Finger Orthoses for Rehabilitation―Part I: Biomedical Insights and Additive Manufacturing Innovations

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The review provides a comprehensive discussion on the role of 3D printing in the fabrication of finger orthoses, highlighting its advantages over traditional methods. It effectively outlines the biomechanics and anatomy of the fingers and thumbs, the design of various splints, technical aspects, applications, and limitations. While the manuscript is generally well-written and presents valuable insights, some minor revisions are necessary to enhance clarity and consistency. I recommend that the authors make these refinements prior to resubmission.

The statement, “Injuries will be more likely to occur in upper limbs due to their extensive use and complex structure,” needs to be verified with appropriate references. The location and frequency of injuries depend on multiple factors such as age, physical activity, occupation, trauma, and lifestyle.

The manuscript discusses bone injuries resulting from sports; however, it should also address injuries and bone diseases relevant to elderly and pediatric populations (page 3, line 76). Additionally, injuries related to muscles, ligaments, and nerves; and their associated functional deficiencies should be included.

To improve the clarity of orthosis applications in finger rehabilitation, a summary table outlining common deficiencies following finger injuries (e.g., trigger finger, mallet finger) and the corresponding orthoses/splints used for immobilization, correction, and support should be included in the Introduction section.

The manuscript offers a detailed description of the anatomy of the hand, particularly focusing on joints, bones, ligaments, and tendons. However, given their essential role in finger and hand movement and sensation, muscles and nerves should also be discussed. Furthermore, conditions resulting from muscle and nerve injuries that require orthotic or splinting interventions should be addressed.

Please include that DLP is also chosen for its precision and superior surface finish (page 16, line 559).

Author Response

Dear Reviewer #1,

Thank you very much for your review report. We have carefully revised the manuscript, and a point-by-point response to reviewers’ comments is provided below. Changes in the revised manuscript are highlighted in blue.

 

The review provides a comprehensive discussion on the role of 3D printing in the fabrication of finger orthoses, highlighting its advantages over traditional methods. It effectively outlines the biomechanics and anatomy of the fingers and thumbs, the design of various splints, technical aspects, applications, and limitations. While the manuscript is generally well-written and presents valuable insights, some minor revisions are necessary to enhance clarity and consistency. I recommend that the authors make these refinements prior to resubmission.

 

1. The statement, “Injuries will be more likely to occur in upper limbs due to their extensive use and complex structure,” needs to be verified with appropriate references. The location and frequency of injuries depend on multiple factors such as age, physical activity, occupation, trauma, and lifestyle.

Response: Thank you for this valuable observation. We agree that the original statement lacked sufficient support. We have now revised the sentence to acknowledge the multifactorial nature of injury occurrence and included appropriate references to support the prevalence of upper limb injuries in specific populations. We have added the following statement in the revised manuscript:

“Injuries will be more likely to occur in upper limbs due to their extensive use and complex structure. However, the location and frequency of injuries also depend on multiple factors such as age, physical activity, occupation, trauma, and lifestyle, which can influence the vulnerability of different anatomical regions.”

2. The manuscript discusses bone injuries resulting from sports; however, it should also address injuries and bone diseases relevant to elderly and pediatric populations (page 3, line 76). Additionally, injuries related to muscles, ligaments, and nerves; and their associated functional deficiencies should be included.

Response: Thank you for this constructive comment. In line with your comment, we have revised the section to broaden the scope and now include injuries and bone diseases relevant to both elderly (e.g., osteoporotic and fragility fractures) and pediatric populations (e.g., greenstick and physeal injuries). We have also expanded the discussion to cover muscle, ligament, and nerve injuries such as tendon ruptures, carpal tunnel syndrome, and brachial plexus injuries, as well as their associated functional impairments, including reduced range of motion, pain, and dexterity loss. The following statement is now added to the revised manuscript:

Beyond sports injuries, upper limb injuries and bone disorders are also prevalent in elderly populations, where conditions such as osteoporosis and fragility fractures (especially of the distal radius) are common due to decreased bone density and increased fall risk. In pediatric populations, injuries such as greenstick fractures and growth plate (physeal) injuries are frequent due to the developing skeleton and high levels of physical activity. Moreover, injuries involving muscles, ligaments, and nerves, including tendon ruptures, ligament sprains, carpal tunnel syndrome, and brachial plexus injuries, can result in significant functional impairments such as reduced range of motion, decreased grip strength, chronic pain, and impaired hand dexterity. These injuries require careful diagnosis and rehabilitation to restore normal function. To address these impairments effectively, appropriate treatment and supportive measures must follow.

3. To improve the clarity of orthosis applications in finger rehabilitation, a summary table outlining common deficiencies following finger injuries (e.g., trigger finger, mallet finger) and the corresponding orthoses/splints used for immobilization, correction, and support should be included in the Introduction section.

Response: Thank you for your thoughtful suggestion. We fully agree that a summary table linking common finger injuries to appropriate orthotic interventions would enhance clarity. However, as this manuscript serves as the first part of a two-part review, we have chosen to limit this section to a brief introduction of the major finger deformities, while reserving a more detailed analysis−including a summary table, clinical classifications, and illustrations−for the second part, which specifically focuses on conditions requiring finger orthoses. Including such a table in this introductory review could lead to redundancy and dilute the focused discussion planned for the next part. That said, in respect of your suggestion and to improve the overall clarity of the introduction, we have expanded the relevant section to include brief descriptions of several well-known finger deformities, and the typical orthoses used to manage them, as follows:

For example, static splints are often used in the treatment of conditions like mallet finger, which involves a drooping fingertip due to extensor tendon injury and requires immobilization of the distal interphalangeal joint. On the other hand, dynamic splints might be used in conditions like Boutonnière deformity which is characterized by flexion of the proximal interphalangeal joint and hyperextension of the distal interphalangeal joint, to gradually restore extension. Other common finger conditions include swan neck deformity, which is characterized by excessive bending backward of the middle finger joint along with downward bending at the fingertip and is typically managed with ring splints. Trigger finger causes painful locking or catching of the finger due to inflammation around the tendon sheath and may benefit from orthoses that limit movement at the base of the finger. Jersey finger, which involves a torn tendon that normally bends the fingertip, is usually treated with splints that hold the injured finger in slight flexion during recovery after surgical repair.

 

4. The manuscript offers a detailed description of the anatomy of the hand, particularly focusing on joints, bones, ligaments, and tendons. However, given their essential role in finger and hand movement and sensation, muscles and nerves should also be discussed. Furthermore, conditions resulting from muscle and nerve injuries that require orthotic or splinting interventions should be addressed.

Response: We thank the reviewer for this valuable comment. We agree that muscles and nerves play an essential role in finger and hand function. In response, we have added a brief paragraph discussing the major nerves and muscles involved in hand movement, along with examples of common neuromuscular conditions that may require orthotic intervention. Nevertheless, as mentioned previously, this manuscript is the first part of a two-part review. We have intentionally limited this section to a concise overview of anatomical structures and major functional impairments. A more detailed analysis of conditions arising from muscle and nerve injuries, including classification, clinical presentation, and orthotic solutions, will be addressed in the second part to avoid redundancy and maintain the manuscript's focused scope. The following information was added in the revised manuscript:

In addition to bones, joints, ligaments, and tendons, the hand's function is critically dependent on its intrinsic and extrinsic muscles, as well as its intricate nerve supply. The intrinsic muscles, located within the hand, allow fine motor control and precise finger movements, while the extrinsic muscles, originating from the forearm, provide strength for grasping and flexion/extension of the digits. The median, ulnar, and radial nerves are responsible for both motor innervation and sensory feedback in the hand. Injury to these nerves, or to the associated muscles, can result in significant functional impairments such as ulnar claw hand, ape hand, or wrist drop, many of which may require splinting or orthotic intervention to restore function, prevent deformity, or maintain joint positioning during recovery.

5. Please include that DLP is also chosen for its precision and superior surface finish (page 16, line 559).

Response: The sentence has been revised accordingly to include that DLP is also chosen for its precision and superior surface finish.

 

Reviewer 2 Report

Comments and Suggestions for Authors

This article systematically reviews the biomechanical principles of finger orthoses and the critical role of additive manufacturing technology (3D printing) in their design and application. The topic has clear clinical significance and technical innovation. The research framework is well-structured, the methodology is rigorous, and the conclusions provide valuable references for interdisciplinary studies in rehabilitation medicine and bioengineering. It is recommended to supplement some details before accepting the publication.

(1) Capitalize the first letter of each keyword.
(2) Avoid spanning pages in tables whenever possible, such as in Table 2 and Table 3.
(3) Are the images in the article original? If they are citations of others' images, proper attribution should be provided.

Comments on the Quality of English Language

English can be improved to more clearly convey the research.

Author Response

Dear Reviewer #2,

Thank you very much for your expert review report. We have carefully revised the manuscript, and a point-by-point response to reviewers’ comments is provided below. Changes in the revised manuscript are highlighted in blue.

 

This article systematically reviews the biomechanical principles of finger orthoses and the critical role of additive manufacturing technology (3D printing) in their design and application. The topic has clear clinical significance and technical innovation. The research framework is well-structured, the methodology is rigorous, and the conclusions provide valuable references for interdisciplinary studies in rehabilitation medicine and bioengineering. It is recommended to supplement some details before accepting the publication.

1. Capitalize the first letter of each keyword.

Response: We thank the reviewer for the suggestion. The first letter of each keyword has been capitalized as requested.

2. Avoid spanning pages in tables whenever possible, such as in Table 2 and Table 3.

Response: We acknowledge the reviewer’s point regarding the readability of tables that span across multiple pages. Indeed, presenting a table on a single page improves visual clarity and facilitates easier interpretation. We repositioned some figures, tables and text content in the revised manuscript to fit Table 4 in one page. We believe that in the final typeset version, the journal production team will optimize table formatting to ensure that long tables are appropriately laid out on a single page or landscape format.

3. Are the images in the article original? If they are citations of others' images, proper attribution should be provided.

Response: Except for Figures 4, 8, and 10 (where proper credit has been provided in the corresponding figure captions with the permission or courtesy of the original source) all other images in the manuscript are original and were created by the authors.

 

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

1. Title: Suggested to be revised to 'Finger Orthoses for Rehabilitation: Biomedical Insights and Additive Manufacturing Innovations'.
2. Abstract: Clarify the scope of research reports involved in the review ("2010-2024 literature"?); Highlight technical comparison (comparison with traditional methods).
3. Suggest adding section: 5.1 Comparison of 3D printing material properties: Compare the mechanical properties and clinical applicability of materials such as PLA, TPU, PA12, etc.
4. Expand Table 1: Add "patient compliance", "production cost", "manufacturing cycle", etc.
5. Explore the potential applications of biodegradable materials such as PHBV and smart materials such as shape memory polymers.
6. Use "Orthosis" uniformly throughout the entire article (avoid mixing with "split").
7. Check the throughout the text and correct redundant sentence (such as "due to the fact that" revise to "because").
8. Figures 4 and 7: It is recommended to supplement the scale and material notes (such as "PA12, SLS printing, layer thickness 0.1mm").
9. Conclusion: At the same time, the limitations of 3D printing should be pointed out, and future research directions such as 4D printing technology should be discussed?
10. The references need to be updated to the latest literature in 2025, and attention should be paid to the uniform citation format. In addition, the number of relevant references needs to be appropriately increased.
11. The conclusion has too many segments and needs to be integrated.
12. Further improvement is needed to enhance the clarity and resolution of the images.
13. Checking the entire text, English writing and language need polishing.

Comments on the Quality of English Language

The English could be improved to more clearly express the research.

Author Response

Dear Reviewer #3,

Thank you very much for your expert review report. We have carefully revised the manuscript, and a point-by-point response to reviewers’ comments is provided below. Changes in the revised manuscript are highlighted in blue.

 

1. Title: Suggested to be revised to 'Finger Orthoses for Rehabilitation: Part I, Biomedical Insights and Additive Manufacturing Innovations'.

Response: We thank the reviewer for the suggestion. The title has been revised to: "Finger Orthoses for Rehabilitation: Biomedical Insights and Additive Manufacturing Innovations" as advised.

2. Abstract: Clarify the scope of research reports involved in the review ("2010-2024 literature"?); Highlight technical comparison (comparison with traditional methods).

Response: We thank the reviewer for the insightful comment. The abstract has been revised to clarify the publication timeframe covered in the review (2010–2025) and to briefly highlight the comparison between 3D printing and traditional orthosis fabrication methods.

Background: Finger orthoses are essential for treating injuries, deformities, and disorders of the upper limbs by supporting, immobilizing, or correcting deformities. Recent advances in 3D printing have significantly enhanced precision and customization compared to traditional fabrication methods such as such as thermoplastic molding, plaster or fiberglass casting, and the use of prefabricated splints.

Methods: The present review was conducted using PubMed, Scopus, and other databases with keywords such as "hand therapy", "additive manufacturing", "finger and thumb", and "orthosis". Only English-language publications were considered, with a primary focus on articles published between 2010 and 2025. Key themes were identified and categorized into conditions necessitating finger orthoses, types and classifications, ergonomic design considerations, and advancements in additive manufacturing.

Results: Finger orthoses are used to manage musculoskeletal injuries, inflammatory conditions, and neuromuscular disorders. Compared to conventional methods, 3D printing offers enhanced customization, reduced material waste, faster prototyping, and the ability to fabricate complex geometries—improving patient comfort and functional outcomes.

Conclusion: Finger orthoses effectively treat various conditions by supporting and stabilizing fingers. A thorough understanding of anatomy, biomechanics, and fabrication methods is crucial for achieving functional and comfortable designs. 3D printing offers a trans-formative approach to producing lightweight, customizable, and cost-effective orthoses, enabling innovative and personalized solutions.

3. Suggest adding section: 5.1 Comparison of 3D printing material properties: Compare the mechanical properties and clinical applicability of materials such as PLA, TPU, PA12, etc.

Response: We thank the reviewer for the valuable suggestion. In addition to the brief overview of 3D printing polymeric materials already included in Section 5, we have also referred readers to our previous publication focused on materials used in the additive manufacturing of ankle–foot orthoses (AFOs) [Nouri, A.; Wang, L.; Li, Y.; Wen, C. Materials and Manufacturing for Ankle–Foot Orthoses: A Review. Adv. Eng. Mater. 2023, 25, 2300238]. Many of these materials are equally applicable to finger orthoses. To further strengthen this section and align with the reviewer’s suggestion, we have added a new paragraph discussing additional materials. Some of them are commonly used and others are less common due to limitations in printability, cost, or mechanical properties. To complement this addition, we have included a new table (Table 3) that summarizes key mechanical and properties of both established and emerging 3D-printable polymers relevant to finger orthosis design.

Additional polymers with niche or emerging potential include polyethylene (PE) and polypropylene (PP), which are valued for their light weight and biocompatibility but are less commonly used in FDM printing due to warping and poor layer adhesion. Polycarbonate (PC) offers high impact resistance and strength but requires elevated printing temperatures and controlled environments. Polyether ether ketone (PEEK), a high-performance thermoplastic with exceptional mechanical and thermal properties, is primarily used in high-load orthopedic or implantable applications and is typically considered over-engineered for finger splints. Table 3 presents a comparison of key 3D-printable polymers, highlighting both widely used and emerging materials relevant to finger orthosis design.

Table 3. Comparison of key 3D-printable polymers, including commonly used and emerging materials relevant to finger orthosis design.

Material	Tensile strength (MPa)	Elongation at break (%)	Properties	Clinical notes
PLA	50–70	4–10	Biodegradable, easy to print	Suitable for rigid splints, prototyping
ABS	30–50	10–50	Tough, slightly flexible	Better impact resistance than PLA
TPU	50–80	200–600	Elastic, shock-absorbing	Ideal for soft splints or inserts
PA11/PA12	40–60	250-400	Durable, wear-resistant	Excellent for functional, long-term splints
PETG	40–50	50-120	Transparent, good strength	Improved heat dissipation
CF-Nylon	60–110	1-15	Reinforced, high strength	Lightweight and strong splints
PP	30–40	100–600	Lightweight, biocompatible	Limited use due to printing challenges
PE	10–40	300–600	Soft, flexible	Rarely used due to adhesion issues
PC	55–75	100–150	High strength, heat resistant	Requires controlled printing environment
PEEK	90–110	40-50	Implant-grade, high-temp	Rare in splints due to high cost and complexity

 

4. Expand Table 1: Add "patient compliance", "production cost", "manufacturing cycle", etc.

Response: Thank you for your constructive comment. We have expanded Table 1 to include the requested aspects: “patient compliance,” “production cost,” and “manufacturing cycle.” For your convenience, the revised table has also been attached below to highlight the updates.

Aspect	Mobilization splints (dynamic)	Immobilization splints (static)
Purpose	Support and protect with limited movement	Fully immobilize to prevent any movement
Use cases	·   Minor sprains and strains ·   Substitute for weak or absent muscle ·   Provide resistance for exercise ·   Increase passive joint range of motion ·   Elongate soft-tissue contractures ·   Post-surgery rehabilitation	·      Fractures ·      Severe sprains ·      Symptom relief ·      Contracture management ·      Improve and/or preserve joint alignment ·      Post-surgical repair
Design characteristics	·   Allow controlled motion ·   Stabilize without full immobilization	·      Rigid design ·      Ensure no movement
Patient compliance	·   More willing to wear than rigid splints ·   Better tolerated when finger movement is allowed ·   Preferred when materials are light and flexible ·   Preferred during rehab for comfort and mobility	·      lower due to discomfort or bulkiness ·      Often removed early if perceived as restrictive ·      Adherence improves when healing benefits are clearly explained
Production cost	·   Moderate; may involve custom designs and more complex fabrication techniques (e.g., springs)	·      Typically lower; standardized forms are easy to mass-produce
Manufacturing cycle	·   Longer; dynamic features may require adjustments or patient-specific tuning	·      Shorter; can often be pre-fabricated or made quickly via thermoforming or 3D printing
Examples	·   Buddy tape ·   Dynamic extension splints	·      Mallet finger splints ·      Stack splints
Benefits	·   Reduce stiffness ·   Maintain some muscle activity	·      Provide maximum support ·      Promote proper healing

 

 

5. Explore the potential applications of biodegradable materials such as PHBV and smart materials such as shape memory polymers.

Response: Thank you for the comment! We have addressed this point in the revised manuscript by expanding Section 5, where we discuss the materials used in the 3D printing of finger orthoses. Specifically, we have included a paragraph that highlights the potential of PHBV as a biodegradable material and shape memory polymers (SMPs) as smart materials with adaptive functionality. The added text is provided below for your convenience:

Emerging biodegradable and smart polymers are gaining attention in the fabrication of finger orthoses. For instance, Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a biodegradable copolymer belonging to the polyhydroxyalkanoates (PHAs) family. PHAs are composed of hydroxyalkanoic acid monomers and exhibit diverse mechanical and thermal properties depending on their monomer composition and fermentation conditions. Among them, PHB is well-known but inherently brittle. To improve flexibility and processability, PHBV is synthesized by incorporating 3-hydroxyvalerate units, making it suitable for additive manufacturing of biomedical products, including customized orthopedic supports and potentially finger orthoses. Owing to its biocompatibility, thermoplasticity, and sustainable degradation profile, PHBV is gaining traction as a promising material for use in 3D-printed devices, especially as a biodegradable alternative to petroleum-based polymers. Moreover, shape memory polymers (SMPs) are another group of materials that open avenues for more responsive, patient-friendly orthotic designs. SMPs are smart mate-rials capable of undergoing temporary deformation and returning to their original shape in response to an external stimulus. Barmouz et al. have employed SMPs in 4D printing of hand orthosis to treat patients with cerebral palsy, and other studies have explored their potential to reduce the need for multiple 3D-printed iterations by allowing post-printing customization.

6. Use "Orthosis" uniformly throughout the entire article (avoid mixing with "split").

Response: We appreciate the reviewer’s attention to terminological consistency. However, we would like to clarify that the distinction between ‘orthosis’ and ‘splint’ has already been acknowledged and explained in the Introduction section of the manuscript. Specifically, we note that “finger and thumb orthoses are also known as finger splints. However, finger splints are designed to immobilize or restrict movement in order to aid healing, while orthoses encompass various devices, including braces and supports, which serve purposes such as immobilization, correction, support, and enhancement of function. In the present review, these two terms are used interchangeably.”

Given that ‘finger splint’ is a widely used and recognized term in both clinical practice and scientific literature, we believe using both terms contextually improves clarity for a broader readership. Therefore, we respectfully maintain the current usage while ensuring the distinction and rationale are clearly stated upfront.

 

7. Check the throughout the text and correct redundant sentence (such as "due to the fact that" revise to "because").

Response: Thank you for the helpful suggestion. We have carefully reviewed the manuscript for redundant expressions. We remain mindful of clarity throughout the revised manuscript.

8. Figures 4 and 7: It is recommended to supplement the scale and material notes (such as "PA12, SLS printing, layer thickness 0.1mm").

Response: We have revised the figure captions for Figures 4 and 7 (now Figure 8 in the revised manuscript) to include material type (e.g., sterling silver and PA12), fabrication method (MultiJet Printing + casting for silver splints; SLS for polymer splints), and approximate size range (35–50 mm in length). These specifications have been provided by the manufacturer. However, additional technical details such as layer thickness, laser power, or scan speed were not disclosed by the supplier due to intellectual property protection. As such, we are unable to include further manufacturing specifications in the manuscript.

 

9. Conclusion: At the same time, the limitations of 3D printing should be pointed out, and future research directions such as 4D printing technology should be discussed?

Response: In the conclusion section of the revised manuscript, we have added a discussion on the limitations of 3D printing and introduced 4D printing as a promising future direction.

Recent advances in 3D printing have enabled the development of customized, light-weight, and cost-effective finger splints. Its ability to rapidly produce patient-specific designs with complex geometries has made it an invaluable tool in both clinical and research settings. However, limitations such as poor surface finish, limited responsiveness to movement, and printing speed remain. These challenges have drawn attention to emerging technologies like 4D printing, where time-responsive smart materials are used to create orthoses that dynamically adapt to the user’s movement and environment, allowing for more personalized care and potentially better clinical out-comes.

10. The references need to be updated to the latest literature in 2025, and attention should be paid to the uniform citation format. In addition, the number of relevant references needs to be appropriately increased.

Response: In the revised manuscript, we have added several recent publications from 2025 to ensure the literature review reflects the latest developments in the field. These new references strengthen the manuscript by bringing in up-to-date findings and supporting the added discussions. Regarding citation format, we have consistently followed the MDPI citation style using EndNote. As this aspect is typically refined during the final proofreading stage before publication, we trust that any remaining minor inconsistencies will be addressed at that point. Furthermore, we have included many relevant references in the newly added sections to improve the overall quality of the manuscript.

 

11. The conclusion has too many segments and needs to be integrated.

Response: Thank you for your feedback. In the revised manuscript, we have followed your suggestion and restructured the conclusion to improve its flow and coherence. It is no longer presented in segmented points, but rather as three connected paragraphs that provide an integrated summary of the key findings and future directions.

12. Further improvement is needed to enhance the clarity and resolution of the images.

Response: All figures included in the manuscript have been checked to ensure sufficient clarity and resolution for publication. The only image that may appear slightly soft is Figure 10, which was provided by B9Creations. This image reflects a common optical limitation caused by depth of field, where elements at different distances from the camera lens cannot all be in sharp focus simultaneously. The resolution of the image is otherwise high, and we are unable to improve its quality further due to these inherent optical constraints.

13. Checking the entire text, English writing and language need polishing.

Response: The manuscript has been thoroughly revised for language clarity and grammar to ensure improved readability and fluency.

 

 

Author Response File: Author Response.docx

Reviewer 4 Report

Comments and Suggestions for Authors

This is a good and timely review that tackles an area of growing interest with impressive clarity and depth. The manuscript walks the reader through everything from finger anatomy to splint function and emerging fabrication methods like 3D printing which are very readable and informative. The tables and illustrations are helpful, which made the classifications and concepts easy to understand. The writing is smooth and professional, and the paper tells a well-connected story from beginning to end. It is important that personalized orthotic care becomes more accessible through additive manufacturing. To me this review article is a valuable resource for both clinical and research communities. I recommend minor revisions. My comments are as follows:

• The abstract wraps things up nicely, but it might be even stronger with a quick closing line that points out why this review matters. How it could help clinicians or support future orthotic innovation.
• Since you discuss deeper into material selection later, it might be helpful to mention early on that materials play a big role in how well a splint performs. It would give the reader a heads-up and improve the flow.
• It could be helpful to add a quick line connecting that biomechanics section more directly to splint design. This is to make the clinical relevance clearer for readers who are not from a biomechanics background.
• Some splints (like silver ring splints) are seen in more than one category. This make sense however a short note saying that some splints can fall under multiple categories depending on how they are used or what they are made of could help avoid any confusion.
• There is a lot of great info in the ergonomic design section. To make it even more digestible for readers from different fields, you might consider adding a simple diagram showing things like skin contact, thickness, or perforations.
• Table 3 is full of useful details. It might be a good idea to guide the reader into it with a quick sentence before the table, maybe something like: “This table highlights how versatile 3D printing is for finger splints, especially with FDM and PLA being the most commonly used.”
• In Table 3, one of the rows has a dash for the printing method. If that info was not included in the original source, write a note in the footnote saying: “— indicates printing method not reported in the study” so it is clear it is not an error.

 

Author Response

Dear Reviewer #4,

Thank you very much for your expert review report. We have carefully revised the manuscript, and a point-by-point response to reviewers’ comments is provided below. Changes in the revised manuscript are highlighted in blue.

 

This is a good and timely review that tackles an area of growing interest with impressive clarity and depth. The manuscript walks the reader through everything from finger anatomy to splint function and emerging fabrication methods like 3D printing which are very readable and informative. The tables and illustrations are helpful, which made the classifications and concepts easy to understand. The writing is smooth and professional, and the paper tells a well-connected story from beginning to end. It is important that personalized orthotic care becomes more accessible through additive manufacturing. To me this review article is a valuable resource for both clinical and research communities. I recommend minor revisions. My comments are as follows:

1. The abstract wraps things up nicely, but it might be even stronger with a quick closing line that points out why this review matters. How it could help clinicians or support future orthotic innovation.

Response: We appreciate your thoughtful suggestion. To emphasize the relevance and potential impact of this review, we have added a closing line at the end of the abstract:
“By bridging clinical needs and design strategies, this review may guide future innovations in patient-specific orthotic development.”

2. Since you discuss deeper into material selection later, it might be helpful to mention early on that materials play a big role in how well a splint performs. It would give the reader a heads-up and improve the flow.

Response: To emphasize the importance of material selection, we have added a sentence towards the end of the Introduction section. The new sentence reads:
“In addition to design flexibility, material selection plays a crucial role in determining the splint’s mechanical behavior, wearability, and patient comfort, which significantly in-fluences the overall performance of 3D-printed orthoses”

3. It could be helpful to add a quick line connecting that biomechanics section more directly to splint design. This is to make the clinical relevance clearer for readers who are not from a biomechanics background.

Response: Thank you for your thoughtful comment. The relationship between biomechanical understanding and orthotic design is reflected in the revised manuscript, through the following statement in the anatomical and biomechanical considerations section:

“Understanding biomechanics helps to design effective and suitable orthoses that are tailored to the unique movements and load-bearing requirements of the hand's intricate structures. This requires detailed knowledge of the forces exerted during various activities, the natural range of motion, and the interplay between different anatomical structures.”

4. Some splints (like silver ring splints) are seen in more than one category. This make sense however a short note saying that some splints can fall under multiple categories depending on how they are used or what they are made of could help avoid any confusion.

Response: Thank you for bringing this to our attention. To address this point, we have added the following sentence in Section 3, before Table 2:

“As shown, some splints, such as silver ring splints, may appear under multiple classifications depending on their intended use, material, or joint involvement.”

5. There is a lot of great info in the ergonomic design section. To make it even more digestible for readers from different fields, you might consider adding a simple diagram showing things like skin contact, thickness, or perforations.

Response: We have illustrated the key ergonomic and functional design factors, including skin contact, material thickness, perforations for breathability, and fixation method, in a new diagram, now included as Figure 6 in the revised manuscript.

6. Table 3 is full of useful details. It might be a good idea to guide the reader into it with a quick sentence before the table, maybe something like: “This table highlights how versatile 3D printing is for finger splints, especially with FDM and PLA being the most commonly used.”

Response: We have added a sentence before the table (now Table 4 in the revised manuscript) to improve readability and provide better context. The revised text now reads:

“To provide an overview of recent research on the application of AM in the production of finger and thumb orthoses, several studies are summarized in Table 4. This table highlights the versatility of 3D printing for orthotic applications, with FDM and PLA being the most commonly used method and material. The table outlines the objective of each study, the printing method employed, the materials used, and a brief description of the findings or outcomes.”

7. In Table 3, one of the rows has a dash for the printing method. If that info was not included in the original source, write a note in the footnote saying: “— indicates printing method not reported in the study” so it is clear it is not an error.

Response: Thank you for bringing this to our attention. As suggested, we have added a footnote to the table (now Table 4 in the revised manuscript):

“—” indicates printing method not reported in the study.

 

 

Author Response File: Author Response.docx

Reviewer 5 Report

Comments and Suggestions for Authors

This review paper offers a well-structured and comprehensive examination of finger orthoses, addressing both the biomechanical foundations and the clinical applications of these devices. The inclusion of detailed classifications, anatomical context, and the integration of additive manufacturing technologies makes this work highly relevant to the fields of prosthetics, orthotics, rehabilitation engineering, and materials science. The paper is well-illustrated, and the tables are thoughtfully constructed to support the textual content. The English language is fluent and coherent, guiding the reader through both foundational concepts and advanced innovations. My comments are below:

 

In abstract, the phrase “upper human limbs” could be simplified to “upper limbs” or even “the hand and fingers” for more specific focus.

 

Can you briefly define the scope and limitations of your review? While the Introduction does a great job outlining what will be discussed, it would help the reader to know what is not covered.

 

Can you include more recent or quantitative statistics to highlight the prevalence and burden of finger injuries? The statement “25% of all sports-related injuries involve the hand or wrist” is good, but adding more recent data or global estimates could make the Introduction even stronger.

 

You dive right into classifications, which is great for structure, but it is suggested to first explain why classifying splints this way matters (e.g., better clinical decision-making, tailored patient treatment).

 

While the section on ergonomic and functional design factors is rich in technical details, I would suggest adding a brief summary statement tying all factors back to clinical relevance, because comfort and compliance are vital for long-term treatment success.

 

In conclusion, you could mention the importance of interdisciplinary collaboration between clinicians and engineers in advancing orthotic design, or highlight gaps where further studies (e.g., long-term patient outcomes or material biocompatibility) are needed.

 

Author Response

Dear Reviewer #4,

Thank you very much for your expert review report. We have carefully revised the manuscript, and a point-by-point response to reviewers’ comments is provided below. Changes in the revised manuscript are highlighted in blue.

 

This review paper offers a well-structured and comprehensive examination of finger orthoses, addressing both the biomechanical foundations and the clinical applications of these devices. The inclusion of detailed classifications, anatomical context, and the integration of additive manufacturing technologies makes this work highly relevant to the fields of prosthetics, orthotics, rehabilitation engineering, and materials science. The paper is well-illustrated, and the tables are thoughtfully constructed to support the textual content. The English language is fluent and coherent, guiding the reader through both foundational concepts and advanced innovations. My comments are below:

1. In abstract, the phrase “upper human limbs” could be simplified to “upper limbs” or even “the hand and fingers” for more specific focus.

Response: We have replaced “upper human limbs” with “upper limbs” in the revised abstract.

2. Can you briefly define the scope and limitations of your review? While the Introduction does a great job outlining what will be discussed, it would help the reader to know what is not covered.

Response: In line with your comment, we have revised the final paragraph of the Introduction to clearly define both the scope and the limitations of our review.

“The present review explores multiple aspects of finger splints, including the biomechanical and anatomical considerations of the fingers and thumb. In addition, the types and designs of finger orthoses and their specific functions in addressing finger injuries and deformities are discussed. Finally, the role of AM in the fabrication of finger orthoses is reviewed, highlighting the advantages of this innovative technology compared to conventional methods. With a primary focus on the design, classification, and fabrication of finger orthoses, this review does not cover clinical conditions, surgical procedures, or rehabilitation protocols.”

3. Can you include more recent or quantitative statistics to highlight the prevalence and burden of finger injuries? The statement “25% of all sports-related injuries involve the hand or wrist” is good, but adding more recent data or global estimates could make the Introduction even stronger.

Response: Thank you for your helpful suggestion. In response, we have expanded the introduction to include more recent and quantitative data to better highlight the prevalence and burden of finger and hand injuries. The revised manuscript now includes the following statistics:

“Falling is the most common cause of injury among individuals over 65, accounting for 75–79% of trauma cases. In this age group, 29% of emergency department presentations involve injuries to the hand and wrist. More broadly, hand injuries account for up to 30% of all cases seen in emergency care across all age groups. Moreover, in sport-related injuries, approximately 25% involve the hand or wrist.”

4. You dive right into classifications, which is great for structure, but it is suggested to first explain why classifying splints this way matters (e.g., better clinical decision-making, tailored patient treatment).

Response: Thank you for your insightful feedback. We have added a short introductory paragraph at the beginning of the Section 3 to explain the importance of classifying finger orthoses. The revised section now begins with the following statement:

“Finger orthoses are classified based on various factors, including their function, the specific joints they target, the materials used in their construction, the conditions they are designed to treat, and their overall configuration. Understanding these classifications is essential not only for organizing the wide variety of splint types but also for supporting clinical decision-making. Each type of classification helps clinicians better understand the purpose of a splint and choose the one that best fits the patient’s condition, treatment goals, and physical needs. By matching the splint type to the patient’s requirements and comfort, these classifications help create more effective and personalized treatment plans and ultimately lead to better outcomes.”

5. While the section on ergonomic and functional design factors is rich in technical details, I would suggest adding a brief summary statement tying all factors back to clinical relevance, because comfort and compliance are vital for long-term treatment success.

Response: Thank you for your thoughtful comment! To address this comment, we have added the following sentence to the end of Section 4 to emphasize the clinical relevance of ergonomic and functional design factors:

“Collectively, these ergonomic and functional design considerations directly impact clinical outcomes, as splints that are comfortable, breathable, and securely fitted are more likely to be worn consistently, thereby enhancing patient compliance and contributing to the long-term success of treatment.”

6. In conclusion, you could mention the importance of interdisciplinary collaboration between clinicians and engineers in advancing orthotic design, or highlight gaps where further studies (e.g., long-term patient outcomes or material biocompatibility) are needed.

Response: Thank you for this helpful comment. In the revised manuscript, we have incorporated your advice by adding a statement to the conclusion highlighting the importance of interdisciplinary collaboration and the need for further research. The following sentence has been included:

“Interdisciplinary collaboration between clinicians, engineers, and researchers remains essential to advancing orthotic design. Further studies on long-term patient outcomes, material biocompatibility, and patient-focused assessment will play a key role in improving finger orthoses for clinical use.”

 

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

Accept in present form.