Anatomic single‐ versus double‐bundle ACL reconstruction: a meta‐analysis

PURPOSE: To determine whether anatomic double-bundle anterior cruciate ligament (ACL) reconstruction compared to anatomic single-bundle ACL reconstruction more effectively restored antero-posterior (A-P) laxity, rotatory laxity and reduced frequency of graft rupture. Our hypothesis was that anatomic double-bundle ACL reconstruction results in superior rotational knee laxity and fewer graft ruptures due to its double-bundle tension pattern, compared with anatomic single-bundle ACL reconstruction. METHODS: An electronic search was performed using the PubMed, EMBASE and Cochrane Library databases. All therapeutic trials written in English reporting knee kinematic outcomes and graft rupture rates of primary anatomic double- versus single-bundle ACL reconstruction were included. Only clinical studies of levels I-II evidence were included. Data regarding kinematic tests were extracted and included pivot-shift test, Lachman test, anterior drawer test, KT-1000 measurements, A-P laxity measures using navigation and total internal-external (IRER) laxity measured using navigation, as well as graft failure frequency. RESULTS: A total of 7,154 studies were identified of which 15 papers (8 randomized controlled trials and 7 prospective cohort studies, n = 970 patients) met the eligibility criteria. Anatomic ACL double-bundle reconstruction demonstrated less anterior laxity using KT-1000 arthrometer with a standard mean difference (SMD) = 0.36 (95% CI 0.214-0.513, p < 0.001) and less A-P laxity measured with navigation (SMD = 0.29 95% CI 0.01-0.565, p = 0.042). Anatomic double-bundle ACL reconstruction did not lead to significant improvements in pivot-shift test, Lachman test, anterior drawer test, total IRER or graft failure rates compared to anatomic single-bundle ACL reconstruction. CONCLUSION: Anatomic double-bundle ACL reconstruction is superior to anatomic single-bundle reconstruction in terms of restoration of knee kinematics, primarily A-P laxity. Whether these improvements of laxity result in long-term improvement of clinical meaningful outcomes remains uncertain. LEVEL OF EVIDENCE: II.