Re: Changes in Condylar Position Within 12 Months After Bilateral Sagittal Split Ramus Osteotomy

Abstract

We read with great interest a recent published paper entitled “Changes in condylar position within 12 months after bilateral sagittal split ramus osteotomy with and without Le Fort I osteotomy by using cone-beam computed tomography” which was published in the Journal of Oral and Maxillofacial Surgery.1 Han Y. Changes in condylar position within 12 Months after bilateral sagittal split ramus osteotomy with and without Le Fort I osteotomy by using cone-beam computed tomography. J Oral Maxill Surg. 2021; 80: 162 Google Scholar In this cohort study, the authors investigated numerical variables at different time points of measurement including before surgery (T1), immediately after surgery (T2), 3 months (T3), 6 months (T4), and 12 months (T5) after surgery. As stated in the Abstract and Statistical Analysis section of the paper, the authors used one-way analysis of variance (ANOVA) and Tukey test for comparison of numerical variables between different time points of measurement. However, as we know, one-way ANOVA is used for comparison of numerical variables among more than 2 independent groups, but the comparisons of this study are completely dependent on each other as they evaluated only 1 group of patients at T1 to T5. 2 Farrokhi M. Amani-Beni A. Statistical comments on “assessment of musculoskeletal strength and levels of fatigue during different phases of menstrual cycle in young adults”. J Clin Diagn Res. 2017; 11: CL01 Google Scholar ,3 Kazemi S.M. Qoreishy M. Keipourfard A. et al. Effects of hip geometry on fracture patterns of proximal femur. Arch Bone Joint Surg. 2016; 4: 248 Google Scholar Indeed, as the authors measured some numerical variables in one group of patients at different time points of measurement, their comparisons are not independent. Repeated measures ANOVA is used for comparison of numerical variables among more than 2 time points of measurement. 4 Kazemi S.M. Shafaghi T. Minaei R. et al. The effect of sagittal femoral bowing on the femoral component position in Total knee Arthroplasty. Arch Bone Joint Surg. 2017; 5: 250 Google Scholar ,5 Kazemi S.M. Abbasian M.R. Esmailijah A.A. et al. Comparison of clinical outcomes between different femoral tunnel positions after anterior cruciate ligament reconstruction surgery. Arch Bone Joint Surg. 2017; 5: 419 Google Scholar Therefore, the authors must use repeated measures ANOVA instead of one-way ANOVA for comparison of their numerical variables between different time points of measurement including before surgery (T1), immediately after surgery (T2), 3 months (T3), 6 months (T4), and 12 months (T5) after surgery. Furthermore, for comparison of numerical variables between 2 time points of measurement, they must use paired t test instead of Tukey’s post hoc test. Changes in Condylar Position Within 12 Months After Bilateral Sagittal Split Ramus Osteotomy With and Without Le Fort I Osteotomy by Using Cone-Beam Computed TomographyJournal of Oral and Maxillofacial SurgeryVol. 80Issue 1PreviewThis study aimed to evaluate the condylar position changes in 12 months after bilateral sagittal split ramus osteotomy (BSSO) with and without a Le Fort I osteotomy in patients with Class III malocclusion and the influence of the 2 surgical approaches on the condylar position. Full-Text PDF