Lateral location of the tibial tunnel increases lateral meniscal extrusion after anatomical single-bundle anterior cruciate ligament reconstruction

Abstract

IntroductionThe tibial footprint of the anterior cruciate ligament (ACL) overlaps with the anterior lateral meniscal root (ALMR), and there is a possibility that an anatomical tibial tunnel reaming might damage the attachment of ALMR. The aim of this study was to investigate the relationship between tibial tunnel location and lateral meniscal extrusion (LME) after anatomical single-bundle ACL reconstruction.MethodsA prospectively collected database and associated intraoperative findings for 153 patients undergoing primary anatomical ACL reconstruction between October 2014 and July 2016 were investigated. Those cases with no meniscal injury seen at surgery and meeting the criteria (52/153) were included. Tibial plateau length (TPL), width (TPW), tibial tunnel location and LME were evaluated from postoperative high-resolution MRI. The location of the centre of the tibial tunnel was evaluated by the position relative to the medial tibial eminence with two measures, the medial–lateral distance (MLD) and anterior–posterior distance. These measures were expressed as a percentage of the TPW and TPL, respectively. The LME was also expressed as a percentage of TPW and correlated with tibial tunnel location.ResultsThere was a positive correlation between percentage of LME (%LME) and percentage of MLD (%MLD) (r=0.478; p<0.001). Applying receiver operating characteristic analysis, we determined that a cut-off value of 4 %MLD was significant. The mean percentage of LME was 1.20 for >4 %MLD, compared with 0.17 for ≤4 %MLD (p<0.001). No significant correlation was found between %LME and clinical outcomes at 1-year follow-up.ConclusionLateral location of the tibial tunnel increases the rate of LME after single-bundle ACL reconstruction.Level of evidenceLevel IV, Case series.