The study analyzes the effectiveness of different ultrasound-guided surgical techniques to treat gastrocnemius contracture and equinus deformity, conditions that affect ankle dorsiflexion and can cause problems such as plantar fasciitis and metatarsalgia. Four techniques were compared: Strayer, Plantaris, Baumann and Gastro-soleo, evaluating their impact on the improvement of ankle motion.

Equinus deformity is a common deformity caused by contracture of the triceps suralis, especially the gastrocnemius. This causes limitation of ankle dorsiflexion, pain and gait incompetence. Treatment includes surgical lengthening techniques such as gastrocnemius tendon recession (Strayer) or isolated plantar tendon transection.

The minimally invasive Strayer technique is effective but carries morbidity. Ultrasound-guided plantar tendon transection is a new minimally invasive technique but its effectiveness has not been well established.

The study will evaluate the effectiveness of four ultrasound-guided surgical techniques in improving ankle dorsiflexion in patients with equinus due to gastrocnemius contracture. The Strayer, Plantaris, Baumann, and Gastro-soleo techniques will be compared, analyzing their impact on mobility before and after surgery.

Patients will be assigned to different groups based on the applied technique, following specific inclusion and exclusion criteria for each procedure. For statistical analysis, Wilcoxon and paired Student's t-tests will be used, depending on data distribution. Additionally, a repeated-measures ANOVA with Tukey's post-hoc tests will be applied to compare the results between techniques and determine which achieves the greatest increase in dorsiflexion range.

All techniques are expected to significantly improve dorsiflexion, with differences in the magnitude of change. The Gastro-soleo technique is anticipated to show the highest absolute increase, while Strayer may be the most statistically effective.

The study complies with ethical requirements and has the approval of the ethics committee of the Catholic University of Valencia.

Inclusion Criteria:

• Clinical and radiological diagnosis of clubfoot.
• Limitation of passive dorsiflexion of the ankle (<10°).
• Associated pain and functional limitation
• Absence of previous ankle/foot surgeries

Exclusion criteria:

• Neurologic or congenital disease.
• Advanced ankle joint osteoarthritis
• Peripheral vascular insufficiency
• Uncontrolled diabetes mellitus
• Severe hepatic or renal disease
• Coagulopathies or anticoagulant therapy

To reduce bias, the study will use double-blind blinding. Patients will not know the group to which they have been assigned. In addition, the assessors performing the ankle range of motion measurements by goniometry will be blinded to each patient's treatment group.

Randomization to each group will be performed using opaque sealed envelopes that will be opened in the operating room just prior to surgery. Neither the surgeon nor the patient will know the assignment until that time.

The statistical analysis will also be performed in a blinded manner, without the statistician knowing the intervention received by each group. Only after the analysis will the groups be unblinded.

In this way, the aim is to reduce the possibility of knowledge of the assigned treatment influencing the evaluation of the results, both on the part of the patients and of the evaluators and analysts.