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

Acceptability and safety of 3D printed wrist-based orthoses compared to fiberglass casts for the treatment of non-surgical distal radius- and scaphoid fractures: A randomized feasibility trial

BACKGROUND

Non-invasiveness and comfort are crucial in the conservative management of distal radius and scaphoid fractures. While fiberglass casts are standard, three-dimensional (3D)-printed orthoses offer a promising alternative.

PURPOSE

To compare patient experiences, safety perceptions, and satisfaction between a 3D orthosis and fiberglass cast for distal radius or scaphoid fractures.

STUDY DESIGN

Randomized feasibility trial.

METHODS

Nineteen adult patients were randomly assigned (3D orthosis group, n = 10; fiberglass cast group, n = 9) and followed until orthosis or cast removal at 6-8 weeks. X-rays at weeks 1 and 6 documented bone healing, with weekly hand therapy visits assessed orthosis satisfaction and function. The Patient-Rated orthosis Satisfaction Questionnaire (PRSEQ) measured satisfaction at weeks 2, 4, and removal. Descriptive statistics and non-parametric correlation tests were used for data analysis.

RESULTS

The 3D orthosis group achieved significantly higher PRSEQ scores (mean difference [MD]= 15.7%, p = 0.005 to 0.01, r = -.581 to -.638) and lower perceived pain (MD=-1.0 to -2.2, p = 0.001 to 0.048, r = -0.45 to -0.75) compared to the cast group. By week 4, the 3D group reported less discomfort (MD=-2.2, p = 0.03, r = -0.5) and felt safer (MD=1.6, p = 0.043, r = -0.46). Routine activities were easier for the 3D group at weeks 2 and 6 (MD=-2.8 to -3.0, p = 0.033 to 0.034, r = -0.49). Satisfaction scores were higher in the 3D group (mean 8.4 vs. 5.6 points, p < 0.001 to 0.01, r = -0.57 to -0.82). Compliance was excellent in both groups. No significant differences were observed in radiological outcomes, finger sensibility, or edema. Bone healing occurred in both groups without fracture displacement; however, one cast patient required subsequent surgery for scaphoid non-union.

CONCLUSIONS

Treatment with a 3D-printed orthosis appeared feasible and safe, with patients reporting higher satisfaction and better self-perceived hand function compared to a custom-made fiberglass cast, although further research is needed to confirm these findings.

In vitro comparative study of deformation of 3D-printed models using different polylactic acids treated by steam sterilization

INTRODUCTION

3D printing, which is becoming ever more widespread in orthopedic surgery, requires specific materials. Polylactic acid (PLA) is the most widely used in general-purpose 3D printing, but its thermosensitivity can be incompatible with sterilization. Even so, it is easy to use, inexpensive, non-toxic and biodegradable. Controversy surrounds its use. 3D printing of directly sterilizable PLA parts according to surgeons' needs would be highly advantageous, but doubts remain. We therefore performed an in vitro study to determine which PLAs resist steam sterilization regarding deformation.

HYPOTHESIS

The study hypothesis was that, depending on make and shape, 3D-printed PLA parts can retain their properties after steam sterilization.

MATERIAL AND METHODS

We selected 4 makes of PLA and used each to print 4 simple cubes and 4 complex shapes corresponding to cuboid bones. They were subjected to steam sterilization under normal French hospital conditions. The size of the cubes was measured before and after sterilization, using a digital caliper.

RESULTS

Cuboid parts in HT-PLA and PLA-WANAO showed mean deformation of -0.02mm and -0.4mm, respectively after sterilization, the differences being non-significant (p=0.679 and p=0.241, respectively). Cuboid parts in PLA-SUNLU and PLA-G3D showed significant mean deformation: respectively, -1.37mm (p=0.026) and -35.03mm (p>0.001). Cubes in all types of PLA showed significant mean deformation: HT-PLA, -0.61mm (p=0.004); PLA-SUNLU, -2.70mm (p=0.002); PLA-G3D, -28.64mm (p>0.001); and PLA-WANAO, -1.33mm (p=0.010).

DISCUSSION

The study confirmed recent findings that steam sterilization is feasible with certain PLA-printed parts, with deformations less than 1mm, and that choice of PLA is crucial for success. Computer-designed objects (here, cubes) did not resist sterilization without significant deformation. Analysis of resistance to various stresses was not performed, and therefore it cannot be claimed that the process could be used other than for printing anatomic parts. Use of 3D printing in French hospitals is probably a real source of innovation and improvement in care quality; however, a legal framework needs establishing for the use of 3D-printed parts, to ensure patient safety and promote research in this field.

LEVEL OF EVIDENCE

III; prospective in vitro study.

Production time and practicability of 3D-Printed wrist orthoses versus low temperature thermoplastic wrist orthoses

Introduction

In recent years, three-dimensional (3D) printing has emerged as a new manufacturing technique for orthoses, showing comparable stability and wearing comfort to traditional orthoses. However, the lengthy designing and printing process is assumed to take more time than the common practice of manufacturing low-temperature thermoplastic orthoses (LTTOs). The aim of this prospective cross-sectional study was to compare the production time of 3D-printed orthoses (3DPO) to LTTOs.

Methods

The active and passive time needed to manufacture the orthoses was measured in a clinical setting. 17 orthoses (8 3DPOs and 9 LTTOs) were included in the data analysis.

Results

The mean total production time of a 3DPO (12:14:50h total time; 0:44:35h active production time) was significantly longer than in LTTOs (0:14:14h; p < 0.001).

Discussion

The longer production time might be a hurdle regarding the implementation of 3DPOs in hand therapy. Although 3D-printing might become more cost- and time-efficient due to future developments in technology and growing experience, some practical advantages of LTTOs prevail, such as the fast and efficient provision of orthoses and the adaptability of the material if subsequent changes are needed. A combination of both manufacturing techniques may be a feasible solution to provide patient-centred orthosis provision in future hand therapy practice.

Short arm splints for wrist stabilization: A mechanical material test and cadaveric radiography study

Purpose

Documentation of the wrist stabilizing effect and mechanical properties of common splinting materials is warranted to support evidence-based condition-specific recommendations for wrist immobilization. The objectives of this study were to assess the wrist stabilizing properties of volar and dorsal short-arm splints made of four different materials and evaluate the mechanical properties of the splinting materials.

Methods

Dorsal and volar short arm splints made of plaster of Paris (PoP) (eight layers), Woodcast (2 mm, rigid vented), X-lite (classic, two layers) or a 3D-printed material (polypropylene) were sequentially mounted on 10 cadaveric arm specimens and fixed in a radiolucent fixture. This enabled the evaluation of maximum wrist flexion and extension relative under an orthogonal load of 42 N via radiographic images. In addition, a three-point bending test was performed on ten sheet duplicates of each of the four splinting materials.

Results

When applied as a volar splint, PoP had the highest capability to resist wrist flexion and extension. However, when applied as a dorsal splint, Woodcast exhibited a lower wrist flexion and a similar wrist extension. The 3D-printed splints-both volar and dorsal-showed the highest mean wrist flexion and extension. The mechanical properties of the Woodcast, X-lite and 3D-printed splinting materials were very similar. PoP exhibited distinct properties with a stiffness of 146 (95% confidence interval [CI]: 120-173) N/mm and a deflection at F max of 0.6 (95% CI: 0.5-0.7) mm compared to ≤7.7 (95% CI: 7.4-7.9) N/mm and ≥20 (95% CI: 18-22) mm for the other materials.

Conclusion

PoP displayed better wrist stabilizing properties and material stiffness than Woodcast, X-lite and 3D-printed polypropylene. When considering wrist stabilizing properties, PoP may still prove to be the preferred choice for wrist immobilization.

Level of Evidence

Not applicable.

The past, present and future of the conservative treatment of distal radius fractures

The distal radius fracture is a common fracture with a prevalence of 17% on the emergency departments. The conservative treatment of distal radius fractures usually consists of three to six weeks of plaster immobilization. Several studies show that one week of plaster immobilization is safe for non- or minimally displaced distal radius fractures that do not need reduction. A shorter period of immobilization may lead to a better functional outcome, faster reintegration and participation in daily activities. Due to upcoming innovations such as three-dimensional printed splints for distal radius fractures, a patient specific splint can be produced which may offer more comfort. Furthermore, these three-dimensional printed splints are expected to be more environmental friendly in comparison with traditional plaster casts.