Here is the design of a clinical trial:

Official Title: Study on Efficacy, Safety and Economy of Tong-Luo-Qu-Tong Plaster Treatment for Knee Osteoarthritis: Study Protocol for a Randomised, Double-blind, Parallel Positive Control, Multi-center Clinical Trial

Included conditions:
- Knee Osteoarthritis
- Chronic Musculoskeletal Disease

Study Armgroups:
- {'label': 'Tong-Luo-Qu-Tong Plaster group', 'type': 'EXPERIMENTAL', 'description': 'Intervention: Tong-Luo-Qu-Tong Plaster, daily 1 time, conventional treatment lasted for 14 days as two courses', 'interventionNames': ['Drug: Tong-Luo-Qu-Tong Plaster']}
- {'label': 'Qi-Zheng-Xiao-Tong Plaster group', 'type': 'ACTIVE_COMPARATOR', 'description': 'Intervention: Qi-Zheng-Xiao-Tong Plaster, daily 1 time, conventional treatment lasted for 14 days as two courses', 'interventionNames': ['Drug: Qi-Zheng-Xiao-Tong Plaster']}

Interventions:
- {'type': 'DRUG', 'name': 'Tong-Luo-Qu-Tong Plaster', 'description': 'for 14 days as two period of treatment, daily 1 time.', 'armGroupLabels': ['Tong-Luo-Qu-Tong Plaster group']}
- {'type': 'DRUG', 'name': 'Qi-Zheng-Xiao-Tong Plaster', 'description': 'for 14 days as two period of treatment, daily 1 time', 'armGroupLabels': ['Qi-Zheng-Xiao-Tong Plaster group']}

Primary Outcomes:
- {'measure': 'WOMAC scores', 'description': 'Western Ontario and McMaster universities osteoarthritis index, ranges 0-96. Higher values represent a worse outcome.', 'timeFrame': 'from baseline to 2 weeks'}

Please estimate the sample size based on the assumption: 
The power is set at 80% and the alpha value is 2.5% (two-tailed). A conservative 20% dropout rate is also assumed.
Sample size estimation
        Our study was designed as a non-inferiority trial and sample size calculations are based on the primary outcome measurement. First, the minimal clinically important difference in WOMAC scales in KOA is estimated from previous studies [28] as 15.50 points. Second, we assume that based on previous literature [29], the square deviation of the WOMAC score is 318.88. For power of 80% and an alpha value of 2.5% (two-tailed), the sample size is calculated using the following formula:\documentclass[12pt]{minimal}
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				\begin{document}$$ n=\frac{\frac{4}{3}{\left({u}_{\upalpha}+{u}_{\beta}\right)}^2{\upsigma}^2}{{\left(\varDelta -\updelta \right)}^2}\ \left({u}_{\upalpha}=1.6449,\kern0.5em {u}_{\beta }=1.2816\right) $$\end{document}n=43uÎ±+uÎ²2Ï2ÎâÎ´2uÎ±=1.6449uÎ²=1.2816
        Thus, we obtained the sample size of 1600 patients for this trial; allowing for a conservative 20% dropout rate, the total sample size was set at 2000 patients (1500 in the Tong-luo Qu-tong plaster group).