Here is the design of a clinical trial:

Official Title: The Soft Tissue Injection of Corticosteroid And Local Anaesthetic Study - A Single Site, Non-inferiority Randomised Control Trial Evaluating Pain After Soft Tissue Corticosteroid Injections With and Without Local Anaesthetic

Included conditions:
- Carpal Tunnel Syndrome
- De Quervains Tenosynovitis
- Trigger Finger

Study Armgroups:
- {'label': 'Corticosteroid injection', 'type': 'EXPERIMENTAL', 'description': 'Single injection of 1ml of triamcinolone (40mg/1ml)', 'interventionNames': ['Drug: 1ml of triamcinolone (40mg/1ml)']}
- {'label': 'Corticosteroid and local anaesthetic injection', 'type': 'ACTIVE_COMPARATOR', 'description': 'Single injection of 1ml of triamcinolone (40mg/1ml) + 1ml 1% Lidocaine', 'interventionNames': ['Drug: 1ml of triamcinolone (40mg/1ml)']}

Interventions:
- {'type': 'DRUG', 'name': '1ml of triamcinolone (40mg/1ml)', 'description': 'Single injection of 1ml of triamcinolone (40mg/1ml)', 'armGroupLabels': ['Corticosteroid and local anaesthetic injection', 'Corticosteroid injection']}

Primary Outcomes:
- {'measure': 'Pain visual analog scale scores at 1 hour', 'description': 'Investigate whether there is a difference in pain visual analog scale scores (where 0 is no pain and 10 is the worst pain possible) at 1-hour after a corticosteroid injection for trigger finger, de Quervains tenosynovitis or carpal tunnel syndrome co-administered with or without local anaesthetic.', 'timeFrame': '1 hour'}

Please estimate the sample size based on the assumption: 
Standard deviation of 25 mm, 95% power, 5% significance level, 20% dropout rate, and 95% confidence intervals.
Sample size
        As part of the literature review, it was identified that a 20-mm MCID on a 100-mm scale has been utilised in other studies evaluating post procedural pain [16], one of which was also investigating pain following soft tissue corticosteroid injections in the hand [14]. The authors are not aware of any studies that have specifically evaluated and set a standardised minimally clinical important difference (MCID) in pain VAS score following soft tissue corticosteroid injection in the hand and wrist. Although this is recognised as a limitation, it was felt that the ubiquitousness of the VAS as previously validated tool in multimodal and multisite pain, and its previously demonstrated utility and patient comprehension meant that it can be regarded as the most appropriate patient-reported pain score.
        A MCID of 20âmm will be used as the clinically admissible margin of non-inferiority. From previous studies, a standard deviation of 25âmm and with a 95% power calculations have determined a required sample size of 41 per study arm, when including a 20% fall out rate a total sample size of 100 patients will be required [14]. All sample size calculations were conducted at the two-sided 5% significance level and 95% CIs with Stata 14 (StataCorp. 2015. Stata Statistical Software: Release 14. College Station, TX: StataCorp LP).