Application and benefit analysis of needle arthroscopy for joint disease diagnosis and treatment

Summary

Needle arthroscopy (NA) is a minimally invasive surgical device that has transformed the management of joint diseases. Characterized by a diameter of less than 2 mm, NA is a cornerstone of minimally invasive orthopedic procedures. The clinical utility of NA has been extensively validated in numerous studies. Studies indicate that NA demonstrates high diagnostic performance for intra-articular pathologies, with reported sensitivity and specificity reaching up to 94.4% and 96.7%, respectively. Moreover, it enables an integrated “diagnosis-decision-treatment” approach, which has been shown to reduce the average cost of management by approximately 50% and shorten the diagnostic period by up to two weeks. However, the steep learning curve associated with using 0° optical systems imposes limitations on its widespread adoption. Additionally, the inherent limited mechanical strength of NA instruments may increase the procedural risk of iatrogenic injury. This review summarizes recent advances and cost-benefit analyses of NA in the management of joint diseases, aiming to provide a valuable reference for its future clinical translation and wider application. This technological advancement holds the potential to revolutionize the management of joint diseases, rendering procedures minimally invasive, precise, and cost-effective. Thereby, it promises to facilitate a technological innovation toward clinic-based, minimally invasive management of joint diseases.

Graphical abstract

Health sciences; Medicine; Medical specialty; Surgery; Orthopedics

Introduction

Needle arthroscopy (NA) is a type of arthroscope characterized by a small objective diameter, typically measuring less than 2 mm.¹ NA evolved from conventional standard arthroscopy. The inception of arthroscopy dates back to 1912, when it was first described by Dr. Nordentoft, a Danish surgeon. Dr. Nordentoft pioneered the technique of inserting an endoscope into the knee joint to examine its structures. A significant advancement in the technique occurred in 1931. This was largely due to the work of Professor Kenji Takagi from Japan. Dr. Takagi introduced the method of distending the knee joint with physiologic saline. This innovation served to both enlarge the joint space and improve visualization. Following this development, the technique gained adoption in the United States and other countries. The 1970s marked a pivotal milestone with the publication of the first major paper on arthroscopy.² Arthroscopy has played a pivotal role in improving the diagnostic accuracy for joint diseases and is established as the gold standard for assessing intra-articular knee pathologies. The application of arthroscopy has been demonstrated to reduce postoperative recovery times and complication rates, thereby promoting the evolution of minimally invasive surgical (MIS) techniques.^3,4 Driven by continual scientific and technological progress, there is a growing clinical demand for less invasive medical tools. Consequently, research on NA is attracting growing interest within the scientific community. NA is a minimally invasive arthroscopic technology that offers substantial advantages, enabling both diagnostic and interventional procedures to be performed under local anesthesia in an outpatient setting. A pivotal milestone was achieved in 1970 when Watanabe introduced the world’s first ultra-thin fiberoptic endoscope, featuring a 2 mm objective lens. This innovation laid the groundwork for the subsequent development of needle endoscopes.² NA and in-office needle arthroscopy (IONA) have been available for some time; however, their widespread clinical adoption has been limited by historical limitations in image quality and technical challenges.^5,6 Initially, this technique relied exclusively on fiberoptic systems. Consequently, comparative studies from that era concluded that NA provided inferior visualization and diagnostic capability for intra-articular structures compared to conventional arthroscopy.⁷ In recent years, NA has gained significant popularity, driven by substantial progress in image quality, instrumentation, and functionality. These technological innovations have consequently broadened the range of surgical indications and facilitated the development of novel techniques.^3,8 Since 2019, research interest in NA has surged, driven not only by progress in conventional optical components, such as lenses and image resolution, but also by advancements in digital image processing and transmission technologies.^9,10,11 The optical lens, located at the distal tip of the NA system, is its most critical optical component despite its miniaturized diameter. Our research group has designed and validated an NA system incorporating a 30° viewing angle lens to facilitate high-resolution visualization and enhance the surgical field of view.¹²

The NA prototype, developed through our collaboration, enables comprehensive visualization of intra-articular structures, thereby providing significant diagnostic utility that addresses the growing demands of modern clinical practice.^12,13 The diagnostic and therapeutic utility of NA has been well-established across a growing body of literature investigating various articular pathologies.^{3,6,7,13,14,15,16,17,18,19,20,21,22} NA provides a safe, accurate, and minimally invasive imaging modality for evaluating intra-articular pathologies, offering a convenient outpatient alternative. Furthermore, it eliminates the need for general anesthesia and an operating room setting compared to standard arthroscopy, thereby substantially reducing both financial costs and time investment.^4,5,13,23 Magnetic resonance imaging (MRI) is the primary non-invasive diagnostic modality for joint diseases. However, concerns have been raised regarding its cost-effectiveness and diagnostic accuracy. Relevant studies have demonstrated that MRI not only increases overall healthcare costs but may also underestimate the severity of intra-articular pathologies.^{23,24,25,26,27} Outpatient NA significantly reduces both the time commitment and financial burden for patients. Furthermore, it can provide a superior diagnostic evaluation of intra-articular knee pathologies through direct visualization, often surpassing the capabilities of MRI.^1,3,8,25 The use of NA enables orthopedic surgeons to perform highly targeted examinations guided by the patient’s specific symptoms and clinical signs. This approach eliminates the need to obtain potentially ambiguous MRI reports that would require subsequent specialist interpretation. Moreover, because radiologists’ interpretations are made without the benefit of physical examination findings, their reports may lack clinical focus and risk overlooking critical pathological details.^19,28 Furthermore, NA provides a crucial alternative for patients with contraindications to MRI, including those with metallic implants (e.g., pacemakers and cerebral aneurysm clips), claustrophobia, or other conditions precluding MRI utilization.^29,30 Despite achieving diagnostic parity with conventional arthroscopy, NA remains considerably less utilized than MRI in the initial diagnostic workup of knee disorders.^24,26,27 This underutilization persists despite the fact that MRI resources are often limited in clinical settings, as this imaging modality is required for a broad spectrum of diagnostic applications beyond musculoskeletal disorders.^31,32,33,34 Consequently, this resource constraint not only creates significant time burdens for patients requiring joint examinations but also places substantial strain on MRI services. This diagnostic pathway from initial clinical assessment to definitive surgical management may extend over six months, substantially prolonging the overall treatment timeline.¹⁹ With ongoing technological and instrumental advancements, NA is gaining increased clinical adoption. This trend is driven by its recognized advantages including minimal invasiveness, procedural efficiency, and cost-effectiveness despite its characterization as a minimally invasive procedural technique.

NA represents an emerging diagnostic technology that is establishing a significant role in orthopedic practice. Its application extends beyond knee pathology diagnosis to various other anatomical regions, facilitated by its miniaturized design and high-resolution imaging capabilities.^{18,21,22,35,36} The evolution of NA has progressed through several key milestones: initial development in the 1970s, expanded research on knee applications in the 1990s, and the recent introduction of advanced systems including the Vision Scope Imaging (VSI), Mi-eye 2 (Trice Medical), and NanoScope (Arthrex). These technological advances have significantly enhanced NA performance capabilities.^3,5,11,16,25 First introduced in 2012, the VSI system has demonstrated significant improvements in clinical outcomes and reduced diagnostic expenses for knee meniscus injuries compared to traditional methods.^25,28 Following its approval by the US FDA in 2016, the Mi-eye 2 system (Trice Medical) incorporated substantial enhancements in both imaging resolution and portability. This regulatory milestone enabled the system to provide real-time, high-resolution image transmission, significantly improving its diagnostic utility in clinical settings.^3,5 Introduced by Arthrex in 2019, the NanoScope system represents the most widely adopted NA platform, featuring an ultra-fine design with exceptional integration capabilities and enhanced operational flexibility. Its all-in-one design combines illumination, imaging, and irrigation systems in a single device, significantly simplifying procedural workflow while maintaining diagnostic accuracy comparable to conventional arthroscopy.^{8,11,14,21,24,37,38,39} Following a series of significant iterations, these systems evolved into representative technologies within the NA field (Figure 1A). NA fundamentally transforms joint disease management through minimally invasive approaches, precise visualization, and cost-effective methodologies. Beyond diagnostic applications across multiple joints, NA systems facilitate postoperative assessment, pathological biopsy, and adjunctive therapeutic procedures, demonstrating remarkable versatility in musculoskeletal care. This integrated diagnostic-therapeutic capability positions NA as a comprehensive solution for modern orthopedic practice, particularly in value-based healthcare environments.^8,14,15,30 Through ongoing technological advancements, NA systems have undergone progressive refinement, evolving from basic diagnostic tools to multifunctional platforms capable of supporting diverse clinical applications. This evolution has significantly enhanced their utility in modern orthopedic practice, enabling more comprehensive patient management through integrated diagnostic and therapeutic capabilities (Figure 1B). In recent years, NA has gained substantial traction in orthopedic practice, particularly for managing various joint pathologies. Its applications encompass multiple joints including the knee, shoulder, ankle, foot, and elbow. This technology provides orthopedic surgeons with an integrated diagnostic-therapeutic approach that combines procedural efficiency, cost-effectiveness, and minimal invasiveness. These benefits are primarily derived from NA’s unique technical characteristics and demonstrated clinical utility, positioning it as a valuable tool in modern musculoskeletal care, as illustrated in Figure 1C. These technological advances have significantly advanced sports medicine practice while simultaneously establishing a technical foundation for NA’s potential applications in other specialized disciplines, including neurosurgery and gastroenterology.^{16,17,40,41,42,43} This review synthesizes recent advances in NA, aiming to support its integration into clinical practice and ultimately contribute to improved patient outcomes.

Figure 1.

Schematic diagram of the technological evolution and clinical applications of NA

This figure is divided into three parts to illustrate the core information related to NA: (A) presents the development course of NA, which has evolved into a representative technology in the field after a series of significant iterations; (B) shows that NA has been gradually optimized from a basic diagnostic tool to a multifunctional diagnosis and treatment platform. Its integrated capability of diagnosis and treatment has significantly enhanced its application value in modern orthopedic clinics, enabling more comprehensive diagnosis and treatment management of patients; and (C) intuitively demonstrates the wide clinical application scenarios of NA in orthopedics. It is suitable for the diagnosis and treatment of joint lesions in multiple sites such as the knee, shoulder, and ankle. With the advantages of minimal invasiveness, high efficiency, and cost-effectiveness, NA has become an important tool in the diagnosis and treatment of modern musculoskeletal system diseases.

NA in the diagnosis and treatment of joint diseases

Application of NA in knee joint

The knee joint represents one of the largest and most complex articulations in the human body, characterized by its superficial placement, intricate architecture, and susceptibility to diverse pathological conditions. This anatomical combination makes it particularly suitable for diagnostic and therapeutic interventions using arthroscopy techniques.⁴⁴ Arthroscopic techniques were first pioneered for knee examination in 1912, marking a seminal advancement in orthopedic surgery that would eventually revolutionize the diagnosis and treatment of intra-articular pathologies. This pioneering work established the foundation for modern minimally invasive joint exploration techniques.² Arthroscopic surgery has become an increasingly prevalent technique in sports medicine, with several hundred thousand knee arthroscopies performed annually in high-income countries such as the United Kingdom and United States. This minimally invasive approach allows for both diagnostic evaluation and therapeutic intervention through small portal incisions, significantly reducing recovery time compared to traditional open procedures. The widespread adoption of arthroscopy reflects its demonstrated efficacy in managing various intra-articular pathologies while minimizing surgical morbidity.⁴⁵ NA provides anatomical visualization comparable to conventional arthroscopy for knee disorders, while offering distinct advantages as an alternative for patients with MRI contraindications. This combination of diagnostic accuracy and accessibility positions NA as a valuable tool in the orthopedic diagnostic arsenal, particularly for patients who cannot undergo MRI or require immediate intervention.^8,24 The procedure requires only minimal incisions, allowing instrument manipulation within a confined surgical field to debride and repair damaged joint tissue. Furthermore, under direct visualization, NA enables precise acquisition of pathological tissue biopsies, enhancing both diagnostic accuracy and therapeutic effectiveness. This combination of minimal invasiveness and procedural precision represents a significant advancement in orthopedic surgical techniques.^14,37,38,39 This capability is particularly valuable in managing various knee pathologies, including ligamentous injuries, cartilage lesions, meniscal tears, and synovial disorders. The ability to directly visualize and intervene in these conditions during a single procedure significantly enhances both diagnostic accuracy and therapeutic outcomes.

In 1992, Drs. Halbrecht and Jackson pioneered the clinical application of needle arthroscopy, conducting examinations on 20 patients with undiagnosed knee symptoms under local anesthesia. They compared findings from 1.7-mm needle arthroscopes with 1.5-T MRI evaluations. Their results demonstrated NA’s superior sensitivity over MRI in detecting articular cartilage lesions. This landmark study first established NA as an accurate outpatient alternative to MRI, demonstrating both diagnostic accuracy and cost-effectiveness that positions NA as a viable alternative to conventional MRI.⁴⁶ In 1993, Ike and colleagues employed 1.8-mm needle arthroscopes alongside conventional 4-mm arthroscopes to assess knee lesions in ten osteoarthritis (OA) patients. Their subsequent research demonstrated that NA provided meniscal detection efficacy comparable to standard arthroscopy in knee OA evaluation. However, NA tended to underestimate lesion extent in cartilage and synovial grading, while its outpatient applicability offered new possibilities for early OA diagnosis. The authors noted that enhanced imaging capabilities and standardized evaluation protocols would be necessary to improve diagnostic accuracy.⁴⁷ Later research by Ike and colleagues advocated for outpatient NA application, highlighting its advantages over conventional operating room arthroscopy for diagnosing unexplained knee pain. Diagnostic arthroscopy constitutes an essential element in the comprehensive management of arthritic conditions, particularly through its capacity to provide direct visualization and immediate therapeutic intervention in appropriately selected cases. The transition toward office-based procedures represents a significant advancement in making these diagnostic capabilities more accessible and efficient.^48,49

In 2018, Gill and colleagues conducted a prospective, blinded, multicenter trial involving 110 patients (aged 18–75 years) presenting with knee pain as their chief complaint. This study aimed to compare the diagnostic performance of NA, standard arthroscopy, and MRI. Results demonstrated that NA achieved diagnostic accuracy comparable to standard arthroscopy for detecting cartilage lesions and meniscal tears. The study established that the VSI NA system demonstrated diagnostic efficacy equivalent to surgical arthroscopy for non-ligamentous pathologies, superior to MRI, while maintaining excellent safety, minimal invasiveness, and cost-effectiveness. These findings support the adoption of the VSI system as a new standard for diagnosing knee pathologies. This investigation provides level I evidence supporting the transition of minimally invasive arthroscopy to outpatient settings.²⁵ In 2019, McMillan and colleagues performed a retrospective cohort study analyzing the safety profile of office-based NA under local anesthesia in 1,419 patients (1,119 knee procedures). They reported a 1.6% incidence rate of neurovascular events and a 0.3% rate of postoperative pain at 24 h, with no reports of serious complications such as infection or deep vein thrombosis. This large-scale analysis demonstrates that NA is a well-tolerated procedure with an excellent safety profile in the outpatient setting.⁵ This study confirms the safety of needle arthroscopy in office-based settings, demonstrating a low complication profile. In 2020, Quinn and colleagues documented the expanded application of NA for both diagnostic evaluation and therapeutic partial medial meniscectomy procedures. Their level IV case series represented the first description of NA being utilized for therapeutic arthroscopic surgery outside the operating room, marking a significant advancement in minimally invasive orthopedic care. This work expanded NA’s role beyond purely diagnostic applications, establishing its potential for definitive treatment in appropriate clinical scenarios.⁸

NA overcomes key limitations of conventional arthroscopy while offering unique clinical advantages. Earlier research primarily focused on its diagnostic applications in outpatient settings, while contemporary studies increasingly explore its therapeutic potential in operating room environments, particularly through technological advances enabling meniscectomy procedures. This evolution from purely diagnostic to comprehensive therapeutic applications represents a significant advancement in minimally invasive orthopedic surgery, with improved optics and instrumentation further expanding NA’s surgical capabilities.⁵⁰ In 2021, Matthew and colleagues introduced a novel percutaneous anterior cruciate ligament (ACL) repair technique utilizing NA with biological augmentation, employing needle arthroscopy with platelet-rich plasma (PRP) for acute ACL tears. This approach represents a paradigm shift from traditional ligament reconstruction toward biologically enhanced in situ repair, potentially offering improved preservation of native knee biomechanics and proprioceptive function.³⁹ That same year, Stornebrink and colleagues described a needle arthroscopy-assisted all-inside meniscal suture repair technique suitable for tears located in the red-red and red-white junction zones. This approach enables procedures under local anesthesia, offering a viable alternative to conventional arthroscopic surgery while potentially reducing surgical morbidity and healthcare costs. The technique demonstrates particular value for patients who are poor candidates for general anesthesia or who prefer office-based procedures, potentially expanding access to meniscal preservation techniques in diverse clinical settings. Further studies are needed to establish long-term outcomes compared to conventional arthroscopic repair.⁵¹ This investigation presents an innovative minimally invasive approach to meniscal repair utilizing local anesthesia, which reduces surgical trauma while maintaining procedural efficacy. The authors also delineate critical future research priorities focusing on instrumental refinement and procedural standardization. Subsequently, this research group demonstrated NA’s potential as a primary intervention for septic arthritis, particularly highlighting its utility in diagnostic confirmation, joint lavage, and therapeutic monitoring in infected joints. Their work suggests that NA may offer advantages over repeated arthrocentesis procedures by enabling direct visualization and targeted intervention in septic joints, though further validation is needed to establish formal treatment guidelines.¹⁴ This standardized approach, performed under local anesthesia in emergency departments or at the bedside, establishes a new paradigm for managing acute joint infections, particularly in resource-constrained settings. The researchers subsequently initiated a prospective cohort study to assess long-term clinical outcomes. In 2022, Shubert and colleagues developed a novel NA-assisted technique for posterior cruciate ligament (PCL) reconstruction, demonstrating the continuing expansion of NA applications into increasingly complex orthopedic procedures. This technique represents a significant advancement in minimally invasive ligament surgery, potentially reducing surgical morbidity while maintaining the precision required for successful PCL reconstruction outcomes.³⁸ Conventional PCL reconstruction necessitates frequent switching between 30° and 70° arthroscopes and typically requires 4–6 surgical portals, increasing the risk of iatrogenic injury to the common peroneal nerve. The NA-assisted technique employs a 1.9-mm diameter scope for continuous visualization through an auxiliary posterolateral portal, utilizing a dual-arthroscope system (conventional 30° scope and 0° NA) that enables parallel instrumentation. This approach markedly reduces instrument exchanges and addresses traditional visualization constraints in the posterior compartment. The innovative posterolateral portal design optimizes the balance between anatomical precision and operative efficiency, rendering it particularly advantageous for complex knee reconstruction procedures. In 2023, Savage-Elliott and colleagues described a novel technique for obtaining articular cartilage biopsies using NA in awake patients, further expanding the diagnostic applications of this minimally invasive technology in the clinical setting.³⁷ Conventional matrix-assisted chondrocyte implantation (MACI) traditionally requires two separate surgical procedures, initial cartilage harvest followed later by implantation, thereby escalating demands on surgical resources and perioperative risks. Utilizing NA, the initial cartilage harvest phase of MACI was successfully completed under local anesthesia alone, facilitating the transition of cell-based cartilage repair toward office-based surgery. This innovation delivers multi-level benefits: at the patient level, it eliminates multiple anesthetic exposures and reduces tissue trauma by 62% compared to conventional techniques; at the institutional level, outpatient procedure costs decrease substantially, with a 76% reduction in surgical resource utilization; while regarding clinical outcomes, MACI maintains long-term therapeutic effectiveness while demonstrating significant cost-effectiveness.^52,53 In 2024, Ford et al. compared healthcare network integrity and patient follow-up rates and timeliness between NA and conventional outpatient advanced diagnostic imaging for intra-articular lesions, and demonstrated NA’s superiority in both metrics.⁵⁴ By integrating diagnosis, clinical decision-making, and treatment, NA enhances patient retention within the healthcare system and minimizes secondary referrals. The authors advocate for prioritizing NA in treatment-naive patients with definitive intra-articular lesions to enhance the efficiency of healthcare resource allocation. We summarize recent findings and limitations of NA in knee applications (Table 1).

Table 1.

NA research highlights in the area of knee disease

Study	Technical specifications	Design	Sample size	Key points	NA limitations
Halbrecht, J.L.46	Diameter of the optic 1.7 mm	Technical note (clinical)	20	Superior diagnostic performance. Low economic cost. High patient acceptance.	Diagnosis has limitations. Potentially hazardous.
Ike et al.47	Diameter of the optic 1.8 mm	Technical note (clinical)	10	Superior diagnostic performance.	Diagnosis has limitations.
Gill et al.25	VSI diameter of the optic 1.4 mm	Prospective, blinded multicenter clinical trial	110	Superior diagnostic performance. Low economic cost.	Diagnosis has limitations.
McMillan et al.5	Trice Mi-eye2 direction of view 0° diameter of the optic 1.9 mm	Technical note (clinical)	1119	Superior diagnostic performance. Low economic cost.	Potentially hazardous.
Daggett et al.21	NanoScopeTM direction of view 0° diameter of the optic 2 mm	Technical note (clinical)	None	Excellent adjunctive therapeutic properties. Low economic cost.	Diagnosis has limitations. Potentially hazardous.
Stornebrink et al.14	NanoScopeTM direction of view 0° diameter of the optic 1.9 mm Sleeve 2.2 mm	Technical note (clinical)	None	Excellent adjunctive therapeutic properties. Low economic cost.	Indications have limitations. Steep learning curve.
Shubert et al.38	NanoScopeTM direction of view 0° diameter of the optic 1.9 mm	Technical note (clinical)	None	Excellent adjunctive therapeutic properties.	Steep learning curve. Potentially hazardous.
Savage-Elliott et al.37	NanoScopeTM direction of view 15° diameter of the optic 1.9 mm	Technical note (clinical)	None	Excellent adjunctive therapeutic properties. Low economic cost.	Indications have limitations. Potentially hazardous.
Blankenburg et al.24	NanoScopeTM direction of view 0° field of view 120° diameter of the optic 1.9 mm	Technical note (clinical and cadaveric)	15	Superior diagnostic performance.	Indications have limitations. Potentially hazardous. Poor mechanical lightness.
Liu et al.12	Direction of view 30° field of view 85° diameter of the optic 2 mm	Technical note (cadaveric)	1	Superior diagnostic performance.	Insufficient mechanical strength.

NA has evolved from a purely diagnostic tool to a therapeutic adjunct. Advances in fiber optic technology have enabled the development of objective lenses smaller than 2 mm, thereby reducing both costs and tissue trauma. Consequently, NA has garnered patient acceptance despite its minimally invasive nature. As a promising diagnostic-therapeutic modality, NA has seen recent developments focusing on enhancing the performance of image transmission systems and expanding therapeutic applications. Our previous work has also confirmed NA’s diagnostic equivalence to conventional arthroscopy for knee joint visualization, with an enhanced capability to detect subtle injuries occult on MRI scans.^12,24 Future NA development for knee joint pathologies must address inherent design constraints specifically a limited field of view and instrument rigidity while prioritizing two strategic directions: (1) initial diagnosis and visualization-guided treatment of uncomplicated pathologies and (2) ongoing device optimization to broaden indications.

Application of NA in shoulder joint

With advancements in medical science and technology, the pivotal role of arthroscopy in the diagnosis and treatment of shoulder joint diseases has garnered increasing recognition.^55,56 NA employs modern high-definition endoscopic imaging technology, enabling the magnification of subtle tissue lesions. NA provides clinicians with clear visualization for precise interventions while minimizing iatrogenic injury and postoperative complications through its miniaturized design. Clinical studies confirm the safety profile of this technique.^5,57

The feasibility of NA was first demonstrated in 1993. Its capacity for direct visualization under local anesthesia in outpatient settings offered a transformative solution to overcome MRI limitations, particularly in postoperative contexts and anatomical variations, laying the groundwork for modern minimally invasive diagnostic shoulder arthroscopy techniques.⁵⁸ Subsequently, NA has advanced rapidly in shoulder joint applications. In 2017, Demirel et al. developed a virtual shoulder arthroscopy simulation platform operational via 5 mm MIS incisions. Using hierarchical task analysis and quantitative metrics, they defined key performance indicators for arthroscopic procedural steps.⁵⁹ This study also provides an objective basis for optimizing surgical training curricula, while highlighting the steep learning curve of NA technology and the limitations of traditional training methods. In 2019, McMillan et al. compared complication risks of NA in knee versus shoulder procedures via a retrospective multi-institutional case series of 1,419 patient surgeries (including 300 shoulder procedures) performed by 13 attending physicians. The study confirmed the technique’s favorable safety profile in outpatient settings.⁵ In 2020, Daggett et al. developed a standardized protocol for outpatient shoulder joint NA. To address MRI’s relatively low sensitivity for certain shoulder pathologies and contraindications in specific patient populations, they proposed extending NA technology to shoulder joint diagnostics. This approach shortens the duration of clinical diagnostic-therapeutic cycles, reduces diagnostic errors, and reduces healthcare costs.²¹ Subsequently in the same year, Shafi et al. utilized a 2 mm small-caliber NA system for diagnostic evaluation of the glenohumeral joint and subacromial space, achieving comprehensive intra-articular visualization. This technique enhances clinical workflow efficiency while reducing operative duration, though instrumentation limitations (e.g., mechanical constraints) necessitate further optimization. It pioneers a novel arthroscopic approach for shoulder joint preservation, offering a paradigm shift in minimally invasive management.⁶⁰ In 2021, Wagner et al. conducted the first prospective double-blinded trial systematically comparing the diagnostic performance of NA and MRI for intra-articular shoulder lesions against conventional arthroscopy (considered the gold standard). Findings demonstrated high diagnostic concordance between NA and conventional arthroscopy, with diagnostic accuracy surpassing that of MRI. No infections or major adverse events were reported during the 6-week follow-up period.²⁰ Since then, the development direction of needle arthroscopy in the field of shoulder joint has turned to therapy.

Also in 2021, Gauci et al. introduced an in-office biceps tenotomy (IOBT) technique under NA guidance. Conventional arthroscopic IOBT under general anesthesia is technically demanding, while ultrasound-guided percutaneous tenotomy is associated with a 75% rate of incomplete release and a risk of iatrogenic cartilage injury. The NA-guided approach thus provides a feasible, minimally invasive alternative for the management of long head of the biceps tendon pathology. Their initial case series of four IOBT procedures were successfully completed, accompanied by significant postoperative pain reduction. The researchers also demonstrated for the first time that replacing saline with air insufflation significantly improves intra-articular visualization, thereby extending the direct visualization utility of the technique.⁶¹ Subsequently, Atoun et al. developed an NA-assisted transosseous suture technique for rotator cuff repair. Conventional anchor-based repair is limited by footprint occupation, compromised bone vascularity, complexity of revision surgery following failure, and elevated costs. The NA-guided transosseous approach circumvents these limitations while maintaining the structural integrity of traditional open suture techniques.⁶² In 2022, DeClouette et al. retrospectively evaluated second-generation NA for the diagnosis of shoulder and knee intra-articular lesions. Building on prior findings, they replaced traditional saline insufflation with gas insufflation and increased the field of view by 30% using lenses of higher refractive index. Demonstrating high sensitivity and specificity, NA demonstrates value as a standalone or adjunctive diagnostic tool particularly for MRI-indeterminate cases thereby reducing diagnostic errors and facilitating optimized treatment planning.⁶³ In the same year, Lavender et al. introduced an NA-based rotator cuff repair technique employing the Passport Dual Lumen Cannula. This approach offers significant advantages such as smaller incisions, shorter recovery times, and a reduced risk of iatrogenic injury. However, limitations include the inability to manage large or retracted tears and the expense of specialized instruments.⁶⁴ In 2023, Chowdhury et al. conducted a prospective diagnostic validation study of 22 patients scheduled to undergo arthroscopic shoulder surgery. NA and MRI were compared across 12 shoulder anatomical sites. NA demonstrated higher diagnostic accuracy than MRI for rotator cuff and biceps pathologies but lower sensitivity in assessing articular cartilage and labral lesions. Thus, NA emerges as a valuable alternative diagnostic tool in outpatient settings or when MRI results are indeterminate.⁶⁵ In the same year, Owusu-Sarpong et al. introduced an innovative approach for diagnosing and treating subacromial impingement syndrome via NA to perform subacromial decompression, including bursectomy and acromioplasty. Local anesthesia was administered to patients with clinically defined anterior subacromial impingement refractory to 6 months of conservative management. Patients reported greater than 94% satisfaction and returned to light labor within 4 weeks postoperatively. This approach demonstrates a viable minimally invasive therapeutic solution for persistent subacromial impingement.⁶⁶ Long head of biceps tendinopathy is a common cause of chronic anterior shoulder pain. Colasanti et al. developed an NA technique enabling real-time diagnosis and treatment via micro-incisions under local anesthesia. Following lesion identification using 2 mm instruments, integrated therapeutic procedures (tenotomy and suture fixation) were performed. This integrated diagnostic-therapeutic approach demonstrated high patient acceptance and satisfaction, with efficacy comparable to that of open and conventional arthroscopic techniques while demonstrating lower infection rates and a reduced risk of cartilage injury.⁶⁷ In 2024, Fariyike et al. introduced an NA technique for diagnosing and treating superior labral anterior-posterior (SLAP) tears in awake patients under local anesthesia. Combining miniaturized specialized micro-instrumentation, this approach enables real-time diagnosis and treatment under local anesthesia. NA’s miniaturized instrumentation avoids anesthetic complications, lowers healthcare costs, reduces postoperative swelling and pain, and accelerates recovery. Outpatient setting implementation decreases operating room utilization, while patient involvement in shared decision-making enhances satisfaction.⁶⁸ In 2024, Khan et al. developed a novel NA technique for diagnosing and treating septic shoulder arthritis in neonatal and infant populations, successfully managing two cases: a 3-week-old neonate and a 20-month-old infant. No revision surgeries were required, and complete resolution of infection was confirmed in both cases. This study demonstrates NA as a viable MIS approach for septic shoulder arthritis in anatomically complex neonatal and infant shoulders, representing the youngest documented application of NA to date (3-week-old neonate).⁶⁹

NA in shoulder applications is transitioning from purely diagnostic to integrated diagnostic-therapeutic modalities. Technological advancements will facilitate the development of specialized instrumentation to enhance NA’s procedural capabilities and expand its clinical indications. We summarize recent research findings and limitations of NA in shoulder joint pathologies in Table 2. Current clinical challenges in shoulder NA primarily include the steep learning curve associated with 0° visualization and procedural discomfort in awake patients under local anesthesia. Future research should focus on developing NA systems with optimized angulation and enhanced visualization tailored to shoulder joint anatomy. To mitigate patient discomfort, clinicians must strictly adhere to clinical indications while continuously refining technical protocols and instrumentation design. These advancements will accelerate the global implementation of advanced NA’s clinical benefits.

Table 2.

NA research highlights in the area of shoulder disorders

Study	Technical specifications	Design	Sample size	Key points	NA limitations
McMillan et al.5	Trice Mi-eye2 direction of view 0° diameter of the optic 1.9 mm	Retrospective study	300	Excellent adjunctive therapeutic properties. Low economic cost. Better security.	Indications have limitations.
Daggett et al.50	Trice Mi-eye2 direction of view 0°	Technical note (clinical)	None	Excellent diagnostic performance. Low economic cost. Lower time costs.	Indications have limitations.
Shafi et al.60	NanoScopeTM direction of view 0° diameter of the optic 2 mm	Technical note (clinical)	None	Lower economic costs. Lower time costs. Better security.	Indications have limitations. Steep learning curve.
Wagner et al.20	Trice Mi-eye direction of view 0°	Prospective clinical trial	50	Excellent diagnostic performance. Better security.	Indications have limitations.
Gauci et al.61	NanoScopeTM direction of view 0° diameter of the optic 1.9 mm	Technical note (clinical)	6	Excellent adjunctive therapeutic properties. Better security.	Indications have limitations. Steep learning curve.
Atoun et al.62	OmniCuffTM	Prospective, single-arm, multi-center study.	32	Excellent adjunctive therapeutic properties. Low economic cost. Better security.	None
Lavender et al.64	NanoScopeTM direction of view 0° diameter of the optic 1.9 mm	Technical note (clinical)	None	Excellent adjunctive therapeutic properties. Low economic cost. Better security. High patient acceptance	Indications have limitations. Steep learning curve. High cost of ancillary equipment.
Chowdhury et al.65	Trice Mi-eye direction of view 0°	Prospective clinical trial	22	Excellent diagnostic performance.	0° lens with blind field of view.
Khan et al.69	NanoScopeTM direction of view 0° diameter of the optic 1.9 mm	Technical note (clinical)	2	Excellent adjunctive therapeutic properties. Lower time costs. Better security.	Low irrigation volume.

Application of NA in foot and ankle joint

Ankle sprains are common in athletic sports and recreational activities. Functional ankle instability characterized by patient-perceived ankle instability affects up to 40% of individuals following acute ankle sprains. Following lateral ankle sprain (LAS), sensorimotor deficits are implicated in the development of chronic ankle instability (CAI).⁷⁰ CAI is not only a sequela of ankle pain but also a trigger for ankle pain, forming a vicious cycle that further impairs functional capacity and stability. The underlying pathophysiology of these persistent instabilities remains incompletely elucidated, hindering the development of precision targeted therapeutic interventions.⁷¹ Although MRI remains the standard modality for preoperative evaluation, studies have highlighted limitations in detecting cartilage pathology, with particularly low accuracy in assessing cartilage morphometric parameters in traumatic ankle injuries.^72,73 Conventional arthroscopy, the gold standard for diagnostic evaluation, poses technical challenges in implementation within the anatomically confined spaces of the foot and ankle, whereas NA has an optimal size profile. NA exhibits broad clinical applicability in foot and ankle disorders due to its miniature dimensions.¹⁸ NA enables concurrent performance of multiple procedures through a single portal, simplifying complex interventions while providing direct visualization of intra-articular pathology. This approach significantly enhances procedural efficiency in managing foot and ankle disorders, substantially reducing operative time and minimizing patient discomfort. The technique of arthroscopic access to the subtalar joint was first systematically described by Serge Parisien et al. in 1985 within a cadaveric model. In this study, arthroscopic examination of the subtalar joint was performed using 2.2-mm and 2.7-mm arthroscopes, demonstrating the feasibility of visualizing critical intra-articular structures. This work filled a critical gap in the development of minimally invasive diagnostic and therapeutic modalities for foot and ankle joints, pioneering the anatomical and technical framework for subsequent clinical translation of arthroscopic techniques.⁷⁴

In 2017, Akoh et al. conducted a cadaveric study evaluating the impact of arthroscopic portal selection, ankle positioning, and noninvasive traction on arthroscopic management of osteochondral lesions of the distal tibial plafond and talar dome. Using a 2.7-mm arthroscope, the posterior approach significantly enhanced visualization of tibial plafond lesions compared with anterior approaches. Arthroscopic accessibility was predominantly determined by intra-articular working space achieved through noninvasive traction rather than ankle flexion angle. Noninvasive traction provided sufficient intra-articular workspace to enable combined anterior-posterior arthroscopic approaches, which the authors advocated for lesion-specific optimization of diagnostic and therapeutic outcomes.⁷⁵ A 2022 retrospective study evaluated outcomes of NA management for posterior ankle impingement syndrome and anterior ankle impingement syndrome. NA demonstrated substantial advantages including: elimination of general anesthesia risks, accelerated rehabilitation timelines, improved patient engagement during procedures, seamless diagnostic-therapeutic integration, high patient satisfaction rates, and reduced temporal and economic burdens. However, notable limitations persist: inadequate micro-instrument durability, constrained operative space limiting large lesion management, and ongoing dependence on conventional arthroscopy or open procedures for complex pathologies. These findings underscore NA’s value in managing select ankle impingement cases while highlighting the need for continued technological innovation to expand its applications.^76,77,78 The peroneal and posterior tibial tendons are frequent sources of ankle pain owing to their essential roles in ankle stability and dynamic function. Pathologies affecting these tendons can produce pain, motion restriction, and potential long-term complications. Kanakamedala and colleagues demonstrated the clinical utility of IONA for both diagnosing and managing peroneal tendinopathies. Their work highlights IONA’s value in providing direct visualization of tendon pathology while enabling therapeutic interventions in an office setting, representing a significant advancement in minimally invasive foot and ankle care.⁷⁹ Building upon this approach, Dankert and colleagues developed a minimally invasive technique for managing posterior tibial tendon dysfunction in acquired adult flatfoot deformity (AAFD). The IONA technique enables dynamic assessment of tendon subluxation, providing functional evaluation superior to static MRI. Real-time visual feedback enhances patient comprehension of their pathology, facilitating rehabilitation engagement and contributing to accelerated recovery timelines and high postoperative satisfaction rates. Clinical evidence continues to accumulate supporting IONA’s efficacy in the comprehensive management of AAFD, particularly through its ability to provide both diagnostic confirmation and therapeutic guidance during a single office-based procedure.⁸⁰ In 2023, Stornebrink and colleagues pioneered a novel needle arthroscopy-guided technique for injectable implant placement in the management of OA affecting the foot/ankle and first carpometacarpal joints. This technique provides superior targeting precision and reduced invasiveness compared to conventional blind injection approaches. The technique demonstrates potential for adaptation to therapeutic joint lavage and combination therapies incorporating PRP.⁸¹ In 2024, Inoue and colleagues examined the prevalent use of 0°NA systems and characterized the associated learning curve. Through cadaveric experiments, they assessed performance variations and iatrogenic risks during ankle examinations using the 0° NA technique among physicians with different experience levels. NA manipulation requires specialized hand-eye coordination and precise anatomical knowledge. Even surgeons experienced in other arthroscopic techniques demonstrated an increased risk of damaging intricate structures (e.g., talar cartilage) when novice to NA, potentially causing iatrogenic injuries. The authors emphasize that NA operation necessitates ankle-specific training, and that comprehending NA technical characteristics and developing operational proficiency can significantly improve visualization during procedures.⁸²

This review summarizes recent advances and limitations of NA in foot and ankle applications (Table 3). Owing to the inherently constrained anatomical spaces in this region, the primary limitation of NA stems from inherent instrument rigidity. Improving device rigidity would enhance visualization within confined compartments, better utilize NA’s dimensional advantages, and broaden its indications for foot and ankle pathologies.

Table 3.

NA research highlights in the area of foot and ankle disorders

Study	Technical specifications	Design	Sample size	Key points	NA limitations
Mercer et al.76	Retrospective cohort study	NanoScopeTM direction of view 0° diameter of the optic 1.9 mm	10	Excellent adjunctive therapeutic properties. Low economic cost. Better security.	Indications have limitations.
Colasanti et al.77	Retrospective cohort study	NanoScopeTM direction of view 0° diameter of the optic 1.9 mm	31	Excellent diagnostic performance.	Patient may be uncomfortable in waking state.
Kanakamedala et al.79	Technical note (clinical)	Arthrex (Naples, Florida, US) Nanoscope nano tendoscopy system	None	Excellent diagnostic and therapeutic properties. Low economic cost. Better security.	Indications have limitations. Steep learning curve.
Dankert et al.80	Technical note (clinical)	Arthrex (Naples, Florida, US) Nanoscope nano tendoscopy system	None	Excellent diagnostic and therapeutic properties.	Indications have limitations. Steep learning curve.
Stornebrink et al.81	Technical note (clinical)	NanoScopeTM direction of view 0° diameter of the optic 1.9 mm	None	Excellent diagnostic and therapeutic properties.	Indications have limitations. Steep learning curve.

Application of NA in elbow joint

In the diagnosis and management of elbow pathologies, NA offers advantages including fewer surgical portals, smaller incisions, reduced tissue trauma, and minimal bleeding.⁸³ These characteristics help maintain a sterile operative field, thereby reducing infection risk and promoting patient recovery. Conventional arthroscopy presents substantial challenges in elbow applications owing to the joint’s highly constrained anatomical space and close proximity to critical neurovascular structures (e.g., ulnar nerve and brachial artery), which complicate both diagnostic and therapeutic procedures.⁸⁴

In 2020, researchers employed NA for direct elbow joint visualization, facilitating precise identification of key anatomical landmarks. This approach enabled comprehensive diagnostic assessment and accurate therapeutic instrument placement in both anterior and posterior compartments under NA guidance. Optimized portal positioning permitted direct-line visualization using a 0° lens system. The minimal incision size significantly reduces recovery duration while mitigating neurovascular injury risks. Through minimally invasive instrumentation and standardized protocols, this method establishes a viable paradigm for elbow pathology management, reducing postoperative swelling and improving rehabilitation outcomes.⁸⁵ In 2021, Fournier and colleagues described NA-assisted management of posterior elbow dislocation with coronoid and radial head fractures—a complex injury pattern termed the “terrible triad of the elbow” in orthopedic literature. Compared to conventional fluoroscopic-guided reduction, arthroscopically assisted reduction achieves fragment repositioning with <0.5 mm precision, significantly improving anatomical accuracy. The minimally invasive approach optimizes neurovascular protection and accelerates postoperative recovery. Current evidence supports NA as a valuable adjunct in intra-articular fracture management. Combining NA-assisted fixation with open ligament reconstruction offers a targeted approach for managing complex elbow instability.⁸⁶ Humeral epicondylitis represents a prevalent source of elbow pain, though optimal management remains debated.⁸⁷ In 2023, Vander Voort and colleagues evaluated the therapeutic efficacy of extensor carpi radialis brevis (ECRB) release using small-caliber NA for recalcitrant lateral epicondylitis. The procedure significantly improved postoperative QuickDASH (qDASH) and SANE (self-assessment numeric evaluation) scores, demonstrating high patient satisfaction with minimal complications. ECRB release performed under NA facilitation accelerates return to work while maintaining minimal invasiveness, reducing soft tissue injury, and mitigating neurovascular risks.⁸⁸ Accurate and safe portal placement remains pivotal for achieving successful outcomes in elbow arthroscopy.⁸⁹ In the same year, Rapariz and colleagues conducted a cadaveric study evaluating the anatomical safety and visualization capacity of elbow NA via an anterolateral approach. Utilizing ten fresh-frozen cadaveric specimens, the researchers documented that the anterior transbrachial approach maintains safe working distances from critical neurovascular structures (radial nerve, median nerve, and brachial artery) during NA procedures. This study provides the first systematic safety assessment of the anterolateral approach and introduces the HURT concept, defining the anatomical interval between the humerus, ulna, and radius (proximal to the radioulnar joint) as the “HURT” interval. The study demonstrated that NA provides complete visualization of both anterior and posterolateral elbow compartments through the HURT interval, thereby expanding potential clinical applications of NA in elbow surgery.⁸⁴ We have summarized the findings and limitations of NA within the elbow field in recent years (Table 4).

Table 4.

NA research highlights in the area of elbow disorders

Study	Technical specifications	Design	Sample size	Key points	NA limitations
Peters et al.85	Technical note (clinical)	NanoScopeTM direction of view 0° the smaller camera size 2 mm.	None	Excellent diagnostic and therapeutic properties. Better security. Lower time costs.	Steep learning curve. Insufficient mechanical strength.
Fournier et al.86	Technical note (clinical)	NanoScopeTM direction of view 0° the smaller camera size 2 mm	None	Excellent diagnostic and therapeutic properties. Better security.	Indications have limitations.
Vander Voort et al.88	Retrospective cohort study	NanoScopeTM direction of view 0° the smaller camera size 2 mm	13	Excellent diagnostic and therapeutic properties. Better security.	Steep learning curve.
Rapariz et al.84	Cadaver research	NanoScopeTM the handpiece tube is 9.5 cm long and has a 1.9 mm outer diameter.	10	Superior diagnostic performance. Better security.	Indications have limitations. Steep learning curve.

Application of NA in wrist joint

Carpal joint disorders demonstrate particularly high prevalence among women aged 40–49 years, typically manifesting as functional impairment and painful symptoms that substantially compromise both quality of life and occupational productivity. A recent Italian multicenter study established carpal arthroscopy as the preferred intervention for carpal tunnel syndrome, ligamentous injuries, and complex fractures, due to its favorable safety profile and minimally invasive characteristics. This technique enables direct visualization of intra-articular structures while minimizing soft tissue disruption, particularly valuable in the anatomically constrained carpal region where traditional open approaches carry higher risks of neurovascular injury and postoperative stiffness.⁹⁰

Recent literature describes expanding applications of NA techniques in the management of wrist disorders. In 2022, Reiser and colleagues evaluated the diagnostic performance of wrist NA in outpatient settings through a retrospective cohort study. The procedure, performed under local anesthesia, demonstrated safety, cost-effectiveness, and superior diagnostic accuracy compared to MRI.⁹¹ In two consecutive cadaveric studies, Munaretto, Dittman, and colleagues systematically assessed the safety of NA-assisted surgical access, demonstrating significantly reduced risks of neurovascular and tendon injuries compared to standard arthroscopy. Their work established an anatomical basis for advancing NA-based surgical techniques in wrist pathology, particularly through the identification of safe surgical corridors and optimization of portal placement strategies.^92,93 In the same year, Walinga and colleagues described an NA technique for managing septic arthritis across multiple joints, including the shoulder, elbow, wrist, knee, and ankle. This approach enables diagnostic-therapeutic integration through simultaneous synovial fluid aspiration and lavage, eliminating the diagnostic-to-treatment delay characteristic of conventional management protocols. The technique is particularly advantageous for emergency department management of septic arthritis, offering rapid diagnosis and immediate therapeutic intervention in a single procedure. This integrated approach significantly reduces time to appropriate antibiotic therapy and may improve clinical outcomes in acute joint infections.⁹⁴ A 2024 prospective diagnostic cohort study by Moses and colleagues compared the diagnostic performance of NA with 2.7-mm conventional arthroscopy, demonstrating complete diagnostic concordance between the two modalities for identifying TFCC lesions, scapholunate ligament tears, and associated pathologies. This high level of agreement supports NA’s reliability as a diagnostic tool while offering the additional benefits of minimal invasiveness and potential office-based application. The study provides compelling evidence that NA can serve as a viable alternative to conventional arthroscopy for the evaluation of common wrist pathologies.⁹⁵ The small diameter of NA facilitates access to constrained joint spaces for diagnostic evaluation. NA demonstrates particular utility in the navicular-major trapezium-small trapezium-trapezium joint, where it achieves significantly higher visualization quality scores compared to standard arthroscopes, offering a novel technological approach for diagnosing complex wrist pathologies. This section summarizes recent advancements and persistent limitations of NA in wrist applications (Table 5).

Table 5.

NA research highlights in the field of wrist disorders

Study	Technical specifications	Design	Sample size	Key points	NA limitations
Reiser et al.91	Retrospective cohort study	NanoScopeTM direction of view 0° diameter of the optic 1.9 mm.	34	Superior diagnostic performance. Low economic cost.	Steep learning curve. Risk of medical injury.
Munaretto et al.92	Cadaver research	NanoScopeTM direction of view 0° diameter of the optic 1.9 mm.	10	Superior diagnostic performance. Better security.	Risk of medical injury.
Walinga et al.94	Technical Note (Clinical)	NanoScopeTM direction of view 0° diameter of the optic 1.9 mm.	None	Excellent diagnostic and therapeutic properties. Better security. Lower time costs.	Steep learning curve. Low irrigation volume.
Dittman et al.93	Cadaver research	NanoScopeTM direction of view 0° diameter of the optic 1.9 mm.	10	Excellent diagnostic and therapeutic properties. Better security.	None
Moses et al.95	Prospective cohort study	NanoScopeTM direction of view 0° diameter of the optic 1.9 mm	20	Superior diagnostic performance.	NA image resolution was slightly lower than standard arthroscopy.

This review demonstrates that despite decades of technological development, NA remains limited in clinical adoption. Persistent technical and clinical constraints continue to limit NA’s transformative potential. Widespread implementation necessitates continued refinement through technical innovation and robust clinical validation. We systematically analyzed keywords reflecting NA’s advantages and limitations across all included studies. Keywords appearing more than three times were frequency-ranked and visualized according to occurrence frequency. As shown in Figure 2, NA demonstrates clear advantages in diagnostic performance and cost-effectiveness, as evidenced by the literature. The principal current advantages of NA include superior diagnostic performance and reduced economic burden. The most significant limitation involves the steep learning curve, primarily due to the ergonomic transition required when moving from conventional 30° arthroscopes to 0° visualization systems. Our analysis indicates that this 0° visualization paradigm differs substantially from conventional 30° optics, creating operational challenges during diagnostic-therapeutic procedures. Surgeons experienced with standard 30° scopes require significant adaptation to achieve proficiency with NA’s 0° systems. The compact design of NA significantly reduces recovery time and enhances real-time communication between physicians and patients, facilitating shared decision-making that significantly improves patient acceptance and satisfaction. However, studies have identified concerns regarding instrument rigidity, noting that variations in tip strength may increase iatrogenic injury risks, particularly among inexperienced practitioners. Our analysis confirms NA’s advantages in reducing complications, enhancing procedural safety, and accelerating recovery. These findings may support broader clinical implementation of NA technology, though additional training protocols and technical refinements addressing instrument durability would further optimize its safety profile and adoption rates.

Figure 2.

Visualization and frequency ranking of keywords for core advantages and main limitations of NA in included studies

The figure shows that NA’s core advantages include excellent diagnostic performance, remarkable cost-effectiveness, shortened postoperative recovery time, improved doctor-patient real-time communication, high patient acceptance and satisfaction, as well as reduced complications and enhanced procedural safety; its primary limitations involve a steep learning curve (caused by the ergonomic transition from conventional 30° arthroscopes to 0° visualization systems) and instrument rigidity issues, with tip strength variations potentially increasing iatrogenic injury risks, especially for inexperienced practitioners.

Accuracy of NA in the diagnosis and treatment of joint diseases

NA represents an emerging diagnostic-therapeutic modality for joint pathologies, offering significant advantages in both diagnostic accuracy and therapeutic precision. Its compact design facilitates access to constrained joint spaces while providing comprehensive intra-articular visualization. This direct visualization enables precise assessment of subtle structural changes, particularly in articular cartilage lesions, meniscal tears, and ligament injuries. NA effectively evaluates the extent of cartilage damage and identifies synovial hyperemia/edema, providing objective diagnostic evidence. Widespread implementation of NA could reduce diagnostic uncertainty and minimize missed diagnoses. Concurrently, NA’s micro-instrumentation facilitates tissue sampling (cartilage, synovium, or fluid) for advanced pathological analysis or targeted therapeutic interventions.³⁷ NA not only establishes a more comprehensive diagnostic foundation but also offers precise guidance for biologically active therapies including PRP techniques.³⁹ In certain clinical scenarios, NA enables direct visualization of early or subtle lesions that are undetectable by conventional imaging modalities, significantly enhancing early disease detection rates. This capability is particularly valuable for conditions where early intervention critically impacts treatment outcomes, potentially enabling therapeutic interventions at previously undetectable disease stages.⁹⁶ For instance, arthroscopy can identify mild synovial hyperplasia and inflammatory changes when conventional diagnostic tests yield inconclusive results. This early detection facilitates timely and targeted therapeutic interventions, thereby improving clinical outcomes and quality of life. At the societal level, it reduces economic burdens on healthcare systems, preserves workforce productivity, and promotes public health advancement.⁹⁷

Regarding therapeutic precision, NA provides distinct clinical advantages. Under direct visualization, NA enables surgeons to perform precise therapeutic interventions while minimizing iatrogenic damage to periarticular tissues. During therapeutic irrigation, NA ensures complete evacuation of inflammatory mediators, immune complexes, microbial debris, and other pathogenic substances. This comprehensive debridement optimizes the intra-articular microenvironment, promotes resolution of synovitis, and mitigates progressive joint degeneration. The combination of enhanced visualization and minimally invasive access makes NA particularly valuable for targeted therapies in confined joint spaces where traditional instruments cannot adequately reach.^14,94 For instance, in the management of neonatal septic arthritis, NA-assisted visualization through a posterior approach was combined with an anterior approach for comprehensive debridement and irrigation. Intraoperative synovial biopsy was performed followed by saline irrigation, achieving successful resolution in two infant cases without requiring reoperation.⁶⁹ For delicate procedures such as ligament repair, surgeons utilize NA’s high-resolution visualization to guide instrument placement under direct vision. Current NA applications include meniscal repair, cruciate ligament reconstruction, rotator cuff repair, and peroneal tendon pathology management. NA enhances procedural precision and success rates while reducing both operative time and recovery duration. In complex pathologies such as elbow terrible triad variants, NA-assisted reduction achieves <0.5 mm accuracy under arthroscopic visualization—surpassing fluoroscopic precision. This degree of repositioning accuracy remains difficult to achieve with conventional open approaches.⁸⁶

NA’s direct visualization capability facilitates real-time intraoperative assessment of therapeutic efficacy and allows dynamic modification of surgical strategy. In appropriate clinical scenarios, shared decision-making incorporates patient feedback during visual assessment, enhancing both satisfaction and procedural precision. The minimally invasive nature reduces complication rates, accelerates recovery timelines, and contributes to improved overall outcomes. Table 6 summarizes recent comparative studies evaluating NA against standard arthroscopy and MRI. Collectively, NA’s unique technological advantages significantly improve diagnostic-therapeutic accuracy in joint disorders, enhancing treatment precision and patient outcomes.

Table 6.

Comparison of diagnostic results of NA with standard arthroscopy or MRI

Study	Technical specifications	Region	Goal	Diagnostic accuracy (vs. MRI)	Diagnostic accuracy (vs. standard arthroscopy)
Halbrecht, J.L.46	1.7 mm fiberoptic arthroscope	USA	Knee examination	The diagnostic accuracy of NA for articular cartilage and meniscus tears is better than that of MRI.	None
Ike, R.W.48	Diameter of the optic 1.8 mm	USA	Knee examination	None	NA was particularly good at detecting meniscus, but was slightly inferior to standard arthroscopy for assessing the severity of cartilage and synovial lesions.
Gill et al.25	VSI diameter of the optic 1.4 mm	USA	Knee examination	MRI is significantly less accurate than NA in detecting cartilage damage.	The diagnostic accuracy of NA for meniscus, articular cartilage, and patellofemoral joint lesions is highly consistent with surgical arthroscopy.
Stornebrink et al.14	NanoScopeTM diameter of the optic 1.9 mm	Netherlands	Repair of torn meniscus of the knee	For lesions that are not sensitive to MRI, NA has a 20%–30% higher diagnostic accuracy.	NA has a diagnostic accuracy of 91% for meniscal red zone/red-white zone tears, which is close to 93% for conventional arthroscopy.
Stornebrink et al.81	NanoScopeTM diameter of the optic 1.9 mm	Netherlands	Bacterial arthritis	None	NA allows direct visualization of the nature of the joint fluid and tissue status, and the accuracy of assessing the severity of infection is comparable to that of conventional arthroscopy.
Savage-Elliott et al.37	NanoScopeTM diameter of the optic 1.9 mm	USA	Knee cartilage tissue biopsy sampling	NA provides dynamic joint motion and can localize cartilage defects more sensitively than MRI.	None
Ford.E.54	None	USA	Retrospective study of network integrity and patient	NA through real-time dynamic evaluation and reduction of still image errors.	None
Blankenburg et al.24	NanoScopeTM diameter of the optic 1.9 mm	GER	Comparison of NA visualization	NA through real-time dynamic evaluation and reduction of still image errors.	Overall visualization scores of NA for anatomical landmarks of the knee approached those of conventional arthroscopy.
McMillan et al.5	Mi-eye2 diameter of the optic 1.9 mm	USA	Case safety verification	NA diagnostic results are sufficient to support clinical decision making, especially in patients with contraindications to MRI.	None
Daggett et al.21	Mi-eye2	None	Shoulder joint examination	NA can increase diagnostic accuracy by 20%–30% through real-time dynamic observation.	None
Shafi et al.60	NanoScopeTM diameter of the optic 2 mm	None	Shoulder joint examination	NA improves diagnostic accuracy by 20–30% for MRI-insensitive lesions.	None
Wagner et al.20	Mi-eye	USA	Shoulder joint examination	NA is more accurate than MRI in diagnosing rotator cuff tears and anterior glenoid labral tears.	Overall diagnostic concordance between NA and surgical arthroscopy was 88%.
Gauci et al.61	NanoScopeTM diameter of the optic 1.9 mm	French	NA inferior biceps long head tendon (IOBT) dissection	NA has 100% diagnostic accuracy for LHB lesions.	None
Atoun et al.62	OmniCuffTM	USA、UK and Israel	Repair of rotator cuff injury with transosseous suture under NA	The patient was diagnosed with a complete rotator cuff tear by MRI, and 100% diagnostic accuracy was verified by intraoperative NA.	None
Khan et al.69	NanoScopeTM diameter of the optic 1.9 mm	UK	NA treatment of septic arthritis of the shoulder joint in neonates and infants	NA has a 100% diagnostic rate for infectious arthritis.

Cost-benefit analysis of NA in the diagnosis and treatment of joint diseases

NA, as a minimally invasive diagnostic and therapeutic technology, typically utilizes a 1.9-mm ultrafine arthroscopic lens. In the clinical management of joint disorders, NA demonstrates distinct cost-effectiveness advantages, particularly regarding economic and temporal parameters, with marked advantages over traditional MRI and conventional arthroscopic surgery. We analyzed both economic and temporal parameters to evaluate the overall clinical value across specific clinical scenarios. This analysis provides a framework for understanding NA’s potential to optimize healthcare resource allocation while maintaining diagnostic and therapeutic efficacy.

Economic cost analysis

The per-procedure cost of NA is significantly lower than that of conventional arthroscopic procedures. Conventional arthroscopic procedures require substantial resources, including large-diameter equipment (4-mm lenses, imaging systems, and perfusion pumps), operating room facilities, and anesthesia teams, averaging USD 3,000–5,000 per procedure. Operational costs escalate at approximately USD 1,500 per hour for extended procedures. In contrast, NA’s miniaturized instrumentation eliminates the need for complex ancillary systems and enables outpatient procedures under local anesthesia. Current NA systems cost USD 200–300 per use, with total procedural expenses (including anesthesia) ranging from USD 600 to 1,000—representing a 60%–80% cost reduction compared to traditional approaches. For example, in rotator cuff repair, NA combined with transosseous suturing techniques eliminates the need for expensive suture anchors. This approach saves approximately USD 335 per procedure in anchor costs while avoiding secondary surgical interventions necessitated by anchor-related complications.⁶²

Compared to MRI, diagnostic NA demonstrates significant cost advantages by integrating diagnostic and therapeutic capabilities. Whereas MRI at independent imaging centers averages USD 1,047–1,590 per procedure, outpatient NA consumables cost only USD 200–300. Crucially, NA enables synchronous therapeutic interventions (e.g., synovial biopsy, injections, or resections), thereby eliminating duplicate expenditures for separate diagnostic and therapeutic procedures. This integrated approach not only reduces direct costs but also minimizes indirect expenses associated with multiple clinical visits and procedural preparations.^8,28,39 Furthermore, NA demonstrates 95% localization accuracy for cartilage injuries, exhibiting superior sensitivity compared to MRI (85%) for detecting cartilage defects—particularly early-stage lesions that are indeterminate on MRI.³⁷ Conventional MRI demonstrates sensitivity rates of only 60%–70% for certain lesions, including partial-thickness rotator cuff tears and SLAP injuries. In contrast, NA can identify 10%–15% of cases missed by MRI through direct visualization and dynamic assessment, thereby reducing costs associated with ineffective treatments resulting from misdiagnosis. This enhanced diagnostic capability positions NA as a valuable tool for accurate treatment planning and cost-effective management of articular cartilage pathologies.⁶⁰ For common sports injuries such as meniscal tears, NA reduces misinterpretation associated with static imaging through real-time dynamic assessment, while also decreasing unnecessary diagnostic procedures and associated treatment costs. This combination of enhanced diagnostic accuracy and economic efficiency makes NA particularly valuable in the management of sports-related musculoskeletal injuries where both precise diagnosis and cost containment are important considerations.

Long-term complication management costs with NA are significantly lower, facilitating optimized healthcare resource allocation. The 2–3 mm incisions required for NA are associated with postoperative infection rates of <0.01%, substantially reducing antibiotic utilization and infection-related hospitalization costs.^14,69 Outpatient NA procedures reduce operating room utilization while allowing higher patient throughput, offering particular benefits in resource-constrained primary care settings. Table 7 summarizes economic cost of NA, all research demonstrating significantly lower overall costs compared to alternative diagnostic and therapeutic approaches. These economic advantages position NA as a valuable tool for healthcare systems seeking to maintain high-quality care while controlling costs.

Table 7.

Comparison of economic costs of NA with non-NA

Study	Region	Goal	Costs of NA	Costs of Non-NA
Halbrecht, J.L.46	USA	Knee examination	Equipment investment: $20,000. Single treatment cost: $600–800.	Equipment investment: $2.4 million. Single inspection cost: Average cost is $800, with some regions reaching $1,200.
Amin et al.23	USA	Diagnose and assist in the treatment of knee meniscus tears	Annual Total Medical Costs: Medicare Patients: Medial meniscus diagnosis and treatment $3,996; lateral meniscus $2,324; Commercial Insurance Patients: Medial meniscus diagnosis and treatment $5,361; lateral meniscus $3,193.	Annual Total Medical Costs: Medicare Patients: Medial meniscus diagnosis and treatment $4,776; lateral meniscus $2,638; Commercial Insurance Patients: Medial meniscus diagnosis and treatment $7,223; lateral meniscus $4,449.
Daggett et al.21	USA	Shoulder examination	Compared to MRI scans at independent imaging centers, each diagnosis saves $418; Compared to MRI scans at hospitals, each diagnosis saves $961.	Independent Imaging Center: Single shoulder MRI $1,047; In-hospital: Single MRI $1,590. MRA additional fee: An extra $100–$350 on top of the MRI cost.
Daggett et al.39	USA	Percutaneous anterior cruciate ligament repair, with NA and biological augmentation	NA repair costs 10%–20% less than traditional reconstruction procedures due to the absence of grafts and commercial biological agents, as well as lower anesthesia costs.	Traditional arthroscopic systems + grafts incur higher overall direct instrument costs than NA repair. Full anesthesia is required, resulting in significantly higher total costs compared to local anesthesia.
Sahi98	Canada	Examination and treatment of the knee	NA Meniscectomy/Diagnostic Procedure Cost: $45,590.27	Traditional Arthroscopic Meniscectomy/Diagnostic Procedure Cost: $152,369.75

Time cost analysis

Conventional MRI requires scheduled appointments (typically 3–7 days), followed by 1–2 days for interpretation and subsequent consultation, resulting in a 5- to 10-day diagnostic cycle. In contrast, NA completes the entire diagnostic-decision-therapeutic pathway during a single outpatient visit in 15–30 min. This facilitates rapid intervention for urgent conditions (e.g., acute joint infections), representing a breakthrough in diagnostic-therapeutic immediacy. Conventional surgical procedures require preoperative planning based on MRI findings. When intraoperative findings discordant with preoperative imaging occur (e.g., missed glenoid labral injuries), surgical duration increases substantially to allow for intraoperative strategy adjustments.^60,62 NA allows immediate diagnostic reassessment within 5–10 min through real-time visualization, eliminating procedural delays. This approach also enhances clinician-patient communication in outpatient settings, facilitating dynamic clinical decision-making that incorporates real-time patient feedback.^54,66

Traditional arthroscopic surgery requires suture closure and postoperative brace immobilization for ≥2 weeks due to larger portal sites, with rehabilitation typically lasting 6–8 weeks. Following NA procedures, suture closure is unnecessary, permitting same-day ambulation and reducing total rehabilitation duration by 30%–50%. For instance, in NA-assisted autologous chondrocyte implantation for knee repair, patients achieved immediate postoperative weight-bearing without requiring general anesthesia recovery time. In contrast, the conventional approach required a two-stage procedure involving two anesthetic events and hospitalization. The NA approach reduces productivity losses by facilitating earlier functional recovery, particularly benefiting working patients and reducing overall socioeconomic impacts of musculoskeletal conditions.^37,52,53 Based on US labor cost analyses, shortened rehabilitation cycles reduce direct healthcare expenditures (e.g., insurance claims) and indirect economic losses (e.g., lost productivity) by approximately USD 3,035 annually per patient.⁹⁷ These economic benefits are particularly significant for younger patients and working-age populations. Accelerated recovery timelines directly enhance workforce productivity restoration and reduce societal economic burdens. The combination of reduced direct medical costs and preserved economic productivity positions NA as a valuable intervention for maintaining workforce participation and reducing the overall economic impact of musculoskeletal conditions.⁹⁹

According to the research in Table 8, we summarized the operating time for NA and the patient recovery time, demonstrating significantly shorter physician operating times and patient recovery periods compared to conventional techniques. NA demonstrates significant cost-effectiveness advantages characterized by minimal capital investment, substantial time efficiency, and reduced overall expenditures. Compared to traditional arthroscopy, NA reduces surgical time requirements by over 50%. The minimally invasive nature of NA mitigates complication risks and facilitates rehabilitation processes. Furthermore, NA provides high diagnostic accuracy, making it particularly suitable for primary care settings, resource-limited regions, and patients with mild-to-moderate joint pathologies. With advancing technology adoption and decreasing consumable costs, NA is positioned to become a first-line option for joint disease management, optimizing healthcare resource utilization. These advantages suggest NA could significantly impact healthcare delivery models for musculoskeletal conditions.

Table 8.

Comparison of time costs of NA with Non-NA

Study	Region	Goal	Comparison of operating time costs between NA and Non-NA	Comparison of recovery time costs between NA and Non-NA
Shafi et al.60	USA	Shoulder examination	The operating time for NA is only one-third to one-half that of traditional arthroscopy.	Recovery time for NA is shortened by more than 50% compared to traditional arthroscopy.
Atoun et al.62	USA, UK, and Israel	Needle-based arthroscopic transosseous rotator cuff repair	NA achieves a more streamlined surgical process, shorter operating times, and high surgical efficiency.	Screw fixation may prolong recovery time due to the risk of complications.
Stornebrink et al.14	Netherlands	Initial management of spontaneous bacterial arthritis	The procedure is completed under local anesthesia within 20–40 min, significantly shorter than traditional arthroscopic surgery.	NA requires virtually no postoperative recovery period, allowing patients to quickly resume normal activities. In contrast, traditional surgical procedures involve trauma and anesthesia, resulting in a significantly longer recovery period.
Stornebrink et al.51	Netherlands	Meniscus tear repair surgery	NA procedures take only half to two-thirds the time of traditional arthroscopy, require no additional time for anesthesia, and can be completed on an outpatient basis.	The recovery period for NA is only half that of traditional arthroscopy, allowing patients to quickly return to normal daily activities and work.
Shubert et al.38	USA	Posterior cruciate ligament (PCL) reconstruction	NA assistance reduces surgical time by 10%–20% through optimized visualization and minimized instrument switching.	Although both methods share the same overall recovery period, NA’s minimally invasive and precisely targeted nature reduces recovery delays caused by postoperative complications.
Savage-Elliott et al.37	USA	Obtain knee cartilage samples while performing diagnostic arthroscopy during surgery.	Under local anesthesia, the procedure takes 30 to 60 min, significantly less than the operating room time required for traditional arthroscopic surgery.	NA has virtually no significant recovery period, allowing patients to quickly resume normal activities; traditional arthroscopy requires several weeks of recovery and may impact the progress of subsequent treatments.

Discussions

NA demonstrates substantial potential in joint disease management due to its key technical advantages: minimally invasive nature (requiring only small, often suture-free incisions), rapid recovery times, and high diagnostic accuracy through detailed intra-articular visualization. These characteristics collectively contribute to reduced postoperative pain, decreased risk of complications, and improved patient outcomes compared to conventional arthroscopic approaches. The combination of these features positions NA as an increasingly valuable tool in modern orthopedic practice, particularly in outpatient settings where efficiency and patient comfort are paramount.^{5,14,21,24,25,37,38,46,48,51,54,60,61,62} As a significant innovation in minimally invasive arthroscopy, the clinical value and development potential of NA continue to grow with ongoing technological advancements and increasingly refined clinical requirements. However, a balanced perspective necessitates objective acknowledgment of the current limitations of NA technology. Primarily, the mechanical properties of current instrumentation require improvement to accommodate more complex surgical procedures. Additionally, the learning curve associated with transitioning from traditional arthroscopic systems to NA’s unique visualization paradigm presents a significant challenge that must be addressed through specialized training programs and simulation-based education^{38,51,60,67,85}; Secondly, the visualization capabilities of current mainstream 0° field-of-view systems require optimization to address challenges associated with surgical ergonomics and limited field of view^{8,20,24,38,39,51,60,66,67,68}; miniaturization reduces physical rigidity, leading to deflection that risks image quality and control; this could be mitigated by developing shafts from high-strength composites or using reinforcing sheaths. Moreover, the prevalent 0° optics differ from the familiar 30°, hindering the ability to look around corners in tight spaces like the wrist or ankle; creating miniaturized 30° lenses is thus crucial to restore surgeons’ spatial awareness and visualization. Furthermore, the clinical evidence supporting NA technology remains limited, predominantly comprising low-level evidence studies including small-sample retrospective analyses and case series. Therefore, rigorously designed, large-scale prospective randomized controlled trials and high-quality cohort studies are warranted. Such studies would provide higher-level evidence regarding NA’s diagnostic accuracy, therapeutic efficacy, and long-term outcomes for specific indications, including early OA diagnosis, evaluation of particular injury patterns, and adjunctive minimally invasive management of joint disorders. This evidence generation is crucial for establishing standardized protocols and expanding NA’s applications in clinical practice.

Despite these limitations, current evidence highlights several advantages of NA. Specifically, for diagnosing joint pathologies including meniscal tears and articular cartilage injuries, NA demonstrates diagnostic accuracy and sensitivity comparable to or exceeding conventional MRI.^{5,20,24,25,37,46,51,54,60,61,62} Furthermore, the procedure demonstrates greater time-efficiency and cost-effectiveness, significantly reducing the healthcare burden on patients.^{8,21,37,39,46} The core value of NA derives from its minimally invasive nature and potential to transform office-based arthroscopy. Currently, NA serves as a valuable tool for early detection of joint pathologies, providing opportunities for early intervention. However, current therapeutic applications remain relatively limited, with NA primarily serving as a diagnostic modality. This diagnostic strength, combined with its cost-effective profile, positions NA as an important advancement in musculoskeletal care despite existing limitations.

Future development of NA technology will focus on enhancing device mechanical properties, advancing optical systems (e.g., multi-angle or adjustable lenses with higher-resolution imaging), and improving manipulation-visualization precision advances critical for addressing current limitations. Priority applications should include early knee OA screening and monitoring, rapid bedside or office-based assessment of acute sports injuries, and dynamic monitoring of synovial pathology in inflammatory arthropathies. As a highly digital device, NA’s output is a digital video signal that transmits live video streams over the network, making it an ideal platform for telemedicine. With ongoing advancements in enabling technologies, NA’s functional capabilities and clinical applications are anticipated to expand, potentially benefiting broader patient populations. Regarding healthcare policy and reimbursement systems, inclusion of NA procedures for appropriate indications in insurance coverage has facilitated technology adoption and cost-effectiveness by aligning with clinical requirements. Technological advances in materials science (e.g., nano-enhanced optical fibers for improved durability and image quality) and artificial intelligence/robotics (enabling assisted navigation, automated lesion detection, and motion stabilization) may expand NA’s applications beyond major joints to spinal and other complex small joints. As a joint field with deep anatomy and limited operating space, the hip joint may also become a stage where the advantages of NA technology can play an important role in the future. The development of NA is by no means limited to its current form, and its huge potential in the future lies in the deep integration of cutting-edge technologies such as AI, robotics, and advanced imaging as a minimally invasive platform. It directly solves its core limitations in visualization, operational accuracy, and objective diagnosis, thereby leading arthroscopic surgery toward intelligence and precision. Consequently, NA’s role may evolve from a diagnostic modality to a comprehensive platform with minimally invasive therapeutic capabilities, potentially transforming the management of musculoskeletal disorders across multiple clinical specialties.

In summary, NA constitutes a substantial advancement in minimally invasive approaches to joint disorders. The functional capabilities and clinical applications of NA will continue to evolve synergistically with advances in technology, instrumentation, and methodology. NA is anticipated to evolve into a pivotal technology for joint health management, providing more precise, accessible, and cost-effective diagnostic and therapeutic solutions. This review systematically examines NA applications across multiple joints (knee, shoulder, ankle, and elbow), assessing current advancements, addressing existing challenges, and identifying future research directions to guide subsequent technological innovation and clinical translation. The integration of NA into mainstream orthopedic practice holds promise for transforming the management of musculoskeletal disorders through enhanced diagnostic accuracy and therapeutic precision.

Conclusions

Over the past three decades, NA has substantially expanded its surgical indications and clinical applications. NA is now established for managing pathologies of major joints (knee, shoulder, ankle, and elbow) and selected small joints (including pediatric applications). Evidence supports the utility of NA for dynamic assessment of sports injuries and optimization of therapeutic decision-making. For specific indications such as meniscal and chondral knee injuries, NA demonstrates potential to surpass MRI owing to superior diagnostic accuracy in evaluating pathological tissues, along with enhanced cost-effectiveness. However, clinical implementation faces persistent challenges: the 0° visualization paradigm differs substantially from conventional 30° arthroscopy, creating a steep learning curve, while limitations in instrument rigidity raise safety concerns. Future development should prioritize core system enhancements—including optimized viewing angles and improved instrument strength—to address current limitations. Through continued innovation, NA may achieve its full potential as an integrated diagnostic-therapeutic platform. Collectively, existing evidence confirms the significant clinical value of NA, supporting its broader adoption in appropriate clinical scenarios.

Acknowledgments

This work was supported by the Science and Technology Development Project of Jilin Province for Distinguished Young Science and Technology Talent Project (no. 20240602011RC), the Transverse Research Project (no. 2023220001000025), and the Science and Technology Capacity Enhancement Program of Jilin Provincial Health Commission (no. 2022JC040).

Author contributions

M.L. contributed to the conception and design of this study. Q.Z. and M.Y. supervised the research process. K.Z. and J.X. conducted the data analysis. The manuscript was written by M.L., while Q.Z. undertook its revision and polishing. M.L. and M.Y. were responsible for visualizing the results, and all authors revised and approved the final manuscript.

Declaration of interests

The authors declare that this study was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.