Comparing the Use of Flexible and Rigid Reaming Systems Through an Anteromedial Portal for Femoral Tunnel Creation During Anterior Cruciate Ligament Reconstruction: A Systematic Review

Abstract

Background: Recent studies have suggested that femoral tunnel drilling during anterior cruciate ligament (ACL) reconstruction (ACLR) with the use of a flexible reaming system through a standard anteromedial portal (AM-FR) may result in a different tunnel geometry compared with a rigid reamer through an accessory anteromedial portal with hyperflexion (AM-RR). Purpose: To summarize radiologic, anatomic, and clinical outcomes from available studies that directly compared the use of AM-FR versus AM-RR for independent femoral tunnel creation during ACLR. Study Design: Systematic review; Level of evidence, 4. Methods: A literature search was performed using the MEDLINE (PubMed) and Web of Science databases to identify all studies that directly compared radiologic, anatomic, and clinical outcomes between the use of AM-FR and AM-RR. The literature search, data recording, and methodological quality assessment was performed by 2 independent reviewers. The outcomes analyzed included resultant ACL graft positioning and graft bending angle; femoral tunnel positioning, aperture morphology, length, and widening; posterior wall breakage; and distance from various posterolateral knee structures. Results: A total of 13 studies met the eligibility criteria for inclusion. There was no difference in femoral tunnel aperture location between techniques. There were conflicting findings among studies regarding which technique resulted in a more acute graft bending angle. One study reported greater femoral tunnel widening upon follow-up with the use of AM-FR. AM-FR produced longer and more anteverted femoral tunnels than did AM-RR. The difference in tunnel length was significant and more prominent in lesser degrees of knee flexion. With AM-FR, femoral tunnels were farther from the lateral collateral ligament and peroneal nerve, and 1 of 5 studies had fewer reports of posterior wall breakage. There has been no literature comparing the clinical or functional outcomes of these techniques. Conclusion: Although no clinical studies exist comparing AM-FR and AM-RR for femoral tunnel creation during ACLR, both systems allow for reproducible positioning of an anatomic femoral tunnel aperture. The use of AM-FR results in longer and more anteverted femoral tunnels than using AM-RR, with exit points on the lateral femur that are different but safe. Surgeons should be aware of the technical differences with each method; however, further study is needed to identify any clinically important difference that results.

Lateral Extra-Articular Tenodesis Staple Risks Penetration of Anterior Cruciate Ligament Reconstruction Tunnel

“…The use of the FR for femoral tunnel creation results in a more anteverted femoral tunnel position compared with the use of a RR, whereas the intra-articular femoral tunnel aperture location is not different. 27 Although this difference in resultant tunnel geometry has been described, there was no significant difference in tunnel violation seen in this study depending on technique used. Outside-in ACL femoral tunnel creation also has been suggested by several authors to potentially allow more precise femoral tunnel positioning and reduce convergence with LET graft fixation, but has not presently been compared with other modern anatomic techniques.…”

“… 19 , 20 Degree of knee flexion during ACL femoral tunnel creation also yields a differing tunnel orientation within the femur. 27 , 28 Kittl et al. 18 found that ACL femoral tunnel creation in lesser degrees of knee flexion (110-120° vs 130-140°) reduced the incidence of femoral tunnel conflict in combined ACL-R using an AMP technique and LET.…”

Flexible Versus Rigid Reaming Systems for Independent Femoral Tunnel Reaming During ACL Reconstruction: Minimum 2-Year Clinical Outcomes

“…Another limitation of this study is that while previous literature 18 exists to suggest that ACLR using AM-FR for femoral tunnel trends toward resulting in a more anatomic ACLR, this study lacks direct radiologic evidence that this difference manifested within our study population. Finally, as a literature review 18 shows that the radiologic and anatomic differences resulting from AM-FR and AAM-RR are more evident when deep flexion is unable to be achieved, it is possible that there would have been a difference observed in patients with less intrinsic flexibility, such as patients who are more muscular or have larger body habitus. This study is more representative of the overall population undergoing ACLR, however, and is therefore more translatable than isolated subgroup analysis based on revision procedures or a certain population characteristic.…”

Femoral Tunnel Geometry and Graft Inclination Angles in Anterior Cruciate Ligament Reconstruction Using a Flexible Reamer System

“…Previous cadaver studies reported that a significantly longer femoral tunnel could be achieved with a flexible guide pin than with a rigid guide pin [ 11 , 12 ]. A recently published systemic review reported that a clinical application of a flexible guide pin resulted in a longer and more anteverted femoral tunnel than a rigid guide pin [ 13 ]. In an attempt to overcome the inherent limitations of the transportal technique, the retrograde drilling method was introduced [ 14 ].…”