Response Letter to the Comments of “Perioperative Music Therapy Enhances Pain Management and Sleep Quality in Patients Aged 50–70 Years Undergoing Total Knee Arthroplasty: A Randomized Controlled Trial” [Response to Letter]

Dear editor

We sincerely thank the authors of the letters to the editor for their thoughtful and constructive comments on our manuscript titled “Perioperative Music Therapy Enhances Pain Management and Sleep Quality in Patients Aged 50-70 Years Undergoing Total Knee Arthroplasty: A Randomized Controlled Trial”. We highly appreciate their recognition of the clinical value of our research and the opportunity they have provided to enhance the methodological transparency of this study. The following is a point-by-point response to the comments raised in the letters.

1. Response to Comment: The recruitment period and registration in design section states that the study ran from January 2023 to January 2024, whereas the Results describe inclusion of 86 patients ‘from June to December 2019’. This inconsistency makes it unclear when the recruitment actually occurred”.

Response: We are grateful to the reviewers for pointing out this discrepancy. It was an inadvertent clerical error during the manuscript preparation. The correct recruitment period was From June to December 2019, which is consistent with the ethical approval date (2019). This has now been corrected.

2. Response to Comment: “The authors mentioned the trial as single blinded study but did not specify who was blinded, nor how blinding was implemented and maintained. Given that the primary outcomes are subjective, patient‑reported measures (VAS pain, NVAS, PSQI components, and satisfaction), this incomplete description of blinding prevents readers from adequately judging the risk of performance and detection bias”.

Response: We agree that the level of detail in the blind operation process is insufficient. In this study, patients were unaware of their grouping: patients in the control group wore non-active headphones and were informed that this was done to reduce environmental noise. Anesthesiologists and outcome assessors were also blinded. Surgeons and researchers who performed randomization did not participate in the outcome assessment. The above-mentioned issues have now been clarified and supplemented.

3. Response to Comment: “But clarification regarding which specific primary outcome these parameters were based on (e.g., PCA presses at a defined time point, VAS, or a PSQI component) is not mentioned, the empirical source of S and δ (pilot data) and how was δ=0.47 determined represents a clinically meaningful or realistic effect size”.

Response: Sample size calculation was performed based on the PCA pressing frequency at 3 hours after surgery, which was designated as the primary outcome indicator in the initial research protocol. The standard deviation (S = 0.91) and expected difference (δ = 0.47) were derived from a pilot study conducted in early 2019, which included a total of 20 patients with 10 cases in each group. According to the consensus of the clinical team, a difference of 0.47 presses is clinically significant. A reduction of approximately half one time in early postoperative PCA pressing demand can effectively relieve patients’ pain and reduce the nursing burden. We have supplemented the above evidence in the manuscript explanation.

4. Response to Comment: The authors mentioned that patients were ‘randomly assigned using a random number table’ but did not describe any allocation concealment method, leaving the risk of selection bias unclear and falling short of CONSORT recommendations to report both sequence generation and allocation concealment”.

Response: We sincerely appreciate the constructive comment. Allocation concealment has been added to the Methods section; we used sequentially numbered, sealed, opaque envelopes prepared by an independent researcher to ensure adequate allocation concealment and minimize selection bias, in accordance with CONSORT guidelines. The revisions have been made and annotated in the original manuscript.

5. Response to Comment: “Sleep on the first postoperative night is assessed using elements of the Pittsburgh Sleep Quality Index (PSQI)… However, PSQI was originally developed and validated to assess sleep quality over a one-month time interval and is usually used as a global score rather than for a single night”.

Response: We sincerely appreciate your valuable comment. We have added a statement in the Discussion section to clarify the adaptation of the PSQI. Specifically, we adopted three components of the PSQI (sleep duration, sleep efficiency, and sleep disturbances) to assess sleep quality on the first postoperative night, with all assessment items restricted to this single night. Although the original PSQI was designed to evaluate sleep over a one‑month period, this short‑term modified version has been widely and validly applied in the acute perioperative population, consistent with the method reported in the newly added reference.¹ These revisions have been clearly marked in the revised manuscript.

In addition, we identified an error in the sample size formula Sample Size Calculation section page 2. We apologize for this authorial oversight: the square term, which should appear outside the brackets, was inadvertently omitted in the manuscript text. The correct formula is:

Disclosure

The authors have no conflicts of interest in this communication.