Abstract
Background
Achilles tenotomy is an integral component of the Ponseti method for treating congenital talipes equinovarus (CTEV). Although traditionally performed using a scalpel in a sterile setting, percutaneous needle tenotomy has emerged as a minimally invasive alternative. However, comparative evaluations of these techniques using clinical and ultrasonographic parameters remain limited.
Methods
This retrospective, dual-center study included 145 feet from 95 pediatric patients treated with the Ponseti method between 2022 and 2024. Seventy-two feet underwent percutaneous needle tenotomy, while 73 feet received traditional percutaneous scalpel tenotomy. Demographic characteristics, initial Pirani and Dimeglio scores, maximum dorsiflexion angles, and ultrasonographic findings (tendon thickness, width, length, echotexture, and elastography values) were compared between groups. All ultrasonographic evaluations were performed using standardized protocols and blinded assessment.
Results
There were no significant differences between groups in terms of age, sex, or initial clinical scores (p > 0.05). Tendon stiffness (kPa), shear wave velocity (m/s), and morphologic parameters (thickness, length, and fibril organization) were similar across both groups. Functional outcomes, as assessed by maximum ankle dorsiflexion angle, also did not differ significantly (p > 0.05).
Conclusions
Percutaneous needle Achilles tenotomy is a safe and effective alternative to percutaneous scalpel tenotomy, yielding comparable clinical, functional, and ultrasonographic outcomes. Both techniques appear equally reliable in terms of tendon healing and biomechanical integrity.
1
Introduction
Congenital clubfoot (congenital talipes equinovarus) is one of the most common orthopedic deformities encountered in infancy. If left untreated, it can lead to permanent functional impairment and severe gait abnormalities. The condition affects approximately 1–2 per 1000 live births . The Ponseti method is a well-established, evidence-based approach that provides high success rates in correcting this complex deformity through manipulation and serial casting . However, to achieve sufficient dorsiflexion of the ankle, Achilles tendon tenotomy is frequently required as part of the treatment protocol ,, .
The traditional scalpel tenotomy is generally performed in a sterile operating room and may require sedation, although many centers now perform it under local anesthesia. Compared to percutaneous needle tenotomy, however, the scalpel technique still typically requires more stringent sterile conditions and sedation. This can reduce patient comfort and present logistical challenges in certain centers. As a result, percutaneous Achilles tenotomy performed with 16G–18 G needles has gained popularity in recent years as a practical, rapid, and less invasive alternative ,, .
Needle tenotomy has been shown to be effective in achieving ankle dorsiflexion and offers advantages in terms of shorter procedure time, absence of skin incision, reduced infection risk, and simpler postoperative care. Additionally, this technique leaves minimal scarring and can be performed in an outpatient setting without the need for sedation ,, .
To more objectively evaluate the outcomes of this technique, the use of ultrasonography (USG) has become increasingly common in recent years. USG provides a noninvasive and reliable method to assess postoperative parameters such as Achilles tendon thickness, length, and echotexture. It is particularly suggested that the needle technique causes less trauma to the tendon, leading to smoother and more homogeneous healing , .
Chandirasegaran and colleagues observed statistically significant changes in tendon length and thickness after percutaneous needle tenotomy, suggesting potential beneficial effects on tendon morphology .
Although our initial hypothesis was that percutaneous needle tenotomy, as a less invasive and closed technique, might offer superior outcomes in terms of tendon healing, length, and thickness compared to the traditional scalpel method, we ultimately expected both techniques to yield comparable results in these aspects.
2
Materials and methods
Between 2022 and 2024, a total of 121 patients diagnosed with congenital talipes equinovarus (CTEV) and treated with the Ponseti method at two tertiary care centers were evaluated for inclusion. Of these, 10 were excluded due to incomplete ultrasonographic data, 6 due to underlying neuromuscular disorders, 5 because of previous surgical intervention for clubfoot, and 5 due to a follow-up period shorter than six months. After applying exclusion criteria, 145 feet from 95 patients were included in the final analysis ( Fig. 1 ). The study received ethical approval from both institutional review boards and was conducted in accordance with the principles of the Declaration of Helsinki.
Flowchart of the patient inclusion process.
Inclusion criteria were as follows: diagnosis of idiopathic clubfoot, initiation of treatment within the first six months of life, treatment performed according to the Ponseti method, complete clinical and ultrasonographic data available, and a follow-up duration of at least one year. Feet with secondary or syndromic clubfoot deformities (e.g., arthrogryposis or meningomyelocele), those with prior Achilles tendon surgery, or cases with incomplete digital foot records were excluded.
All patients underwent the standard Ponseti protocol, and Achilles tenotomy was performed as the final step of the treatment process. In patients requiring tenotomy, the method—needle or scalpel—was randomly assigned. Based on the tenotomy method used, patients were divided into two groups. Group 1 underwent percutaneous Achilles tenotomy using a 16 G hypodermic needle, while Group 2 received percutaneous scalpel tenotomy using a #15 blade. Both groups were followed using the same postoperative protocol.
For each foot, the following data were recorded: sex, side of involvement (right, left, or bilateral), age at initial casting (in days), time since final cast removal (in weeks), initial Pirani and Dimeglio scores, maximum dorsiflexion angles, and final ultrasonographic findings. At final follow-up, ultrasonographic measurements of the Achilles tendon—including mediolateral width, anteroposterior thickness, and longitudinal length—were obtained in millimeters for both lower extremities. The tendon volume was calculated as width × thickness × length. Missing length values were imputed using the group-specific mean. B-mode ultrasonography was used to assess tendon echogenicity and fibrillar organization, while elastography provided measurements of tendon stiffness (kPa) and shear wave velocity (m/s). Functional assessment included manual goniometric measurement of the maximum dorsiflexion angle.
Ultrasound examinations were performed using a high-frequency linear transducer (GE L8–18i-D, General Electric Healthcare), which offers high spatial resolution and superficial penetration, making it ideal for pediatric musculoskeletal imaging. The Achilles tendon was evaluated in both axial and longitudinal planes. In axial imaging, anteroposterior (AP) and mediolateral (ML) diameters were measured. Shear wave elastography (SWE) was performed with the probe centered over the surgical site, and tendon stiffness and elasticity were assessed using three different regions of interest (ROIs) ( Fig. 2 ). Quantitative measurements included Young’s modulus (kPa) and shear wave velocity (m/s).
In the axial view of the Achilles tendon, shear wave elastography was performed over the surgical area to evaluate tendon stiffness and elasticity across three regions of interest (ROIs), along with quantitative measurements of Young’s modulus (kPa) and shear wave velocity (m/s), while anteroposterior (AP) and mediolateral (ML) diameters were also recorded.
In longitudinal views, SWE was similarly applied to the surgical region to evaluate tendon biomechanics ( Fig. 3 ). Anatomically, the Achilles tendon originates proximally from the musculotendinous junction of the gastrocnemius-soleus complex and inserts distally into the calcaneus.
In the longitudinal view of the Achilles tendon, the shear wave elastography map focused on the surgical area demonstrates tendon stiffness and elasticity across three different regions of interest (ROIs), along with quantitative values for Young’s modulus (kPa) and shear wave velocity (m/s).
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Statistical analysis
Statistical analyses were performed using SPSS version 26.0 (IBM Corp., Armonk, NY, USA). Normality of continuous variables was evaluated using the Kolmogorov–Smirnov test. Depending on the distribution of the data, comparisons were made using either the independent samples t -test or the Mann–Whitney U test. Categorical variables were compared using the chi-square test. Data are presented as mean ± standard deviation (SD), and a two-sided p-value of less than 0.05 was considered statistically significant.
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Results
4.1
Patient demographics
This study included 145 feet from 95 pediatric patients diagnosed with congenital clubfoot and treated with the Ponseti method, including Achilles tenotomy. Fifty patients had bilateral involvement, and 45 had unilateral involvement. Seventy-two feet underwent percutaneous Achilles tenotomy with a 16 G needle (needle group), while 73 feet underwent percutaneous scalpel tenotomy (scalpel group). There were no significant differences between the groups in terms of age, sex, or laterality. The mean age at initiation of casting was 27.3 ± 39.2 days in the needle group and 37.1 ± 47.3 days in the scalpel group (p = 0.1251). Other demographic variables, such as sex distribution, affected side (right, left, or bilateral), and duration since final cast removal, were also similar between groups ( Table 1 ).
Table 1
Comparison of demographic and clinical score characteristics between the groups.
| Parameter | Needle Group (mean±SD) | Scalpel Group (mean±SD) | p-value |
|---|---|---|---|
| Sex (Male/Female) | 48/ 24 | 50/ 23 | 0.891 |
| Side (Right/Left) | 38/ 34 | 36/ 37 | 0.762 |
| Age at Cast Start (days) | 27.35 ± 39.20 | 37.14 ± 47.31 | 0.1773 |
| Pirani Score (Right) | 3.67 ± 1.87 | 3.26 ± 2.09 | 0.2190 |
| Pirani Score (Left) | 2.72 ± 2.19 | 3.14 ± 1.93 | 0.2133 |
| Dimeglio Score (Right) | 11.17 ± 5.30 | 10.40 ± 6.11 | 0.4194 |
| Dimeglio Score (Left) | 8.35 ± 6.80 | 9.70 ± 6.20 | 0.2127 |
| Months Since Last Cast | 15.26 ± 3.63 | 15.05 ± 3.52 | 0.7256 |
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