Here is the design of a clinical trial:

Official Title: DynMPFL - Comparison of Dynamic and Static Medial Patellofemoral Ligament Operation Technique for Recurrent Patellar Dislocation

Included conditions:
- Patellar Instability

Study Armgroups:
- {'label': 'Static reconstruction technique according to Schöttle', 'type': 'ACTIVE_COMPARATOR', 'description': 'Static reconstruction technique according to Schöttle', 'interventionNames': ['Procedure: Static reconstruction technique according to Schöttle']}
- {'label': 'Dynamic reconstruction technique according to Becher', 'type': 'ACTIVE_COMPARATOR', 'description': 'Dynamic reconstruction technique according to Becher', 'interventionNames': ['Procedure: Dynamic reconstruction technique according to Becher']}

Interventions:
- {'type': 'PROCEDURE', 'name': 'Static reconstruction technique according to Schöttle', 'description': 'In static MPFL reconstruction, a graft (harvested autologous gracilis tendon or allogen transplant) is attached to the femoral and patellar bones using tunnels, screws, and/or anchors.', 'armGroupLabels': ['Static reconstruction technique according to Schöttle']}
- {'type': 'PROCEDURE', 'name': 'Dynamic reconstruction technique according to Becher', 'description': 'Dynamic MPFL procedure by detaching and reinserting only the distal part of a hamstring muscle to the patella and leaving the proximal tendon attached to its muscle. This way the patella position can be adjusted dynamically by hamstring contraction.', 'armGroupLabels': ['Dynamic reconstruction technique according to Becher']}

Primary Outcomes:
- {'measure': 'Change in Kujala score', 'description': 'Patient reported knee function and anterior knee pain as assessed with the Kujala score at preoperative screening, at the hospitalization time and four postoperative follow ups . The Kujala scale consists of 13 questions covering a range of physical symptoms and limitations that are presented in a multiple choice answer format, with a different point value assigned to each answer. The maximum score is 100, with higher scores indicating better function.', 'timeFrame': 'up to 24 months'}

Please estimate the sample size based on the assumption: 
80% power, 5% significance level, and a 10% dropout rate.
Sample size calculation
          We based our sample size calculation on the primary outcome, the Kujala score. To date, no high-quality study (randomized trial) on the difference in change in Kujala score between dynamic and static MPFL reconstruction is available. However, in a prospective randomized control trial, Kang et al. [56] compared two different tensioning techniques for static MPFL reconstruction. They reported an effect size of 7.8 for the improvement in the Kujala score for both groups and a group difference in change in Kujala score of 1.9. Based on biomechanical considerations, we expect a larger improvement in patients stabilized using the dynamic MPFL reconstruction. Assuming a 3.8-point improvement in the Kujala score in patients with dynamic MPFL reconstruction compared to patients with static MPFL reconstruction, 54 patients (27 per group) are required to detect a significant difference in change in Kujala score between the two groups with 80% power at a significance level of 5%. We expect a dropout rate of about 10%, and will thus we will target a study cohort of 60 patients (30 per group).