Randomization:
Patients will be allocated to two intervention (titanium tilting anchor) and control (screw-type anchor) groups in a 1:1 ratio using a block randomization method. The randomization list with variable blocks (sizes 4 and 6) will be generated by an independent statistician using computer software (such as Random Allocation Software) and kept confidential. To protect confidentiality (allocation concealment), numbered, opaque, and sealed envelopes will be used, which will only be returned by an independent research assistant at the appropriate time.
In this study, a two-stage randomization approach will be used to reduce the risk of selection bias and increase the internal validity of the results.
Stage 1: Preoperative Screening and Informed Consent
All potentially eligible patients who are clinically and MRI-confirmed to have a complete supraspinatus tendon tear and are candidates for open rotator cuff repair surgery are evaluated in the preoperative screening phase. In this phase, after providing a full explanation of the study objectives, procedure, potential benefits, and risks, written informed consent is obtained from the patients and basic information including demographic characteristics and baseline clinical variables is recorded.
Stage 2: Preoperative Randomization
After meeting the inclusion criteria and before the patient enters the operating room, patients are randomly assigned to one of the two treatment groups in a 1:1 ratio. Randomization is performed using a randomized block design with alternating blocks and by an independent statistician. Patient group allocation is maintained in opaque, sealed, and consecutively numbered envelopes and will not be disclosed until appropriate.
Step 3: Intraoperative Eligibility Verification and Activation of Treatment Allocation
After the start of surgery and direct intraoperative lesion examination, the patient’s final eligibility for entry into the interventional phase of the study is confirmed by the surgeon. Only if the intraoperative findings are consistent with the preoperative diagnosis and the patient is eligible to continue the study, will the randomization envelope be opened and the allocated intervention be implemented.
Blinding:
In this study:
• Patients are blinded to the type of anchor used.
• Clinical outcome assessors and statistical analysts will be blinded to the group allocation of patients.
• The surgeon, operating room team, and radiologist are aware of the treatment group due to the nature of the intervention.
In order to reduce bias, radiological and clinical data for statistical analysis will be provided to the statistical analyst in coded form without mentioning the type of implant. In the event of a specific clinical situation that requires immediate information about the type of implant, it will be possible to open the blinding emergency according to a predefined procedure.
Blinding assessment test: At the end of the study, assessors and patients can be asked which group they think they received (a simple blinding index question) to assess the success of blinding.
Emergency Unblinding
• In the event of a serious complication requiring knowledge of the implant type (e.g. for therapeutic decision-making or if there is a risk to the patient), there is a controlled procedure for unblinding:
1. A formal request for unblinding should be made in writing by the surgeon or treating physician and should include a compelling clinical reason.
2. The randomization officer (independent statistician) or allocation list keeper should provide specific information after recording the time/reason.
3. Each unblinding should be recorded in the study file with the reason, time, and identity of the requester and reported in the final study report.
4. It is preferable to unblind only when absolutely necessary and to the minimum extent necessary to minimize damage to the validity of the study.