Here is the design of a clinical trial:

Official Title: SporTRIA Study: A Multicentre Trial for Excretion Kinetics of Triamcinolone Acetonide Following Sport Related Intra-articular Injections in Knees; Definitions of the Washout Periods

Included conditions:
- Doping in Sport
- Glucocorticoids

Study Armgroups:
- {'label': 'athletic subjects', 'type': 'OTHER', 'description': 'athletic subjects who may need intra-articular knee infiltration', 'interventionNames': ['Drug: knee intra-articular infiltration with Triamcinolone acetonide']}

Interventions:
- {'type': 'DRUG', 'name': 'knee intra-articular infiltration with Triamcinolone acetonide', 'description': 'knee intra-articular intra-articular ultrasound-guided infiltration of Triamcinolone acetonide', 'armGroupLabels': ['athletic subjects']}

Primary Outcomes:
- {'measure': 'Determination of the excretion profile of triamcinolone acetonide in urine following intra-articular ultrasound-guided injection', 'description': 'For subjects with a glucocorticoids urinary value below the 15 ng/ml threshold at D0 (before injection), identification of the date (up to 35 days) following the intra-articular ultrasound-guided injection which will correspond in the standards of the World Agency (under 15 ng/ml)', 'timeFrame': 'Change from baseline, pre-injection (day 0) to date (up to 35 days) where glucocorticoids urinary value below the 15 ng/ml'}

Please estimate the sample size based on the assumption: 
Not explicitly stated; focuses on recruitment potential and inclusion criteria.
Sample size
        It is a pilot study. The inclusion of 20 patients is envisaged to be in accordance with the potential for recruitment. We are considering the possibility of at least two subjects with a value above WADA standards (<30 ng/mL) at baseline which will not be included for the primary or secondary endpoints. However, they will be integrated into the kinetics analysis and will be identifiable there.