Abstract
Background
Needle arthroscopy (nanoscopy) is gaining recognition as a minimally invasive alternative to standard arthroscopy, offering improved visualization of intra-articular structures. This cadaveric study evaluates its feasibility, effectiveness, and learning curve in the ankle joint.
Methods
Twenty fresh-frozen cadaveric ankle specimens were examined using a 1.9 mm NanoScope™ (Arthrex, Naples FL, USA). Four orthopedic surgeons (two experienced– Group 1, two inexperienced– Group 2) performed the procedures. Visualization of five key anatomical structures was assessed using a 5-point Likert scale.
Results
Needle arthroscopy enabled complete visualization of all predefined structures. The tibiofibular syndesmosis had the highest visualization scores (Group 1: 4.8 ± 0.16; Group 2: 4.5 ± 0.26), while the visualization of the ankle joint was the most challenging (Group 1: 4.53 ± 0.36; Group 2: 3.53 ± 0.51; p < 0.05). Deltoid ligament visualization was significantly better in experienced surgeons (4.65 ± 0.23 vs. 3.75 ± 0.29; p = 0.048).
Conclusion
Needle arthroscopy enhances visualization of deep ankle structures while remaining minimally invasive. Despite a learning curve, visualization scores were comparable across experience levels. Further research is needed to assess clinical outcomes and optimize training.
1
Introduction
Minimally invasive techniques are reshaping orthopedic surgery, with needle arthroscopy emerging as a less invasive alternative to standard arthroscopy. Initially developed in the 1990s, its adoption was limited by poor image quality and handling challenges. Advances in optics and instrument design have since improved its clinical utility.
The ankle joint is particularly challenging due to its compact structure and deep ligamentous attachments. Standard 4.0 mm arthroscopes often fail to access posterior regions. A 2.7 mm arthroscope, designed for narrow joints and pediatric patients, offers improved access and is available in 30° and 70° versions. Needle arthroscopy, with its 1.9 mm diameter and superior maneuverability, allows visualization of structures such as the deltoid ligament and posterior malleolus, often inaccessible with larger instruments. This is particularly beneficial for managing lateral ankle instability and syndesmotic injuries.
Beyond diagnostics, needle arthroscopy is increasingly applied therapeutically. It is valuable for confirming syndesmotic instability and guiding suture-button fixation, providing real-time assessment of joint widening and cartilage lesions, reported in 94 % of elite athletes undergoing stabilization. Nanoscopy also enables early diagnosis and minimally invasive treatment of osteochondral defects, with superior cartilage assessment compared to MRI.
Anterior ankle impingement, traditionally treated with open surgery or standard arthroscopy, can be addressed in-office with needle arthroscopy under local anesthesia, reducing costs and recovery time. Recent studies confirm its effectiveness for soft tissue and osseous impingement with minimal trauma.
Despite these advantages, technical challenges remain for surgeons less experienced with ankle arthroscopy, particularly regarding spatial orientation and stabilization. This study aims to evaluate the feasibility, accuracy, and learning curve of needle arthroscopy in the ankle joint using a cadaveric model.
2
Methods
2.1
Specimens
This study utilized 20 fresh-frozen cadaveric ankle specimens from 20 donors. The specimens included limb sections extending from the knee to the foot. Radiographic evaluation confirmed the absence of osteoarthritis and fractures.
2.2
Needle arthroscopy procedure
A 1.9 mm NanoScope™ (Arthrex, Naples, FL, USA) was used for all procedures. The examination followed the standardized protocol described by Vega et al.
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1.
Lateral area , including the lateral gutter.
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2.
Central area , including the anterior tibial rim.
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3.
Medial area , including the medial gutter.
2.3
Talar neck
Four orthopedic surgeons—two experienced and two inexperienced —performed anteromedial (AM) and anterolateral (AL) portal placements without joint traction .
The visualization effects are presented in Figs. 1–6 .
Anterior Tibiofibular Ligament (NanoScope™).
Anterior view of ankle joint (NanoScope™).
Deltoid Ligament (NanoScope™).
Lateral compartment of the ankle joint (NanoScope™).
Syndesmosis (NanoScope™).
Posterior Inferior Tibiofibular Ligament (NanoScope™).
2.4
Evaluation
Five anatomical structures were assessed for visualization quality using a 5-point Likert scale (1 = no visualization, 5 = complete visualization): (a) Entire ankle joint, (b) Anterior talofibular ligament (ATFL), (c) Tibiofibular syndesmosis, (d) Posterior malleolus, (e) Deltoid ligament.
2.5
Statistical analysis
Statistical analysis was performed using Statistica 13.3 (Tibco, Palo Alto, CA, USA). A significance level of 0.05 was applied for all analyses.
The Shapiro-Wilk test was used to assess the normality of data distribution. Based on the results, either parametric or non-parametric statistical tests were applied.
To compare the two independent groups, the Mann-Whitney U test was used, as the data did not follow a normal distribution. This test was applied to assess differences in overall joint visualization and deltoid ligament visualization.
All statistical tests were two-tailed, and p- values below 0.05 were considered statistically significant.
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