Here is the design of a clinical trial:

Official Title: Outcome and Complications After Percutaneous Needle Versus Blade Achilles Tenotomy in Clubfoot Treated With the Ponseti Method

Included conditions:
- Club Foot
- Achilles Tendon Surgery

Study Armgroups:
- {'label': 'Needle tenotomy', 'type': 'EXPERIMENTAL', 'description': 'Patient will receive an Achilles tendon tenotomy using a 22G needle when randomized into the needle group. Follow-up to measure dorsiflexion and register complications will be assured at 3 weeks and 3 months.', 'interventionNames': ['Procedure: Achilles tendon tenotomy']}
- {'label': 'Blade tenotomy', 'type': 'ACTIVE_COMPARATOR', 'description': 'Patient will receive an Achilles tendon tenotomy using a 11 blade when randomized into the needle group. Follow-up to measure dorsiflexion and register complications will be assured at 3 weeks and 3 months.', 'interventionNames': ['Procedure: Achilles tendon tenotomy']}

Interventions:
- {'type': 'PROCEDURE', 'name': 'Achilles tendon tenotomy', 'description': 'Achilles tendon tenotomy during Ponseti treatment for clubfoot', 'armGroupLabels': ['Blade tenotomy', 'Needle tenotomy']}

Primary Outcomes:
- {'measure': 'Dorsiflexion', 'description': 'Ankle dorsiflexion measured in degrees', 'timeFrame': '3 months'}

Please estimate the sample size based on the assumption: 
Alpha (significance level) is set at 5%, power is set at 95%, and the standard deviation is 9.02. A dropout rate of 10% is expected during the first year of follow-up.
Sample size
        
          Change of sample size after initial protocol creation
          The sample size for this trial has been adapted after submission of the initial protocol. In preparation of submission of the final protocol for publication, it was brought to our attention that a sample size calculation for a non-inferiority trial requires the determination of a non-inferiority margin. The initial sample size, which had been calculated based on an expected difference in success rate between both tenotomy techniques, has been abandoned and replaced by a sample size calculation based on the calculation of an inferiority margin. The full calculation can be found below.
        
        
          Non-inferiority margin determination
          Dorsiflexion was defined as âtrue dorsiflexionâ at the ankle joint and not mobility at the midfoot level. True maximal dorsiflexion measures the tibiocalcaneal angle when the foot is put in maximum dorsiflexion. Only a limited number of studies report on the range of dorsiflexion achieved after tenotomy. We identified two studies that used post-tenotomy radiographs to assess for dorsiflexion range [19, 20]. One study assessed evolution of ankle dorsiflexion over time post-tenotomy. The study states that children who still maintained 15Â° dorsiflexion at age 12 all had a minimum of 20Â° dorsiflexion under the age of 3Â years [21]. This raises the question if the ideal dorsiflexion under the age of 3Â years should be 20Â° instead of 15Â° as initially proposed by Ponseti. We identified 17.5Â° dorsiflexion, mid-way between both proposed cut-offs, minimally acceptable range of post-operative dorsiflexion in our study.
          The mean range of dorsiflexion and standard deviation including the data of both radiologic studies mentioned above was determined using an inverse-variance model with random effects (Fig.Â 3). The obtained mean range was 21.42Â° of dorsiflexion. The mean range of dorsiflexion obtained from the literature is very close to the mean range of dorsiflexion (20.2Â°) obtained in our pilot study before starting the full RCT.Fig. 3Inverse-variance model with random effects to determine mean dorsiflexion rate using blade tenotomy\documentclass[12pt]{minimal}
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				\begin{document}$$\begin{array}{c}\mathrm{Non}-\mathrm{inferiority \,margin}\\ =\mathrm{ mean \,range \,of\, dorsiflexion \,from\, literature }-\mathrm{ minimally\, acceptable\, range\, of\, post}-\mathrm{operative\, dorsiflexion}\\ = 21.42^\circ - 17.5^\circ \\ = 3.92^\circ \end{array}$$\end{document}Non-inferioritymargin=meanrangeofdorsiflexionfromliterature-minimallyacceptablerangeofpost-operativedorsiflexion=21.42â-17.5â=3.92â
          For practical purposes, a non-inferiority margin of 4Â° will be applied instead of 3.92.
        
        
          Sample size and power calculation
          Sample sizes are calculated using the WHO sample size determination software [22].
          Sample size calculation for primary outcome:Alphaâ=â5%Power 95%Non-inferiority margin: 4Standard deviation: 9.02
          Required sample sizeâ=â222 feet (111 in each arm).
          Drop-out from clubfoot programs is a common event in LMICs, especially throughout the bracing phase. In literature, drop-out rates of up to 30% have been reported over the total period of bracing which is about 3Â years on average [17, 18, 23]. Internal data from the Pehla Qadam clubfoot program shows similar outcome with about 30% drop-out over the entire course of the treatment. We therefore expect during the first year of follow-up to lose about 10% of our patients. We will therefore increase the sample size by 10% to adjust for the expected drop-out.
          A total sample size of 244 feet (122 per arm) will be recruited for this trial.