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

Patient-specific implants combined with 3D-printed drilling guides for corrective osteotomies of multiplanar tibial and femoral shaft malunions leads to more accurate corrections

PURPOSE

The aim of this study was to evaluate the feasibility of using patient-specific implants (PSI) for complex shaft corrective osteotomies in multiplanar deformities of long bones in the lower extremities. Additionally, it aimed to investigate the added value of these implants by quantifying surgical accuracy on postoperative CT, comparing their outcomes to two commonly used techniques: 3D virtual visualizations and 3D-printed surgical guides.

METHODS

Six tibial and femoral shaft corrective osteotomies were planned and performed on three Thiel embalmed human specimen. Depending on the specimen a different respective technique was used; 1) '3D Visualization' using 3D virtual plan preoperatively and free-hand corrective osteotomy techniques with standard manually contoured plates; 2) '3D guided' utilizing 3D surgical guides and manually contouring of conventional implant; and 3)'3D PSI' utilizing a 3D surgical guide with a patient-specific implant. Accuracy of the corrections was assessed through measurements for varus/valgus angulation, ante/recurvation, rotation and osteotomy plane error as quantified on postoperative CT-scans.

RESULTS

Twelve corrective osteotomies were performed. For, the median difference between the surgical plan and postoperative CT assessment was 3.4°, 4.6°, and 2.2° for the '3D visualization', '3D guided', and '3D PSI' methods respectively. Regarding ante/recurvation, the differences were 3.8°, 43.8°, and 1.2°, respectively. For rotation, the differences were 11.9°, 18.7°, and 3.5°, respectively. Discrepancies between planned and executed levels of osteotomy plane were 6.2 mm, 3.2 mm, and 1.4 mm, respectively.

CONCLUSION

PSIs with 3D-printed drilling guides for complex multiplanar corrective osteotomies of femoral and tibial shaft malunions is feasible and achieves accurate corrections. This technique enables precise determination of the osteotomy plane, guides correction in all three planes, and ensures satisfactory implant fitting; thus accurately translating the virtual surgical plan into clinical practice. The 3D PSI method is beneficial for complex cases with significant multiplanar deformities in bone anatomy, particularly with rotational malalignment.

Postoperative accuracy quantification of corrective osteotomies: standardisation of Q3D-CT methodology

PURPOSE

Currently, no gold standard exists for 3D analysis of virtually planned surgery accuracy postoperatively. The aim of this study was to present a new, validated and standardised methodology for 3D postoperative assessment of surgical accuracy in patients undergoing 3D virtually planned and guided corrective osteotomies.

METHODS

All patients who underwent 3D planned corrective osteotomy in 2021-2022 at our center with a postoperative CT were included. Postoperative surgical outcome was analysed with a postoperative CT and compared to the preoperative virtual surgical planning to determine achieved accuracy. Validation of the analysis was performed by evaluating the individual assessment of six experienced observers. A postoperative quantification was performed according to the proposed innovative methodology based on rotation axes of a virtual postoperative bone model aligned to the virtual preoperative bone model and virtual surgical planned bone model. To evaluate the intra-observer variability, one observer performed the assessment twice.

RESULTS

Quantification of 13 patients according resulted in measurements with a median range (and its interquartile range) for 3D translation of: 2.43 mm (3.17), for the angle deviations: 3D rotation, 2D coronal, 2D sagittal and 2D axial were: 0.66° (1.66°), 0.74° (0.44°), 0.99° (1.27°), 2.37° (5.00°), respectively. The inter- and intraobserver reliability established with the Intraclass correlation coefficient was for all measurements excellent (> 0.76).

CONCLUSION

The proposed 3D CT technique provides an significant more accurate and objective method for assessment of surgical outcome of a guided corrective osteotomy. The present proposed novel methodology showed excellent inter- and intra-observer reliability with clinically acceptable absolute surgical outcome measurements.

The Use of 3-Dimensional Modeling and Printing in Corrective Osteotomies of the Malunited Pediatric Forearm: A Systematic Review and Meta-Analysis

INTRODUCTION

Forearm fractures contribute up to 40% of all pediatric fractures, with ≤39% of conservatively managed fractures resulting in malunion. Surgical management of malunion is challenging as precise calculation of multiplanar correction is required to obtain optimal outcomes. Advances in 3D computer modeling and printing have shown promising results in orthopaedics, reducing surgical time, blood loss, and fluoroscopy. This systematic review and meta-analysis are the first to explore the accuracy and functional outcome of 3D techniques in pediatric diaphyseal forearm malunion correction.

METHODS

A systematic review was carried out according to PRISMA guidelines.

RESULTS

Sixteen studies (44 patients) were included. Average 2D residual deformity was 1.84° (SD=1.68°). The average gain in range of movement (ROM) was 76.08° (SD=41.75°), with a statistically significant difference between osteotomies ≤12 months from injury and >12 months (96.36° vs. 64.91°, P = 0.027). Below a 2D residual deformity of 5.28°, no statistically significant difference on gain of ROM was found, indicating this as a nonconsequential residual deformity (P = 0.778). Multivariate regression analysis showed that 2D residual deformity and time to osteotomy only account for 6.3% gain in ROM, indicating that there are more factors to be researched.

CONCLUSION

This study found superior accuracy of 3D techniques, reporting lower residual deformities than published standard osteotomy data; however, the volume of literature was limited. Larger studies are required to explore additional factors that influence accuracy and ROM, such as 3D residual deformity and the effect of particular 3D printed adjuncts. This will aid clarity in determining superiority and improve cost-effectiveness.

Management of rotational malalignment following operative treatment of fractures of the lower extremities. A scoping review

BACKGROUND

Rotational malalignment after operative fracture treatment of the lower extremity may be associated with increased pain and functional impairment. Despite its clinical relevance, there are no uniform management guidelines. The aim of this scoping review is to provide an overview of all available evidence to diagnose and treat rotational deformities of the lower extremity following operative fracture treatment.

METHODS

This scoping review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. A literature search was carried out on 22 August 2023 by two independent reviewers in the Pubmed (MEDLINE), Embase, Web of Science, and Cochrane library databases. The search strategy was developed with the assistance of a biomedical information specialist. The main search terms were tibial and femoral malrotations. Disagreements were resolved through discussion with a third reviewer.

RESULTS

After screening and quality assessment of 3929 unique identified records, 50 articles were included for qualitative synthesis. Most studies were retrospective case reports or case series. Thirty studies focused on the femur, 11 on the tibia and nine included both femur and tibia. Most of the included studies presented cases where malrotation was associated with other limb deformities. Only 18 studies focused solely on the treatment of malrotation of the lower extremities after operative fracture treatment. Regarding diagnosis, bilateral CT-scans were used in 34 studies. Regarding treatment, external fixation was used in two studies, internal fixation (either intramedullary nail or plate) in 45 studies, and in three studies the authors used both. Overall, revision surgery resulted in good clinical outcomes with low complication rates.

CONCLUSION

This scoping review reveals that rotational malalignment following operative treatment of lower extremity fractures remains an important complication. Although it occurs frequently and is associated with severe disability for the patient, standardized guidelines regarding the terminology, diagnosis, indications for intervention and treatment are lacking. CT-scan is the most used diagnostic modality in daily clinical practice. Revision surgery, using diverse operative techniques, demonstrated positive results, significantly alleviating patient complaints with few complications. Nevertheless, an international consensus regarding the optimal management pathway is needed, and future prospective clinical studies seem therefore necessary.

The Panflute Technique: Novel 3D-Printed Patient Specific Instrumentation to Guide Curved Intra-Articular Osteotomies for Tibial Plateau Malunions

Background/Objectives: 3D patient-specific corrective osteotomies are optimized for use with oscillating saws, thereby rendering it incapable of executing curved osteotomies. The aim of this technical note is to introduce and evaluate the Panflute technique, which facilitates curved osteotomies with precise depth control for intra-articular corrective osteotomies in posttraumatic tibial plateau malunions. Methods: A 33-year-old male patient with an intra-articular malunion was treated one year after index surgery of a lateral split-depression tibial plateau fracture with the Panflute technique. The guide design allowed for multiple drill trajectories in a curved path, recreating the original fracture lines. Cylindrical drill tubes in the guide were tailored to match bone trajectory length. This resulted in a patient-specific Panflute-like design enabling precise depth control, safeguarding posterior neurovascular structures. Secondly, the recreated fragment was reduced with a reduction guide, applied to the plate in situ, to facilitate reposition using the plate as tool and reference. Results: The procedure went without technical drawbacks or surgical complications. Postoperative assessment showed that repositioning of the osteotomized articular fragment was performed accurately: pre- to postoperative translational corrections were 5.4 to 0.5 mm posterior displacement for AP deformity (x-axis); 2.9 to 1.0 mm lateral to medial reduction (y-axis); and 5.9 to 0.6 mm cranial-caudal correction (z-axis). Clinically, at 3 months, the fracture united, the patient regained full flexion, and valgus defect-laxity resolved. Conclusions: The presented Panflute-osteotomy guide allows for a pre-planned curved osteotomy. Additionally, for every drill trajectory, the depth could be controlled. The proposed method may expand our surgical armamentarium of patient-specific 3D techniques and solutions for complex intra-articular osteotomies.

Functional outcome of 2-D- and 3-D-guided corrective forearm osteotomies: a systematic review

We performed a systematic review to compare conventional (2-D) versus 3-D-guided corrective osteotomies regarding intraoperative results, patient-reported outcome measures, range of motion, incidence of complications and pain score. PubMed (MEDLINE), Embase and Cochrane CENTRAL were searched, and 53 articles were included, reporting 1257 patients undergoing forearm corrective osteotomies between 2010 and 2022. 3-D-guided surgery resulted in a greater improvement in median Disabilities of the Arm, Shoulder and Hand (DASH) score (28, SD 7 vs. 35, SD 5) and fewer complications (12% vs. 6%). Pain scores and range of motion were similar between 3-D-guided and conventional surgery. 3-D-guided corrective osteotomy surgery appears to improve patient-reported outcomes and reduce complications compared to conventional methods. However, due to the limited number of comparative studies and the heterogeneity of the studies, a large randomized controlled trial is needed to draw definitive conclusions.Level of evidence: III.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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