A single-center, single-blinded, randomized, parallel-group, non-inferiority trial to compare the efficacy of a 22-gauge needle versus a 15 blade to perform an Achilles tendon tenotomy in 244 clubfeet—study protocol

BACKGROUND: Achilles tendon tenotomy is an integral part of the Ponseti method, aimed at correcting residual equinus and lack of dorsiflexion after correction of the adductus deformity in clubfoot. Percutaneous tenotomy using a number 15 scalpel blade is considered the gold standard, resulting in excellent results with minimal complications. The use of a large-bore needle to perform Achilles tendon tenotomies has been described in literature, but a large-scale randomized controlled trial is currently lacking. In this trial, we aim to show the non-inferiority of the needle tenotomy technique compared to the gold standard blade tenotomy technique. METHODS: We will randomize 244 feet into group A: needle tenotomy or group B: blade tenotomy. Randomization will be done using a block randomization with random block sizes and applying a 1:1 allocation to achieve an intervention and control group of the exact same size. Children will be evaluated at 3 weeks and 3 months post-tenotomy for primary and secondary clinical outcomes. The primary clinical outcome will be the range of dorsiflexion obtained the secondary clinical outcomes will be frequency of minor and major complications and Pirani score. The non-inferiority margin was set at 4°, and thus, the null hypothesis of inferiority of the needle technique will be rejected if the mean difference between both techniques is less than 4°. The statistical analysis will use a multi-level mixed effects linear regression model for the primary outcomes and a multi-level mixed effects logistic regression model for the secondary clinical outcomes. The physician performing the evaluations post-tenotomy will be the only one blinded to group allocation. TRIAL REGISTRATION: This trial was registered prospectively with ClinicalTrials.gov registration number: NCT04897100 on 21 May 2021. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13063-023-07728-9.