Transtibial versus independent femoral tunnel drilling techniques for anterior cruciate ligament reconstruction: evaluation of femoral aperture positioning

Abstract

Background Femoral tunnel can be drilled through tibial tunnel (TT), or independent of it (TI) by out-in (OI) technique or by anteromedial (AM) technique. No consensus has been reached on which technique achieves more proper femoral aperture position because there have been evolving concepts in the ideal place for femoral aperture placement. This meta-analysis was performed to analyze the current literature comparing femoral aperture placement by TI versus TT techniques in ACL reconstruction. Methods We performed a comprehensive systematic review and meta-analysis of English-language literature in PubMed, Cochrane, and Web of Science databases for articles comparing femoral aperture placement by TI versus TT techniques with aperture position assessed by direct measurement or by postoperative imaging, PXR and/or CT and/or MRI. Results We included 55 articles with study population of 2401 knees of whom 1252 underwent TI and 1149 underwent TT techniques. The relevant baseline characteristics, whenever compared, were comparable between both groups. There was nonsignificant difference between TI and TT techniques in the distance from aperture center to footprint center and both techniques were unable to accurately recreate the anatomic footprint position. TI technique significantly placed aperture at more posterior position than TT technique. TI technique significantly lowered position of placed aperture perpendicular to Blumensaat’s line (BL) than TT technique, and modifications to TT technique had significant effect on this intervention effect. Regarding sagittal plane aperture placement along both AP anatomical axis and BL, there was nonsignificant difference between both techniques. Conclusion Modifications to TT technique could overcome limitations in aperture placement perpendicular to BL. The more anterior placement of femoral aperture by TT technique might be considered, to some extent, a proper position according to recent concept of functional anatomical ACL reconstruction.

Modification of Outside-In Technique In Preparing Femoral Tunnel During Anterior Cruciate Ligament Reconstruction—“PL-Portal Outside-In Technique”

“…In spite of these, the choice of femoral tunnel preparation technique is usually a preference of the surgeon. 12 …”

“… 2 , 11 This is likely related to the ability of placing the femoral tunnel in its anatomical position when the AMP technique is used. 2 , 12 However, the use of the AMP technique is associated with the disadvantages of posterior-wall blowout, short or bicortical sockets, difficulty in passing the reamer, and iatrogenic damage to the cartilage of the medial femoral condyle. These are likely secondary to the limited working space and difficulty in visibility when the knee is put in hyperflexion during the AMP technique.…”

Lateral femoral tunnel preparation and graft fixation for anterior cruciate ligament reconstruction–A discussion

“…With the current research, AM and OI techniques remain the standard of care for lateral femoral tunnel preparation in ACLR. However, it has been noted that the choice of procedure technique is usually surgeon-specific[ 13 ].…”

The proximal posterior cartilage of the lateral femoral condyle can be used as a reference for positioning the femoral tunnel in ACL reconstruction

“…Nonetheless, it is still subject to debate regarding issues, such as the presence or absence of two bundles [10], the ribbon‐like appearance of the two bundles when flexing the knee [25], the presence of direct and indirect fibers with different functions [17] and the different functions of the bundles or anteromedial and posterolateral regions [16, 21]. Nevertheless, biomechanical studies indicate that the anteromedial region or bundle is the main element related to knee stabilization [11, 16], and there are also studies showing that direct fibers are more important than indirect fibers [13, 25, 27].…”