Reply to comment on Gong et al.: Single-bundle versus double-bundle anterior cruciate ligament reconstruction: an up-to-date meta-analysis

Abstract

1. The readers argue that we did not focus specifically or in any detail on the issue of the completeness of the search strategy report for databases. We agree with them that the search strategy report is important in a meta-analysis. We did not list detailed index terms in the article, however, this did not mean that we neglected the role of the search strategy. Two authors (XL and CPX) independently retrieved relevant studies by means of electronic search. In addition, the reference lists of identified studies were manually checked to identify other potentially eligible trials. This process was performed iteratively until no additional articles could be identified. But we thank the readers for the suggestion all the same. 2. The readers point out that the method of Mantel-Haenszel (M-H) or inverse-variance (IV) with the assumptions of a random-effects model detail should be changed to the DerSimonian and Laird random-effects model which is more suitable. We greatly appreciate the advice by the readers, whereas we are sorry to state that the statistical software used in our article is Revman 5.0, so that we could not consider the latter statistical choice due to the functional limitations of the software. But, again, we pooled the data of the groups and performed further meta-analysis using the DerSimonian and Liard random effects model with the help of STATA version 11.0 (Stata Corporation, College Station, Texas, USA), and found that it did not materially alter the previous pooled results which show our main finding was robust. 3. The results of the objective International Knee Documentation Committee (IKDC) are really incorrect. Amazingly, the standpoint of the readers is also wrong. By our scrutiny, there is an obvious clerical error in the context: “The forest plot showed doublebundle reconstruction had better objective IKDC final score, and the difference was statistically significant.” It is not difficult to see that “the difference was statistically significant” should be replaced by “the difference was not statistically significant” according to the consecutive content. 4. We also agree that statistical quantitative tests should be adopted to evaluate funnel plot symmetry. Nevertheless, the mission is also impossible to complete by Revman software. Additionally, the readers recommend that publication bias should be assessed for all the outcomes. Actually, we really considered the issue beforehand. Because of space limitation, we decided to adopt a typical funnel plot. Besides, we agree that limited publication language may cause a bias. So the language limitation has been already emphasised in our discussion, furthermore, it is a common limitation in a meta-analysis [3, 4], so we do not think it is a controversial. X. Li : J.<q. Song :N. Jiang : B. Yu (*) Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, No.1838, Guangzhou Avenue North, Guangzhou 510515, People’s Republic of China e-mail: nanfanghot@126.com