Response: Efficacy and Safety of High Density LED Irradiation Therapy for Patients With Hand Osteoarthritis: A Single-Center Clinical Study (Ann Rehabil Med 2024;48:50-6)

Article information

Ann Rehabil Med. 2025;49(1):3-4

Publication date (electronic) : 2025 February 6

doi : https://doi.org/10.5535/arm.240082

Jiseon Hong, MD

Department of Rehabilitation Medicine, Wonju Severance Christian Hospital, Yonsei University Wonju College of Medicine, Wonju, Korea

Correspondence: Jiseon Hong Department of Rehabilitation Medicine, Wonju Severance Christian Hospital, Yonsei University Wonju College of Medicine, 20 Ilsan-ro, Wonju 26426, Korea. Tel: +82-33-741-1455 Fax: +82-33-742-1409 E-mail: g7284@naver.com

Received 2024 September 8; Accepted 2024 December 17.

We appreciate your interest in our manuscript, “Efficacy and safety of high density LED irradiation therapy for patients with hand osteoarthritis: a single-center clinical study” [1]. We are grateful for your thorough review and for providing constructive feedback.

Firstly, regarding the hypothesis: As you noted, the use of ANOVA indicates that a two-sided hypothesis was applied in our study. The specific hypotheses were as follows:

Null hypothesis: high-density light-emitting diode (LED) irradiation therapy might not have a significant difference in the visual analogue scale (VAS), ring size, or passive joint range of motion at baseline, post-treatment (week 4), and two weeks post-treatment (week 6).

Alternative hypothesis: high-density LED irradiation therapy might have a significant difference in VAS, ring size, or passive joint range of motion at baseline, post-treatment (week 4), and two weeks post-treatment (week 6).

Secondly, regarding the selection and exclusion criteria for study participants: While disease duration wasn’t considered, we agree this should have been included. Although not detailed in the manuscript, two specialists in Physical and Rehabilitation Medicine verified that patients met the American College of Rheumatology criteria, excluding those with congenital hand deformities or prior injuries. Additionally, we screened for conditions such as autoimmune diseases, myocardial infarction, severe heart disease, or uncontrolled hypertension, which may affect outcomes. We appreciate your comments on the contraindications for LED irradiation, including photosensitizing medications, skin sensitivity, and prior physiotherapy.

Thirdly, regarding the sample size calculation: Although this was performed during the research design, it was not included in the manuscript. The details are as follows:

Due to the lack of prior clinical studies using LED phototherapy for hand osteoarthritis, we referenced data from studies using laser therapy [2]. It was hypothesized, based on clinical judgment, that the improvement in VAS scores with LED phototherapy would not exceed 80% of that observed with laser therapy, with reported changes ranging from 1.75 to 1.86 after six weeks.

Assuming a two-sided significance level of α=0.05 and a standard deviation of 3.0, the calculated sample size was 18 participants. The mean change in VAS score for LED phototherapy is estimated to be 1.4. To accommodate a potential dropout rate of 20%, the total target recruitment was set at 23 participants.

Lastly, regarding the methodology: As you rightly indicated, the study design should have included an observation period extending to week 6.

We acknowledge that the explanation of the statistical tests in the manuscript was insufficient. We used a chi-square test to examine sex differences among the 23 participants and found a significant difference in the sex ratio within the group (p<0.05). Additionally, although not included in the manuscript, we performed a t-test to assess age differences between sexes, which was not statistically significant. ANOVA was then used to evaluate changes in pain, finger circumference, and range of motion across three time points followed by a post-hoc Bonferroni test to identify specific differences between these time points. The mention of Pearson’s was mistakenly included and should have been removed during revision.

Thanks for your feedback.