Where Are We Now?
The current study by Arno and colleagues compares the footprint coverage of anteromedial portal and modified transtibial ACL reconstruction, and its influence on validated outcomes scores and objective measurements of knee stability. The study confirms the current knowledge that transtibially drilled femoral tunnels are more vertical compared to both the native ACL and bone tunnels drilled through an anteromedial portal. Interestingly, the tibial bone tunnels are located posterior and medial to the native ACL in both groups. This finding is consistent with previous studies for the transtibial group [2, 5], but not for independently drilled tunnels. However, at short-term followup, the study groups were comparable in terms of knee stability and patient-reported outcomes.
Two recently published meta-analyses [2, 5] showed that ACL reconstruction with independently-drilled tunnels results in more anatomic femoral and tibial bone tunnels. In particular, the femoral posterolateral bundle of the ACL is missed with the transtibial technique. Drilling the femoral tunnel through an anteromedial portal leads to superior stability of the knee joint compared to the transtibial technique.
Where Do We Need To Go?
It is well known that nonanatomical graft placement results in inferior joint biomechanics and kinematics with potentially detrimental long-term effects due to nonphysiological loading patterns [3, 6]. The goal of every surgical intervention should be to restore function by restoring knee anatomy. Drilling both tunnels independently, either by outside-in or anteromedial technique, best ensures that this goal is achieved. However, individualizing ACL surgery refers not only to graft placement at the center of the native insertion site, but also to the selection of graft type, size, and surgical technique given the patient’s intraoperative measurements—the area and shape of the footprint, bone morphology (that is, the morphology of the intercondylar notch) [1, 4]. The concept of individualized anatomic ACL surgery continues with a rehabilitation protocol tailored to the patient and a proper clearance for returning to sports.
To really compare the two different techniques, we need longer-term followup investigations to evaluate the effects of the altered kinematics and biomechanics on development and progression of osteoarthritis.
How Do We Get There?
Despite an ongoing discussion regarding anteromedial versus transtibial tunnel placement, especially in terms of the risk of failure after ACL reconstruction, the current study demonstrates that anatomical bone tunnel placement can only be achieved using the anteromedial portal.
Treatment of ACL injuries needs to be anatomic and individualized to get the best result for the patient. Long-term followup studies are needed to evaluate potential negative factors associated with technical errors and inaccuracy related to ACL reconstruction. These studies should include radiographic, kinematic, and patient-reported outcome data during a period of at least 10–15 years. Researchers and clinicians should be encouraged to reexamine their patients regularly. Data collection from randomized controlled trials should exceed the obligatory 2 years followup.
Footnotes
This CORR Insights® is a commentary on the article “ Does Anteromedial Portal Drilling Improve Footprint Placement in Anterior Cruciate Ligament Reconstruction?” by Arno and colleagues available at: DOI: 10.1007/s11999-016-4847-7.
The author certifies that he, or a member of his immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article.
All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research ® editors and board members are on file with the publication and can be viewed on request.
The opinions expressed are those of the writers, and do not reflect the opinion or policy of CORR ® or The Association of Bone and Joint Surgeons®.
This CORR Insights® comment refers to the article available at DOI: 10.1007/s11999-016-4847-7.
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