Computer-Aided Surgical Simulation for Correcting Complex Limb Deformities in Children

In Situ Fixation and Intertrochanteric Osteotomy for Severe Slipped Capital Femoral Epiphysis Following Femoral Neck Fracture: A Case Report with Application of Virtual Surgical Planning and 3D-Printed Patient-Specific Instruments

Background: Femoral neck fractures are rare but serious injuries in children and adolescents, often resulting from high-energy trauma and prone to complications like avascular necrosis (AVN) and nonunion. Even rarer is the development of slipped capital femoral epiphysis (SCFE) following femoral neck fracture, which presents unique diagnostic and treatment challenges. SCFE can destabilize the femoral head, with severe cases requiring complex surgical interventions. Case presentation: This report details a case of a 15-year-old male with autism spectrum disorder (ASD) who developed severe SCFE one month after treatment for a Delbet type III femoral neck fracture. The condition was managed with an Imhäuser intertrochanteric osteotomy (ITO), in situ fixation (ISF), and osteochondroplasty (OChP), supported by virtual surgical planning (VSP) and 3D-printed patient-specific instruments (PSIs) for precise correction and fixation. Discussion: The surgery was completed without complications. Six months after the operation, the patient exhibited a pain-free, mobile hip with radiographic evidence of fracture healing and no signs of AVN. Functional outcomes were favorable despite rehabilitation challenges due to ASD. Conclusions: The Imhäuser ITO, combined with ISF and OChP, effectively addressed severe SCFE after femoral neck fracture, minimizing AVN risk. VSP and PSIs enhanced surgical accuracy and efficiency, demonstrating their value in treating rare and complex pediatric orthopedic conditions.

Opening-Wedge High Tibial Osteotomy with a Cancellous Strut Bone Allograft Is Inadequate for Achieving Satisfactory and Lasting Correction in Neglected Infantile Tibia Vara: Results from a Cohort of 29 Patients

Background: Infantile tibia vara (ITV) is a rare proximal tibia deformity in infancy, leading to progressive knee varus. High tibial osteotomy is commonly practiced but has high recurrence rates. This study analyzed factors affecting treatment failure and recurrence in children undergoing opening-wedge high tibial osteotomy (OWHTO) for ITV. Methods: We retrospectively studied children with ITV who had OWHTO with a press-fit cancellous bone allograft between 2000 and 2020, with ≥2-year follow-up. Outcomes included recurrence (knee varus with tibiofemoral angle > 10°), complications, and reintervention. Results: We analyzed 39 knees in 29 patients (mean age: 4.8 ± 1.9 years; median follow-up: 7.4 years). Recurrence occurred in 22 cases (56%). Age at surgery significantly influenced recurrence, with rates of 16% before age 5 versus 95% later (hazard ratio: 12.0, p = 0.001). Langenskiöld stage also affected recurrence (β-coefficient: 2.7, 95% C.I. 1.0-4.5, p = 0.002; pseudo-R-squared: 0.50, p = 0.001), with recurrence in all stage IV or higher cases. Conclusions: Early diagnosis and treatment before age 5, ideally with Langenskiöld stage III or lower, are crucial for stable correction with OWHTO alone. Late, high-grade ITV may require combined, acute or gradual, and/or staged correction. Further evidence is needed for optimal management.

High-Temperature Polylactic Acid Proves Reliable and Safe for Manufacturing 3D-Printed Patient-Specific Instruments in Pediatric Orthopedics-Results from over 80 Personalized Devices Employed in 47 Surgeries

(1) Background: Orthopedic surgery has been transformed by 3D-printed personalized instruments (3DP-PSIs), which enhance precision and reduce complications. Hospitals are adopting in-house 3D printing facilities, using cost-effective methods like Fused Deposition Modeling (FDM) with materials like Polylactic acid (PLA) to create 3DP-PSI. PLA's temperature limitations can be overcome by annealing High-Temperature PLA (ann-HTPLA), enabling steam sterilization without compromising properties. Our study examines the in vivo efficacy of ann-HTPLA 3DP-PSI in pediatric orthopedic surgery. (2) Methods: we investigated safety and efficacy using ann-HTPLA 3DP-PSI produced at an "in-office" 3D-printing Point-of-Care (3DP-PoC) aimed at correcting limb deformities in pediatric patients. Data on 3DP-PSI dimensions and printing parameters were collected, along with usability and complications. (3) Results: Eighty-three ann-HTPLA 3DP-PSIs were utilized in 33 patients (47 bone segments). The smallest guide used measured 3.8 cm3, and the largest measured 58.8 cm3. Seventy-nine PSIs (95.2%; 95% C.I.: 88.1-98.7%) demonstrated effective use without issues. Out of 47 procedures, 11 had complications, including 2 infections (4.3%; 95% CI: 0.5-14.5%). Intraoperative use of 3DP-PSIs did not significantly increase infection rates or other complications. (4) Conclusions: ann-HTPLA has proven satisfactory usability and safety as a suitable material for producing 3DP-PSI in an "in-office" 3DP-PoC.

Side-to-Side Flipping Wedge Osteotomy: Virtual Surgical Planning Suggested an Innovative One-Stage Procedure for Aligning Both Knees in "Windswept Deformity"

(1) Background: The adoption of Virtual Surgical Planning (VSP) and 3D technologies is rapidly growing within the field of orthopedic surgery, opening the door to highly innovative and individually tailored surgical techniques. We present an innovative correction approach successfully used in a child affected by "windswept deformity" of the knees. (2) Methods: We report a case involving a child diagnosed with "windswept deformity" of the knees. This condition was successfully addressed through a one-stage bilateral osteotomy of the distal femur. Notably, the wedge removed from the valgus side was flipped and employed on the varus side to achieve the correction of both knees simultaneously. The surgical technique was entirely conceptualized, simulated, and planned in a virtual environment. Customized cutting guides and bony models were produced at an in-hospital 3D printing point of care and used during the operation. (3) Results: The surgery was carried out according to the VSP, resulting in favorable outcomes. We achieved good corrections of the angular deformity with an absolute difference from the planned correction of 2° on the right side and 1° on the left side. Moreover, this precision not only improved surgical outcomes but also reduced the procedure's duration and overall cost, highlighting the efficiency of our approach. (4) Conclusions: The integration of VSP and 3D printing into the surgical treatment of rare limb anomalies not only deepens our understanding of these deformities but also opens the door to the development of innovative, personalized, and adaptable approaches for addressing these unique conditions.

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.

A 20-Year Retrospective Study of Children and Adolescents Treated by the Three-in-One Procedure for Patellar Realignment

BACKGROUND

Patellar instability is the most common disorder of the knee during childhood and adolescence. Surgical treatment significantly reduces the rate of redislocation, but the underlying pathologies and pattern of instability may affect the results. We aimed to report the clinical and functional outcomes of the three-in-one procedure for patellar realignment in a cohort of skeletally immature patients with or without syndromes and various patterns of chronic patellar instability.

METHODS

We retrospectively investigated 126 skeletally immature patients (168 knees) affected by idiopathic or syndromic patellar instability, who underwent patella realignment through a three-in-one procedure. We classified the instability according to the score proposed by Parikh and Lykissas.

RESULTS

Patellar dislocation was idiopathic in 71 patients (94 knees; 56.0%) and syndromic in 55 (74 knees; 44.0%). The mean age at surgery was 11.5 years (range 4-18) and was significantly lower in syndromic patients. Syndromic patients also exhibited more severe clinical pattern at presentation, based on the Parikh and Lykissas score. The mean follow-up was 5.3 years (range 1.0-15.4). Redislocation occurred in 19 cases, with 10 cases requiring further realignment. The Parikh and Lykissas score and the presence of congenital ligamentous laxity were independent predictors of failure. A total of 22 knees in 18 patients required additional surgical procedures. The post-operative Kujala score was significantly lower in patients with syndromic patellar instability.

CONCLUSIONS

The type of instability and the presence of underlying syndromes negatively affect the rate of redislocation and the clinical and functional outcome following patellar realignment through the three-in-one procedure. We recommend the consideration of alternative surgical strategies, especially in children with severe syndromic patellar dislocation.

Three-dimensional technologies in presurgical planning of bone surgeries: current evidence and future perspectives

BACKGROUND

The recent development of three-dimensional (3D) technologies introduces a novel set of opportunities to the medical field in general, and specifically to surgery. The preoperative phase has proven to be a critical factor in surgical success. Utilization of 3D technologies has the potential to improve preoperative planning and overall surgical outcomes. In this narrative review article, the authors describe existing clinical data pertaining to the current use of 3D printing, virtual reality, and augmented reality in the preoperative phase of bone surgery.

METHODS

The methodology included keyword-based literature search in PubMed and Google Scholar for original articles published between 2014 and 2022. After excluding studies performed in nonbone surgery disciplines, data from 61 studies of five different surgical disciplines were processed to be included in this narrative review.

RESULTS

Among the mentioned technologies, 3D printing is currently the most advanced in terms of clinical use, predominantly creating anatomical models and patient-specific instruments that provide high-quality operative preparation. Virtual reality allows to set a surgical plan and to further simulate the procedure via a 2D screen or head mounted display. Augmented reality is found to be useful for surgical simulation upon 3D printed anatomical models or virtual phantoms.

CONCLUSIONS

Overall, 3D technologies are gradually becoming an integral part of a surgeon's preoperative toolbox, allowing for increased surgical accuracy and reduction of operation time, mainly in complex and unique surgical cases. This may eventually lead to improved surgical outcomes, thereby optimizing the personalized surgical approach.

Cementless Ceramic-on-Ceramic Total Hip Replacement in Children and Adolescents

Background: total hip replacement (THR) is a rare surgical option in children and adolescents with disabling hip diseases. The aim of this study is to report results from a retrospective cohort of patients aged 18 years or less who underwent cementless Ceramic-on-Ceramic (CoC) THR at a single institution, investigating clinical and radiographic outcomes, survival rates, and reasons for revision of the implants. Materials and methods: we queried the Registry of Prosthetic Orthopedic Implants (RIPO) to identify all children and adolescents undergoing THR between 2000 and 2019 at a single Institution. Inclusion criteria were patients undergoing cementless CoC THR, aged less than 18 years at surgery, followed for at least 2 years. Sixty-eight patients (74 hips) matched all the inclusion criteria and were enrolled in the study. We assessed the clinical and radiographic outcomes, the rate of complications, the survival rate, and reasons for revision of the implants. Results: The mean follow-up was 6.6 ± 4.4 years (range 2-20). The most frequent reason for THR was post-traumatic or chemotherapy-induced avascular necrosis (38%). The overall survival rate of the cohort was 97.6% (95% CI: 84.9-99.7%) at 5 years of follow-up, 94.4% (95% CI: 79.8-98.6%) at 10 years and 15 years of follow-up. Two THR in two patients (2.7%) required revision. With the numbers available, Cox regression analysis could not detect any significant interaction between preoperative or intraoperative variables and implant survivorship (p-value 0.242 to 0.989)." The average HOOS was 85 ± 14.3 (range 30.6-100). Overall, 23 patients (48%) reported excellent HOOS scores (>90 points), 21 patients (44%) reported acceptable HOOS scores (60-90 points) while 4 patients (8%) reported poor outcomes (<60 points). Twenty-one patients (43%) were regularly involved into moderate- to high-intensity sport activities (UCLA ≥ 6). Conclusions: Cementless CoC THR is a successful procedure in children and teenagers, having demonstrated high implant survivorship and low rates of complications and failure. A meticulous preoperative planning and implant selection is mandatory, to avoid implant malposition, which is the main reason of failure and revision in these cases. Further studies are needed to assess the impact of the THR on the psychosocial wellbeing of teenagers, as well as risks and benefits and cost-effectiveness in comparison to the hip preserving surgical procedures.

In-House, Fast FDM Prototyping of a Custom Cutting Guide for a Lower-Risk Pediatric Femoral Osteotomy

Three-dimensional printed custom cutting guides (CCGs) are becoming more and more investigated in medical literature, as a patient-specific approach is often desired and very much needed in today’s surgical practice. Three-dimensional printing applications and computer-aided surgical simulations (CASS) allow for meticulous preoperatory planning and substantial reductions of operating time and risk of human error. However, several limitations seem to slow the large-scale adoption of 3D printed CCGs. CAD designing and 3D printing skills are inevitably needed to develop workflow and address the study; therefore, hospitals are pushed to include third-party collaboration, from highly specialized medical centers to industrial engineering companies, thus increasing the time and cost of labor. The aim of this study was to move towards the feasibility of an in-house, low-cost CCG 3D printing methodology for pediatric orthopedic (PO) surgery. The prototype of a femoral cutting guide was developed for its application at the IOR—Rizzoli Orthopedic Institute of Bologna. The element was printed with an entry-level 3D printer with a high-temperature PLA fiber, whose thermomechanical properties can withstand common steam heat sterilization without bending or losing the original geometry. This methodology allowed for extensive preoperatory planning that would likewise reduce the overall surgery time, whilst reducing the risks related to the intervention.

Impact of the Application of Computer-Based 3D Simulation on Acquisition of Knowledge of Guidance of Mandibular Movement

Recently, computer-aided three-dimensional (3D) simulation has expanded to modern education. This study aims to investigate the effects of 3D computer simulation on the learning and self-assessment of the guidance of the mandibular movement. Sixty second-grade dental students were randomly distributed into three groups in an occlusion class. Various teaching protocols were used for each group. Students in the first group (lecture (L)) were taught exclusively through a textbook and two-dimensional illustrations. The conventional lecture method followed by computer-aided 3D simulation was applied to the second group (lecture-to-simulation (LtS)). Lastly, students in the third group (lecture with simulation (LwS)) were simultaneously taught using the conventional lecture and computer-aided 3D simulation methods. After teaching each group, a paper-based examination was conducted; actual and expected scores were obtained on the same day as the occlusal class. Analyses of variance with Tukey’s post-hoc analysis were used to compare the teaching protocols, whereas the independent t test was used for comparing between actual and expected scores (α = 0.05). The LwS group exhibited significantly higher actual and student-expected scores than the L and LtS groups (p < 0.001). The expected score was significantly lower than the actual score in the L group (p = 0.035). However, in the LtS and LwS groups, no statistical difference was observed between expected (p = 0.114) and actual (p = 0.685) scores. The distribution of actual scores in the grading systems indicated higher percentages of excellent (grade A) and good (grade B) scores in the LwS (96.7%) and LtS (79.7%) groups, respectively, than in the L group (53.4%). Using computer-aided 3D simulation to teach the guidance of mandibular movement improved the learning outcomes and self-assessment of students, especially when 3D simulation was combined with conventional lecturing.

Computer-Based 3D Simulation Method in Dental Occlusion Education: Student Response and Learning Effect

Occlusion is a fundamental subject in dental education, and occlusal adjustment is clinically essential in daily dental practices. This study aimed to assess the effects of computer-based 3D simulations on learner responses and learning effect on the principles of occlusal adjustment in undergraduate dental students in comparison with the traditional approach. Two teaching methods, i.e., paper-based 2D presentation and computer-based 3D simulation, were used for teaching the occlusal adjustment concepts. Sixty dental students were divided into two groups using a pair-matching randomization method. In the 2D presentation group, a textbook with 2D illustrations was used. 3D graphic dental models and computer design software were applied in the 3D simulation group. After the course, an attitudinal survey and examination were conducted to evaluate the participants’ feedback and the learning effects resulting from the teaching methods. The independent t test was used to compare the test scores between groups (with α = 0.5). Pearson’s correlation coefficient was calculated to investigate the agreement between the survey data and test scores. Most of the students’ feedback indicated that the 3D simulation method would be effective in acquiring knowledge on occlusion and jaw movement. The examination scores were significantly higher in the 3D simulation group compared with those in the 2D presentation group in the questions for centric relation (P = 0.034). Conversely, the scores were insignificant in the questions for eccentric relation (P = 0.403). There was no correlation observed between the survey data and the actual examination score. Computer-based 3D simulation could increase the participants’ expectations and learning effects in dental occlusion education. Further studies in diversified learning environments are required on the efficacy of digital educational modality.