Accuracy of Patient-Specific Drilling Guides in Acetabular Fracture Surgery: A Human Cadaver Study

[3D printing/implants in traumatology]

The use of 3D printing offers numerous application possibilities in traumatology, including anatomic models, repositioning and drilling guides as well as patient-specific implants. The greatest challenge lies in the rapid availability as many procedures require an immediate intervention. Anatomic models support surgical planning by complementing visual impressions with tactile ones. Printed models not only help in the establishment of surgical strategies but also enhance patient clarification. Studies demonstrate that these models significantly reduce the operating time, duration of fluoroscopy and blood loss, particularly for joint fractures. Repositioning and drilling guides simplify complex procedures and improve outcomes; however, they require precise planning and critical evaluation by the surgeon. Intraoperative guides are helpful, for instance, in accurately placing screws, especially in difficult to access areas or in metaphyseal fractures lacking clear references. Individualized implants play a lesser role in acute care but are useful for posttraumatic defects or corrective osteotomy. In the conservative segment, such as customized splints, 3D printing is being tested but with mixed results. Key requirements for 3D printing in traumatology include high-resolution computed tomography (CT), precise data processing and swift production. Regulatory hurdles and lack of reimbursement currently limit the widespread use. An optimized collaboration between technology and medicine, along with standardized processes, are essential for effectively integrating this technology into practice.

Clinical Application of 3D-Assisted Surgery Techniques in Treatment of Intra-Articular Distal Radius Fractures: A Systematic Review in 718 Patients

Objectives: Three-dimensional (3D) technology is increasingly applied in the surgical treatment of distal radial fractures and may optimize surgical planning, improve fracture reduction, facilitate implant and screw positioning, and thus prevent surgical complications. The main research questions of this review were as follows: (1) "How do 3D-assisted versus 2D-assisted distal radius fracture surgery compare in terms of intraoperative metrics (i.e., operation time and fluoroscopy frequency)?", and (2) "What are the effects of 3D-assisted versus 2D-assisted surgery on postoperative outcomes (patient-reported outcome measures (PROMs), range of motion (ROM), fracture reduction, complication rate, and screw placement accuracy)?" Methods: This review was performed according to the Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines. In total, 873 articles were found between 1 January 2010 and 1 April 2024, of which 12 (718 patients) were suitable for inclusion. The quality of the studies, assessed using the McMaster quality assessment, ranged from moderate to excellent, although the surgical techniques and outcome measures varied widely. Articles comparing a 3D group to a 2D group (conventional imaging) and reporting on primary or secondary outcomes were included in the analysis, for which weighted means and ranges were calculated. Results: Three different concepts of 3D-assisted surgery techniques were identified: (1) 3D virtual surgical planning (VSP), (2) 3D-printed handheld models, and (3) 3D intraoperative guides. Differences between 3D-assisted and conventional 2D-assisted surgery were evaluated. Regarding intraoperative metrics, 3D-assisted surgery significantly reduced operation time by 6 min (weighted mean 66.9 versus 73.2 min) and reduced the fluoroscopy frequency by 1.1 images (5.8 versus 4.7 times). Regarding postoperative outcomes, the weighted mean of the DASH score differed between the 3D- and 2D-assisted groups (17.8 versus 23.9 points), and no differences in PRWE or VAS score were found. Furthermore, our results showed no significant differences in the ROM and fracture reduction parameters. In terms of complications, the application of 3D-assisted surgery decreased the complication rate from 10.7% to 3.6%, and the use of screws with appropriate lengths improved from 75% to 86%. Conclusions: Applications of 3D-assisted surgery in distal radial fracture surgery can slightly reduce the operation time and fluoroscopy frequency. Evidence for the improvement of fracture reduction and functional outcomes is still lacking, although it likely reduces the complication rate and improves the use of appropriate screw lengths.

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.

Development of patient-specific osteosynthesis including 3D-printed drilling guides for medial tibial plateau fracture surgery

PURPOSE

A substantial proportion of conventional tibial plateau plates have a poor fit, which may result in suboptimal fracture reduction due to applied -uncontrolled- compression on the bone. This study aimed to assess whether patient-specific osteosyntheses could facilitate proper fracture reduction in medial tibial plateau fractures.

METHODS

In three Thiel embalmed human cadavers, a total of six tibial plateau fractures (three Schatzker 4, and three Schatzker 6) were created and CT scans were made. A 3D surgical plan was created and a patient-specific implant was designed and fabricated for each fracture. Drilling guides that fitted on top of the customized plates were designed and 3D printed in order to assist the surgeon in positioning the plate and steering the screws in the preplanned direction. After surgery, a postoperative CT scan was obtained and outcome was compared with the preoperative planning in terms of articular reduction, plate positioning, and screw direction.

RESULTS

A total of six patient-specific implants including 41 screws were used to operate six tibial plateau fractures. Three fractures were treated with single plating, and three fractures with dual plating. The median intra-articular gap was reduced from 6.0 (IQR 4.5-9.5) to 0.9 mm (IQR 0.2-1.4), whereas the median step-off was reduced from 4.8 (IQR 4.1-5.3) to 1.3 mm (IQR 0.9-1.5). The median Euclidean distance between the centre of gravity of the planned and actual implant was 3.0 mm (IQR: 2.8-3.7). The lengths of the screws were according to the predetermined plan. None of the screws led to screw penetration. The median difference between the planned and actual screw direction was 3.3° (IQR: 2.5-5.1).

CONCLUSION

This feasibility study described the development and implementation of a patient-specific workflow for medial tibial plateau fracture surgery that facilitates proper fracture reduction, tibial alignment and accurately placed screws by using custom-made osteosynthesis plates with drilling guides.

3D surgical planning including patient-specific drilling guides for tibial plateau fractures

Aims

Proper preoperative planning benefits fracture reduction, fixation, and stability in tibial plateau fracture surgery. We developed and clinically implemented a novel workflow for 3D surgical planning including patient-specific drilling guides in tibial plateau fracture surgery.

Methods

A prospective feasibility study was performed in which consecutive tibial plateau fracture patients were treated with 3D surgical planning, including patient-specific drilling guides applied to standard off-the-shelf plates. A postoperative CT scan was obtained to assess whether the screw directions, screw lengths, and plate position were performed according the preoperative planning. Quality of the fracture reduction was assessed by measuring residual intra-articular incongruence (maximum gap and step-off) and compared to a historical matched control group.

Results

A total of 15 patients were treated with 3D surgical planning in which 83 screws were placed by using drilling guides. The median deviation of the achieved screw trajectory from the planned trajectory was 3.4° (interquartile range (IQR) 2.5 to 5.4) and the difference in entry points (i.e. plate position) was 3.0 mm (IQR 2.0 to 5.5) compared to the 3D preoperative planning. The length of 72 screws (86.7%) were according to the planning. Compared to the historical cohort, 3D-guided surgery showed an improved surgical reduction in terms of median gap (3.1 vs 4.7 mm; p = 0.126) and step-off (2.9 vs 4.0 mm; p = 0.026).

Conclusion

The use of 3D surgical planning including drilling guides was feasible, and facilitated accurate screw directions, screw lengths, and plate positioning. Moreover, the personalized approach improved fracture reduction as compared to a historical cohort.

The optimal fluoroscopic views to rule out intra-articular screw penetration during acetabular fracture fixation

PURPOSE

To determine the ideal view(s) and the minimum number of intraoperative fluoroscopic views required to rule out any intra-articular screw violation in acetabular fractures fixation.

METHODS

This study was conducted using a series of fluoroscopic examinations of pelvic synthetic models with screws positioned in different planes around the acetabulum. Ten screws were placed in the synthetic pelvis models in different planes of the acetabulum. Seven views were taken for each screw. Radiographic images were evaluated by 14 orthopaedic surgeons who were asked to assess joint violation and the view(s) required for assessment.

RESULTS

The observers' accuracy rate in identifying joint violation was 82.1% for the anterior part of the anterior column and the superior part of the posterior column, 89.3% for the posterior part of the anterior column and the inferior part of the posterior column, and 92.9% for the quadrilateral plate. The sensitivity was 100% for the anterior and posterior parts of the anterior column and the inferior part of the posterior column, 87.5% for the superior part of the posterior column, and 85.7% for the quadrilateral plate. The specificity was 100% for the quadrilateral plate, 80% for the superior part of the posterior column and the posterior part of the anterior column, 78.6% for the inferior part of the posterior column, and 66.7% for the anterior part of the anterior column. There was a strong overall interobserver and intra-observer agreement with intraclass correlation coefficient (ICC) of 0.709 and 0.86, respectively.

CONCLUSIONS

This study confirms the hypothesis that in a concave surface/joint fixation, such as the acetabulum, the probability of joint violation is unlikely if there is no evidence of it within a single fluoroscopic view. In acetabulum fracture fixation with a screw violating the joint, the screw's presence was evident within the joint space in all fluoroscopic views. However, the absence of joint violation in one fluoroscopic view was adequate to rule out joint penetration.

Single pararectus approach combined with three-dimensional guidance for the treatment of acetabular fracture

Background

Surgery for acetabular fractures involving both columns is difficult and traumatic, making it necessary to explore a minimally invasive and accurate surgical method.

Methods

This retrospective case-control study analyzed the clinical data of 34 patients and divided them into two groups: a control group (9 males and 8 females) and a research group (11 males and 6 females) with acetabular fractures involving the anterior and posterior columns. All patients were placed in the supine position via the pararectus approach. A three-dimensional (3D) guide was placed at the position where the posterior column screw was inserted in the second window, and a posterior column screw was placed percutaneously on the medial side of the iliac spine in the research group. The operation time, intraoperative blood loss, and fracture union time of the two groups were recorded. Pelvic radiographs and computed tomography (CT) scans were routinely performed before and after surgery to evaluate reduction and fixation. Residual gap and step displacement were measured using a standardized CT-based method after the surgery. Hip mobility was assessed according to the modified Merle, d'Aubigné, and Postel criteria.

Results

All patients were followed up for 6-30 (16.941±6.571) months. The operation times of the two groups were 126 [interquartile range (IQR), 95-133] min (control group) and 110 (IQR, 85-124) min (research group), the intraoperative blood losses were 430 (IQR, 290-550) mL (control group) and 380 (IQR, 260-500) mL (research group). All patients achieved bone healing, with a union time of 15 (IQR, 12-17) weeks (control group) and 13 (IQR, 11.5-15) weeks (research group). According to the standardized CT-based method, the reduction after surgery was acceptable in 13 (control group) and 14 (research group) of these patients (defined as a gap <5 mm or a step-off <1 mm), and the anatomical reduction rates were 76.47% and 82.35%, respectively.

Conclusions

The use of a single pararectus approach combined with 3D guide-assisted percutaneous anterograde posterior column screws can shorten the operation time and place effective posterior column screws precisely with minimal invasiveness. At the same time, the acetabular reduction and functional recovery are satisfactory, and there are fewer postoperative complications, which makes this procedure an ideal surgical option.

Entry Point Variation in the Osseous Fixation Pathway of the Anterior Column of the Pelvis—A Three-Dimensional Analysis

Fractures of the superior pubic ramus can be treated with screw insertion into the osseous fixation pathway (OFP) of the anterior column (AC). The entry point determines whether the screw exits the OFP prematurely. This can be harmful when it enters the hip joint or damages soft tissues inside the lesser pelvis. The exact entry point varies between patients and can be difficult to ascertain on fluoroscopy during surgery. The aim of this study was to determine variation in the location of the entry point. A retrospective single center study was performed at a level 1 trauma center in the Netherlands. Nineteen adult patients were included with an undisplaced fracture of the superior pubic ramus on computer tomography (CT)-scan. Virtual three-dimensional (3D) models of the pelvises were created. Multiple screws were placed per AC and the models were superimposed. A total of 157 screws were placed, of which 109 did not exit the OFP prematurely. A universally reproducible entry point could not be identified. A typical crescent shaped region of entry points did exist and was located more laterally in females when compared to males. Three-dimensional virtual surgery planning can be helpful to identify the ideal entry points in each case.

Does 3D-Assisted Acetabular Fracture Surgery Improve Surgical Outcome and Physical Functioning?-A Systematic Review

Three-dimensional technology is increasingly being used in acetabular fracture treatment. No systematic reviews are available about the added clinical value of 3D-assisted acetabular fracture surgery compared to conventional surgery. Therefore, this study aimed to investigate whether 3D-assisted acetabular fracture surgery compared to conventional surgery improves surgical outcomes in terms of operation time, intraoperative blood loss, intraoperative fluoroscopy usage, complications, and postoperative fracture reduction, and whether it improves physical functioning. Pubmed and Embase databases were searched for articles on 3D technologies in acetabular fracture surgery, published between 2010 and February 2021. The McMaster critical review form was used to assess the methodological quality. Differences between 3D-assisted and conventional surgery were evaluated using the weighted mean and odds ratios. Nineteen studies were included. Three-dimensional-assisted surgery resulted in significantly shorter operation times (162.5 ± 79.0 versus 296.4 ± 56.0 min), less blood loss (697.9 ± 235.7 mL versus 1097.2 ± 415.5 mL), and less fluoroscopy usage (9.3 ± 5.9 versus 22.5 ± 20.4 times). The odds ratios of complications and fracture reduction were 0.5 and 0.4 for functional outcome in favour of 3D-assisted surgery, respectively. Three-dimensional-assisted surgery reduces operation time, intraoperative blood loss, fluoroscopy usage, and complications. Evidence for the improvement of fracture reduction and functional outcomes is limited.