Three-dimensional-printed patient-specific Kirschner-wire guide for percutaneous fixation of undisplaced scaphoid fractures: a cadaveric study

3D printed guide-assisted percutaneous screw fixation for minimally displaced scaphoid waist fractures with delayed diagnosis or presentation

OBJECTIVES

To Investigate the value of 3D printed guide-assisted percutaneous management of minimally displaced scaphoid waist fractures(Herbert's B2) with delayed diagnosis or presentation.

METHODS

From October 2018 to February 2022, 10 patients with established delayed diagnoses and presentation of minimally displaced scaphoid waist fractures were treated with 3D printed guides assisted with percutaneous internal fixation without bone grafting. This technique was based on the patient's preoperative CT and imported into the software. Based on Boolean subtraction, the most centralized screw placement position was identified and a customized guide was produced. Intraoperative percutaneous insertion of the guide wire was assisted by the custom guide.

RESULTS

All 10 patients were successful in one attempt. The fractures healed at a mean of 7.7 weeks postoperatively (range 6-10 weeks). At a mean follow-up of 7.7 months (6-13 months), patients had excellent recovery of wrist function with minimal pain reduction. There were no major postoperative complications and the patients all returned to their previous activities before the injury.

CONCLUSIONS

Percutaneous internal fixation based on 3D printed guides is a safe and effective technique for delayed diagnosis or presentation of patients with minimally displaced fractures of the scaphoid waist. This method allows for easy insertion of screws and avoids multiple attempts.

Minimally Invasive Percutaneous Screw Guided by 3-Dimensional-Printed Guide for the Treatment of Scaphoid Fractures

PURPOSE

This study aimed to explore the feasibility and efficacy of percutaneous fixation of minimally displaced scaphoid waist fractures using a 3-dimensional-printed guide in 10 cases.

METHODS

Fractures were examined using preoperative computed tomography. The skin interface and bone models were reconstructed using computed tomography data. Guidewire insertion was assisted by a guide. Computed tomography was performed 4-6 weeks after surgery until healing of the fracture was confirmed. The mean follow-up period was 7 months (range, 6-9 months). The fracture healing time, grip strength, flexion-extension arc, patient-rated wrist evaluation, and Mayo wrist score were recorded.

RESULTS

A total of 6 hands were in the dominant limb. The mean operation time was 41 minutes (range, 32-70 minutes). Three (30%) scaphoids healed at 6 weeks after surgery, 8 (80%) scaphoids healed at 8 weeks after surgery, and 100% scaphoids healed at 12 weeks after surgery. After correcting for hand dominance, the mean grip strength was 84% (range, 71% to 95%) of that of the contralateral side. The flexion-extension arc was 97% (range, 82% to 100%) of that of the contralateral side. The mean Mayo wrist score was 95 (range, 85-100), and pain decreased to minimal levels. All patients returned to their preinjury activities.

CONCLUSIONS

Three-dimensional printing is an effective and feasible technology that can help guide intraoperative processes.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.

A Review of the Use of 3D Printing Technology in Treatment of Scaphoid Fractures

Background: Three-dimensional (3D) printing technology is increasingly commercially viable for pre-surgical planning, intraoperative templating, jig creation and customised implant manufacture. The challenging nature of scaphoid fracture and nonunion surgery make it an obvious target. The aim of this review is to determine the use of 3D printed technologies in the treatment of scaphoid fractures. Methods: This is a review of the Medline, Embase and Cochrane Library databases examining studies aimed at therapeutic use of 3D printing, also known as rapid prototyping or additive technology, in the treatment of scaphoid fractures. All studies published up to and including November 2020 were included in the search. Relevant data extracted included modality of use (as template/model/guide/prosthesis), operative time, accuracy of reduction, radiation exposure, follow-up duration, time to union, complications and study quality. Results: A total of 649 articles were identified, of which 12 met the full inclusion criteria. Analysis of the articles showed that 3D printing techniques can be utilised in myriad ways to aid planning and delivery of scaphoid surgery. Percutaneous guides for Kirschner-wire (K-wire) fixation of non-displaced fractures can be created; custom guides can be printed to aid reduction of displaced or non-united fractures; patient-specific total prostheses may recreate near-normal carpal biomechanics and a simple model may help graft harvesting and positioning. Conclusions: This review found that the use of 3D printed patient-specific models and templates in scaphoid surgery can improve accuracy and speed, and reduce radiation exposure. 3D printed prostheses may also restore near-normal carpal biomechanics without burning bridges for potential future procedures. Level of Evidence: Level III (Therapeutic).

A customized percutaneous three-dimensional-printed guide for scaphoid fixation versus a freehand technique: a comparative study

The aim of this study was to compare the accuracy and reliability of percutaneous fixation of minimally displaced scaphoid fractures using a customized three-dimensional (3-D)-printed guide with a conventional freehand method. A prospective cohort of ten patients underwent scaphoid fixation with the aid of a customized 3-D-printed guide. The final screw position, total surgery time (minutes) and fluoroscopy time (seconds) was compared with a retrospective cohort of ten patients who underwent fixation with a conventional technique. There were no differences in final screw position between both methods. The patients in which the 3-D guide was used had a surgery time reduction of 43% and a fluoroscopy time reduction of 52% compared with the control freehand group. The use of a customized 3-D-printed guide permits a fixation that is as accurate as the standard freehand technique, with reduction in surgical time and intraoperative radiation exposure.Level of evidence: III.

Three-Dimensional Printing in Hand Surgery

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

Scaphoid fracture displacement is not correlated with the fracture angle

Classifications of scaphoid fractures associate the angle of the fracture with its stability. To examine this assumption, we measured acute scaphoid fracture angles and inclinations in relation to different scaphoid axes, using fracture displacement as an indicator of instability. We examined the effect of using different axes on the measurements of angles. CT scans of 133 scaphoid fractures were classified according to the location of the fractures. Using a three-dimensional computer model, we computed four scaphoid axes. For each fracture, we then measured the fracture angle and the direction of the fracture inclination in relation to each one of the axes. We found a correlation between displacement and the angles of proximal fractures using one of these axes (the surface principal component analysis axis). No such correlations were found for waist fractures, which were the majority of fractures. There were significant differences between the measurements made with different axes. The findings indicate that the angle of the fracture and the direction of the fracture inclination are minor factors in the displacement of most scaphoid fractures.Level of evidence: III.

Diagnostic and Therapeutic Approach to Acute Scaphoid Fractures

The scaphoid is the carpal bone that most often fractures, accounting for up to 70% of carpal fractures and 11% of hand fractures. It is the second most common arm fracture, only surpassed by fractures of the distal radius. Despite being so common, these fractures can be difficult to diagnose and treat due to the anatomic and physiological particularities of the bone, including its precarious vascularization, its complex three-dimensional structure, and its ligament connections, which greatly contribute to the risk of complications such as malunion, pseudoarthrosis and avascular necrosis. Although there are many published studies on the treatment of these injuries, there is still controversy over what is the most suitable one for certain fracture types. The present article is a comprehensive and updated review of the literature. Combining strategies for clinical and radiological diagnosis, we propose a complete algorithm for the diagnosis of scaphoid fractures based on the varying availability of resources, and we also describe the most appropriate therapeutic approach for the different types of acute fractures of this bone.