Does anatomic single-bundle ACL reconstruction using hamstring autograft produce anterolateral meniscal root tearing?
BACKGROUND The current standard for treating complete tears of the anterior cruciate ligament (ACL) is reconstruction, which requires reaming a tibial tunnel. Based on recent anatomic and biomechanical studies, this reconstruction tunnel may cause injuries to the anterior meniscal root attachments. PURPOSE/HYPOTHESIS The purpose was to determine if injuries occurred to the anteromedial (AM) and anterolateral (AL) meniscal root attachments because of reaming a tibial reconstruction tunnel in the anatomic center of the ACL footprint. It was hypothesized that tibial tunnel reaming for ACL reconstruction would result in significant decreases in the attachment area and in ultimate failure strength for the AL root. STUDY DESIGN Controlled laboratory study. METHODS Twelve matched pairs of human cadaveric knees were tested. One knee from each pair remained intact, while the contralateral knee was reamed with a tibial tunnel for an anatomic ACL reconstruction. The attachment areas of the anterior meniscal roots were measured with a coordinate measuring device before and after tunnel reaming. The anterior meniscal roots were then pulled to failure with a dynamic tensile testing machine. RESULTS There was a significant mean decrease in the attachment area for the AL root (%Δ, 38%; 95% CI, 25-51) after ACL tunnel reaming compared with the intact state (P=.003). The mean ultimate failure strength of the native AL root (mean, 610 N; 95% CI, 470-751) was significantly stronger (P=.015) than that of the AL root with a reamed ACL reconstruction tunnel (mean, 506 N; 95% CI, 353-659). Tunnel reaming did not significantly affect the AM root attachment area or ultimate failure strength. CONCLUSION Tibial tunnel reaming during anatomic single-bundle ACL reconstruction significantly decreased the AL meniscal root attachment area and ultimate failure strength. The AM root was not significantly affected by reaming of the ACL reconstruction tunnel. Future studies should investigate the clinical importance of these iatrogenic injuries to the AL root. CLINICAL RELEVANCE The ACL reconstruction tunnels reamed in the center of the ACL tibial footprint caused a significant decrease in the attachment area and ultimate strength of the AL meniscal root attachment. Clinically, repositioning guide pins placed in the lateral aspect of the ACL attachment before tibial tunnel reaming may minimize iatrogenic injuries to the AL meniscal root attachment.