Here is the design of a clinical trial:

Official Title: Effects of Open and Closed Kinetic Chain Exercise on Functional Outcomes and Lower Limb Biomechanics in Mild Knee Osteoarthritis Patients

Included conditions:
- Osteoarthritis, Knee
- Aging Problems

Study Armgroups:
- {'label': 'Open kinetic chain exercise', 'type': 'EXPERIMENTAL', 'description': 'In the OKC exercise group, participants will be taught by a physiotherapist about open kinetic chain exercises. Then, they will do the exercises at their home for eight weeks, with three session per week. The physiotherapist will contact the participants to monitor their adherence to the intervention. A diary is also provided to monitor their progress, pain level and any adverse events related to the intervention.', 'interventionNames': ['Other: Exercise']}
- {'label': 'Closed kinetic chain exercise', 'type': 'EXPERIMENTAL', 'description': 'In the OKC exercise group, participants will be taught by a physiotherapist about open kinetic chain exercises. Then, they will do the exercises at their home for eight weeks, with three session per week. The physiotherapist will contact the participants to monitor their adherence to the intervention. A diary is also provided to monitor their progress, pain level and any adverse events related to the intervention.', 'interventionNames': ['Other: Exercise']}
- {'label': 'Control', 'type': 'NO_INTERVENTION', 'description': "The untreated control group will receive patient's usual care of local government hospital which includes information about clinical manifestations, risk factors, diagnosis, treatment and nursing care for knee OA. Control group did not receive any home exercises guidance."}

Interventions:
- {'type': 'OTHER', 'name': 'Exercise', 'description': 'CKC: exercise with joints fixed on the ground OKC: exercise with joints not fixed on the ground', 'armGroupLabels': ['Closed kinetic chain exercise', 'Open kinetic chain exercise']}

Primary Outcomes:
- {'measure': 'Change from baseline of pain intensity score at post-intervention', 'description': 'pain intensity will be assessed using a visual analogue scale. It consists of a bidirectional 10-cm straight line, where 0 cm is "no pain" and 10 cm is "worst imaginable pain," located at either end of the line. Patients will be instructed to draw a vertical mark on the line indicating their pain level.', 'timeFrame': '8 weeks'}
- {'measure': 'Change from baseline of disability score at post-intervention', 'description': 'Western Ontario and McMaster Universities Arthritis Index consists of a number of questions designed to assess the clinical severity of the disease (5 questions for pain, 2 questions for stiffness and 17 questions for physical function). It includes 24 questions, each question scored using a five-point scale (0-4) with higher scores representing greater levels of pain, stiffness and severity of the disease. The overall score (index) is determined by summing the scores across the three dimensions and the score ranges between 0-96 (derived from a 0-4 Likert scale).', 'timeFrame': '8 weeks'}
- {'measure': 'Change from baseline of quality of life score at post-intervention', 'description': 'The Osteoarthritis Knee and Hip Quality of Life in Malay Version consists of 43 items divided into five dimensions: physical activity, mental health, pain, social support, and social functioning Each item in the five dimensions is measured on a numerical rating scale from 0 to 10. Each item is scored on a scale from 0 to 10, and the normalized scores were obtained by computing the sum of item scores for each domain and calculated to a scale from 0 (worst) to 100 (best) possible quality of life.', 'timeFrame': '8 weeks'}

Please estimate the sample size based on the assumption: 
The significance level (alpha) is set at 0.05, the statistical power is 0.8, and a dropout rate of 20% is anticipated.
Sample size calculation
        The sample size was determined using G*Power statistical software version 3.1.9.2 (UniversitÃ¤t DÃ¼sseldorf, Germany) based on the primary outcome variables of pain and function based on the visual analog scale (VAS) scores as well as the Western Ontario and McMaster Universities Arthritis (WOMAC) Index respectively. The sample size for this study was determined to detect an effect size of 0.5, based on a previous study [21] with an alpha value of 0.05. Eighteen participants per group will be sufficient to achieve a statistical power of 0.8. By anticipating a dropout rate of 20%, a total of 22 participants per group (total N = 66) will be recruited.