Application of 3D-printed and patient-specific cast for the treatment of distal radius fractures: initial experience

In-house 3D-printed custom splints for non-operative treatment of distal radial fractures: a randomized controlled trial

We compared patient satisfaction and clinical effectiveness of 3D-printed splints made of photopolymer resin to conventional fibre glass casts in treating distal radial fractures. A total of 39 patients with minimally displaced distal radius fractures were included and randomized. Of them, 20 were immobilized in a fibre glass cast and 19 in a 3D-printed forearm splint. The 3D-printed splints were custom-designed based on forearm surface scanning with a handheld device and printed in-house using digital light processing printing technology. Patient satisfaction and clinical effectiveness were assessed with questionnaires 1 and 6 weeks after the initiation of immobilization. Fracture healing, pain, range of motion, grip strength and the DASH and PRWE scores were assessed up to 1-year follow-up. 3D-printed splints proved to be equally well tolerated by the patients and equally clinically effective as conventional fibre glass casts although there was a higher rate of minor complications. 3D-printed splints present a safe alternative, especially in young, active patients, for non-operative treatment of distal radial fractures.Level of evidence: I.

Improved Comfortability and Satisfaction of Hybrid-mesh Casts in the Conservative Management of Pediatric Supracondylar Humeral Fractures: A Randomized Controlled Trial

BACKGROUND

Cast immobilization is the mainstay of treatment for stable pediatric supracondylar humeral fractures (SCHFs). In recent years, a waterproof and breathable hybrid-mesh (HM) cast has emerged and been marketed to address common complaints such as itch, skin irritation, and malodor. Hence, this randomized controlled trial seeks to assess the overall satisfaction, comfort, and clinical outcomes of using HM casts in the conservative treatment of stable pediatric SCHF.

METHODS

Seventy-nine patients (age range: 1 to 10 y) with modified Gartland's classification Type I and Type IIa SCHF were recruited and randomized for immobilization with either fiberglass or HM long-arm cast for 3 weeks. During follow-up visits, patients were assessed for any loss of reduction and skin rash. The weight of casts, the presence of cast breakage, the duration of cast application, and removal were recorded. A self-reported patient comfort and satisfaction questionnaire was also administered during the same visit.

RESULTS

The final analysis included 38 patients immobilized with fiberglass casts and 39 patients with HM casts. Despite the significantly longer duration required for HM cast removal (4.18±1.25 min vs. 2.25±0.55 min, P <0.001), the HM cast was significantly lighter than its fiberglass counterpart (162.82±23.94 g vs. 203.95±36.52 g, P <0.001). The HM casts have better comfort (4.05±0.887 vs. 3.47±0.951, P =0.007) and satisfaction (3.69±1.055 vs. 3.11±0.953, P =0.012) scores as compared to fiberglass casts for immobilizing pediatric SCHF without compromising clinical outcome.

CONCLUSIONS

HM casts have better comfort and overall satisfaction as compared to conventional fiberglass casts for immobilizing pediatric SCHF without compromising clinical outcomes.

LEVEL OF EVIDENCE

Level II-therapeutic studies-investigating the results of treatment.

Topology-Optimized Splints vs Casts for Distal Radius Fractures: A Randomized Clinical Trial

Importance

To date, there is currently no evidence-based medical support for the efficacy of topology-optimized splints in treating distal radius fractures.

Objective

To assess the clinical efficacy and complication rates of topology-optimized splints in the treatment of distal radius fractures after closed manual reduction.

Design, Setting, and Participants

This 12-week, multicenter, open-label, analyst-blinded randomized clinical trial (comprising a 6-week intervention followed by a 6-week observational phase) was carried out from December 3, 2021, to March 10, 2023, among 110 participants with distal radius fractures. Statistical analysis was performed on an intention-to-treat basis between June 3 and 30, 2023.

Intervention

Participants were randomly assigned to 2 groups: the intervention group received topology-optimized splint immobilization and the control group received cast immobilization after closed manual reduction for 6weeks. After this period, immobilization was removed, and wrist rehabilitation activities commenced.

Main Outcomes and Measures

The primary outcome was the Gartland-Werley (G-W) wrist score at 6 weeks (where higher scores indicate more severe wrist dysfunction). Secondary outcomes encompassed radiographic parameters, visual analog scale scores, swelling degree grade, complication rates, and 3 dimensions of G-W wrist scores.

Results

A total of 110 patients (mean [SD] age, 64.1 [12.7] years; 89 women [81%]) enrolled in the clinical trial, and complete outcome measurements were obtained for 101 patients (92%). Median G-W scores at 6 weeks were 15 (IQR, 13-18) for the splint group and 17 (IQR, 13-18) for the cast group (mean difference, -2.0 [95% CI, -3.4 to -0.6]; P = .03), indicating a statistically significant advantage for the splint group. At 12 weeks, no clinically significant differences in G-W scores between the 2 groups were observed. Complication rates, including shoulder-elbow pain and dysfunction and skin irritation, were less common in the splint group (shoulder-elbow pain and dysfunction: risk ratio, 0.28 [95% CI, 0.08-0.93]; P = .03; skin irritation: risk ratio, 0.30 [95% CI, 0.10-0.89]; P = .02).

Conclusions and Relevance

Findings of this randomized clinical trial suggest that patients with distal radius fractures that were managed with topology-optimized splints had better wrist functional outcomes and fewer complications at 6 weeks compared with those who received casting, with no difference at week 12. Therefore, topology-optimized splints with improved performance have the potential to be an advisable approach in the management of distal radius fractures.

Trial Registration

Chinese Clinical Trial Registry: ChiCTR2000036480.

Evolution in Casting Techniques: A Narrative Review of Casting Methods, Techniques, and Innovation

Orthopedic casting has seen a remarkable evolution from ancient practices to cutting-edge innovations. Beginning with ancient Egyptian methods employing bark, linen, and bandages, casting techniques have progressed through historical milestones, including the adoption of plaster of Paris in the 19th century and the introduction of synthetic materials like fiberglass and thermoplastics in the 20th century. Historical progressions transitioned from primitive materials to more sophisticated techniques, such as resin-soaked bandages and starch-based casts. While thermoplastics showcased benefits like adjustability and comfort, widespread adoption faced hurdles due to cost and water resistance limitations. The emergence of 3D printing introduced patient-specific casts with improved ventilation but faced challenges in accessibility, cost, and immediate immobilization. FlexiOH presents as a groundbreaking foam cast by Orthoheal, offering customizable fit, lightweight design, improved ventilation, and moisture resistance. Its potential to reduce ER visits, enhance patient comfort, and streamline application procedures positions it as a promising technology for the future. This paper discusses each casting generation's advantages and drawbacks, highlighting the potential of innovative technologies like FlexiOH to revolutionize orthopedic casting practices, promising improved outcomes, reduced costs, and enhanced efficiency.

Clinical application of instant 3D printed cast versus polymer orthosis in the treatment of colles fracture: a randomized controlled trial

BACKGROUND

The shortcomings of plaster in water resistance, air permeability, skin comfort, fixed stability and weight of wearing are still to be solved. 3D printed cast can overcome the above shortcomings. At present, there is a relative lack of data on the clinical application of 3D printed cast, probably due to its complexity, relatively long operating time, and high price. We aimed to compare and evaluate the short-term effectiveness, safety and advantages of 3D printed wrist cast versus polymer orthosis in the treatment of Colles fracture.

METHODS

Forty patients with Colles fracture in our hospital from June to December 2022 were selected and divided into an observation group (20 patients, treated with instant 3D printed cast) and a control group (20 cases, treated with polymer orthosis). Both groups treated with manual reduction and external fixation. The visual analogue scale (VAS), immobilization effectiveness and satisfaction scores, Disability of the Arm, Shoulder and Hand (DASH) score, complications and imaging data were collected and compared before immobilization and at 2, 6 and 12 weeks after the fracture.

RESULTS

VAS at 2 weeks after the fracture was significantly lower in the observation group than in the control group ( P < 0.05). The immobilization effectiveness and satisfaction scores at 6 weeks after the fracture were significantly higher in the observation group than in the control group (all P < 0.05). The DASH scores at 2 and 6 weeks after the fracture were significantly lower in the observation group than in the control group (all P < 0.05). There wasn't rupture of the printed cast or orthosis in both groups. There were 2 cases of skin irritation in the control group, and no skin irritation occurred in the observation group. The palmar tilt angle and ulnar inclination angle at 2 weeks and 12 weeks after the fracture were significantly higher in the observation group than in the control group (all P < 0.05).

CONCLUSIONS

Both instant 3D printed cast and polymer orthosis are effective in the treatment of Colles fracture. But instant 3D printed cast is better than polymer orthosis in areas of good clinical and imaging performance, and high patient satisfaction and comfort.

Innovative Approaches to 3D Printing of PA12 Forearm Orthoses: A Comprehensive Analysis of Mechanical Properties and Production Efficiency

This research paper aims to explore the mechanical characteristics of polyamide PA12 (PA12) as a 3D material printed utilizing Selective Laser Sintering (SLS) and HP MultiJet Fusion (HP MJF) technologies in order to design and manufacture forearm orthoses. The study assessed the flowability of the materials used and compared the mechanical performance of PA12 with each other using tensile, flexure, and impact tests in five different fabrication orientations: X, Y, Z, tilted 45° XZ, and tilted 45° YZ. The results of the study provide, firstly-the data for testing the quality of the applied polyamide powder blend and, secondly-the data for the design of the orthosis geometry from the aspect of its strength parameters and the safety of construction. The mechanical parameters of SLS specimens had less variation than MJF specimens in a given orientation. The difference in tensile strength between the 3D printing technologies tested was 1.8%, and flexural strength was 4.7%. A process analysis of the forearm orthoses revealed that the HP MJF 5200 system had a higher weekly production capacity than the EOS P396 in a production variance based on obtaining maximum strength parameters and a variance based on maximizing economic efficiency. The results suggest that medical device manufacturers can use additive manufacturing technologies to produce prototypes and small-batch parts for medical applications. This paper pioneers using 3D printing technology with Powder Bed Fusion (PBF) methods in designing and manufacturing forearm orthoses as a low- to medium-volume product. The applied solution addresses the problem of medical device manufacturers with regard to the analysis of production costs and mechanical properties when using 3D printing for certified medical devices.

Reduced Isocyanate Release Using a Waterproof, Resin-Based Cast Alternative Relative to Fiberglass Casts

The effects of occupational isocyanate exposure range from asthma and contact dermatitis to neurotoxicity and cancer. Respiratory sensitization due to orthopedic cast application has been well documented. This study aims to compare the safety of standard-of-care fiberglass casts and a novel waterproof cast alternative by measuring the amount of isocyanate released during off-gassing over time. A 3D-printed arm simulator with comparable casing material amounts was placed in a sealed chamber. An isocyanate-sensing color-changing (SafeAir) tag was used to measure the levels of toxic exposure. Triplicate trials were conducted across all time periods (15 min, 1 h, and 24 h) and conditions. The bare arm simulator and freshly opened tags served as negative controls. Normalized pixel intensity indexes and isocyanate release estimates in ppb were derived from ImageJ-analyzed SafeAir tag photos. Fiberglass casts exhibited greater isocyanate release than both the waterproof alternative (p = 0.0002) and no-cast controls (p = 0.0006), particularly at 24 h. The waterproof alternative and no-cast control did not statistically differ (p = 0.1603). Therefore, the waterproof alternative released less isocyanate than the fiberglass casts. Waterproof cast alternatives may be safer than fiberglass by limiting medical professionals' exposure to toxic isocyanates and, thus, decreasing their risk of suffering occupational asthma.

Predictive analysis of the scoliotic curve using a subject's 3D model

A predictive analysis of the conservative scoliosis treatment is necessary, in which a 3D model of an optimal treatment algorithm is a basic part in the design of a prosthetic corset. Since CAD technology has proven to be very useful in the field of prosthetics and orthotics, we used an open-source software to plan the correction of the scoliotic curve on a virtual model of the subject's torso. The shape of the scoliosis was simplified by means of a directional polygon, which was drawn in a reverse manner depending on the directional arcs of the scoliotic curve. The resulting scoliosis correction, simulated in a predictive analysis, was defined by changing the Cobb angle, eccentricity, and torso height. With the proposed low-cost method of predictive analysis, it is possible to help CPOs to a more accurate and effective design of orthoses and corrective aids and to comprehensively determine the entire treatment procedure.

Personalized 3D-printed forearm braces as an alternative for a traditional plaster cast or splint; A systematic review

Forearm fractures such as distal radius fractures are traditionally treated with a plaster or synthetic cast. Patients commonly report inconvenience of the cast, skin problems, and occasionally radial sensory nerve numbness. A known issue with casting is that the rate of secondary dislocation is high. As an alternative to casts, personalized 3D-printed braces are increasingly used. This review provides an inventory of current developments and experience with 3D-printed forearm braces. Main focus was on the design requirements, materials used, technical requirements, and preclinical and clinical results. Review of 12 studies showed that all printed braces used an open design. Fused Deposition Modelling is most commonly used 3D-printing technique (seven studies) and polylactic acid is the most commonly used material (five studies). Clinical evaluation was done in six studies, mainly involving distal radius fractures, and generally showed a low complication rate and high patient satisfaction with the printed brace. Whether or not the results obtained with 3D-printed braces are superior to results after casting requires further studies.

The 3D Printability and Mechanical Properties of Polyhydroxybutyrate (PHB) as Additives in Urethane Dimethacrylate (UDMA) Blends Polymer for Medical Application

The integration of additive manufacturing (3D printing) in the biomedical sector required material to portray a holistic characteristic in terms of printability, biocompatibility, degradability, and mechanical properties. This research aims to evaluate the 3D printability and mechanical properties of polyhydroxybutyrate (PHB) as additives in the urethane dimethacrylate (UDMA) based resin and its potential for medical applications. The printability of the PHB/UDMA resin blends was limited to 11 wt.% as it reached the maximum viscosity value at 2188 cP. Two-way analysis of variance (ANOVA) was also conducted to assess the significant effect of the varied PHB (wt.%) incorporation within UDMA resin, and the aging duration of 3D printed PHB/UDMA on mechanical properties in terms of tensile and impact properties. Meanwhile, the increasing crystallinity index (CI) of X-ray diffraction (XRD) in the 3D printed PHB/UDMA as the PHB loading increased, indicating that there is a strong correlation with the lower tensile and impact strength. FESEM images also proved that the agglomerations that occurred within the UDMA matrix had affected the mechanical performance of 3D printed PHB/UDMA. Nonetheless, the thermal stability of the 3D printed PHB/UDMA had only a slight deviation from the 3D printed UDMA since it had better thermal processability.

Use of a 3D-printed splint for the treatment of distal radius fractures: A randomized controlled trial

BACKGROUND

Management of distal radius fractures typically includes a period of immobilization with either a cast or a splint. Traditional immobilization methods can have inconveniences such as poor resistance to water and poor ventilation, which can result in skin maceration, skin breakdown, and infection in case of wetting.

HYPOTHESIS

3D-printed splints could potentially overcome the inconveniences of traditional casts. In this report, we compare a 3D-printed splint (3DPS) with a conventional removable splint (CRS) and a traditional cast in a randomized clinical trial.

PATIENTS AND METHODS

Thirty-four patients with a recent distal radius fracture were randomized to receive either a 3DPS or a CRS. An additional subset of nine patients benefitted from both splints for a direct comparison. Primary outcomes were measured based on a subjective assessment questionnaire and a clinical outcome.

RESULTS

There was no statistical difference in the subjective assessment between the 3DPS and the CRS groups. Based on the clinical assessment, patients with the 3DPS experienced more pressure-related pain. Among the sub-sample of nine patients that benefited from both splints, eight preferred the CRS and one chose the 3DPS. The 3DPS was judged better for perspiration, coolness, and water resistance.

DISCUSSION

The 3DPS was successful in solving shortcomings of conventional splints and cast (better ventilation, less perspiration, less warmness, more durability and water resistance). However, the rigid structure and sharp edges made it less comfortable, overall favouring the CRS.

LEVEL OF EVIDENCE

II.

Evaluation and Comparison of Traditional Plaster and Fiberglass Casts with 3D-Printed PLA and PLA–CaCO3 Composite Splints for Bone-Fracture Management

Bone fractures pose a serious challenge for the healthcare system worldwide. A total of 17.5% of these fractures occur in the distal radius. Traditional cast materials commonly used for treatment have certain disadvantages, including a lack of mechanical and water resistance, poor hygiene, and odors. Three-dimensional printing is a dynamically developing technology which can potentially replace the traditional casts. The aim of the study was to examine and compare the traditional materials (plaster cast and fiberglass cast) with Polylactic Acid (PLA) and PLA–CaCO₃ composite materials printed using Fused Filament Fabrication (FFF) technology and to produce a usable cast of each material. The materials were characterized by tensile, flexural, Charpy impact, Shore D hardness, flexural fatigue, and variable load cyclic tests, as well as an absorbed water test. In addition, cost-effectiveness was evaluated and compared. The measured values for tensile strength and flexural strength decreased with the increase in CaCO₃ concentration. In the fatigue tests, the plaster cast and the fiberglass cast did not show normal fatigue curves; only the 3D-printed materials did so. Variable load cyclic tests showed that traditional casts cannot hold the same load at the same deflection after a higher load has been used. During these tests, the plaster cast had the biggest relative change (−79.7%), compared with −4.8 % for the 3D-printed materials. The results clearly showed that 3D-printed materials perform better in both static and dynamic mechanical tests; therefore, 3D printing could be a good alternative to customized splints and casts in the near future.

In-hospital production of 3D-printed casts for non-displaced wrist and hand fractures

Objectives: To examine the clinical feasibility and results of a multidisciplinary workflow, employing rapid three-dimensional (3D) scanning and modeling software along with a high-speed printer, for in-hospital production of patient-specific 3D-printed casts, for the treatment of non-displaced wrist and hand fractures. Methods: Consenting adult patients admitted to the emergency department (ED) due to wrist or hand fractures between January and February 2021 were prospectively enrolled. The study participants underwent conversion of the standard plaster of Paris cast to a 3D-printed cast one week after the ED visit, and follow-up examinations were performed around two, six, and twelve weeks later. The primary objective was to examine the clinical feasibility in terms of complexity and length of the overall procedure. Secondary outcomes were patient-reported impressions and radiological results. Results: Twenty patients (16 males, mean age 37 ± 13.1 years) were included. The entire printing workflow took a mean of 161 ± 8 min. All patients demonstrated clinical improvement and fracture union at final follow-up, with no pressure sores or loss of reduction. Patient-reported comfort and satisfaction rates were excellent. The mean Visual Analog Scale was 0.9 ± 1.1 and 0.6 ± 1, and the mean Disabilities of the Arm, Shoulder, and Hand score was 18.7 ± 9.5 and 7.6 ± 7.6 at 2 and 6 weeks after application of the 3D-printed cast, respectively. Conclusion: The in-hospital workflow was feasible and efficient, with excellent clinical and radiographic results and high patient satisfaction and comfort rates. Our medical center now routinely provides this cast option for non-displaced wrist and hand fractures.

Level of evidence: IV, Therapeutic Study

Contactless Remote 3D Splinting during COVID-19: Report of Two Patients

We used calibrated 2D images uploaded by patients to an online platform to generate a 3D digital model of the limb. This was used to 3D print a splint. This method of 3D printing of splints was used for two patients who were not able to visit the hospital in person due to restrictions placed by the COVID-19 pandemic. Both patients were satisfied with the splint. We feel that this technology could be used to offer additional options to conventional splinting that allows contactless splint fitting. Level of Evidence: Level V (Therapeutic).

3D-Printed Patient-Specific Casts for the Distal Radius in Children: Outcome and Pre-Market Survey

Background: Orthopaedic and Trauma surgery is expected to undergo profound transformation as a result of the adoption of 3D technology. Among the various applications, patient specific manufacturing of splints and casts would appear to be, particularly in children, an interesting implementation. This study aims to assess the safety of patient specific 3D casts obtained with a newly developed 3D-scanning devise in a small case series. We therefore conducted a clinical outcome and pre-marketing study in 10 consecutive patients with distal radius fractures treated at an Academic Level I Pediatric Trauma Center. After the application of the 3D cast, patients underwent three consecutive evaluations in the following 21 days. The main outcome measurements were: pain, skin lesions and general comfort, and acceptance of the cast. The three domains were measured with the Visual Analogue Scale (VAS), the NPUAP/EPUAP classification and the Positive affect-Negative affect Scale for Children (PANAS-C), the Self-Assessment Manikin (SAM) clinical psychology tests and a Likert-type five item questionnaire, respectively. A final mechanical analysis of the cast was carried out to confirm product integrity. Results: The results obtained were consistently positive in the investigated domains of general comfort, efficacy of contention and mechanical integrity of the 3D-printed cast as well as in the practicability of the supply chain. Conclusions: This study provides Level IV evidence that patient specific 3D printed casts obtained with a specifically designed software were safe in the management of “buckle” fractures of the distal radius in children. These results encourage to extend the technology to the treatment of more demanding fractures.

Evaluation of the patient satisfaction of using a 3D printed medical casting in fracture treatment

OBJECTIVES

This study aims to assess, through a questionnaire, the functionality, and efficacy of using three-dimensional (3D) printed medical casts.

PATIENTS AND METHODS

Between February 2017 and March 2019, a total of 24 patients (14 males, 10 females; mean age: 33.1±9.4 years, range, 12 to 62 years) with upper extremity fracture who were applied 3D printed medical cast were included. Patient satisfaction was evaluated using the Quebec User Evaluation of Satisfaction with Assistive Technology 2.0 (QUEST 2.0). Each item is scored on a five-point scale.

RESULTS

The mean follow-up was 14 (range, 6 to 18) months. All fractures healed within four to six weeks without any complications. In all cases, there was no loss of reduction. The total mean QUEST 2.0 satisfaction score for the participants was 4.7. The ratings on each scale ranged from 4.5 to 4.9.

CONCLUSION

Almost all patients with upper extremity fractures were satisfied with the 3D printed medical cast. The patients found the 3D printed medical cast to be comfortable, safe, easy-to-apply, lightweight, and effective.

Three-dimensional analysis of the gap space under forearm casts

PURPOSE

Secondary displacement represents a frequent complication of conservative treatment of fractures, particularly of the distal radius. The gap space between skin and cast may lead to a certain degree movements and this increased mobility might favor redisplacement. The aim of this study was to develop a new 3D method, to measure the gap space in all 3 geometrical planes, and to validate this new technique in a clinical setting of distal radius fractures.

METHODS

This study applies 3D imaging to measure the space between plaster and skin as a potential factor of secondary displacement and therefore the failure of conservative treatment. We developed and validated a new methodology to analyze and compare different forearm casts made of plaster of Paris and fiberglass. An unpaired t-test was performed to document differences between the investigated parameters between plaster of Paris and fiberglass casts. The significance level was set at p < 0.05.

RESULTS

In a series of 15 cases, we found the width of the gap space to average 4 mm, being slightly inferior on the radial side. Comparing the two different casting materials, plaster of Paris and fiberglass, we found a significantly larger variance of space under casts made of the first material (p=0.39). A roughness analysis showed also a markedly significantly higher irregularity of the undersurface of plaster of Paris as compared with fiberglass.

CONCLUSION

This study allows for a better understanding of the nature of the "gap space" between cast and skin and will contribute to develop and improve new immobilization techniques and materials.

Utilization of 3D printed orthoses for musculoskeletal conditions of the upper extremity: A systematic review

STUDY DESIGN

Systematic Review INTRODUCTION: 3D printed orthoses are emerging as a possible option in the field of hand therapy to fabricate conventional casts and orthoses. It is unknown how this technology is currently being used to treat upper extremity musculoskeletal conditions, and if 3D orthoses are comparable to custom- made low temperature thermoplastic orthoses fabricated by hand therapists.

PURPOSE OF THE STUDY

The primary aim of this review was to investigate the utilization, effectiveness and feasibility of 3D printed technology to manufacture custom orthoses for musculoskeletal conditions of the upper extremity.

METHODS

Studies describing 3D printed orthoses or casts used in treatment with patients were included following a comprehensive literature search using CINAHL, PubMed, Medline, ProQuest, and EBSCO databases. The selected studies had to address musculoskeletal conditions of the elbow, wrist, hand and/or digits that would typically be immobilized with a cast or brace or orthotic or orthosis.

RESULTS

Ten studies met the inclusion criteria. Study designs included case studies, case series, and 1 randomized clinical trial. 3D printed orthoses/casts appear to be comfortable, provide adequate immobilization, and have pleasing aesthetics. However, expensive equipment, lack of appropriate software and scanning tools and lack of highly skilled clinicians are all factors preventing the implementation of 3D printed orthoses into current clinical practice.

DISCUSSION

3D printed orthoses appear to be effective at immobilization of a limb, aesthetically pleasing, and utilize lightweight and well -ventilated materials. However, the feasibility of implementing 3D printing technology in hand therapy settings remains challenging in part due to the resources required.

CONCLUSIONS

While 3D printing shows promise, the high cost of equipment, lack of training and skill of clinicians and the long time required for production are all factors that need to be improved to make 3D printing a viable option in the hand therapy setting.

Effectiveness of 3D-printed orthoses for traumatic and chronic hand conditions: A scoping review

Background

In the field of orthotics, the use of three-dimensional (3D) technology as an alternative to the conventional production process of orthoses is growing.

Purpose

This scoping review aimed to systematically map and summarize studies assessing the effectiveness of 3D-printed orthoses for traumatic and chronic hand conditions, and to identify knowledge gaps.

Methods

The Cochrane Library, PubMed, EMBASE, CINAHL, Web of Science, IEEE, and PEDro were searched for studies of any type of 3D-printed orthoses for traumatic and chronic hand conditions. Any outcome related to the effectiveness of 3D-printed orthoses was considered. Two reviewers selected eligible studies, charted data on study characteristics by impairment type, and critically appraised the studies, except for case reports/series.

Results

Seventeen studies were included: four randomized controlled trials, four uncontrolled trials, four case series and five case reports. Only three studies had a sample size >20. Impairments described were forearm fractures (n = 5), spasticity (n = 5), muscle weakness (n = 4), joint contractures (n = 2) and pain (n = 1). Four poor to fair quality studies on forearm fractures supported the effectiveness of 3D-printed orthoses on hand function, functionality, and satisfaction. One good quality study on spasticity demonstrated the effectiveness of 3D-printed orthoses on hand function. One poor quality pain study reported limited positive effects on satisfaction. Studies on muscle weakness and joint contractures showed no benefits.

Conclusion

Current literature addressing the effectiveness of 3D-printed orthoses for traumatic and chronic hand conditions consists primarily of small and poor methodological quality studies. There is a need for well-designed controlled trials including patient-related outcomes, production time and cost analyses.

An industrial oriented workflow for 3D printed, patient specific orthopedic cast

The clinical use of 3D printed patient specific orthopaedic cast is of wide interest. However, design and production have problems such as production time, which can take up to 35 h, and standardized procedure considering that there are medical devices that must comply mandatory and/or voluntary standards. Moreover, the proposed procedures do not fully consider the traceability of this innovative medical device design to comply with standards and industrial proposes. The aim of this work is to propose a semi-automatic workflow for the production of the 3D printed orthopaedic casts. The procedure is oriented towards a reduction time in different phases (as scan setting, designing technique, printing orientation) of the production flow. The workflow is compliant with recognized quality standards for the production of additive manufactured medical devices. This approach offers the possibility to introduce new 3D printed medical devices in clinical practice as well as to design an optimized industrial workflow.

Three Dimensionally Printed Versus Conventional Casts in Pediatric Wrist Fractures

Background and objective With significant advancement in the field of biomaterials, alternatives to conventional fiberglass casts such as customized three-dimensional (3D) orthotics have been developed. However, there is a scarcity of reported experience regarding 3D-printed orthoses. The purpose of this study was to compare radiographic outcomes and patient satisfaction with fractures treated with either conventional or 3D-printed casts. Materials and methods We included 23 limbs from 22 patients, who were aged between 8-18 years, and with a diagnosis of an acute nondisplaced wrist or forearm fracture. Patients were randomized into two groups: consisting of those treated with a 3D-printed orthosis and those with conventional fiberglass cast. Outcomes included X-ray alignment and healing, cast fit, the appearance of the skin, ease of care, and overall satisfaction. Results Of note, 10/11 (91%) in the 3D cast group healed in an excellent position, and 1/11 healed in an acceptable position. Also, 11/12 (92%) in the conventional cast group healed in an excellent position, and 1/12 healed in an acceptable position. Radiographically, 11/11 (100%) of the fractures in the 3D group and 11/12 (92%) in the conventional cast group were found to be fully healed. No differences were found in terms of skin irritation by a blinded hand therapist. Patients reported significant differences in skin irritation, comfort, satisfaction, and cast care favoring 3D casts (p<0.05). Conclusions 3D orthoses offer a promising opportunity to improve patients' experiences with upper extremity casting while also providing appropriate immobilization.

An Evaluation of the Bacterial Adherence to Casting Materials

Introduction: The purpose of this study was to evaluate bacterial adherence to common casting materials including plaster of Paris (plaster), fiberglass, three-dimensional (3D) printed plastic, and silicone-coated 3D printed plastic.

Methods: The minimal inhibitory concentration of a phosphate-free detergent (Palmolive) needed to achieve total bacterial kill off was determined. 3D printed polylactic acid plastic samples were coated with silicone. Plaster, fiberglass, plastic, and silicone-coated plastic samples were inoculated with Staphylococcus aureus. After bacterial inoculation, scanning electron microscopy of the samples was performed to visualize bacterial adherence to the materials' surface. Using either sterile water or a 5% detergent solution, the materials were subjected to washings. Each material was run in 30 replicates: 6 without washing, 6 with sterile water for 1 minute, 6 with detergent for 1 minute, 6 with sterile water for 3 minutes, and 6 with detergent for 3 minutes. The replicates that did not undergo a washing trial represented the initial bacterial inoculation. Samples were then rinsed and sonicated in polysorbate to isolate the remaining adherent bacteria on the materials’ surface. The sonicated solutions were plated, incubated, and counted for quantification of colony forming units (CFU) of bacteria. This protocol was repeated for a total of four trials.

Results: During inoculation, there were significantly less bacteria that adhered to silicone-coated 3D printed plastic (58879 CFU) compared to plastic (217479 CFU), plaster (140063 CFU), and fiberglass (550546 CFU). Silicone coating showed further superiority. Silicone-coated 3D printed plastic was able to be decontaminated as demonstrated by significantly fewer remaining bacteria (9.3%) on its surface after being washed with a 5% detergent solution (1797 CFU) compared to sterile water (19321 CFU). The mean remaining bacteria on silicone-coated 3D printed plastic was significantly less than that remaining on all other materials when washed with either sterile water or a detergent solution for both durations of 1 minute and 3 minutes.

Conclusions: The current study demonstrates that significantly less bacteria adhere to the surface of 3D printed plastic with silicone coating showing added protection and that this material can be decontaminated to a greater degree with washing than conventional casting materials. These results provide evidence that 3D printed casts can be washed and successfully decontaminated during a patient’s period of immobilization, which is advantageous especially during an infectious crisis such as the coronavirus disease 2019 (COVID-19) pandemic.

Production Time and User Satisfaction of 3-Dimensional Printed Orthoses For Chronic Hand Conditions Compared With Conventional Orthoses: A Prospective Case Series

Objective

Hand orthoses are often prescribed for persons with chronic hand and wrist impairments. This study assessed the feasibility, in terms of production time and user satisfaction, of 3-dimensional printed hand orthoses compared with conventional hand orthoses for this population.

Methods

In this prospective case series, both a conventional hand orthosis and a 3-dimensional printed hand orthosis were manufactured for 10 participants. Production time (in minutes) of each orthosis was recorded. Each orthosis was worn for one week, after which participants completed a self-designed questionnaire on satisfaction, scored on a 5-point Likert scale. Functionality and orthosis preference were also assessed.

Results

The mean (standard deviation (SD)) production time for the 3-dimensional printed orthoses, of 112 (11.0) min, was significantly shorter compared with 239 (29.2) min for the conventional orthoses (95% confidence interval (95% CI) 71-182 min, p = 0.001). Satisfaction scores were similar for both orthoses, except for comfort item "fitting method", which was rated significantly higher for scanning compared with casting (median [IQR] score: 5 [0.0]; 4 [2.0], p = 0.034). Functionality and orthosis preference were rated similar for both orthoses.

CONCLUSION

As the production time was halved, user satisfaction similar, and scanning experienced as slightly more comfortable than casting, 3-dimensional printed hand orthoses seem feasible and potentially beneficial for use in people with chronic hand and wrist impairments.

The Use of 3D Printed Customized Casts in Children with Upper Extremity Fractures: A Report of Two Cases

3D printing is an evolving technology which has a potential application in the treatment pediatric forearm fractures. Very little has been published with regard to 3D casting in children. We present two cases in which upper extremity fractures in pediatric patients were treated by wearing a custom made 3D printed cast. At latest follow-up at least one year post-injury, the clinical outcomes were excellent. Orthopaedic surgeons may benefit from familiarizing themselves with the potential of 3D printing technology and utilizing its current applications, as well as devising future applications, in clinical practice.

Overview of In-Hospital 3D Printing and Practical Applications in Hand Surgery

Three-dimensional (3D) printing is spreading in hand surgery. There is an increasing number of practical applications like the training of junior hand surgeons, patient education, preoperative planning, and 3D printing of customized casts, customized surgical guides, implants, and prostheses. Some high-quality studies highlight the value for surgeons, but there is still a lack of high-level evidence for improved clinical endpoints and hence actual impact on the patient's outcome. This article provides an overview over the latest applications of 3D printing in hand surgery and practical experience of implementing them into daily clinical routine.

Three-dimensional imaging and three-dimensional printing for plastic preparation of medical interventions

Three-dimensional (3D) imaging has been available for nearly four decades and is regarded as state of the art for visualization of anatomy and pathology and for procedure planning in many clinical fields. Together with 3D image reconstructions in the form of rendered virtual 3D models, it has helped to better perceive complex anatomic and pathologic relations, improved preprocedural measuring and sizing of implants, and nowadays enables even photorealistic quality. However, presentation on 2D displays limits the 3D experience. Novel 3D printing technologies can transfer virtual anatomic models into true 3D space and produce both patient-specific models and medical devices constructed by computer-aided design. Individualized anatomic models hold great potential for medical and patient education, research, device development and testing, procedure training, preoperative planning, and fabrication of individualized instruments and implants. Hand in hand with 3D imaging, medical 3D printing has started to revolutionize medicine in certain fields and new applications are developed and introduced regularly. The demand for medical 3D printing will likely continue to rise, as it is a promising tool for plastic preparation of medical interventions. However, there is ongoing debate on the appropriateness of medical 3D printing and further research on its efficiency is needed. As experts in 3D imaging, radiologists are not only capable of advising on adequate imaging parameters, but should also become adept in 3D printing to participate in on-site 3D printing facilities and randomized controlled trials on the topic, thus contributing to improving patient outcomes via personalized medicine through patient-specific preparation of medical interventions.

In-hospital professional production of patient-specific 3D-printed devices for hand and wrist rehabilitation

The reported use of 3D printing in hand and wrist rehabilitation has been mostly limited to feasibility studies and case series so far. Some of the reasons are the lack of purpose-built scanning applications, complicated digital design software, and lengthy and error-prone printing processes. We propose a multidisciplinary workflow for in-hospital mass production of patient-specific 3D-printed devices for hand and wrist rehabilitation.

3D printing technology as innovative solutions for biomedical applications

3D printing was once predicted to be the third industrial revolution. Today, the use of 3D printing is found across almost all industries. This article discusses the latest 3D printing applications in the biomedical industry.

A Biomechanical Comparison of Fiberglass Casts and 3-Dimensional-Printed, Open-Latticed, Ventilated Casts

Background: The aim of this study was to quantify the stabilizing properties of a 3-dimensional (3D)-printed short-arm cast and compare those properties with traditional fiberglass casts in a cadaveric subacute distal radius fracture model. Methods: A cadaveric subacute fracture model was created in 8 pairs of forearms. The specimens were equally allocated to a fiberglass cast or 3D-printed cast group. All specimens were subjected to 3 biomechanical testing modalities simulating daily life use: flexion and extension of digits, pronation and supination of the hand, and 3-point bending. Between each loading modality, radiological evaluation of the specimens was performed to evaluate possible interval displacement. Interfragmentary motion was quantified using a 3D motion-tracking system. Results: Radiographic assessment did not reveal statistically significant differences in radiographic parameters between the 2 groups before and after biomechanical testing. A statistically significant difference in interfragmentary motion was calculated with the 3-point bending test, with a mean difference of 0.44 (±0.48) mm of motion. Conclusions: A statistically significant difference in interfragmentary motion between the 2 casting groups was only identified in 3-point bending. However, the clinical relevance of this motion remains unclear as the absolute motion is less than 1 mm. The results of this study show noninferiority of the 3D-printed casts compared with the traditional fiberglass casts in immobilizing a subacute distal radius fracture model. These results support the execution of a prospective randomized clinical trial comparing both casting techniques.

Treatment of dorsally dislocated distal radius fractures with individualized 3D printed bracing: an exploratory study

Background

The aim of this work was to develop a three-dimensionally (3D) printed brace for the acute treatment of dorsally dislocated and correctly reduced distal radius fractures (DRF). The hypothesis was that a brace shaped to the mirror image of the contralateral (non-fractured) wrist will have an optimal anatomical fit, resulting in improved comfort and lower rates of secondary fracture displacement.

Method

Validation: the circumference of both wrists and comfort of the brace were studied in healthy volunteers and effectiveness of the brace was evaluated in an ex vivo fracture model.

Clinical study: the brace was tested for comfort and effectiveness in patients with a well reduced unstable DRF.

Results

Validation: the circumference of both wrists may be different, the brace retained the reduction in the ex vivo fracture model and was well tolerated in the volunteers.

Clinical study: in DRF patients comfort scores were lower and pain scores higher compared to the healthy volunteers. After 3 and 5 weeks all patients were independent in ADL according to the Katz-index. Posttraumatic swelling subsided in the first week. In two of the five patients secondary fracture dislocation occurred.

Conclusions

Treatment of a dislocated DRF in the acute setting (day one) with a custom-made 3D printed brace, anatomically modelled from a 3D scan of the contralateral wrist, is possible. Difference between both wrists and posttraumatic swelling must be adapted for. The high rate of secondary fracture displacement led to early discontinuation of the study and a small sample size.

Trial registration

Name of the registry: ClinicalTrials.Gov

Trial registration number: NCT03848702

Date of registration: 02/21/2019, retrospectively registered

Application of 3D-Printed Orthopedic Cast for the Treatment of Forearm Fractures: Finite Element Analysis and Comparative Clinical Assessment

Objective

This pilot study is aimed at investigating the mechanical characteristics of a cast-wrapped fractured forearm and performing a clinical comparative study of our own developed 3D-printed orthopedic cast.

Methods

An integrated finite element (FE) model including a forearm and a 3D-printed cast wrapping the forearm was created. The distal radial ulna in this model was cut through to mimic the bone fracture. A 400 N force and 1 Nm rotation moment, which were much larger than the loading conditions encountered in daily life for a human being, were applied on the palm. We conducted a comparative clinical study by using statistical assessment. 60 patients with forearm fractures were selected and treated with manual reduction and external fixation cast. All patients were divided into three groups with equal members (20): (a) 3D-printed external cast group, (b) traditional plaster external fixation group, and (c) splint external fixation group. The clinical efficacy, wrist function, and patient satisfaction were scored and compared.

Results

In the condition of 400 N loading, the fracture displacements in anterior-posterior (AP), posterior-anterior (PA), medial to lateral (ML), and lateral to medial (LM) compression directions were 1.2648, 1.3253, 0.8503, and 0.8957 (mm), respectively, and the corresponding fracture stresses were 4.5986, 3.9129, and 5.0334, 7.9197 (MPa), respectively. In the inward (IR) and outward (OR) rotations, the fracture displacements were both 0.02628 (mm), and the corresponding fracture surface stresses were 0.1733 and 0.1723 (MPa), respectively. In the clinical efficacy, wrist function, and patient comfort evaluation, the total scores of group A were both higher than those in groups B and C (P < 0.05).

Conclusion

A 3D-printed orthopedic cast was capable of exerting appropriate mechanical correction loads on specific areas to maintain optimal alignment of a fractured forearm and thus could achieve the favorable clinical efficacy and patient comfort.

3D printing in hand surgery

While 3D printing in hand surgery is still in its infancy, it offers new avenues in research, teaching, and personalized medicine. For these reasons, some surgeons may want to jump on the bandwagon of this trendy technology. But we cannot forget that its superiority over conventional techniques has not been demonstrated. Surgeons who want to work with 3D printed objects must master their use and the entire manufacturing process, otherwise they risk becoming dependent on engineers and/or medical device companies.

Lightweight Splint Design for Individualized Treatment of Distal Radius Fracture

A systematic design approach is proposed for medical splints for individualized treatment of the distal radius fracture. An initial split structural model is first constructed by 3D scanning of an injured limb. Based on the biomechanical theory and clinical experiences, the topology optimization method is applied to design the splint structure. The optimized lightweight splint is realized by additive manufacturing using polylactic acid. Compared to the traditional designs for the distal radius fracture, the optimized design by the proposed approach exhibits a weight reduction of more than 40%. Besides, the mechanical properties of the splint meet the requirements of medical treatment according to the simulation results. Numerical examples are provided to demonstrate the applicability of the approach.

Rapid customization system for 3D-printed splint using programmable modeling technique - a practical approach

Background

Traditional splinting processes are skill dependent and irreversible, and patient satisfaction levels during rehabilitation are invariably lowered by the heavy structure and poor ventilation of splints. To overcome this drawback, use of the 3D-printing technology has been proposed in recent years, and there has been an increase in public awareness. However, application of 3D-printing technologies is limited by the low CAD proficiency of clinicians as well as unforeseen scan flaws within anatomic models.

A programmable modeling tool has been employed to develop a semi-automatic design system for generating a printable splint model. The modeling process was divided into five stages, and detailed steps involved in construction of the proposed system as well as automatic thickness calculation, the lattice structure, and assembly method have been thoroughly described. The proposed approach allows clinicians to verify the state of the splint model at every stage, thereby facilitating adjustment of input content and/or other parameters to help solve possible modeling issues. A finite element analysis simulation was performed to evaluate the structural strength of generated models. A fit investigation was applied on fabricated splints and volunteers to assess the wearing experience.

Results

Manual modeling steps involved in complex splint designs have been programed into the proposed automatic system. Clinicians define the splinting region by drawing two curves, thereby obtaining the final model within minutes. The proposed system is capable of automatically patching up minor flaws within the limb model as well as calculating the thickness and lattice density of various splints. Large splints could be divided into three parts for simultaneous multiple printing.

Conclusions

This study highlights the advantages, limitations, and possible strategies concerning application of programmable modeling tools in clinical processes, thereby aiding clinicians with lower CAD proficiencies to become adept with splint design process, thus improving the overall design efficiency of 3D-printed splints.