Objective: This meta-analysis study compares the treatment outcomes between single bundle (SB) and double bundle (DB) anterior cruciate ligament reconstructions (ACLR) including manual laxity tests, KT-1000 measurements and functional knee scores including International Knee Documentation Committee (IKDC) and Lysholm scores. 
Data sources: Medline, Scopus, Web of Science and Cochrane Central Register of Controlled Trials (January 1985 to March 2008).
Material and Method: All randomized controlled trials reporting one or more outcomes related to single bundle versus double bundle ACLR were recruited in the present study. Random effect models were used to pool the data. Heterogeneity in the effect of treatment was tested on the basis of study quality, randomization status and type of ACLR.
Results: There were 2,119 studies initially identified, 7 studies met our inclusion criteria. Four hundred and eighty two patients (238 in SB group and 244 in DB group) were included in the present study. The results of KT 1,000 arthrometry in 7 studies favor DB-ACLR with statistical significance (p < 0.05). Pivot shift test were available for 374 patients from 6 studies, 183 and 191 patients in SB group and DB group respectively. The results favor DB-ACLR with statistical significance (p < 0.001). IKDC scores were available for 257 patients from 4 studies. The results trend to favor DB-ACLR but not statistically significant (p = 0.17). Lysholm scores were available for 174 patients from 3 studies. The results trend to favor DB-ACLR without statistical significance (p = 0.10).
Conclusion: The present study shows that DB-ACLR provides better AP and rotational stability than SB ACLR. There is no difference in the results of functional scores. DB-ACLR should be considered in patients who particularly require rotational stability of the knee. In the future, the interesting issue is to develop the functional knee score that is more specific to rotational stability evaluation.

Keywords: Anterior cruciate ligament, Single bundle, Double bundle, Meta-analysis, Randomized controlled trials