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Author Reply to “Regarding ‘A Prospective Randomized Trial Comparing Suture Bridge and Medially Based Single-Row Rotator Cuff Repair in Medium-Sized Supraspinatus Tears’”

      I would like to thank Datt, Jain, Morankar, and Digge for their interest in our article “A Prospective Randomized Trial Comparing Suture Bridge and Medially Based Single-Row Rotator Cuff Repair in Medium-Sized Supraspinatus Tears,”
      • Yamakado K.
      A prospective randomized trial comparing suture bridge and medially based single-row rotator cuff repair in medium-sized supraspinatus tears.
      and I wish to address their concerns.
      First, regarding the concept of sample size calculation in a prospective randomized trial, one must distinguish a priori sample size calculation and the post-hoc power analysis. Estimation of sample size should be done before the data collection starts, which I conducted using our pilot data. On the other hand, post hoc sample size computation is not encouraged conventionally.
      • Das S.
      • Mitra K.
      • Mandal M.
      Sample size calculation: Basic principles.
      Regarding the study power, they cited a prospective randomized trial by Carbonel et al., recruiting 183 patients.
      • Carbonel I.
      • Martinez A.A.
      • Calvo A.
      • Ripalda J.
      • Herrera A.
      Single-row versus double-row arthroscopic repair in the treatment of rotator cuff tears: a prospective randomized clinical study.
      This study represents a massive effort and is laudable; however, the sample size calculation was not shown in the article. To answer a research question, a large sample size may detect the small difference between the treatment groups, but too large a sample is resource-intensive and may be unethical; thus, many randomized trials utilize small pilot study, personal experience, or expert opinions.
      Second, Datt et al. criticized our randomization method, stating that “the author obtained an equal sample size in both the groups, which indicates that they must have implemented some kind of randomization blocking”; however, it is a misjudged assumption. Randomization was performed at the end of preparation: the procedure used for each patient was chosen by opening a sealed, randomly assigned envelope that indicated the suture-bridge or medially-based single-row technique and prepared the same number for each treatment arms ahead of time. A randomized trial is an essential tool for comparing the efficacy of treatment modalities.
      • Randelli P.
      • Arrigoni P.
      • Lubowitz J.H.
      • Cabitza P.
      • Denti M.
      Randomization procedures in orthopaedic trials.
      With proper randomization, the validity of data analysis is ensured. Simple randomization can result in the imbalanced assignment of treatment groups because randomly assigned groups of smaller numbers of patients are more likely to result in different numbers of a patient in each group. The method used in our study is a modification of simple randomization but could be regarded as a variation of block randomization.
      Finally, I really appreciated their comments regarding the number of recruited patients. The CONSORT flow is correct.
      Thank you once again for your kind interest in the article. We hope this letter can help clarify the statistical part of the method and may clear up the misunderstandings.

      Supplementary Data

      References

        • Yamakado K.
        A prospective randomized trial comparing suture bridge and medially based single-row rotator cuff repair in medium-sized supraspinatus tears.
        Arthroscopy. 2019; 35: 2803-2813
        • Das S.
        • Mitra K.
        • Mandal M.
        Sample size calculation: Basic principles.
        Indian J Anaesth. 2016; 60: 652-656
        • Carbonel I.
        • Martinez A.A.
        • Calvo A.
        • Ripalda J.
        • Herrera A.
        Single-row versus double-row arthroscopic repair in the treatment of rotator cuff tears: a prospective randomized clinical study.
        Int Orthop. 2012; 36: 1877-1883
        • Randelli P.
        • Arrigoni P.
        • Lubowitz J.H.
        • Cabitza P.
        • Denti M.
        Randomization procedures in orthopaedic trials.
        Arthroscopy. 2008; 24: 834-838