Outcome of single-bundle versus double-bundle reconstruction of the anterior cruciate ligament - A meta-analysis

Background: The anterior cruciate ligament (ACL) has 2 anatomic bundles. Standard ACL reconstruction is with a singlebundle graft, but double-bundle reconstruction may better control knee rotational torque, a potential cause of failure after single-bundle reconstruction. The authors investigated outcomes of single-bundle versus double-bundle ACL reconstruction. Hypothesis: There is no difference in outcomes of single-bundle versus double-bundle reconstruction. Study Design: Meta-analysis. Methods: The authors systematically identified randomized controlled trials (RCTs) comparing single-bundle versus doublebundle ACL reconstruction (secondary analysis includes nonrandomized trials). Outcomes reported in a majority of included trials were meta-analyzed. Results: Four RCTs were included (secondary analysis including 5 additional trials yielded reassuringly similar results). Two outcome measures were reported (in a manner permitting meta-analysis) in at least 3 of 4 trials: KT-1000 arthrometer and pivot-shift testing. On average, KT-1000 arthrometer side-to-side difference was 0.52 mm closer to normal in patients treated with doublebundle reconstruction. This difference is demonstrated to be clinically insignificant. In addition, there was no statistical difference in the odds of having a normal or nearly normal pivot-shift result in patients treated with double-bundle versus single-bundle reconstruction. Conclusion: Double-bundle reconstruction does not result in clinically significant differences in KT-1000 arthrometer or pivotshift testing. The pivot-shift results have particular clinical relevance because the test is designed to evaluate knee rotational instability; the results do not support the theory that double-bundle reconstruction better controls knee rotation. Improved quality of future RCTs would allow meta-analysis of a greater number of outcome measures including measures of symptoms and disabilities most important to patients.