4 patients. Patients were assessed before and after surgery after a mean follow-up of 42 months (range, 29-51 months).

RESULTS

The mean planned angular corrections of the ulna and radius before surgery were 9.9° and 10.0°, respectively. The mean postoperative corrections obtained were 10.1° and 10.8° with corresponding mean errors in correction of 1.8° (range, 0.3°-5.2°) for the ulna and 1.4° (range, 0.2°-3.3°) for the radius. Forearm supination improved significantly from 47° (range, 25°-75°) before surgery to 89° (range, 85°-90°) at final review. Forearm pronation improved from 68° (range, 45°-84°) to 87° (range, 82°-90°). In addition, there was a statistically significant improvement in pain and grip strength.

CONCLUSIONS

This study demonstrates that 3-dimensional planned patient-specific guides and implants allow the surgeon to perform precise corrective osteotomies of complex multiplanar forearm deformities with satisfactory preliminary results.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.

Corrective Osteotomy of Malunited Diaphyseal Fractures of the Forearm Simplified Using 3-Dimensional CT Data: Proposal of Our Simple Strategy Through Case Presentation

BACKGROUND

Reconstruction of malunited diaphyseal fractures of the forearm is one of the most difficult treatments due to its complicated structure. Widespread usage of Digital Imaging and Communications in Medicine (DICOM) data of 3-dimensional (3D) computed tomography (CT) and 3D printing can make estimating the true plane of the deformity easy.

METHODS

A 21-year-old man with limited supination due to left forearm nonunion deformity initially treated by locking plate fixation was referred to our hospital. We evaluated the deformity by superimposing the mirror image bone model of the contralateral normal bone onto a model of the affected bone and 3D real full-scale bone model.

RESULTS

The patient underwent a manual corrective osteotomy according to our planning. He had satisfactory improvement of his symptoms with no complications.

CONCLUSIONS

We postulated that our simple preoperative simulation and manual osteotomy with the aid of 3D CT reconstruction and 3D real full-scale bone model fit in the clinical practice as a recent trend.

Near-anatomical correction using a CT-guided technique of a forearm malunion in a 15-year-old girl: A case report including surgical technique

BACKGROUND

In this case report, we describe a left-arm both-bone forearm fracture in a 15-year-old girl who fell off a swing. Conservative treatment with an above-elbow cast failed, resulting in a malunion with functional impairment. The pro- and supination were 90/0/10, respectively. The patient complained of difficulties performing daily activities. For this pediatric case, a corrective osteotomy was proposed using a CT-guided technique aiming for maximum anatomical and functional outcome. It was the first time this technique was used in our hospital.

METHODS

A corrective osteotomy of the patient's left arm was performed using 3D printed templates to guide the osteotomy orientation. These templates were produced using specialized software in which CT images of her malunited left forearm were overlaid with the mirrored images of her healthy right forearm.

RESULTS

The postoperative CT-scan showed a near-anatomical reduction with close to 1° correction in all three planes, as compared to the preoperative planning. Three months after surgery, the patient had regained full function of her left forearm.

CONCLUSION

Although this was the first time this technique was used in our hospital, it resulted in excellent anatomical and functional outcomes making it a safe, reliable and precise treatment option that may be useful for even more complex corrections.

LEVEL OF EVIDENCE

Level V.

Mechanical stability of 2-plate versus 4-plate osteosynthesis in advancement Le Fort I osteotomy. An in vitro study

INTRODUCTION

Stability in orthognathic surgery is nowadays considered as efficient and adequate. The objective of this study was to determine and to compare the mechanical resistance to vertical load of a Le Fort I advancement osteotomy stabilized by mean of two different osteosynthesis techniques, one using two 10-hole pre-bent T-shaped plates, the other using four manually bent 4-hole L- and J-shaped plates.

MATERIEL AND METHODS

Standardized Le Fort I advancement osteotomies have been made on polyurethane models. The maxillary advancement was 5mm. Two groups of five models each were created. Group 1 was stabilized by mean of two 10-hole pre-bent T-shaped plates fixed by monocortical screws in the paranasal region. Group 2 was stabilized by mean of manually bent four 4-hole L-shaped plates fixed monocortical screws in the zygomatic and paranasal regions. A testing machine was used to load vertically the models at the range of 1mm/min linear displacement until peak load and system failure. Statistical analysis was realized using ANOVA and t-test, considering P as significant if <0.005.

RESULTS

The maximal tolerated load was 15N in group 1and 42.71N in group 2 (P=0.003).

DISCUSSION

The use of two T-shaped 10-holes pre-bent plates allows for less resistance in vertical loading than the use of four 4-holes manually bent L-shaped plates.

Putting 3D modelling and 3D printing into practice: virtual surgery and preoperative planning to reconstruct complex post-traumatic skeletal deformities and defects

3D printing technology has revolutionized and gradually transformed manufacturing across a broad spectrum of industries, including healthcare. Nowhere is this more apparent than in orthopaedics with many surgeons already incorporating aspects of 3D modelling and virtual procedures into their routine clinical practice. As a more extreme application, patient-specific 3D printed titanium truss cages represent a novel approach for managing the challenge of segmental bone defects. This review illustrates the potential indications of this innovative technique using 3D printed titanium truss cages in conjunction with the Masquelet technique. These implants are custom designed during a virtual surgical planning session with the combined input of an orthopaedic surgeon, an orthopaedic engineering professional and a biomedical design engineer. The ability to 3D model an identical replica of the original intact bone in a virtual procedure is of vital importance when attempting to precisely reconstruct normal anatomy during the actual procedure. Additionally, other important factors must be considered during the planning procedure, such as the three-dimensional configuration of the implant. Meticulous design is necessary to allow for successful implantation through the planned surgical exposure, while being aware of the constraints imposed by local anatomy and prior implants. This review will attempt to synthesize the current state of the art as well as discuss our personal experience using this promising technique. It will address implant design considerations including the mechanical, anatomical and functional aspects unique to each case.

Three-dimensional corrective osteotomies of complex malunited humeral fractures using patient-specific guides

BACKGROUND

Corrective osteotomies of malunited fractures of the proximal and distal humerus are among the most demanding orthopedic procedures. Whereas the restoration of the normal humeral anatomy is the ultimate goal, the quantification of the deformity as well as the transfer of the preoperative plan is challenging. The purpose of this study was to provide a guideline for 3-dimensional (3D) corrective osteotomies of malunited intra-articular fractures of the humerus and a detailed overview of existing and novel instruments to enlarge the toolkit for 3D preoperative planning and intraoperative realization using patient-specific guides.

METHODS

We describe the preoperative 3D deformity analysis, relevant considerations for the preoperative plan, design of the patient-specific guides, and surgical technique of corrective osteotomies of the humerus.

RESULTS

The presented technique demonstrates the benefit of computer-assisted surgery for complex osteotomies of the humerus from a preoperative deformity analysis to the creation of feasible surgical procedures and the generation of patient-specific guides.

CONCLUSIONS

A 3D analysis of a post-traumatic deformity of the humerus, 3D preoperative planning, and use of patient-specific guides facilitate corrective osteotomies of complex malunited humeral fractures.

Rapid prototyping for patient-specific surgical orthopaedics guides: A systematic literature review

There has been a lot of hype surrounding the advantages to be gained from rapid prototyping processes in a number of fields, including medicine. Our literature review aims objectively to assess how effective patient-specific surgical guides manufactured using rapid prototyping are in a number of orthopaedic surgical applications. To this end, we carried out a systematic review to identify and analyse clinical and experimental literature studies in which rapid prototyping patient-specific surgical guides are used, focusing especially on those that entail quantifiable outcomes and, at the same time, providing details on the guides’ design and type of manufacturing process. Here, it should be mentioned that in this field there are not yet medium- or long-term data, and no information on revisions. In the reviewed studies, the reported positive opinions on the use of rapid prototyping patient-specific surgical guides relate to the following main advantages: reduction in operating times, low costs and improvements in the accuracy of surgical interventions thanks to guides’ personalisation. However, disadvantages and sources of errors which can cause patient-specific surgical guide failures are as well discussed by authors. Stereolithography is the main rapid prototyping process employed in these applications although fused deposition modelling or selective laser sintering processes can also satisfy the requirements of these applications in terms of material properties, manufacturing accuracy and construction time. Another of our findings was that individualised drill guides for spinal surgery are currently the favourite candidates for manufacture using rapid prototyping. Other emerging applications relate to complex orthopaedic surgery of the extremities: the forearm and foot. Several procedures such as osteotomies for radius malunions or tarsal coalition could become standard, thanks to the significant assistance provided by rapid prototyping patient-specific surgical guides in planning and performing such operations.

Advantages and disadvantages of 3-dimensional printing in surgery: A systematic review

BACKGROUND

Three-dimensional (3D) printing is becoming increasingly important in medicine and especially in surgery. The aim of the present work was to identify the advantages and disadvantages of 3D printing applied in surgery.

METHODS

We conducted a systematic review of articles on 3D printing applications in surgery published between 2005 and 2015 and identified using a PubMed and EMBASE search. Studies dealing with bioprinting, dentistry, and limb prosthesis or those not conducted in a hospital setting were excluded.

RESULTS

A total of 158 studies met the inclusion criteria. Three-dimensional printing was used to produce anatomic models (n = 113, 71.5%), surgical guides and templates (n = 40, 25.3%), implants (n = 15, 9.5%) and molds (n = 10, 6.3%), and primarily in maxillofacial (n = 79, 50.0%) and orthopedic (n = 39, 24.7%) operations. The main advantages reported were the possibilities for preoperative planning (n = 77, 48.7%), the accuracy of the process used (n = 53, 33.5%), and the time saved in the operating room (n = 52, 32.9%); 34 studies (21.5%) stressed that the accuracy was not satisfactory. The time needed to prepare the object (n = 31, 19.6%) and the additional costs (n = 30, 19.0%) were also seen as important limitations for routine use of 3D printing.

CONCLUSION

The additional cost and the time needed to produce devices by current 3D technology still limit its widespread use in hospitals. The development of guidelines to improve the reporting of experience with 3D printing in surgery is highly desirable.

Emerging Applications of Bedside 3D Printing in Plastic Surgery

Modern imaging techniques are an essential component of preoperative planning in plastic and reconstructive surgery. However, conventional modalities, including three-dimensional (3D) reconstructions, are limited by their representation on 2D workstations. 3D printing, also known as rapid prototyping or additive manufacturing, was once the province of industry to fabricate models from a computer-aided design (CAD) in a layer-by-layer manner. The early adopters in clinical practice have embraced the medical imaging-guided 3D-printed biomodels for their ability to provide tactile feedback and a superior appreciation of visuospatial relationship between anatomical structures. With increasing accessibility, investigators are able to convert standard imaging data into a CAD file using various 3D reconstruction softwares and ultimately fabricate 3D models using 3D printing techniques, such as stereolithography, multijet modeling, selective laser sintering, binder jet technique, and fused deposition modeling. However, many clinicians have questioned whether the cost-to-benefit ratio justifies its ongoing use. The cost and size of 3D printers have rapidly decreased over the past decade in parallel with the expiration of key 3D printing patents. Significant improvements in clinical imaging and user-friendly 3D software have permitted computer-aided 3D modeling of anatomical structures and implants without outsourcing in many cases. These developments offer immense potential for the application of 3D printing at the bedside for a variety of clinical applications. In this review, existing uses of 3D printing in plastic surgery practice spanning the spectrum from templates for facial transplantation surgery through to the formation of bespoke craniofacial implants to optimize post-operative esthetics are described. Furthermore, we discuss the potential of 3D printing to become an essential office-based tool in plastic surgery to assist in preoperative planning, developing intraoperative guidance tools, teaching patients and surgical trainees, and producing patient-specific prosthetics in everyday surgical practice.

Postoperative accuracy analysis of three-dimensional corrective osteotomy for cubitus varus deformity with a custom-made surgical guide based on computer simulation

BACKGROUND

For correction of cubitus varus deformity resulting from supracondylar fracture of the humerus, we developed an operative method with use of a custom-made surgical guide, designed on the basis of 3-dimensional (3D) computer simulation with computed tomography data. The purpose of this study was to investigate the postoperative accuracy of this system in clinical cases.

METHODS

Subjects included 17 consecutive patients (13 males and 4 females) with cubitus varus deformity after supracondylar fracture. Patients underwent 3D corrective osteotomy with use of a custom-made surgical guide. Postoperative computed tomography scan was performed after bone union diagnosis on plain radiographs, and postoperative 3D bone models were compared with preoperative simulation by surface registration technique. In addition, we evaluated radiographic parameters (humerus-elbow-wrist angle and tilting angle) and range of elbow motion at the most recent follow-up.

RESULTS

Mean errors in 3D corrective osteotomy were 0.6° ± 0.7° in varus-valgus rotation, 0.8° ± 1.3° in flexion-extension rotation, 2.9° ± 2.8° in internal-external rotation, 1.7 ± 1.8 mm in anterior-posterior translation, 1.3 ± 1.8 mm in lateral-medial translation, and 7.1 ± 6.3 mm in proximal-distal translation. The mean humerus-elbow-wrist angle on plain radiographs of the affected side was 15° in varus before surgery and improved to 6° in valgus after surgery. The mean tilting angle of the affected side was 31° before surgery and improved to 40° after surgery.

CONCLUSION

The 3D correction of cubitus varus deformity was performed accurately within the allowable error limits.

Reconstruction of malunited diaphyseal fractures of the forearm

The forearm is a complex anatomical and functional unit with unique osseous, soft tissue and articular relationships. Disruption of these important relations can have a significant impact, leading to pain, instability of the radio-ulnar articulation and reduced range of motion. The gold standard for treating forearm fractures in adults remains anatomic reduction, stable plate fixation and preservation of the surrounding blood supply. Failure to achieve these goals may lead to malunion, requiring reconstructive surgery, which can be technically challenging. In this review, we discuss the essential aspects of anatomy and pathomechanics, clinical and radiological assessment and the state of the art in pre-operative planning and deformity correction surgery.